Unit 1 Notes

Introduction to Genetics - A Review of Cells and Processes

Sponge 1

Describe in your own words, what is the study of genetics?

Define the following: DNA, RNA and Protein? How do they work together?

How are chromosomes, genes, and DNA related?

What do you think is the earliest genetic manipulation of living things? Next slide

Prehistory Times and Heredity (8000 B.C.)

Fossils provide evidence of domesticated animals and cultivated plants.Dogs, Camels, Horses, Corn, Wheat, Rice

• Cultivated for optimal cultural needs Provided evidence of artificial selection

The Greek Influence Hipparcus (500 B.C.) - Theory of Preformation - “Sex

cells” contain a complete miniature adult called the homonuculus. Physical Substance of offspring acquired from the body

of father & transported to offspring via semen Generative Forces directs the physical substance as

develops Humors act bear traits of physical substance The Hippocratic Oath - used today by Medical Doctors

as derived from the Hippocratic School of Medicine

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The Greek Influence Aristotle (384 B.C.) - A naturalist interested in Hippocrates

analysis of humans and heredity. Graduate of Hippocratic School of Medicine and leading

philosopher of his time Said male and female contained “vital heat”

• allowed offspring to “cook” in basic structure and capacities Females contributed half of hereditary sources and shaped

offspring combined with male contribution Essential difference between Aristotle and Hippocrates?

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Modern Biology William Harvey (1600 A.D.) - Extensive work on

circulatory system of animals. Trained Medical “Doctor” Theory of Epigenesis - Organism derived from

substances present in the egg• Substance develops into adult structures during

embryonic development• Structures such as organs not present in embryo,

but grow as development takes place Conflicted Theory of Preformation

Modern BiologyOthers and Their Work John Dalton (1808) - Atomic Theory Schleiden and Schwann (1830) - Microscopes and The Cell Theory Lois Pastuer (1850) - Theorem three of the cell theory disproved

the Spontaneous Generation Carlos Linnaeus (1710) - Fixity of Species=Plants and animals

remain unchanged in form from the moment of their appearance on Earth Binomial Nomenclature System of Classification still used today

Joseph Kolreuter (1750) - Work on tobacco and carnation plants. Crossbred two groups and derived a new hybrid form Supported the Law of Segregation, but because of his belief is special

creation never published

Modern Biology

Charles Darwin (1860) - On the Origin of Species - existing species arose by descent, with modification, from ancestral species The foundation to the Theory of Natural Selection

Natural Selection - the environment can support only so many offspring There are more offspring than the environment can support,

competition arises among them because of the numbers Surviving organisms are those with the heritable traits able to survive

and reproduce over those less-adaptive

Over long periods of time populations of organisms will show variation due to the pressure from the environment for organisms to obtain food, not become food and reproduce.

Finding food becomes a driving force for organisms to fit into places in the environment (habitat selection theory)

Modern Biology

Darwin lacked understanding of the genetic basis of variation Inheritance was the primary gap between theory and what is seen in

nature Variations in Animals and Plants under Domestication explained that

heritable variation through pangenesis and inheritance of acquired characteristics

Hypothesis of Pangenesis - Gemmules (humors) were physical traits acquired or lost and become heritable

Who did he reference for this hypothesis? Darwin borrowed hypothesis from Lamarck’s Doctrine of Use and

Disuse - organisms acquire or lose characteristics that then become heritable through population fitness

Modern Biology Gregor Mendel (1866)

Developed Transmission Genetics Postulates

Statistical studies of plant breeding data Factors in germ cells

(sperm and egg) transmit traits from parent to offspring over successive generations in patterns of heritability

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Conceptual Issues and Terminology

Genetics is the study of heredity and variation found in populations of living things.

Chromosomes are cellular structures containing genes. Chromosomes are made of DNA and proteins. Humans have 23 pairs of chromosomes in each

body cell, one of each pair from the mother and the other from the father.

DNA is an acronym that stands for Deoxyribonucleic Acid and DNA - molecule stores genetic information. DNA - strands of ribose sugars with nucleic acids. DNA - stored in nucleus of eukaryotic cells. Nucleoid region in cells serve as center for

reading genetic code into a physical trait

Conceptual Issues and Terminology Genetic code contains instructions that tell

cells what to do in units called genes The DNA code is written in an alphabet of

four chemical "letters" known as bases Bases are part of larger structures, called

nucleotides, that form the building blocks of DNA.

Four bases—adenine, thymine, cytosine, and guanine, abbreviated A, T, C, and G— can be strung together in billions of ways Billions of coded instructions can be sent to cells

Nucleotides are groups of three bases that “code” for the production of protein

Genes are codes for traits (what we see=phenotype) Made of sequences of nucleic acids that serve as a code = genotype, and

there are several versions (i.e. black, brown, red, etc) of a trait = allele Alleles may be a dominant or recessive version. Dominant alleles

usually express over recessive versions of the same trait

Given the right conditions (radiant energy such as sunlight) genes and whole parts of chromosomes can change their genotype and therefore decode into a different phenotype

A short gene change in genotype is called a gene mutation A whole change in chromosome genotype(s) is called a

chromosomal mutation

Conceptual Issues and Terminology

Conceptual Issues and Terminology Nucleic Acids - bio-chemicals that serve as the genetic code

within a strand of DNA Sequences of nucleic acids that code for a trait = genes Genes on chromosomes code for production of a protein Protein is the chemical substance contained in all living

things that serve as a structural component to cells or an enzyme for chemical reactions to take place

Proteins are made of smaller components called amino acids Enzymes are catalysts and most enzymes are proteins

Catalysts - chemicals made of protein that help chemical reaction in cells happen quickly. Without enzymes, life processes could not happen quickly and multi-cellular life (like humans) would not exist

DNA reproduces into two different types of cells. Somatic cells are cells that contain diploid or 2N sets of chromosomes. Sex cells are haploid that reduce chromosome number to N in ploidy

number. Mitosis - type of cell division by which somatic cells (2N cells) are

produced. Mitosis involves a replication and the production of identical copies of genetic material. One cell makes an identical copy of itself.

Meiosis is the type of cell division by which germ cells (eggs and sperm) are produced. Meiosis involves a reduction in the amount of genetic material. One cell makes four smaller, half chromosome number cells.

Conceptual Issues and Terminology

Investigative Approaches

Transmission Genetics - tracking patterns of inheritance of traits using Mendelian Laws and Principles Pedigree Analysis is a type of transmission genetics used to track traits

in a family of organisms Cytogenetics is the study of the chemical nature of chromosomes, their

reproduction and segregation using Mendelian Genetics Molecular Analysis - use of biotechnology to determine exact sequence of a

genotype Genomics - Uses molecular and cytogenetics to study all DNA related to an

organism and a population, their interactions and how those interactions relate to the phenotypic expression

Population Genetics is the study of gene pool phenotypes and genotypes Population Geneticists study the gain or loss of traits in populations of

organisms over time (Darwinian Principles) Forensics is a mix of all fields that profiles DNA in criminal cases

Cell Structure and Function

Types of Cells

Prokaryotes - Eubacteria and Archeabacteria Cells have no internal membranes inside cell

Eukaryotes - Plantae, Animalia, Protista and Fungi Cells have internal membranes that help carry

out specific functions All Cells have Cell Membrane, Cytoplasm,

DNA and RNA

Cell BarriersMembranes and Walls

Bacteria and Plants have cell walls Bacterial cell walls are made of peptidoglycan (a complex toxic

sugar substance) Plants cell walls are made of a chemical called cellulose (a complex

sugar substance) All cell types have cell membrane

Bacteria and plants have a cell wall and inside of cell membrane Animals, Fungus, Protists have a cell membrane, but no cell wall

Prokaryote Membrane Structures

Plant Membrane Structures

Cell Membranes

All cells have a cell membrane (or plasma membrane) The cell membrane is made of protein and fat

(=phospholipid) Fats are linked together with gaps between them Gaps between proteins and fats in cell

membrane allow some things to move into the cell because of their size

• Property of cell membranes = selective permeability

Cell Membrane

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Purpose of the Cell Membrane

The purpose of the cell membrane is to maintain homeostasis Homeostasis is the process of maintaining a

relatively constant internal environment To do this a cell must get rid of waste and carbon

dioxide built up and allow sugars and oxygen into the cell

• Water is used to carry all objects across the membrane barrier (in and out)

Sponge 2

All living things share certain properties. List and describe the general cell structures

that all living things share. Explain the central dogma utilized by all

living things. Describe why it is important for geneticists

to know and understand cell structures and functions and the central dogma.

Central Dogma

Proteins are made of smaller units called amino acids Proteins are made by cells from RNA RNA is made from DNA, so the template for cells (=Central

Dogma) works like this:

DNA -> RNA -> Protein DNA are the instructions, RNA are the copies of DNA the cell

uses to make protein Three types of RNA help this process: mRNA, tRNA and rRNA Protein carries out the functions the cell needs. Here are some

functions:• Transport Carriers, Enzymes (help speed up chemical reactions in

cells), Structure Components, etc

DNA and the Nucleus

Bacteria have DNA, but it is not contained within a membrane Bacteria have a one, double stranded

circular chromosome made of DNA Eukaryotes’ DNA is stored in double strands

of chromatin (=chromosomes) contained within a centralized storage compartment held together by a membrane called the nucleus The nucleolus is another membrane

structure found within the nucleus and helps the nucleus provide a location for the production of RNA, while not getting in the way of DNA not in current use

NucleusER

Assembly and Transport Organelles in Eukaryotic Cells

Eukaryotes are very efficient at making protein and fat Fat is used for cell membrane structure and protein is used for

just about everything including structure of the cell membrane, transport and chemical reactions within the cell

The Endoplasmic Reticulum (ER) is responsible for making and refining protein and Fat

The Golgi Apparatus is responsible for packaging and telling the protein where it is going in the cell.

The Rough ER assembles the protein, the Smooth ER refines then, preparing them for their jobs, and the Golgi Apparatus packages it

• The Smooth ER also makes and refines fats for the cell membrane

Protein Production

1. Nucleus. 2. Nuclear pore. 3. Rough endoplasmic

reticulum 4. Smooth endoplasmic

reticulum 5. Ribosome on the rough ER 6. Proteins that are

transported 7. Transport vesicle 8. Golgi apparatus 9. Cis face of the Golgi

apparatus 10. Trans face of the Golgi

apparatus 11. Cisternae of the Golgi

apparatus.

Cytoplasm

Cytoplasm is a clear, gelatinous fluid inside all cells

Cytoplasm provides a fluid internal environment that allows for the movement of DNA, RNA and other chemicals needed to carry out cell functions.

Storage

Given the relative quantity of sugar produced they must sore sugars into locations inside cells Vacuoles in plant cells are temporary

storage containers for sugar, enzymes and even waste

Plants sugar through photosynthesis

Policing the cell

Lysosomes are organelles that contain digestive enzymes Removes and “digests” old organelles

Peroxisomes are organelles similar to lysosomes Removes and “digests” complex sugars in

the cell into small sugars that can be used as an energy source

Carbon Metabolism

Chloroplasts - Capture light energy and produce sugar for use in energy production for the cell A Chloroplast is one type of plastid. Plastids are

organelles that either make or store sugars Mitochondria - Use sugar from the Chloroplasts

to produce energy for the cell ATP (adenosine triphosphate) - Energy made by

mitochondria. ATP is Chemical Energy for the cell Chemical that all living things use for energy

Skeleton For Cells

Actin filaments made of protein hold the cell membrane into place Actin filaments link together to form the

cytoskeleton Microtubules and microfilaments are made of

protein and are the skeleton that hold organelles into place and help move organelles when the cell divides into two cells during cellular replication

Cell Motility

Some cells have tails and projections that help them move around in their environment. Our cells obviously do not move around like this, but some bacteria, some fungi, some plants and most protists do move around. A Flagella is made of protein and is a whip like tail used to move

the organism in it’s environment. Cilia are hair like projects that help the organism move.

• Most organisms have only one flagella, but many cilia.

• The flagella is contained on the tail portion of the organism, whereas the cilia can be contained all around an organism.