Transcript Unit1.1Notes

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

QuickTi me™ and a TIFF (U ncompressed) decompressor are needed to see this picture.
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
The Greek Influence

QuickTi me™ and a TIFF (U ncompressed) decompressor are needed to see this picture.
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?
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 Biology
Others 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
Q ui ck Ti m e ™ an d a T I FF ( U nc om p r es se d) de co m pr e ss or ar e n ee de d t o
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


Four bases—adenine, thymine, cytosine, and
guanine, abbreviated A, T, C, and G— can be
strung together in billions of ways


Bases are part of larger structures, called
nucleotides, that form the building blocks of DNA.
Billions of coded instructions can be sent to cells
Nucleotides are groups of three bases that
“code” for the production of protein
Conceptual Issues and
Terminology

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






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
Conceptual Issues and
Terminology

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.
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


Eukaryotes - Plantae, Animalia, Protista and
Fungi


Cells have no internal membranes inside cell
Cells have internal membranes that help carry
out specific functions
All Cells have Cell Membrane, Cytoplasm,
DNA and RNA
Cell Barriers
Membranes 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
QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture.
QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture.
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
ER
Nucleus
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
 Plants sugar through
photosynthesis

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
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.