biology regents review

7/31/2019 Biology Regents Review

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Cassie Greco

Bio Regents Review

o Scientific method- ask questiondo background research

construct hypothesis

test with experimentanalyze results and draw conclusions

if the hypothesis is true report results

if the hypothesis is false report results and think again

o This needs to be done to test a hypothesis:for setting up an experiment.

o Variable- factors that changeo 2 types of variables are dependent and independent.o Independent- the variable that is changed:

example: temperature; water in a plant.

o Dependent variable- the variable that changes as a result of the independentvariable. Examples: plant growth; nutrition.

o Cells- all living things have cells. Cells are very small; they grow and respond totheir surroundings, and reproduce. They are complex and organized.

o Unicellular- only has one cell and it is very small. Example: bacteria.o Multicellular- consists of many ells that and small and large. Example: humans.o Living things reproduce.o Organisms produce new organisms through reproductions.o Asexual- one parent.o Sexual- when you have two parents.o Universal genetic code- DNA that determines the traits for every organism on

earth. Very small variations in DNA lead to very large differences in organisms.

o Grow and develop- occurs at leas part of lifespan. Some organisms only grow insize, others develop.

o Use materials and energy- energy used for development. Material taken is usedfor energy. Some organisms use photosynthesis while others consume to obtain

energy.

o Respond to environment- organism detect signals internally and externally andrespond accordingly.

o Maintain stable environment- homeostasis.o Homeostasis- process by which organisms maintain an internal balance.o Change over time- organisms evolve, basic traits inherited from parents. Do not

change. Changes over long periods of time, can be dramatic.

o MR.STRANGERo M-etabolismo R-espirationo S-ynthesiso T-ransporto A-ssimulationo N-utritiono G-rowth


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o E-xcretiono R-eproductiono Discovery of Cell- Robert Hooke observed a piece of cork using a compound

light microscope. Noticed empty chambers and referred to them as cells. These

cells contain living matter. Microscopes also used to observe pond water, which

contains many tiny organisms.o Cell theory- cells become known as the basic units if life. All living things are

composed of cells. They are the basic units of structure and function in living

things. Cells are produced from existing cells.

o Prokaryotic cells- cells that lack a nucleus. Most are unicellular. Smaller andsimilar than eukaryotic cells.

o Eukaryotic cells- contains a nucleus. Larger and more complex. Genetic materialof cell is found in nucleus.

o Surfacecell wall and cell membranes.o Cell Wall - Found mostly in plant cells. Provides support for the cell.

Extracellular structure that surrounds the cell membrane. Main functions are

support for the cell and protection for the cell. Allows substances (water, oxygen,carbon dioxide, etc.) to pass into and out of cell. Made from carbohydrates and

proteins made by cell.

o Cell Membrane - AKA plasma membrane. Outer membrane of the cell. Allowssubstances into and out of the cell. Contains proteins, which allow for the passage

of materials. Proteins are surrounded by a phospholipid bi-layer (lipid bilayer)

o Centrioles -Cylindrical organelles that are near the nucleus in pairs. Involved incellular division

o Chloroplasts - Found in plant cells. Contain green chlorophyll. Wherephotosynthesis takes place

o CytoskeletonSupports cell and provides shape. Aids in movement of materialsinto and out of cell.

o Endoplasmic Reticulum- Tubular network fused to nuclear membrane. Is locatedfrom membrane, throughout the cytoplasm. Serves as cells transport system. 2types: smooth ER and rough ER. Smooth- lacks ribosomes. Roughcontains

ribosome

o Golgi- Protein packaging plant. Found near nucleus. Composed of layersforming a sac.

o LysosomeDigests lipids, proteins and carbs. Transports undigested material tocell membrane for removal. If lysosome breaks down, cell explodes

o Mitochondria- Powerhouse of cell. Generate ATP. Double layered foldedmembrane. Controls level of water in cell. Forms urea

o RibosomesProtein Factories. Embedded in Rough ERo Vacuoles- Membrane bound sacs for digestion, storage, and waste

removal. Contains water solution. Contractile vacuoles for water removal

o ChromosomesUsually in the form of chromatin. Contains genetic information.Composed of DNA. Set number for each species

o Nuclear envelope-Surrounds nucleus. Contains 2 layers. Contains pores to allowmaterials into and out of nucleus.

o Nucleolus-Contains RNA for protein synthesis


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o Cell Membrane

Head- hydrophilic tail- hydrophobic

o Cell membranes are selectively permeable.o Allows for passage of water and solution.o Small molecules pass through large dont.o 2 ways substances leave/ enter a cell: passive & active.o Types f solutions: isotonic; hypotonic; hypertonico Isotonic: solution concentration of solute is equal.

o Hypotonic solution: starts with more water less solute outside than inside.


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o Hypertonic solution: starts with more solute less water outside than inside.

o Diffusion- passive movement of particles goes from HIGH TO LOWconcentration. NO ENERGY. Movement continues until concentration ofsubstances is equal (equilibrium) example: gas exchange in lungs. Oxygen

from air to blood carbon dioxide from blood to air.

o Osmosis- special example of diffusion. The diffusion of water throughmembrane it is passive NO ENERGY.

o Transport through the membrane.o Facilitate diffusion- movement of molecules down a concentration gradient

passing through membrane via specific carrier protein. Each protein has itsown shape. Only lets one molecule pass through selected by size shape and

change. Common molecules include glucose and amino acids. Passive NO

ENERGY.

o Active transport- transport of a substance across a membrane against itsconcentration gradient. LOW TO HIGH. This requires energy. Proteins in cell

membrane act as the protein carriers. The energy for active transport comes

from ATP.

o Biochemo Atoms- Very small. Neutral. Consist of protons, neutrons and electrons.

Protons = positive charge. Neutrons = neutral charge. Electrons = negativecharge

o Elements- Pure substance. Consists of only one type of atom. Over 100 knownelements. 24 of the 100 exist in the living organism. Examples: Carbon,

Nitrogen, Hydrogen, etc.

o Chemical compounds- Substance formed by chemical combination of two ormore elements. Written as chemical formulas. Ex: Water = H2O

o Carbon COMPOUNDS- ORGANIC.o Macromolecules- giant molecules made from thousands of smaller molecules.

Built by joining smaller molecules together. Organic compounds classifiedinto groups: carbs, lipids, nucleic acid, and proteins.

o Carbohydrates- made up of carbon hydrogen and oxygen. Living things usecarbs as main energy source. Plants and animals use carbs for structural

purposes. Extra sugar is stored as a complex carb aka starch.

o Monomers- in starches are sugar molecules. Single sugar molecules =monosaccharides. (Sugar) aka monomer. Ex: glucose, golactose, and


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fructose. Multiple sugar molecules= polysaccharides. Many animals store

excess sugar aka glycogen.

o Lipids- not soluble in water. Made from carbon and hydrogen. Categories arefats, oils and waxes. Used to store energy. Parts of biological membranes and

waterproof coverings. Made from 3 fatty acids and 1 glycerol.

oFatty acid chains- can be saturated, unsaturated, or polysaturated. Saturated=no double bonds. Unsaturated= one double bond. Polysaturated= 2 or more

double bonds.

o Nucleic acids- macromolecules. Contain hydrogen, nitrogen, carbon, andphosphorus. Assembled from nucleotides. Nucleotides- has 3 parts. 5-carbon

sugar phosphate group and nitrogen base.

o Proteins- macromolecules containing nitrogen, carbon, hydrogen and oxygen.Subunits called amino acids. More than 20 different amino acids exist. Some

proteins control the rate of reaction for self-processes. Others form bones and

muscles. Others transport substances into and out of cells and help to fight

disease.

oChemical reactions- process that changes one set of chemicals to another setof chemicals. Some reactions are very fast. Reactants- elements or compounds

at the beginning of a chemical reaction. Products- elements or compoundsmade by a chemical reaction. Every organism needs a source of energy to stay

alive. Plants get energy from sun. Animals get energy from consuming plants

or other animals.

o Activation energy- energy needed to get reaction started.o Enzymes- certain chemical reasons are too slow or have high activation

energies. These reactions are made possible by using enzymes. They are

specific and usually only catalyze one chemical reaction. Work in certain ph.levels and certain temperature. Cells contain proteins that turn enzymes on

and off as they are needed by the organism. Proteins that act as catalysts. Cells

use enzymes to speed up chemical reaction that take place within cell.

o Catalyst- speeds up rate of reaction. Lower activation energy.o The enzyme- substrate complex.o Enzymes provide a site where reactants can be brought together to react.o This site reduces the energy needed for the reaction.o The reactants of these reactions are called substrates.o Activate- place where substrate binds to enzyme.


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o Cells- specialized. They are given specific jobs that determine the tasks theyaccomplish.

o Tissue- made of a group of cells. Carries out a specific function. Mostmulticellular organisms have 4 types: muscle, epithelial, nervous, connective.

o Organs- groups of tissue working together. Takes are too complicated to becarried out by 1.

o Organ systems- group of organs that work together to form a specializedfunction. 11 major organ systems. Muscularly, circulatory, respiratory,

digestive, reproductive, endocrine, skeletal, urinary, lymphatic, nervous, and

integumentary.

o Smallest to largest:organelle-cell-tissue-organ-organ system- and organism.

o Assigning scientific names- 18th century- referring to an organism by itscommon name was confusing. Common names vary among regions and

languages, even in the same country. To eliminate confusion, it was agreed that

one single name would be used for each species. Greek and Latin was used toname the organisms

o Binomial nomenclature- Carrolus Linnaeus developed a two word namingsystem called binomial nomenclature. Each species is assigned a two part

scientific name. Name is always written in italics. First word is alwayscapitalized and the second is always lowercase.

o Example: Grizzly Bear is Ursus arctos. Ursus is the genus name (genus towhich the organism belongs). A genus is a group of closely related species

o System classification- TaxonA group or level or organization. Linnaeussystem uses seven taxonomic categories. Kingdom, phylum, class, order,

family, genus, species

o Classification- Speciesgroups of organisms that are identical to each other.Genusgroup of closely related species. Familygenera that share many

characteristics. Orderbroad category of families that share characteristics.


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Class- composed of similar orders. Phylum- different classes with similar

characteristics grouped together. Kingdomlargest and most inclusive of thetaxonomic categories.

o Waxy Cuticle - Forms a waterproof layer to stop any loss of water.o Upper Epidermis - Consisting of epidermal cells. These have no chloroplasts.o

Palisade cells - These contain lots of chloroplasts, which contain lot ofchlorophyll. This is where photosynthesis is carried out.

o Spongy Mesophyll Layero Air Spaces - allow for diffusion of water vapor etc.o Guard Cells - These form stomata (pores), which allow for the diffusion of

gases in and out of the plant.

o Leaf Vein - containing xylem and phloem tubes.o Maintenance of water- plants need to regulate water loss and carbon dioxide

intake for photosynthesis and other life activities. When plants do not keep

enough water in their cells, they wilt and die

o Stomate- a microscopic hole in a plant leaf that allows gases to enter and leaveand water vapor to leave as well. Stomata are the plural of stomate.

o Guard cells- open and close the stomata. The ability of the guard cell to closeduring periods of limited water availability for the plant allows the plant tomaintain water homeostasis

o Photosynthesis in overview- Process by which plants and other autotrophs storethe energy of sunlight into sugars. Requires sunlight, water, and carbon dioxide.Overall equation: 6 CO2 + 6 H20 C6H12O6 + 6 O2. Occurs in the leaves of

plants in organelles called chloroplasts.

o Chloroplast Structure- Inner membrane called the thylakoid membrane.Thickened regions called thylakoids. A stack of thylakoids is called a granum.(Pluralgrana). Stroma is a liquid surrounding the thylakoids.

o Pigments- Chlorophyll A is the most important photosynthetic pigment. Otherpigments called antenna or accessory pigments are also present in the leaf.

Chlorophyll B. Carotenoids (orange / red). Xanthophylls (yellow / brown).These pigments are embedded in the membranes of the chloroplast in groups

called photosystems.

o Photosynthesis- Occurs in two main phases. Light reactions. Dark reactions (akathe Calvin Cycle). Light reactions are the photo part of photosynthesis.Pigments absorb light. Dark reactions are the synthesis part of photosynthesis.

Trapped energy from the sun is converted to the chemical energy of sugars.

o Light reactions- Light-dependent reactions occur on the thylakoid membranes.Light and water are required for this process. Energy storage molecules are

formed. (ATP and NADPH). Oxygen gas is made as a waste product.

o Dark reactions- Dark reactions (light-independent) occur in the stroma. Carbondioxide is fixed into the sugar glucose. ATP and NADPH molecules createdduring the light reactions power the production of this glucose.

o Cellular respiration- in the powerhouse of the cell! Mitochondria- uses innermembranes of mitochondria to go through respiration.

o Respiration equation- C6H12O6 + 6 O2 6 CO2 + 6 H2O what is ATP?ENERGY!!!


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o How is ATP used? ATP is used by the organism to digest, transform andtransport materials, and also to eliminate waste products

o Aerobic- w/o oxygeno Anaerobic- with oxygeno Anaerobic- AKA fermentation. Makes alcohol in yeast and bacteria. Makes

lactic acid in animalsthis is why your muscles are sore during and afterexercise. This process makes less ATP and is not as efficient as aerobic

respiration.

o Respiratory system-o General Informationo Passageways allow air to pass directly into tissues of the body.o Air entering must be warmed, moistened and filtered.o Warmed- the capillaries.o Moistened- mucus secreting cells.o Filtered- nose hairs and mucus.o Cilia sweep the trapped particles from the lungs toward pharynx.o

The mucus is then swallowed or spit out.o Pathwayo Air moves through nose into pharynx.o Pharynx-throat.o The pharynx is the passageway for both air and food.o Air moves from pharynx into the trachea.o Trachea is the windpipe.o A piece of Cartilage covers entrance to the trachea when you swallow.o Cartilage- epiglottis.o At the tip of the trachea is the larynx.o Larynx is the vocal cords.o When muscles pull the vocal cords together, the air moving between them

causes vibrations that produce sounds.

o From the larynx, air passes through he trachea into two large passagewayscalled bronchi.

o Each bronchus leads to one of the lungs.o Within each lung each bronchus divides into smaller bronchi.o Which divide into smaller bronchioles.o The bronchioles divide until they reach a series of dead ends.o Dead ends- alveoli.o Alveolio They are grouped in clusters.o Clusters aka groups.o A network of capillaries.o Capillaries aka small blood vessels.o Surrounds each alveolus.o This is the site of the gas exchange.o Gas Exchangeo Oxygen dissolves in the moisture of the inner surface of the alveoli.o Next they diffuse across capillaries into the blood.


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o Carbon Dioxide in the bloodstream diffuses across membranes into the alveolus.o The process of gas exchange is efficient.o Air inhaled contains 21% oxygen and 0.04% carbon dioxide.o Air exhaled contains less than 15% oxygen and 4% carbon dioxide.o Hemoglobino

Oxygen carrying protein in blood.o It binds with oxygen.o Increases carrying capacity of blood 60x.o Without hemoglobin you would be 300L of blood.o Breathingo This is the movement of air into and out of the lungs.o Air pressure is responsibleNOT muscles.o Lungs are sealed in 2 sacs. (Pleural Membranes)o At the bottom of the respiratory cavity is the diaphragm.o When you breathe in, the diaphragm contracts and expand the value of the chest

cavity.

oThis creates a vacuum like atmosphere because the chest cavity is sealed.

o Air gets sucked into the lungs.o Why Smoking is Bado The upper part of the respiratory system is able to filter dust and dirt that could

damage the lungs and the ability to filter.

o Nicotine, carbon monoxide and tar are 3 of the most dangerous substances incigarettes.

o Nicotine-stimulant that increases heart rate and blood pressure.o Carbon Monoxide- poisonous gases that blocks transport of oxygen by

hemoglobin.

o Tar- contains compounds that cause cancer.o These 3 compounds also paralyze cilia when inhaled in the respiratory system.o Without cilia, inhaled particles stick to the walls of respiratory system and enter

the lungs.

o Mucus becomes trapped which explains smokers cough.o Also it causes inflammation of the respiratory system, which reduces airflow to

alveoli.

o Diseases Caused by Smokingo Chronic Bronchitis- bronchi becomes clogged with mucus and swollen.o People have a hard time doing daily tasks. Ex: walking up stairs.o Emphysema loss of elasticity in lungs.o Makes breathing difficult.o People cannot get enough oxygen to the body tissues.o Therefore they cannot get rid of the CO2 produced by cellular respiratory.o Human Digestive System (10% of test)o Digestive Systemo Made up of digestive tract and accessory glands.o Digestive tract is 9 meters long.o Purpose is to get energy and nutrients out of the food we eat.o Digestive Tract Pathway


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o This is the pathway that takes the food through the digestive system.o Mouth-Esophagus-Stomach-Small Intestine- Large Intestine-rectum-Anus.o Accessory Glandso Exocrine glands that secrete digestive liquids through ducts into the digestive

tract.

o3 Main glands are: salivary glands-pancreas-liver.

o Mouth and Salivary Glandso Mouth mechanically and chemically break up the food.o Teeth mechanically break up food.o Mechanical digestion- breaks down food into smaller pieces to increase surface

area so it can be more easily digested.

o Salivary Glands-produce saliva.o Saliva is made up of mostly water, which moistens food making it easier to

swallow.

o Ptyalin and Amylase are 2 digestive enzymes in saliva, which begin thebreakdown of starch to simple sugar.

oEsophagus

o Is aka gullet or a muscular tube.o Peristalsis- waves of muscle contraction that push food through the digestive

tract.

o It takes food from the throat and pushes it down through the neck and into thestomach.

o This takes 5-10 seconds.o Stomacho The thick muscles in the stomach wall contract to mash up the food.o Chemical digestion of protein begins here.o Gastric glands secrete glastic juice, which contains digestive enzymes acids and

mucus.

o Pepsin- begins with protein digestion.o Hydrochloric acid- produces acidic environment in stomach so digestive

enzymes can work better.

o Mucus-protects the stomach wall from acids.o Digestion here takes 2-6 hours.o Small Intestineo 6 meters long.o Final digestion and nutrient absorption occur here.o Takes 5-6 hours.o In the beginning mostly digestion is occurring.o In the end mostly absorption is occurring.o Villi are the small finger like projections that increase surface area of the small

intestine, which maximizes absorption.

o Villio Capillaries- simple sugars.o Amino acids, vitamins, and minerals are absorbed into the blood stream.o Lateral- fatty acids and glycerol are absorbed into these tiny lymphatic vessels.o Pancreas


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o Produces several digestive enzymes the chemically digest.o They break down proteins, fats, and nucleic acids in the small intestine.o Chemical Digestiono Protein to amino acidso Carbs to simple sugarso

Lipids to fatty acidso Nucleic acids to nucleotideso Livero Among many other functions in the body it produces bile, which doesnt contain

any digestive enzymes.

o Bile is stored in the gall bladder.o Bile emulsifies the fat into smaller globules.o This aids in the absorption of fats.o Large Intestineo For reabsorptiono 12-24 hours.o

Rectum and Anuso Feces are stored in the rectum until eliminated.o Pushed through muscle- the anus.o Disorders of the Digestive Systemo Heart burn- painful burning sensation in the center of the chest caused when the

stomach acid moves out of the stomach into the esophagus. Caused by overeating or drinking.

o Peptic Ulcer- holes in wall of stomach caused by acid. For years people thoughtthis was caused by stress and spicy food. Really caused by a bacteria

helicobacter pylori. 90% of ulcers cured by antibiotics.

o Appendicitis- inflammation of the appendix small organ located below colon.No function in humans used for cellulose digestion in some animals.

o Diarrhea- not enough water absorbed by large intestine. Loss of salts and watercan be life threatening.

o Human Circulatory System (10% of test)o We have a closed circulatory system.o Blood is pumped through a system of vessels.o System consists of heart (pump) blood vessels and blood.o The Hearto Located near the center of the chest.o Hallowo Composed almost entirely of muscle.o Size of clenched fist.o In walls of heart 2 layers of tissue from a sandwich around a thick layer of

muscle called myocardium.

o Contractions of this pump blood through the circulatory systemo The heart contracts about 73 times per min.o Pumps 70 mL of plod with each contraction.o Right and left sides of heart separated by septum.o Septum-wall prevents mixing of oxygen rich and oxygen poor blood.


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o R.R.L.L.L.B.o RAtrium. RVentricle. Lungs. LAtrium LVentricle. Bodyo Heart Beato Composed of individual fibers.o Atrium and ventricles contracts as a unit.o

It begins with a group of cardiac muscle cells in the right atrium known assinoatrial node (sa node.)

o SA node paces the heartbeat.o Aka pacemaker.o Impulse spreads from pacemaker to atria.o From atria signal is sent to atrioventricular node and then to bundle of fibers in

ventricle.

o When ventricle contracts blood flows out.o Blood Vesselso As blood moves through system it moves through 3 typed of blood.o Arteries, Capillaries, and Veins.o

Arterieso Large vessels carry blood from heart to tissue of body.o Carries oxygen rich blood with exception of pulmonary arteries.o Thick walls need to withstand pressure produced when heart pushes blood into

them.

o Capillarieso Smallest blood vessels.o Walls are one cell thick and narrow.o Important for bringing nutrients and absorbing CO2 and other waste products.o Veinso Once blood passed through the capillary system it must be returned to the heart.o Done by veins.o Walls contain connective tissue and smooth muscle.o Largest veins contain one-way valves that keep blood flowing toward the heart.o Many found near skeletal muscles.o When muscles contract, blood is forces it thorough veins.o Disorders of Circulatory Systemo Atherosclerosisis fatty deposits (plaque) in walls of arteries Deposits can

obstruct flow of blood, which can raise blood pressure. Increase risk of blood

clots. If clot breaks free it can obstruct flow to tissues and heart attack is due tothis. Coronary arteries may become blocked; Heart muscle begins to die due to

lack of O2.

o Stroke- is when blood clot may be leading to brain. Brain cells are starved ofoxygen and nutrients. Loss of function may occur. Can cause paralysis, loss ofspeech or death.

o Bloodo Is composed of plasma and blood cells.o Types of cells are: red and white blood cells, and platelets.o Plasmao Straw colored.


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o 90% water 10% dissolved gasses, salts, nutrients, enzymes, hormones, wastesand proteins.

o Red Blood Cellso Most numerous types.o Transport oxygen, and get color from hemoglobin.o

Disk shaped made in red bone marrow.o Circulate for 120 days.o White Blood Cellso Guard against infection, parasites, and bacteria.o They increase when body is fighting.o Lymphocytes produce antibodies. Which fight against pathogens and remember

them.

o Plateletso Aid in body clotting.o Small fragments.o Stick to edges of broken blood cell and secrete clotting factor help from clot.o

Blood Clotting Problemso Itemophelia-genetic disorder disrupts clotting. Very careful to avoid injury.

Treated by injecting extracts that contain missing clotting factor.

o Excretory System:o General

every cell in the body produces metabolic wastes, such as excess salts, carbondioxide and urea (a toxic compound produced when amino acids are used for

energy.) The process by which these metabolic wastes are eliminated is known

as excretion. The skin lungs and kidneys make up the excretory system.

o The KidneysMain organs of the excretory system. Located on either side of the spinal

columns near the lower back. Each kidney is about the size of a clenched fist. A

tube called ureter causes urine to the bladder from the kidney.

o Kidney FunctionWaste filled blood enters the kidney (via renal artery.) As blood travels through

urea, excess water and other wastes are collected as urine. Clean filtered blood

is returned to the body via the renal vein.

o Kidney Structure2 distinct regions.

Inner part: renal medullaouter part: renal cortex

o NephronsFunctional units of the kidneys called nephrons. Each is a small individual

processing unit. About 1 million per kidney. Nephrons located in the renalcortex. Each nephron has its own blood supply consisting of an arteriole, a

venule, and a network of capillaries. Blood enters through arteriole. Blood is

filtered as it passes through the capillaries. Waste products collected in a duct,leading to a ureter. Clean blood leaves the nephron through the venule.

o FiltrationBlood enters the nephron and flows into the glomerulus. Glomerulus- small


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network of capillaries in the upper end of the nephron. Encased by a cup shaped

structure called the Bowmans capsule. Fluid flows from the bloods into

Bowmans Capsule (aka filtration.) Materials filtered from the blood are calledfiltrate (contains water, urea, glucose, salts, amino acids, and vitamins.) Some

particles such as plasma proteins, cells and platelets are too large to pass

through capillary walls so they stay in the blood.o Reabsorption and Secretion

Kidneys filter entire volume of blood every 45 mins. Not all filtrate is secreted.

Most material removed from the blood at Bowmans Capsule returns to bloodvia reabsorption. Nutrients (amino acids and glucose) are removed from filtrate

by active transport. Water follows these materials by osmosis and about 99% of

water that enters Bowmans capsule is reabsorbed into blood. Material thatremains after reabsorption, called urine, is emptied into a collecting duct. Urine

is concentrated in loop of henle (water is conserved and urine is minimized.

Purified blood is returned to circulation. Urine is collected in the urinary

bladder. Urine is stored until it is released from the body through urethra.

oDisorders of the excretory systemGout- caused by increased levels of uric acid. Crystallizes and deposits in joints

tendons and tissues. May be caused by sugar, alcohol, dairy and seafood.Sweat- release of water and salts from the body through sweats glands. Function

is to regulate body temperature. Increase in body temperature= sweating. Sweat

evaporates, pulling heat from the body.

o The Immune Systemo Vocabularyo Antigens- molecules on outer surfaces of cells that immune system recognizes

as part of the body or an outside invader. GOOD OR BAD.

o Pathogens- organisms that invade the body and cause disease. BAD.o Antibodies- proteins produced by immune system, either attacks invading

pathogens or marks them from killing. GOOD

o Histamines- a chemical that is released as the immune systems response to anallergy.

o Antihistamines- a substance that reduces the effects of histamines and thesymptoms they cause.

o Vaccine- substances made of weakened pathogens to protect the body fromfuture invasion of the pathogen.

o Microbes- microscopic organism.o Immunity- destroys pathogens before they cause disease.o Passive Immunity- antibodies were acquired from outside source (injection

would be temporary, or from mother to embryo.)

o Active immunity- development of antibodies in response to an antigen (can becaused by vaccine.)

o Factors that Upset homeostasis1- viruses, bacteria, fungi, and other parasites may infect plants and animals andinterfere with normal life functions.

2- sometimes the immune system attacks something harmless inside the body,

even the bodies own cells. Allergic reactions: caused by bodys immune


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response to usually harmless environmental substances. Autoimmune diseases:

immune system may attack some of the bodys cells. Transplanted organs thatcontain cells unrecognized by the body can be attacked.

3- Gene mutations in a cell can result in uncontrolled cells divisions, called

cancer. Exposure to certain chemical and radiation increases risk of cancer.

4- other doctors which may show up right away or not for many years include:toxic substances

poor nutrition

organ malfunctionpersonal behavior

o Immune SystemWhite blood cells- some of them engulf invaders others produce antibodies that

attack them or mark them for killing. Some specialized WBCs will remain,

able to fight off invaders of the same kind. This is how organisms become

immune to an invader those WBCs already have antibodies.

o Vaccinationsuse weakened microbes to stimulate the immune system to react. This reactionprepares the body to fight invasions by the same microbes.

o Immune SystemSome viral diseases such as AIDS damage the immune system leaving the body

unable to deal with multiple infectious agents and cancerous cells.

o The Lymphatic SystemNetwork of vessels that works with circulatory system. As blood circulates

some plasma leaks out of capillaries and surround the cells (intercellular fluid.)

The blood needs some of this fluid lack so it uses a network of vessels to collect

the lost plasma. This network of vessels makes the lymphatic system. One fluidinside this system is known as lymph. These vessels connect and become larger.

This system is released to the immune system. Along the vessels are

enlargements called lymph nodes. Nodes act as filters trapping bacteria and

other microorganisms; they become swollen (swollen glands.)

o Fighting infectious Diseasesresearch allows for developments in diagnosing preventing treating controlling

and curing diseases of plants and animals.

o Antibiotics- compounds that kill bacteria without harming cells. Work byinterfering with cellular processes of microorganisms.

o Penicillin was first discovered (Fleming.)o Streptomycin- disrupts the ribosomes of the bacteria.o Nervous systemo Nearly all-multicellular organisms have communication systems.o Specialized cells carry messages from one cell to another so that communication

throughout the body is smooth and efficient.

o In humans, these cells are in the nervous system.o The nervous system controls and coordinates functions throughout the body and

responds to internal and external stimuli.

o Neurons


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o Messages carried by the nervous system are electrical signals called impulses.o

o

oo Dendriteso Spreading out from the cell body are short, branched extensions called

dendrites.

o Dendrites carry impulses from the environment or from other neurons towardthe cell body.

o Axono The long fiber that carries impulses away from the cell body is called the axon.o The axon ends in a series of small swellings called axon terminals.

The cells that transmit these impulses are

called neurons.

Neurons can be classified into three

types:

1. Sensory neurons carry impulses

from the sense organs to the spinal cord

and brain.

2. Motor neurons carry impulses

from the brain and the spinal cord to

muscles and glands

3. Interneurons connect sensory and

motor neurons and carry impulses

Cell Body

The largest part of a typicalneuron is the cell body.

The cell body contains thenucleus and much of the

cytoplasm.

This is the place where most ofthe metabolic activity in the

neuron takes place.


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ooo In some neurons, an insulating membrane known as the myelin sheath

surrounds the axon.

o The myelin sheath that surrounds an axon leaves many gaps, called nodes,where the axon is exposed.

o As an impulse moves along the axon, it jumps from one node to the next, whichincreases the speed at which the impulse travels.

o The nerve impulseo Nerve impulses are electrical.o Think about electricity moving through a metal wire.o Lets start by looking at a neuron at rest (not carrying an impulse).o Resting potentialo A neuron has an electrical potential across its cell membrane of about 70

millivolts.

o The cell produces a voltage roughly equal to one twentieth of a flashlightbattery.

o Where does this voltage come from?o The potential, or voltage, comes from actions of the cell membrane pump,

which is powered by the energy of ATP?

o This pump consists of a membrane protein that forces sodium ions out of thecell and pumps potassium ions in.

o This process, which involves active transport, ends with the cytoplasm of theneuron containing for potassium ions and fewer sodium ions then thesurrounding medium.

o Potassium ions leak out across the cell membrane more easily than sodium ionsleak in. This creates a negative charge on the inside of the cell membrane.

o The charge difference is known as the resting potential of the neuron.o The moving impulseo Think about a ripple passing along the surface of a pond.o The impulse causes a movement of ions across the cell membrane.

Neurons may have a large numberof dendrites, but usually only has

one axon.

In most animals, axons anddendrites are clustered into bundles

of fibers called nerves.

Some nerves contain only a few

neurons, but many others have

hundreds to thousand of neurons.


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o An impulse begins when a neuron is stimulated by another neuron or by theenvironment.

o Once the impulse begins, it travels rapidly down the axon away from the cellbody and toward the axon terminals.

o An impulse is a sudden reversal of the membrane potential.o

What causes the reversal of the membrane potential?o The cell membrane of a neuron contains thousands of protein channels that

allow ions to pass through.

o In many cases, these channels are closed.o As the impulse travels down the axon, the sodium gates open which allow

positively charges sodium ions to flow inside the membrane. The inside of the

membrane becomes more positive than the outside.

o The reversal of charges is called an action potential.o As the impulse passes, potassium gates open allowing potassium ions to flow

out.

o This restores the resting potential so the neuron is again negatively charged onthe inside of the cell membrane and positively charged on the outside.

o An impulse at any point on the membrane causes an impulse at the next pointalong the membrane.

o Think about a line of dominoes falling. As each domino falls it causes the next

domino in line to fall.

o Thresholdo The strength of an impulse is always the same.o The stimulus must be strong enough to cause the impulse to happen.o The minimum level of a stimulus required to activate a neuron on called the

threshold.

o Any stimulus that is stronger than the threshold will produce an impulse.o Any stimulus weaker than the threshold will produce no impulse.


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o The synapseo At the end of the neuron, the impulse reaches the axon terminal.o This is usually the place where the neuron makes contact with another cell.o The neuron may pass the impulse along to the second cell.o For example: motor neurons pass their impulses to muscle cells.o

The location at which an impulse is transferred to another cell is called thesynapse.

o A small gap separates the axon terminal from the dendrite of the adjacent cell.o The terminals contain tiny sacs, or vesicles, filled with neurotransmitters.o Neurotransmitters are chemicals used by a neuron to transmit an impulse across

a synapse to another cell.

o When an action potential arrives at an axon terminal, the sacs releaseneurotransmitters into the gap between the two adjacent cells.

o The neurotransmitters diffuse across the gap and attach themselves to receptorson the membrane of the adjacent cell.

o This stimulus causes positive sodium ions to rush across the cell membrane,which stimulates the second cell.

o If the stimulus exceeds the cells threshold, a new impulse begins.o The neurotransmitters are only bound to the receptors for a second before they

are released from the cell surface.

o They may then be broken down by enzymes, or may be taken up and recycledby the axon terminal.

o Divisions of the nervous systemo Neurons join together to form a complex network called the nervous system.o The human nervous system is separated into two major divisions: the central

nervous system and the peripheral nervous system.

o The central nervous system is the control center of the body.o The central nervous system relays messages, processes information, and

analyzes information.

o The peripheral nervous system receives information from the environment andrelays commands from the CNS to organs and glands.

o The central nervous systemo Consists of:o The brain and the spinal cord.o The skull and the vertebrae in the spinal column protect the brain and spinal

cord.

o Both the brain and spinal cord are wrapped in three layers of connective tissueknown as meninges.

o Between two of the three layers is a space filled with cerebrospinal fluid.o Cerebrospinal fluid bathes the brain and spinal cord and acts as a shock

absorber.

o The fluid also allows for the exchange of nutrients and waste products betweenthe blood and nervous tissue.

o The Braino


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oo The Cerebrumo The cerebrum is the largest and most prominent region of the human brain.o It is responsible for the voluntary (conscious) activities of the body.o It is the site of intelligence, learning and judgment.o A deep groove separates the cerebrum into the right and left hemispheres.o A band of tissue called the corpus callosum connects these two hemispheres.o

Folds and grooves on the cerebrum increase surface area.o Each hemisphere of the cerebrum is divided into lobes.o Each half of the cerebrum deals with the opposite side of the body.o The opposite brain controls sensations and movements.o The cerebrum consists of two surfaces.o The outer surface is called the cerebral cortex and consists of grey matter.o Gray matter is densely packed nerve cell bodies.o The cerebral cortex processes information from the sense organs and controls

body movements.

o The inner surface of the cerebrum consists of white matter.o White matter is bundles of axons with myelin sheaths.o The myelin sheaths give the white matter its color.o The cerebellumo Its the second largest region of the brain.o Located at the back of the skull.o Center for coordination and balance of the muscles so the body can move

smoothly and efficiently.

o The Brain Stemo The brain stem connects the brain and spinal cord.o Its located just below the cerebellum and includes two regions, the pons and the

medulla oblongata.

o Each of these regions regulates the flow of information between the brain andthe rest of the body.

o The brain stem controls things like blood pressure, heart rate, breathing andswallowing.

o The thalamus and hypothalamuso They are found between the brain stem and the cerebrum.o The thalamus receives messages from the sense organs. It relays the message to

the proper region of the cerebrum.

o The hypothalamus is just below the thalamus.

The brain contains approximately 100

billion neurons.

The neurons in the brain are mainly

interneurons.

The brain has a mass of about 1.4

kilograms.


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o It is the control center for recognition and analysis.o It controls things like hunger, thirst, fatigue, anger, and body temperature.o The spinal cordo Its the main communication link between the brain and the rest of the body.o Thirty-one pairs of spinal nerves branch out from the spinal cord, connecting the

brain to the body.o Certain information, such as reflexes, is processed directly in the spinal cord.o A reflex is a quick, automatic response to a stimulus.o Sneezing is an example of a reflex.o A reflex allows your body to respond to danger without spending time or

thinking about it.

o The peripheral nervous systemo The PNS lies outside of the CNS.o It consists of all the nerves and associated cells not part of the brain and spinal

cord.

o Included are the cranial nerves, spinal nerves, and ganglia (collections of nervecell bodies).

o The PNS can be divided into two divisions: the sensory division and the motordivision.

o The sensory division of the PNS transmits impulses from sense organs to theCNS.

o The motor division transmits impulses from the CNS to muscles or glands.o The motor division is divided into the somatic nervous system and the

autonomic nervous system.

o The somatic nervous systemo Regulates activities that are under conscious control, such as movement of

skeletal muscles.

o Motor neurons of the somatic nervous system are used every time you move.o Some somatic nerves are involved with reflexes and can act with or without

conscious control.

o If you step on a tack your leg may recoil before you feel the pain.o This happens because receptors in your skin stimulate sensory neurons, which

carry an impulse to your spinal cord.

o Before the information is relayed to your brain a group of neurons in your spinalcord activates the appropriate motor neurons.

o The autonomic nervous systemo Regulates activities that are automatic, or involuntary.o Nerves of the ANS control functions not under conscious control.o For example, heartbeat is controlled by the ANS.o The two parts of the Autonomic Nervous System are the sympathetic and

parasympathetic nervous systems.

o Most organs are under control of both the sympathetic and parasympatheticnervous systems.

o These two systems have opposite effects on the same organs.o Heart rate is increased by the sympathetic nervous system and decreased by the

parasympathetic nervous system.


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o The two systems are comparable to a car. One is the gas pedal and one is thebreak.

o Disorders of the nervous systemo Polio

viral. Disruption in motor neurons. Cause muscle weakness and paralysis.

oStrokeclot in cranial artery deoxygenation of part of brain. Can result in inability to

move limbs disrupt speech. Can cause blindness.

o Meningitisinflammation of protective covering of brain and spinal cord. Symptoms

headache, stiff neck, light sensitivity, vomiting. Treated with antibiotics. Can

lead to deafness, epilepsy cognitive difficulties.

o Cerebral palsynon-progressive, non-contagious motor disease. Can develop from development

to age 3. Leads to problems with communication, movement, and sight.

Involves interruption between cortex and other parts of brain/ body.

oThe skeletal system

o Functionso Supporto Protection (internal organs)o Allows for movemento Stores mineral reserveso Site of blood cell formationo Generalo 2 main parts of skeleton: axial and appendicularo Axialo Supports central axis of bodyo Consists of skull, vertebral column and ribso Appendicularo Consists of arms, legs, pelvis and shoulder areao Structureo Bones are living!o Made of a network of cells and protein fibers that are surrounded by calcium

salts.

o Bones surrounded by tough CT (periostium)o Blood vessels pass through periostium and carry O2 and nutrients to bone.o Structureo Below periostium is compact boneo Bone is not solid.o Running through bone is a network of canals (Haversian canals).o Haversian canals contain blood vessels and nerves.o Structureo Inside of compact bone is spongy bone.o Found on the ends of long bones and in middle of short, flat bones.o Not really soft and spongy.o Strong


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o Structureo Bones contain soft tissue (bone marrow)o 2 types: red and yellowo Yellow is made of fat cellso Red produces RBCs, some WBCs and platelets.o

Bone Developmento Cartilage replaced by bone during the process of ossification (bone formation).o Cells that have names starting with osteo are bone cells.o Osteoblasts create bone, osteocytes maintain cellular activities of bones,

osteoclasts break down bones.

o Bone Formationo Osteoblasts secrete mineral deposits that replace cartilage in developing bones.o When osteoblasts become surrounded by bone tissue they turn into osteocytes.o Bone Formationo Long bones have growth plates at either end.o The growth of cartilage at these plates causes bones to lengthen.o

Bone eventually replaces the new cartilage.o Growth plate eventually becomes ossified as well.o Bone Formationo Occurs when a bone is broken.o Osteoclasts remove damaged bone tissueo Osteoblasts make new bone tissueo Types of Jointso Jointso Connect bones to other boneso Permit movement without damaging each othero Some allow extensive movemento Others allows no movement at allo Depending on the type of movement joints are classified as immoveable,

slightly moveable or freely moveable.

o Immoveable Jointso Called fixed jointso No movemento Bones are interlocked or fused and held by CT.o Ex: place where bones of skull meeto Slightly Moveableo Allow for small amounts of movemento Bones are separated from each othero Ex: Joints between vertebraeo Freely Moveable Jointo Permit movement in one or more directionso Ball and socket joint (circular movement)o Hinge joint (back and forth movement)o Pivot joint (one bone rotates around another)o Saddle Joint (one bone slides in 2 directions)o Ball and Socket


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o Hinge Jointo Pivot Jointo Saddle Jointo Structure of Jointso Freely moveable jointso

Ends of bone covered in cartilage for protectiono Joints surrounded by capsule that holds bones together but still allows

movement

o 2 layers: one forms ligaments (CT that hold bones together), the other formssynovial fluid (lubrication for bones)

o Structure of Jointso Sometimes-small sacs of fluid form.o Reduces friction and acts as shock absorber.o When tissue is damaged, body responds through inflammation.o Arthritis is inflammation of one or more joints.o The muscular systemo

Typeso 3 types of muscle tissue: skeletal, smooth and cardiac.o Skeletal Muscleo Attached to boneso Responsible for voluntary movementso Has striationso Controlled by CNSo Consist of muscle fibers, connective tissues, blood vessels and nerves.o Smooth Muscleso Not under voluntary controlo Spindle shaped cellso Found in hollow structures such as stomach, blood vessels and small and large

intestines.

o Smooth Muscleso Responsible for:o Moving food through digestive tracto Controlling blood flowo Decreasing size of pupils in bright lighto Most functions without nervous system stimulation.o Cardiac Muscleso Found ONLY in hearto Striated cells that are smaller than mosto Muscle Contractiono Skeletal muscle striations caused by alternating bands of thick and thin

filaments

o Thick filaments have myosino Thin filaments have actino Muscle Contractiono A muscle contracts when thin filaments slide over the thick filamentso To contract:


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o Myosin filament forms a cross bridge with the actin filament.o The actin filament is pulled and the distance decreaseso When the cross bridge detaches the muscle relaxes.o How Muscles and Bones Interacto Skeletal muscles joined to bones by CT called tendonso

Tendons make bones act as levers by pulling them.o The joint is the fixed part around which the lever moves.o Muscles provide force neededo Muscular disorderso Strains, cramps, and tendinitis.o Pancreas

digestive organ whose secretions help break down food. Also releases hormonesinto blood made of clusters of cells called islets of Langerhans. Cells release

insulin and glucagon. These help to keep blood glucose level stable. Insulin

stimulates cells in liver and muscle to remove sugar from blood and store it as

glycogen. Glucagon stimulates liver to break down glycogen and release

glucose back into blood.o Type 1- develops before 15. Little or no secretion of insulin. Must have strict

diet and receive insulin injections.

o Reproductionoo Asexual vs. Sexualo Asexual=o Done by single celled organismso Ex: Amoebaso Sexual=2 cells from different parents combine to make one organismo Done by plants, animalso Ex: maple trees, giraffeso Sexual Developmento Gonads are the male and female reproductive structures that contain hormoneso Ex: Ovaries and Testeso Gonads do not become active until pubertyo =Sexual maturation; when reproductive system becomes fully functionalo Male Reproductive Systemo FSH and testosterone stimulate the development of spermo Sperm are one-celled organisms that carry genetic information of the fathero Male Reproductive Systemo 2-6 milliliters of semen contain more than 200-600 million spermo The chances of one sperm fertilizing one egg, if one is available is very goodo Male Reproductive Systemo Main Structures that deliver sperm:o Testes: make spermo Epididymis: where mature sperm are storedo Vas deferens: sperm travel through hereo Urethra: exit way for sperm/urineo Penis: where urethra passes through


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o See handouto Female Reproductive Systemo Ovulation=egg releaseo When follicle has matured, egg is releasedo Egg is swept from ovary into one of the Fallopian tubeso

Egg moves in fluid in tubes and is pushed by cilia in tubeso Egg can become fertilized in tubeo After a few days, egg is passed into Uteruso Lining of uterus is ready to receive fertilized egg and nurture development of

embryo

o Female Reproductive Systemo FSH and LH stimulate cells in ovaries to produce estrogeno Follicles are the clusters of cells that surround a single eggo Follicles help an egg mature for release into the reproductive tracto Females are born with 400,000 immature eggs (primary follicles) and do not

produce any more eggs in her lifetime. Only 400 of the eggs will actually be

released.o Menstrual Cycleo Occurs after pubertyo Regulated by hormones FSH, Estrogen, LH, Progesteroneo Controlled by negative feedback of endocrine system and reproductive systemo On a monthly (28 day) cycleo Menstrual Cycleo 4 stageso 1. Follicular phase:o Hormones cause follicle to develop into maturityo Estrogen makes lining in uterus thicken to receive a possibly fertilized eggo Development of egg takes 10 days in this cycleo Menstrual Cycleo 2. Ovulation phase:o Flood of FSH and LH are released and cause follicle to rupture releases egg

to fallopian tubes

o Shortest phase in cycle (approx. 3-4 days)o 3. Luteal Phaseo Follicle turns yellow (corpus luteum) and releases estrogen and progesterone to

stimulate cell growth and tissue development in lining of uterus

o Chances for fertilization are greatest during first 2 days of luteal phaseo This phase is 10-14 days after completion of last menstrual cycleo

Menstruation

o If fertilization does not occur, within 2-3 days of ovulation, egg will passthrough uterus without implantation

o Follicle will break down and release less estrogen and progesteroneo Lining of uterine wall will detach and with blood and unfertilized egg, will pass

through vagina

o Menstruation lasts 3-7 days


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o First day of menstruation begins new cycleo Early Developmento Fertilization=sperm and egg joiningo Zygote=the fertilized eggo Embryo=when fertilized egg had divided into 2 or more cells, to form a ball of

cellso Ball of cells will attach itself to uterine wall and continue to divide and

differentiate

o Placenta=connection b/w mother and embryo; the embryos organ ofrespiration, nourishment and excretion

o Early Developmento Twinso Fraternal twins= when 2 sperm fertilize two eggso Identical twins= when 1 zygote splits into twoo Mitosisoo

Asexual Reproductiono Reproduction in which all genetic material comes from one parent.o Types of Asexual Reproductiono Binary fission involves an equal division of both the organisms cytoplasm and

nucleus to form two identical organisms (amoeba)

o Budding involves one parent dividing its nucleus (genetic material) equally, butcytoplasm unequally (yeast)

o Sporulation (spore formation) is reproduction involving specialized single cellscoming from one parent (mold spores)

o Cloning is the production of identical genetic copies.o Cell Cycleo Part of the cell cycle (describes the different stages a cell goes through)o 3 main stages: Interphase, mitosis, cytokinesiso Mitosiso Mitosis is the method used for cell division and reproduction in cells not

involved in sexual reproduction.

o This process starts with one replication (copying of the chromosome material)and one division of the chromosome material.

o This results in the chromosome numbers in the two cells produced being thesame as in the parent cell

o Results of Mitosiso The same chromosome number is retained from generation to generation.o Each daughter cell receives an exact copy of the chromosomes of the parent

cell. (Clones)

o Stages of Mitosiso Stages of Mitosiso During Interphase, the cell replicates its DNAo Mitosis is the division of the nucleuso One copy of DNA is given to each new cello There are four phases of Mitosis:


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Prophase Metaphase Anaphase Telophase

o Prophaseo

The DNA condenses and coils into Chromatids. The DNA doubled duringInterphase, so there are 2 copies of each Chromatid.

o The 2 copies are held together by a Centromere and form a Chromosome.o Metaphaseo Each chromosome attaches to a spindle fiber at its centromereo Chromosomes line up across the center of the cello The centromere holds both of the chromatids togethero Anaphaseo The centromeres split and the two chromatids separate as the spindles pull them

apart.

o The spindles pull the chromatids to opposite ends of the cell.o

The ends begin to pull apart and the cell becomes stretched out.o Telophaseo Chromosomes stretch out and lose their rod-like appearance.o New nuclear membranes begin to form around each region of chromosomes.o Cytokinesiso Cells actually split apart.o The cell membrane squeezes togethero Cytoplasm divides and the organelles are distributed into each daughter cell.o End of the cell cycle. From here the cells go into Interphase.o Meiosiso Generalo Lets start with a fruit fly which has 8 chromosomeso 4 of the chromosomes came from the flys father and 4 came from the flys

mother.

o These two sets of chromosomes are known as homologous, which means thateach chromosome from the male has a corresponding chromosome from the

female.

o Fruit Flies Continuedo A cell containing BOTH SETS of homologous chromosomes is known as diploid

(meaning two sets)

o The number of chromosomes in a diploid cell is represented as 2N.o Since the diploid number in a fruit fly is 8, we write 2N=8.o Gameteso Gametes are sex cells.o Gametes contain ONLY a single set of chromosomeso Called haploid cells.o The fruit fly is written as N=4, meaning the haploid number is 4o Phases of Meiosiso Meiosisprocess of division in which the number of chromosomes per cell is cut

in half through the separation of homologous chromosomes in a diploid cell.


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o 2 stages: 1st is Meiosis I and the 2nd is Meiosis 2o Meiosis Io Each chromosome is replicatedo Cell begins to divide in a way that looks like mitosiso Each chromosome pairs with its corresponding homologous chromosome to

form a tetrado Portions of tetrads are exchanged during crossing overo The chromosomes separate and 2 new cells form.o Meiosis IIo The 2 cells produced by meiosis I enter a 2nd division.o Neither goes through replication before entering meiosis IIo During metaphase II, the chromosomes line up in the center of each cello In anaphase II, the chromatids separateo Meiosis IIo Each of the four cells contains half of the number of chromosomeso This is the haploid number (N)o

DNA and DNA Replicationo Whats It Made Of?o Made of nucleotideso Each nucleotide has 3 parts:o A 5 carbon sugar (deoxyribose)o A phosphate groupo A nitrogenous base (adenine(A), guanine(G), cytosine(C) or thyamine (T) )o A and G are purineso C and T are pyrimidineso The Structureo Double helix (twisted ladder)o The rungs are made of nitrogenous baseso C always binds with Go A always binds with To Where is it Found?o Found in the nucleus of every cello Situated in chromosomeso Number of chromosomes varies between specieso DNA Replicationo Structure allows us to understand how it can be copiedo Discovered by Watson and Cricko Each strand of DNA has all the information needed to construct other halfo Strands are complimentary to each other (can be used to make each other)o How Does it Happeno Bonded nucleotides separated by DNA helicaseo This unzips the DNA in either directiono DNA polymerase adds the correct base pair to either strand in opposite directionso Mutationso What are they?o Occasionally cells make mistakes when copying their DNA.


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o Results in inserting incorrect base into sequence or skipping a base.o Changes affect genetic informationo Gene mutations result from changes in single geneo Chromosomal mutations involve whole chromosomes (multiple genes)o Gene Mutationso

Majority include just one nucleotide, some do involve several nucleotides.o Point mutation-mutation affecting only one nucleotideo Occur at single point on DNA sequence.o Gene Mutationso Some point mutations substitute one nucleotide for another.o This changes the amino acid being coded for.o Gene Mutationso Sometimes a nucleotide is inserted or deleted- called frame shift mutations.o The reading frame is shifted in either direction.o This affects every amino acid following the insertion or deletion.o This can alter proteins to the point that they dont functiono

Chromosomal Mutationso Involves changes in number or structure of chromosomes.o May change the locations of genes on chromosomes and even the number of

copies of some genes.

o Chromosomal Mutationso 4 types:o Deletion- loss of all or part of chromosomeo Duplicationsegment of chromosome is repeatedo Inversion- when part of chromosome becomes oriented in reverse of usual

direction.

o Translocation- when part of the chromosome breaks off and attaches to anotherchromosome.

o Evolutiono Natural Selectiono The evolutionary process that selects the variations of organisms best suited for a

particular environment.

o Provides scientific explanation for the fossil record as well asmolecular/structural similarities among organisms.

o How closely organisms are related can be estimated from DNA similaritieso Natural Selectiono The graph shows:o All of the primates had a common ancestoro Humans and chimps have the greatest similarity in DNA (they are evolutionary

the closest)

o Theory of Natural Selectiono First suggested by Charles Darwino Controlled by nature rather than by peopleo Individuals that survive are able to reproduce and pass genetic information to the

next generation.

o Organisms not successful in the environment die.


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o Types of Natural Selectiono Overproduction: within a population more offspring born than can survive.o Competition: size of population remains constant due to limited resourceso Types of Natural Selectiono Survival of the Fittest: individuals who survive are best adapted due to variations

that fit with the environment.o Genetic variability mainly due to mutation and genetic recombinationo Variation increases the chance that some members will survive under changed

environmental conditions.

o Types of Natural Selectiono Reproduction: Best adapted individuals survive and reproduce (favorable

variations passed on)

o Speciation: As time and generations continue, adaptations are passed and newspecies evolve from a common ancestor.

o What is an Adaptation?o Variation, which assists an organism or species in survival.o

Adaptations include: structural changes, behaviors, or physiology that enhancessurvival and reproductive success in an environment.

o Other Concepts to Understando Some characteristics give individuals an advantage over others in surviving and

reproducing.

o Advantages offspring are more likely to survive and reproduceo Behaviors evolve through evolution-behaviors ensure reproductive success.o Modern Examples of Natural Selectiono Peppered Moth:o Two varieties existed (dark and light)o Light colored moth hid on birch tree bark to avoid being eaten by birds.o As industrialization and coal burning increased the environment in England

became dirtier

o Dark colored moth blended into treeso Light colored moths easily seen and eaten by birdso Peppered Motho Modern Examples of Natural Selectiono Insects resistant to insecticides:o Insecticides kill insects not resistanto Insects that are resistant live and reproduceo Insecticide acts as a selecting agento Modern Examples of Natural Selectiono Bacterial resistance to antibioticso Bacteria not resistant are killed by ito Resistant bacteria live to reproduceo Acts as a selecting agento Evolution and Extinctiono Changes often occur like growth of a bush. Some branches survive from

beginning with little change, some die out, others branch repeatedly (giving rise

to more complex organisms).


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o Called cladogram or phylogenetic treeo Fossil Recordo Remains of organisms are preservedo Relative Dating of Sedimentary Rock and Fossilso Upper strata contains younger fossils (more complex organisms)o

Lower strata has older fossils (simpler life forms)o Tendency for increasing complexity amongst organisms.o Variationo Sources of variation:o Exchange and recombining of genes during meiosis and fertilizationo Mutations are random changes in the genes or DNA of sex cells-may result in

new gene combinations creating variation

o Mutationso Only mutations occurring in sex cells can be passed on to offspring.o Mutations are the source for genetic variationo Sexual reproduction leads to genetic variationo

Variation and Evolutiono Evolution is the consequence of the following factors:o The potential for a species to increase numberso Genetic variability of offspring due to mutation and recombinationo Finite supply of resources required for lifeo Ensuing selection by the environment of those offspring better able to

survive/reproduce

o Variation and Evolutiono Some characteristics give individuals an advantage over others in surviving and

reproducing.

o The proportion of individuals with advantageous characteristics increases.o Example of Variation Driving Natural Selectiono Natural selection favors long necks.o Better chance to get higher leaves.o Favored characteristic passed on to next generation.o Example Continuedo Original group exhibits variation in neck length.o After generations, still variation in group, but tendency is toward longer neck.o Support For Theory of Evolutiono Chemistry-all living things have same nucleic acidso Nucleic acids all have same structure and function (DNA is always similar)o Leads to similarities in proteins and enzymes\o Same proteins=same DNAo Support for Theory of Evolutiono Cell Structureso All living things made of cells (organelles similar)o Anatomical Featureso Organisms have similar features.o Basis for development of five kingdomso Embryology


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o Early embryos of organisms resemble each othero Geographic Isolation leads to Speciationo When small group is separated from main population, the gene frequency is

changed.

o New population becomes its own species.o

Different mutations occur within main population and new populationo Different environmental factors may be acting on each population leading to

different adaptations

o How Life May Have Begun on Eartho Heterotroph Hypothesiso First life forms not able to make their own foodo Organisms made of simple sugars, amino acids and nucleic acidso Molecules worked together to form cell like structureso Used anaerobic respiration ( like yeast)o O2 in atmosphere allowed for aerobic respirationo Levels of organizationo

Living organisms interact with and are dependent upon their environment andeach other.

o The components of living systems interact to maintain balance.o The most basic level is a single organism.o Groups of organisms belonging to a single species form a population.o An ecological community formed by the living organisms in an area.o Ecosystem- the living things in an area and the physical factors of the

environment that influence them.

o The biosphere encompasses all the levels of organization to represent theportions of the earth that can sustain life.

o An ecosystem is the living community and the non-living environment togetheras an interdependent and relatively stable system.

o An ecosystem involves interaction between abiotic and biotic factors.o The abiotic factors are non living and influence an organisms ability to live and

reproduce,

o The biotic factors are living and also have an influence on survival andreproduction.

o The non-living environment as well as its interacting species shapes anecosystem.

o The world contains a wide diversity of physical conditions, which creates avariety of environments.

o Requirements of a self-sustaining ecosystem.o There must be a constant source of energy.o There must be a living system capable of incorporating this energy into energy

rich organic compounds.

o Energy flows through an ecosystem in one direction from the sun throughphotosynthetic organisms to herbivores and then carnivores and decomposers.

o Food chains and webs illustrate the interrelationships and interdependence ofproducers consumers and decomposers in an ecosystem.


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o The energy for an ecosystem made from organic compounds created byproducers (autotrophic nutrition)

o Consumers are organisms that arent able to synthesize own nutrients and mustget hem from organisms (heterotrophic nutrition)

o Consumers include herbivores and carnivores.o

Decomposers are organisms, which break down organic wastes, and deadorganisms into simpler substances to the environment to be reused.

o Energy pyramido Used to show flow of energy through levels of an ecosystem.o Base made of producers.o 2nd- herbivores.o Higher levels are carnivores.o A small amount of energy is stored from one organism to the next.o The remaining energy is dissipated as heat.o This is why energy from the sun is constantly needed.o Number of producers must be greater than consumers to account for energy lost

through heat.o There must be a recycling of materials between organisms and abiotic

environment.

o Chemical elements (carbon, hydrogen, and oxygen) pass through food webs andare combined and recombined.

o Carbon dioxide and water are used in photosynthesis to make glucose.o These compounds are returned to the environment during cellular respiration.o Maintaing a stable environmento The number of organisms a habitat is limited by energy. Water, oxygen, and

minerals.

o Ability to recycle dead organisms through bacteria, fungi needed to maintainstable environment.

o Interactions among living thingso Competition- when organisms living in the same limited abiotic and biotic

factors can be between members of the same species or different species.

o More similar the requirements the more intense the competition.o 2 types of organisms compete, one will be successful and the other will be

eliminated.

o This establishes 1 species per ecological niche.o Niche- organisms role in the environment.o Interactions between organisms may be negative, neutral, or positive.o Ecosystems can changeo Changes occur until a stable ecosystem is formed.o Ecological successiono Community of organisms modifies the environment making it more suitable for

another community.

o Long-term changes help community reach a point of stability.o Ecosystems can change.o A stable ecosystem can be altered through activities of organisms or through

changes in climate/ natural disasters.


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o An altered ecosystem can undergo succession again.o This may lead to the original stable community being reestablished.o Evolutionary changeso Result in diversity of organisms and roles in the ecosystem.o Biodiversity increases stability of ecosystem and provides variety of genetic

materials.o This may lead to future agricultural/ medical discoveries.o Diversity increases the chance that some species would survive large

environment changes.

o Improvements in agriculture health and medicine have produced a dramatic risein the human population.

o This increase in population size leads to an increase in pollution and higherdemand for the worlds resources.

o Humans are using up the earths resources, including fossil fuels.o Burning fossil fuels in cars and power stations produces carbon dioxide, sulphur

dioxide and other greenhouse gasses.

oCarbon dioxide traps heat in the atmosphere and causes the temperature of theearth to rise.

o This leads to disruption of the weather patterns.o Some weeds may thrive on the extra carbon dioxide while other plants are killed.o Sulphur dioxide will dissolve in rain producing acid rain.o Acid rain damages trees and pollutes rivers and lakes.o Acid rain causes erosion of building and statues particularly if they are made of

limestone.

o Deforestationo In many countries people are chopping down forests to provide timber or space

for agriculture for the growing population.

o This causes several problems :o Burning timber increases the level of carbon dioxide in the air.o Less trees means less carbon dioxide absorbed for photosynthesis.o Soil is eroded as it is exposed to wind and rain.o Less water is transpired into the atmosphere.o Many animals and plant habitats are destroyed causing extinction of species.o Intensive farmingo Farming has become more intensive to provide a higher % yield from land.o Many people regard intensive farming of animals to be cruel.o In order to produce more food from the land farmers have to use more fertilizers

and pesticides.

o Problems with fertilizerso Fertilizers enable farmers to grow more food as they are replacing the nutrients

removed from soil by plants.

o However if too much fertilizer is added and it then rains the fertilizer finds itsway into rivers and lakes.

o This causes the water plants to grow and as there is competition for light somewill die.

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