biology honors midterm review
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Biology Honors Midterm Review
Scientific Method
The organized way of using evidence to learn about the natural world
The goal of science is to investigate and understand nature. Also, to explain events in nature
and to use those explanations to make useful predictions
Scientists
They make observations using one or more of their senses to gather information
-Qualitative - Can not be easily counted or measured (Odor or texture)
-Quantitated - Can be easily measure (Like objects)
Interpreting Evidence
An observation must be understood to be useful
An inference is a logical interpretation based on proper knowledge and experience
Explaining the Observation
When faced with a problem, scientists may formulate several hypotheses for why it is
happening
A hypothesis is a possible explanation for a set of observations or an answer to a scientific
question
Hypotheses arise from prior knowledge, logical inferences or imaginative guesses
Designing an Experiment
I. State the problem -What are we trying to learn?
II. Form the hypothesis
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III. Set up a controlled experiment - Only one variable should be changed, others remain
constant
IV. Record and analyze your data
V. Draw a conclusion: evaluate the data and state whether it supports or refutes the hypothesis
Characteristics of Life
All living things are:
-Made of cells
-Reproduce
-Based on a genetic code
-Grow and develop
-Obtain and use materials
-Respond to their environment
-Maintain homeostasis
Made of Cells
A cell is a collection of living matter enclosed by a barrier that separates that cell from its
surroundings
-Unicellular - Consists of one cell (Bacteria)
-Multicellular - Consists of many cells (Complex organisms)
Life Processes
Metabolism - All the chemical reactions that occur within the cell of a metabolism.
-Digestion, Synthesis, Hydrolysis
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Respiration - This is not the same as breathing and is sometimes called cellular respiration.
Chemical bond energy stores in nutrients are released for us by cells
-Anaerobic - Fermentation without oxygen
-Aerobic - With oxygen
Synthesis - Involves combing simple substances into complex substances.
-Most common is dehydration: Joins two simple substances by removing water. Amino
acids in your food are used to create protein with this process
Transport - This is not the same as locomotion. This is the movement of materials into and
within a living thing
-IE- Our circulatory system moves oxygen and nutrients into our cells. (Locomotion is
movement, such as plants bending towards the sun or animals moving their bodies)
Regulation - Control and coordination
-Includes communication, like the endocrine and nervous system
Assimilation - The process by which materials are incorporated into a living thing.
-Proteins we ingest are used by our bodies
Nutrition - Obtaining and processing food
-Autotrophs - Make their own food (photosynthesis and chemosynthesis)
-Heterotrophs - Must obtain food
Growth - An increase in either the size or number of cells. All organism grow during at least
one part of their life cycle.
-Organisms also develop which is a change in the appearance of the organisms structure
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Excretion - The removal of all wastes produced by the ells of the body
-We exhale CO2 as a waste product of cellular respiration
-One celled organisms such as ameba excrete wastes through their cell membranes
Reproduction - Process by which organisms produce new organisms
-This is the one process that is not necessary for the individual but is necessary for the
survival of the specie.
-Can be asexual with one parent or sexual with two parents
Homeostasis
When all life functions are maintained.
The process by which living things keep a stable internal environment
Images Under the Microscope
Images under microscope appear upside down and backwards
When viewing under the microscope, move slide in opposite direction to center
Field of Vision
Switch to high power from lower power, the field of vision gets smaller but the detail of the
object gets smaller.
Light
Higher magnification = you need more light
Measure
Use millimeters or micrometers (1 Micrometer = 1,000 millimeters)
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Cells
Cells have been particular structures that perform specific jobs. These cell parts coordinate and
work together just as systems within an organism are coordinated and work together
Cell Theory
This is one of the fundamental concepts of Biology
-All living things are composed of cells
-Cells are the basic units of structure and function in living things
-New cells are produced from living cells
Exceptions to the Theory
Viruses can not reproduce on their own, they must be inside a living thing in order to reproduce
Mitochondria and Chloroplast contain their own DNA and can reproduce
Organelles
Specialized cell structures that are formed from many different molecules and perform specific
jobs
-Cytoplasm - Transports materials
-Mitochondria - Extracts energy from nutrients in a process called cellular respiration
-Ribosome - Protein building
-Lysosome - Contains enzymes
-Cell Membrane - A thin flexible selectively permeable membrane
-Endoplasmic Reticulum - Modifies components of the cell membrane and modifies
some proteins
-Vacuoles - Storage of the cell
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-Nucleus - Information center; the nucleus contains the DNA
Plant Cells
There are two organelles that are found in plant cells but not in animal cells
-Cell Wall - Provides support and structure for the cell
-Chloroplast - Use energy from sunlight to make energy rich food molecules in a process
called photosynthesis
Levels of Organization
Cells are grouped into tissues > organs > organ systems > organism
The body is composed of different kinds of cells grouped in ways that enhance how they
function together
The structures present in single - celled organisms act in a manner similar to the tissues and
systems found in multicellular organisms
Fluid Mosaic Model
The cell membrane regulates what enters and leaves the cell and also provides protection and
support
The core of the cell membrane is a double layered sheet called a lipid bilayer
Embedded within the cell membrane are protein channels that allow certain molecules to enter
the cell
Carbohydrate chains are attached to the outside of the membrane and act for identification
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Diffusion
Diffusion causes substances to move across a membrane but does not require energy
-All cells contain liquid and are surrounded by liquid
-When molecules are in solution they move constantly
-When the concentration of a substance is different in one of these liquids, it moves from
the area of high concentration to low concentration
-Equilibrium is reaches when the concentration is the same both inside and outside of the
cell
Osmosis
The diffusion of water through a permeable membrane
-When the concentration of a substance that can not pass through the membrane is lower
on one side of the membrane, water diffuses through the side of the membrane until
equilibrium is reaches
-Water like other substances move from an area of high to low concentration
Osmotic Pressure
Because cells contain numerous salts, sugars and protein, the concentration of water is usually
lower inside a cell, so water is constantly diffusing into a cell
The extra water pressure creates osmotic pressure
Osmotic pressure can cause a cell to burst if they do not have a way to remove water
Most cells in multicellular organisms do not come in contact with fresh water. So this is not a
problem
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Single celled organisms that live in fresh water have mechanisms to move water out of the cell.
These mechanisms require energy
Facilitated Diffusion
For molecules that can not pass through, the cell membrane can move through a protein
channel
-Different protein channels allow ions, sugars and salts to cross various membranes
-This process is fast and specific but still moves from areas of high to low concentration
and does not require energy from the cell
Active Transport
Moves substances from low areas to high areas of concentration. This process requires the cell
to input energy
-Endocytosis - When the cell folds over to take in large molecules
-Phagocytosis - The cell membrane engulfing food. The membrane pinches off, forming a
vacuole
-Exocytosis - The process where a vacuole fuses with a cell membrane, forcing the
contents out of the cell
Classification
Needs for classification
I. All living things are basically alike in functions
II. There is however a great variety in the ways and means by which different organisms
carry out these functions
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III. In order to study the variety of life in an organized and systematic manner, the different
kinds of organisms are grouped together or classified on the basis of certain common
characteristics or the relationships they share
Classification of organisms are based mainly on similarities of structure
I. Some classification is supplemented by other evidence such as:
A. Fossil record
B. Biochemical date - genetic makeup
C. Behavioral information
D. Embryonic development
E. Cellular structure
II. Modern classification is based on the assumption that all present forms of life development
from earlier forms and have have common ancestors. The grouping of organisms suggest
relationships among them that may be the result of common ancestry
Modern Classification Systems
I. Carolus Linnaeus - Father of modern taxonomy
A. Developed the classification system today
B. Based mainly off of structural similarities
II. Binomial Nomenclature
A. Names are in Latin
B. Italicized with the genus name
III.They are first separated into kingdoms
A. Not all scientists agree on the number
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B. Most used is 5 kingdoms
1. Animal - Multicellular organisms ingest food.
2. Plants - Multicellular organisms that make their own food
3. Fungi - Cells are usually organized into multicellular filaments called hypae, They
reproduce by the means of spores
4. Protists - Mainly one celled plants-like or animal-like organisms. They have distinct
nucleus surrounded by a double membrane
5. Monera - Primitive cells, lacking a nuclear membrane (Prokaryotic)
C. Linnaeus System of Classification
1.Kingdom
2.Phylum
3.Class
4.Order
5.Family
6.Genus
7.Species
Biochemistry
The study of organic compounds
Chemical Bonds
Ionic Bonds - Transfer electrons (Like salt crystals dissolving in water)
Covalent Bonds - Share electrons
Van Der Waals Bonds - Atoms attracted to each other
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Way to remember: King Philip Came
Over For Good Soup/Salad/Other words
that start with S
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Water
Has 2 H+ molecules and one O-
Polar - Has 2 different charges
Adhesion - Sticks to other things (Like rain on a window)
Cohesion - Sticks to itself (Like a puddle)
pH
Measure of H+ (Positive Hydrogen atoms in a solution)
Scale of 1-14
1 - Very acidic (Lots of H+)
7 - Neutral (Pure Water)
14 - Very little H+ (A Base)
Buffers - Control pH to prevent sharp changes (Maintains homeostasis)
Organic - Has carbon and hydrogen ( Like C6H12O6 )
Carbohydrates - Main source of energy for living things
Subunits - Sugar (Saccharide)
Inorganic - No carbon (Like H2O)
Monomer - One, small unit
Polymer - Big unit, from small units
Carbohydrates
Monosaccharide - 1 Sugar (Glucose)
Disaccharide - 2 Sugars (Lactose)
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Polysaccharide- Many Sugars (Starch)
Lipids (Fats)
Store energy
Made of mostly carbon and hydrogen
Subunits - 1 glycerol and 3 fatty acids
Saturated - Max # of hyrdogens; no double bonds in the molecule
Unsaturated - 1 Carbon double bonded to another
Polyunsaturated - More than 2 double bonds (Missing 4 or more Hs)
Protein
Regulate cell processes and control rate of reactions inside cells -Enzymes
Made of nitrogen, carbon, hydrogen, and oxygen
Subunit - Only 20 different amino acids
DNA tells amino acids what order to get in to make certain proteins
Enzyme
Made of protein
End in Ase, like Lactase
Involved in all chemical reactions
They are catalysts - Increase rates (speed) of reactions by lowering activation energy
Substrate/Reaction = Product
Fits into the enzyme at the active site
The fit is specific and must be exact for the reaction to occur
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Enzyme substrate complex - When theyre together, the enzyme does not change shape after a
reaction and can be re-used over and over
Enzyme Reactions are affected by:
Temperature - Too high/Too low = denatures enzyme
pH - Too high/Too low = denatures enzyme
Concentration of Substrate -
More substrate = Higher concentration = Faster reactions
Fewer substrate = Lower concentration = Slower reactions
C6H12O6 + C6H12O6 X C12H24O11 + H2O
Reactants Products
X=Enzyme
Nucleic Acid
Store and Transmit hereditary information
DNA and RNA
Made of carbon, phosphate and nitrogen
Subunit - Nucleotides
Nucleic Acid - Carbon, hydrogen, nitrogen, oxygen, phosphates
Lipids - Carbon and hydrogen
Proteins - Hydrogen, Oxygen, Carbon and Nitrogen
Carbohydrates - Hydrogen, Oxygen, Nitrogen, Carbon
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Leaf Structure
The structure of a leaf is optimized for absorbing light and carrying out photosynthesis
To collect sunlight, most leaves have thin flattened sections called blades.
Leaves are covered on the top and bottom by an epidermis.
The leaf epidermis is sometimes covered with a cuticle
The epidermis and cuticle protect leaves from water loss
Transpiration
The loss of water from a plant through its leaves. Water is lost in ways by being replaced by
water drawn into the leaf through the Xylem
Xylem - Tubes through which water moves from the roots to the leaves
Plants keep their stomata open just enough to allow photosynthesis to take place, but not so
much that they lose an excessive amount of water
-Stomata - Are pore like openings in the underside of the leaf that allow CO2 and Oxygen
to diffuse in and out of the cell
-Each stoma consists of two guard cells that control the opening and closing of
stomata by responding to changes in water pressure
-When the pressure is hugh, the outer walls of the cells are forced into a curved
shape and the stoma is opened. Wen pressure is low, the guard cells are not curved
and the stoma closes
Biochemical processes are necessary to maintain homeostasis in living things. Life is
dependent upon the availability of an energy source and raw materials that are used in the basic
enzyme controlling biochemical processes of living organisms
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-The energy for life comes from primarily from the sun. Photosynthesis provides a vital
connection between the sun and the energy needs of living systems
Plant cells and some one celled creatures contain chloroplasts (The site of photosynthesis)
-Photosynthesis uses solar energy to combine the inorganic molecules (CO2 and H20) into
energy-rich organic compounds (Glucose - C6H12O6)
-Oxygen is released into the environment as a result of this process
( http://www.youtube.com/watch?v=aupr9qT2qgc ) Song for Photosynthesis
6CO2 + 6H2O -> C6H12O6 + 6CO2
Carbon Dioxide + Water = Sugar and Oxygen
In addition to Water and Carbon Dioxide, photosynthesis requires light and chlorophyll, a
molecule found in chloroplast
The Reactions of Photosynthesis
The process of photosynthesis includes the light dependent reactions as well as the Calvin
cycle
Calvin Cycle - Light Independent Reactions
The light dependent reactions produce oxygen gas and convert ADP and NADP into ATP and
NADPH
The light dependent reactions occur in different areas of the thylakoid called Photosystem I and
Photosystem II
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http://www.youtube.com/watch?v=aupr9qT2qgchttp://www.youtube.com/watch?v=aupr9qT2qgchttp://www.youtube.com/watch?v=aupr9qT2qgc -
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The Calvin Cycle uses ATP and NADPH from the light-dependent reactions to produce high
energy sugars.
The chemical energy stored in the bonds or organic compounds can be used as a source of
energy for life processes. This energy may be released during the process of cellular respiration
C6H12O6 -> H2O + ATP
Sugar + Oxygen = Carbon Dioxide + Water + ATP
-ATP - Adenosine Triphosphate
This energy is temporarily stored in ATP molecules
This energy from ATP is used by the organism to obtain, transform, and transport materials and
to eliminate wastes.
In organisms that use oxygen, carbon dioxide and water are released and ATP is produced.
Cellular respiration is concluded in the mitochondria
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In organisms that do not use oxygen or if oxygen is not available, less ATP is produced
With Aerobic - 36 ATP is used
With Anaerobic - 6 ATP
The Reactions
Glycolysis - The process in which one molecule of glucose is broken in half, producing two
molecules of pyruvic avid
When oxygen is not present, a different pathway follows glycolysis. Glycolysis and the
pathway are called fermentation, because fermentation does not require oxygen, it is anaerobic
respiration
The two main types of fermentation are alcohol fermentation and lactic acid fermentation
Yeast and a few micro-organisms perform alcohol fermentation
Produces Carbon Dioxide and Alcohol
Pyruvic Acid -> Alcohol + CO2 + ATP
Lactic Acid fermentation takes place in cells during exercise when the body cannot supply
enough oxygen to the muscles. The buildup of lactic acid causes a painful burning
sensation (This is why muscles are sore after exercise)
Pyruvic Acid -> Lactic Acid + CO2 + ATP
The energy to make ATP comes from Catabolic Reactions that are Exergonic
(Exergonic = Chemical reactions that release energy)
(Catabolic Reactions- Breakdown of more complex organic molecules into
simpler substances)
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Respiration and Photosynthesis
Different Similar Different
Uses: CO2
Uses: H20
Uses: Sunlight
Produces: Glucose
Produces: O2
Occurs in: Chloroplast
Aerobic: (Oxygen + Glucose -> Carbon Dioxide + Water + Energy)
Digestive System
Made up of digestive tract and accessory glands
15 feet/9 Meters long
Purpose - To acquire energy and nutrients out of the food we eat
The pathway that food travels through the digestive system:
-Mouth
-Esophagus
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ses: Oxygen
ses: Glucose
oduces: CO2
oduces: H2O
oduces: ATP
ccurs in: Mitochondria
< Respiration >
Occurs in Cells
Chemical Reactions
Needs Enzymes
Involves Energy
< Photosynthesis >
lcohol Fermentation : C6H12O6 -> Alcohol + CO2 + ATP
actic Acid Fermentation: Lactic Acid + ATP
erobic Cellular Respiration: 6O2 + C6H12O6 -> 6CO2 + 6H2O +AT
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-Stomach
-Small Intestine
-Large Intestine
-Rectum
-Anus
Accessory Glands
Exocrine glands that secrete digestive liquids through ducts into the digestive system
Salivary Glands
Pancreas
ALiver
Mouth and Salivary Glands
Teeth mechanically break up food
Breaks down food into smaller pieces to increase the surface area so that it can be digested
easier
Salivary Glands - Produce saliva
Made up of mostly water which moistens food, making it easier to swallow
Ptyalin and Amylase are digestive enzymes in saliva which begin the breakdown of simple
sugars.
Esophagus
A gullet or muscular tube
Peristalsis - Waves of muscle contraction in the throat that push food through the digestive tract
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-Takes food from the throat and pushes it down the neck and into the stomach (Takes
5-10 seconds
Stomach
The thick muscles in the stomach wall contract to mash the food up
Chemical digestion of protein begins here
Gastric glands secrete gastric juice which contain digestive enzymes, acids, and mucus
Pepsin - Begins protein digestion
Hydrochloric Acid - Produces acidic environment in stomach so digestive enzymes can
work better
Mucus - Protects the stomach wall from acid
Digestion here takes about 2-6 hours
Small Intestine
6 Meters long
Final digestion and nutrient absorption occurs here over a 5-6 hour period
In the beginning, mostly digestion is occurring whereas in the end, mostly absorption is
occurring
Villi - Small fingerlike projections that increase surface area of the small intestine which
maximizes absorption/diffusion
-Capillaries - Simple sugars, amino acids, vitamins and minerals are absorbed into the
bloodstream here
-Lacteal - Fatty acids and glycerol are absorbed into these tiny lymphatic vessels
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Pancreas
Produces a couple of digestive enzymes that chemically digest or breakdown proteins,
carbohydrates, fats, and nucleic acids in the small intestine
Chemical Digestion:
-Protein -> Amino Acids
-Carbohydrates -> Simple Sugars
-Lipids -> Fatty Acids
-Nucleic Acids -> Nucleotides
Liver
Among many other functions in the body, it produces bile which doesnt contain any digestive
enzymes
Bile is stored in the gall bladder
Bile emulsifies the fat into smaller globules
(Mechanical Digestion), Which aids in the absorption of fats in the small intestine
Large Intestine
Any useful substances in the leftovers, such as spare water and body minerals are absorbed
through the walls of the large intestine, back into the blood
Usually takes about 12-24 hours to move through the large intestine
The remains are formed into brown, semi-solid feces, ready to be removed from the body
Over 7 liters of water are released into the digestive tract with secretions throughout a day (this
is much more than the average person drinks). 90% of this water is recovered in the small and
large intestines
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Rectum and Anus
Feces are stored in the rectum until they can be eliminated/egested
These are finally pushed through a ring of muscles (the anus) and out of the body
Gall Stones
Deposits of bile that became hardened stone like structures and can be surgically removed
Disorders of the Digestive System
Heart Burn
-Painful burning sensation in the center of the chest
-Caused when stomach acid moves out of the stomach and into the esophagus
-Happens when you drink or over eat
Peptic Ulcer
-Holes in the wall o the stomach caused by acid
-For many years, people thought this was caused by stress and spicy food
-Caused by Helicobacter Pylori Bacteria
-Doctors can cure 90% of ulcers with antibiotics
Appendicitis
-Inflammation of the appendix
-Located below colon/large intestine
-No function in humans
Diarrhea
-When not enough water is absorbed by the large intestine
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-A lot of salts and water can be life threatening
-Can be caused by contaminated water
-Leading cause of childhood death in under-developed countries
The Human Circulatory System
Consists of:
The heart
A series of blood vessels and the blood that flows through them
The Heart
Located near the center of your chest and is composed entirely of muscle
The size of a clenched fist and contracts roughly 72 times a minute pimping 70 milliliters of
blood each time
Parts of the Heart
Pericardium - Protective sac of tissue
Myocardium - A thick layer of muscle in the walls
Septum - Divides the left side and the right side of the heart
Prevents oxygen rich blood from mixing with oxygen poor blood
Upper chamber which receives blood is the Atrium
Lower chamber which pumps blood out is the Ventricle
There are two atriums and two ventricles: A total of four chambers
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Heartbeat
Contractions begin in a small group of cardiac muscle cells
Located in the right atrium called the sinoatrial node
Because these cells set the pace for the whole heart, they are also known as pacemakers
Circulation
Blood flows through the lungs through the pulmonary artery, where it picks up oxygen and
returns through the pulmonary vein
Blood then enters through the left atrium and is pumped to the left ventricle, then through the
aorta to the body
Oxygen rich blood flows to the left side of the heart and is pumped to the body (Systemic
Circulation)
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Blood that returns to the right side of the heart is oxygen poor because the cells of the body
have absorbed so much of the oxygen and are loaded with CO2 (both types of blood are shades
of red)
Blood Vessels
Arteries - Large vessels that carry blood away from the heart, except for the pulmonary artery,
they always carry oxygen rich blood
-They have thick walls to help them withstand pressure
-Exerted when the heart contracts and pushed through them
Capillaries - Smallest vessel (the walls are only once cell thick)
-Blood must pass through in single file and the bring the nutrients to the tissues and
absorb CO2 and other wastes
Veins - Returns blood to the heart and the walls contain connective tissue and muscle like
arteries
-They contain one way valves that keep the blood flowing toward the heart
-Many are located near skeletal muscles so when these muscles contract, blood is forced
through the veins
Blood
Blood is made 45% of cells
Suspended in the other 55%, a straw colored fluid called plasma
Plasma is 90% water and 10% dissolved gases, salts, nutrients, enzymes, hormones, waste
products, and proteins called plasma proteins
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Red Blood Cells
Transport oxygen and get their color from hemoglobin
The iron containing protein that binds to oxygen in the lungs and transports it to the tissues
White Blood Cells and Platelets
White blood cells attack foreign substances or organisms
Blood clotting is made possible by plasma and proteins and cell fragments called platelets
Blood Types
A, B, AB, O
Blood can be given to individuals with the same blood type and all blood types can receive O
Blood Pressure
When the heart contracts, it produces a wave of fluid pressure in the arteries
The pressure the blood exerts on the artery walls is known as blood pressure
Blood pressure decreases when the heart relaxes but the system remains under pressure
Measuring Blood Pressure
Medical workers can measure blood pressure with a cuff placed on the arm
An average adults blood pressure is 120/80
First number is the systolic pressure: the force in the arteries when the ventricles contract
Second number is the diastolic pressure: the force in the arteries when the ventricles relax
Disorders of the Circulatory System
Arteriosclerosis - Fatty acids known as plaque build up on the walls of the arteries
If the deposits get too big they obstruct blood and can increase blood pressure
The plaque buildup also increases risk of blood clots
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High Blood Pressure/Hypertension - Forces the heart to work harder which may weaken or
damage the heart muscle and blood vessels (Increases risk for heart attack and stroke)
Heart Attack - When the arteriosclerosis blocks one of the arteries bringing blood to the heart
Part of the heart muscle begins to die from lack of oxygen
Symptoms include nausea, shortness of breath, and severe crushing chest pain
Stroke - Blood clots break free and stuck in one of the blood vessels leading to the brain
Brain cells die from lack of oxygen
Can also occur when a weakened blood vessel in the brain bursts
Prevention - These disorders are easier to prevent than cure
Exercise, weight control, sensible diet and not smoking seem to be the best ways to keep
the heart healthy
Lymphatic System
A network of vessels called the lymphatic system
Collects the fluid that is lost by the blood and returns it to the circulatory system
Along the length of the lymph vessels are small enlargements called lymph nodes
They act as filters that trap bacteria and other microorganisms; they can become enlarged
as a result
Respiratory System
Two meanings: when glucose and oxygen are converted into CO2, water and ATP into the
mitochondria
Oxygen and CO2 are exchanged between cells, the blood and air in the lungs
Nose, pharynx, larynx, trachea, bronchi and lungs
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Nose
Filters dust particles in the air
Hairs lining the entrance to the nasal cavity traps large dust particles
Mucus, produced by cells lining the system, moistens the air and traps inhaled particles
Cilia sweeps trapped particles and mucus away from the pharynx
The mucus is either spit out or swallowed
Airflow
Air moves from the nose to a tube at the back of the throat called the pharynx
This is the passageway for both air and food
When food is swallowed, a piece of cartilage called the epiglottis covers the trachea
-Trachea - Tube from pharynx
-Vocal Cords - Two highly elastic folds of tissue in the larynx. When the muscles pull the
chords together, the air moving between the folds causes the chords to vibrate
Air moves the trachea and enters two large passageways n the chest cavity called the bronchi
(Each bronchus leads to the lungs)
In each lung, the large bronchi subdivides into smaller bronchi which lead to even smaller
bronchi called bronchioles
The bronchi and bronchioles are surrounded by smooth muscles that regulate the size fo the
passageways
Alveoli - Tiny air sacs at the end of the bronchioles and are grouped together like
grapes. A delicate network of capillaries surrounds each alveoli
This is where the exchange of oxygen and CO2 happen within the blood
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Gas Exchange
Oxygen diffuses through the inner surface of the alveoli and through the capillary to the blood
CO2 diffuses in the opposite direction
Very efficient process: inhaled air is 21% oxygen and .04 CO2
-Exhaled air is 15% oxygen and 4% CO2
Breathing
The movement of air into and out of the lungs
Lungs have no muscles attached to them so the large flat muscle at the bottom of the chest
cavity is called the diaphragm
Because the cavity is sealed, this causes a vacuum and atmospheric pressure causes air to rush
to the lungs
The system works because the cavity is sealed and if it is punctured, then it is very difficult to
breathe
Breathing is controlled by the amount of CO2 in the blood, not oxygen
Diseases
Asthma - Constriction of the bronchioles caused by allergens or exercise
Emphysema - Loss of elasticity in the lungs
Bronchitis - Bronchi are swollen and filled with mucus
Lung Cancer - Particular deadly because it easily spreads to other locations (It metastasizes or
spreads), mostly caused by smoking or asbestos
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Excretion
Metabolic waste is ousted
-CO2 is a waste of cellular respiration
-Water is a waste of cellular respiration and dehydration synthesis
-Mineral salts are produced by many processes
-Nitrogenous wastes
-Result of metabolism of proteins and when proteins are used in cellular
respiration
Ammonia: Very toxic
Urea: Less toxic
Uric Acid: Generally non-toxic
Results
Toxic materials are released by animals
Toxic materials are sealed and stored in the vacuoles of plants
Non-toxic wastes are retained, released, or recycled in other metabolic activities
Human Excretory System
Two kidneys on either side of the spinal column near the lower back
Two ureter tubes that leave each kidney and cary urine to the bladder
-Bladder - Where urine is stored
-Urethra - Is the tube in which urine travels to leave the body
Kidney
Made of two parts
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-Inner: The renal medulla
-Outer: The renal cortex
Functional unit of the kidney is called the nephron (1 million nephrons in each kidney)
Kidney Function
Waste containing blood enters the kidney through the renal artery
Blood travels through the kidney and urea and other wastes & water are filtered out as urea
The cleaned filtered blood is returned to circulation through the renal vein
Blood Purification
A complex mechanism that involves three distinct processes
I. Filtration
II. Reabsorption
III. Secretion
Filtration
Occurs in the Glomerulus
Diffusion causes substances to leave the blood and enter the Bowmans Capsule
Water, salt, glucose, amino acids and urea are filtered
Proteins and blood cells remain in the the blood because they are too large to diffuse
Reabsorption
The kidneys play an important role in homeostasis; they regulate blood volume, water content,
blood pH, and remove wastes from the body
If anything goes wrong, serious medical problems can ensue; humans can only live with one
kidney
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If both kidneys fail there are two options:
Transplant from healthy, compatible donor
Dialysis blood is removed and pumped through a machine that does the work of a nephron
(Expensive and time consuming - 3 times a week for several hours)
Immune System
Homeostasis - An organisms homeostasis is constantly threatened (Failure to respond can
result in disease or death)
Agents of Disease: V
-Viruses - Common Cold, Chicken Pox, Influenza
-Bacteria - Tetanus, Meningitis, Strep Throat
-Fungi - Athletes foot, ringworm
-Parasites - Protists - Malaria, African Sleeping Sickness
- Worms - Tapeworm
Factors of Disease
Many show up right away or not show up for many years
Inheritance, Toxic Substance, Poor Nutrition, Organ Malfunction, Personal Behavior
Person-to-Person (Through coughing, sneezing and physical contact or sexual
transmission)
Contaminated food or water
Exposure to an infected animals (Vectors- Insects tat spread disease via bite)
First Line of Defense
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A nonspecific response like skin which is the most important nonspecific response. This is the
barrier that keeps pathogens out of the body (even a small cut can become infected)
Pathogens can enter through the mouth and nose
Mucus in your nose and throat trap viruses and bacteria
Cilia push them away from lungs
Stomach acid and digestive enzymes destroys pathogens
Body secretions including mucus, saliva. sweat and tears contain lysozyme (breaks down
cell walls of bacteria)
Second Line of Defense
Inflammatory response (When pathogens enter the body and release toxins)
Blood vessels near the infection site grow larger and white blood cells leak into the infected
area
-Phagocytes (Macrophages) - White blood cells that engulf and destroy pathogens
-B Cells - Produce antibodies
-Killer T Cells - Attach to and kill infected cels
-Memory B and T Cells - Remain after an infection, ready to kill the pathogen before you
get sick if you are ever exposed again
Fever
The immune system releases chemicals that raise the body temperature
Many pathogens can only survive in a narrow temperature range
This slows or stops their growth and speeds up metabolism in the body to repair damaged
cells
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Specific Defenses
If a pathogen gets past the nonspecific defense, the body starts a defense called the immune
response.
The substance that triggers this response is an antigen
-A carbohydrate, lipid or protein on the outside of the pathogen that triggers the immune
response
Humoral Response
Carried out by B Lymphocytes (B Cells)
They produce antibodies
-A protein that helps destroy pathogens and are Y shaped and have identical binding sites
-Antibodies attach to pathogens and mark them for phagocytes and other white blood
cells (Keeps them from entering other cells)
Antibody Production
Specific for each pathogen; B cells each create a different antibody
When infected with a pathogen, the B cell that produces and makes plasma cells, also produces
the specific antibody needed to destroy the pathogen
T Lymphocytes (T Cells) Assist the body
Cell Mediated Immunity
Body cells infected with a pathogen must also be destroyed by T Cells
Organ Transplant Rejection
Killer T cells cause problems during organ transplants. They see the new organ as foreign
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They damage or destroy transplanted organs this is called rejection. To prevent rejection
transplant patients are given drugs to suppress the immune system. This leaves the patients
open to other infections.
Permanent Immunity
Once the body has been exposed to a pathogen, memory B and T cells remain. They are
capable of producing the specific antibody to the pathogen before you ever get sick
Active Immunity
1. Once the body has been exposed to a pathogen memory B cells and T cells remain. They
are capable of producing the specific antibody to the pathogen before you ever get sick.
This is why you can only get certain diseases once in a lifetime
2. Injection of weakened or dead forms of a pathogen is called vaccination. Vaccines cause
the body to produce memory B and T cells without having been infected with the disease
Passive Immunity
1. Travelers are sometimes injected with antibodies produced in animals to give them
protection from certain disease
2. Antibodies can be passed from mother to child through the placenta and through breast
milk
Disorders
1. Allergies happen when an allergen attaches to a type of immune cell called a mast cell
which releases histamine. Histamine causes the sneezing, runny eyes and nose associated
with an allergy. Antihistamines are drugs that counteract histamine.
2. The immune system needs to recognize your own tissues and cells as self in order to
work effectively. When the body makes a mistake and attacks cells of the body it is an
autoimmune disease
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3. Acquired Immune Deficiency Syndrome or AIDS happens when one is infected with the
Human Immunodeficiency Virus or HIV. The HIV replicates in helper T cells which
destroys them. This makes the immune system unable to fight off other diseases
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