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194 Cards in this Set

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LECTURE 1
LECTURE 1
Three pioneers of evolution
Darwin
Wallace
Huxley
Darwin Wallace and Huxley believed in
gradualism - gradual and continual evolution
Who promoted catastrophism and what is it
Agassiz
creation after catastrophic events
Evolution is based off of what concept
heredity
what is heredity
passing down of traits
what is the study of heredity
genetics
Who is the father of modern genetics
Mendel
where did Mendel study genetics
in peas
Mendel's 1st law
Law of Independent Segregation
What does the law of Independent Segregation deal with
alleles of the same gene
The law says that
dominate and recessive alleles segrate independently
Mendel's 2nd law
Law of Independent Assortment
Law of independent Assorment deals with
alleles from different genes
The law says that
Alleles of different genes sort randomly, they dont stick together. R is just as likely to end up with y as it would with Y
ASK FOR HELP ON THE CROSSES
ASK FOR HELP ON THE CROSSES
Incomplete dominance means
allels of the same gene are not completely dominant or recessive
Polygenic traits means
More than one gene can contribute to a single trait
LECTURE 2
LECTURE 2
What did Sutton postulate
That the units of heredity (genes) reside of chromosomes
Who proved Suttons theory that genes were on chromosomes
Morgan
How did Morgan observe this
By looking at the eye color of drosphilla
how do Genes on different chromosomes behave during meiosis
independantly
how do genes on the same chromosome assort?
not independently
These genes that do not undergo random assortment are called
linked genes
During meiosis , genes on homologous chromosomes
cross over
What is the result of crossing over
the two chromatids break at the points of contact and fuse a portion of the other
This whole process of crossing over is known as
recombination
Genes located close together on a chromosome will
assort with one another more regularly
Genes located close together on a chromosme have a
high recombination frequency
Who was the first describe this process of crossing over?
Janssens
Who accuatlly proved Janssens hypothesis of crossing over ?
McClintock and Creighton
How did McClintock and Creighton show that Chromosomes actually break and rejoin
they used visible tags (knob and extrachromosomal material) in maize to confirm meiotic crossing over
The order of people for Heredity
Sutton (theory genes are on chromosome)
Janssens (theory- genes cross over)
Morgan et al (theory- Genes close together assort more)
McClintock&Creighton (proof- maize)
LECTURE 3
LECTURE 3
3 reasons why they use model organisms
- simple (easy to maintain, short generation time)
- accessible
- Genetically manipulatable
Bacteriophage is useful as a model organism because
viruses play a big role in disease
Two ways bacteriophage reproduce
Lysogenic and lytic cycle
During the lysogenic cycle what happen
The phage incorporates instelf into the genome
once it has incorporated itself into the genome what happens
it is replicated passively
What are the daughter cells then called
lysogens
What happens in the lytic stage
The bacteria is expressed and produces more phage
once there is a lot of phage in the cell what happens
the cell lysis and releases more phage
four things bacteriophage has been used to study
1- recombination
2- cell attachment
3- lytic/lysogenic infections
4- DNA transfer
Yeast as a model organism: who discovered that yeast is responsible for fermentation
Pasteur
Why is yeast useful?
it has many stages of life, so it is useful to study mechanism that control each stage of the life cycle
What is homologous recombination?
crossing over
Where should homologous recombination be done?
haploid cells
How were homologous recombination methods used in yeast as a MO
ANy region of the yeast genome can be exchanged with a DNA sequence of choice
Yeast cells do not split, they
bud
Yeast cells are not ideal for ? studies beause they are ?
Developmental

Unicellular organisms
Yeast are also good for studding
aging
Two things that make Arabidopsis useful as a MO
- Diploid, simple to manipulate for small studies
- Thousands in small area
Arabidopsis is the MO of choice for
Plant biologist
Nematodes were used as a MO mainly to study
differentiated cell types (cells that actually gain function)
What about the nematodes made this conveinient?
They have transparent cells so you can directly observe them develop
What is unique about nematodes?
They have hermaphroditic reproduction
what does hermaphroditic reproduction mean
they have both male and femal sex organs and can creat a lot of self progeny
In the C. elegans, the entire genome is
sequenced
Three things that are readily studied in C elegans
Pain
Locomotion
Cell Death
In Dorsphillia , Balancer chromosomes are
chromosome that contain all of the same genes as the normal chromosomes, but they contain several regions where the genes are flipped
Why are they important
- surpress recombination
- allows you to keep a mutation in a place on a chromosome (not recombined away
- allows scientists to keep perfect stocks of mutationa
Mice as a MO, easy to produce
Transgenic mice
Easy to isolate and work with mice
stem cells
What did Grittith do that helped show DNA is a hereditary material
Heat killed S strain bacteria (Pathogenic)
After he heat killed the S strain bacteria he
Injected the S strain int the R strain (non pathogenic)
What did he do with this S/R strain hybrid/
Injected it inot mice
what happened
mice died
this showed
something changed non pathogenic bacteria to pathogenic bacteria
The thing that changed the non pathogenic bacteria to pathogenic bacterim was called a
transformation factor
What did Avery do?
He altered Griffiths experiment
How did he alter the experiment
he isolated the DNA from the heat killed S strain
after he isolated the DNA from the heat killed S strain, what did he do
He mixed the heat killed DNA with R strain and injected it into the mice
what happened
mice died
this shows what
that DNA is the transforming factor
What did Hershey and Chase do?
Proved that DNA was the transforming factor
How did they prove this?
marked DNA with radioactive phosphate and marked protein coat with radio active sulfate and they could track and see that radioactive DNA was passed on to bacteria
What did this do?
Confirm that DNA is the hereditary material
LECTURE 4
LECTURE 4
Who obtained the first diffraction pictures of DNA?
Franklin and Wilkins
How did they obtain these?
X-ray crystallography
Who used these diffraction pictures
Watson and Crick
what did Watson and Crick do with those images
dtermined the double helix structure of DNA
Three things DNA is composed of
- Sugar
-phospahte
-Base (A,G/C,T)
Each DNA nucleotide can be joined into a chain of nucleotides by its
Phosphodiester bond
How do these nucleotides combine
The 3'C of one nucleotide binds to the 5'C of the next nucleotide
DNA posses a ? backbone
sugar-phosphate
what helps form this sugar-phosphate back bone?
phosphodiester bonds
There are 4 bases which fall into which two categories?
Purines
Pyrimidines
Purines are
A and G
Purines are ? rings
2
Pyrimidines are
T and C
pyrimadines have ? rings
1
What did Chargaff experimentally determine
that the ratio of A:T is about 1 &
the ratio of C:G is about 1
A forms how many hydrogen bonds with T?
2 (AT2)
C forms how many hydrogen bonds with G?
3 (GC3)
Why doesn't A form 3 H bonds with T?
Because one of As hydrogens is attached to a carbon and C is not electronegative enough
DNA is double straned, and the two strands are
anti-parallel
Three things you need for DNA synthesis
DNA template
Nucleotides
DNA Pol I
When trying to determine what DNA replication is, distributive strands had a
mix of old and new DNA
When put into the centrafuge, where did the Distributive DNA go?
in the bottom with the heavey (N15) nitrogen
What is the Semi-conservative strands made of
had new (daughter) on top of old (mother) strands
what happened when semi-conservative strands were put into the centrifuge
there was a hybrid between heavy (N15) and light N(14)
what is the conservative strands made of
separate old and new double helixs
what happend when the conservative strands were spun in the centrifuge
There was nitrogen in the medium and high parts of the tube
This shows that DNA replication is
Semi-conservative
2 difference between RNA and DNA
-RNA has an extra OH group
-RNA associates with Uracil, DNA associates with Thymine
Another difference is that RNA is ? stranded and can ? on itself
single
fold
DNA is read in the ? direction
5'-3'
DNA is called the ? strand
sense
What helps make RNA, and how does it do it
- RNA Pol
- by using a strand of DNA as the template
this RNA that is formed from the DNA is called the ? strand
Anti-sense
RNA synthesis occurs in the
5'-3'
What are the steps of the central dogma?
DNA-Transcripes-RNA-Translates-Protein
3 types of RNA
mRNA
tRNA
rRNA
mRNA serves as
the template for protein synthesis
tRNA does what
RNA adaptor that links mRNA to growing polypeptide
? on the tRNA pairs with the ? on the mRNA
Anticodon on the tRNA pairs with the codon on the mRNA
rRNA is what
Ribosomal RNA
rRNA contains how many different subunits and whats unique about them
2 and they are different sized
What is the most abundent form of RNA
rRNA
what is the least abundent form of RNA
mRNA
Can mRNA vary in length
mRNA can vary in length depending on the size of the gene that encodes it
The sense strand is what? and it reads in what direction?
DNA
5'-3'
The anti-sense strand is what? and it reads in the
mRNA
3'-5'
Which DNA strand codes for the mRNA
sense strand
LECTURE 5
LECTURE 5
a codon is
a group of 3 nucleotides
nluceoltides are
A C G U
the codons encode for
Amino acids
how many codons are stop codons
3
DNA double helix is held together but these two forces
Hydrogen bonds
plannar stacking
Proper base pairing only occurs when the purines are in the ? form and the pyrimidines are in the ? form
amino
keto
purines need to be in the
amino
pyrimidines need to be in the
keto
opposite of amino is the
imino
opposite of keto is the
enol
two ways that DNA bonding is flexible
-base flipping
- strand can separate and reassociate
what does base flipping do
bases can flip out to allow modification
how does the strands being able to separate and re associate make bonding flexible?
you can denature (heat,strong acid,strong base) and break the H bonds of the DNA allowing it to form with different strands
Melting temperature of DNA depends on 2 factors
G:C content
salt concentration of the solution
Why does G:C content matter more than A:T content?
There is more hydrogen bonding it G:C
The more G:C content..
the higher the boiling point because you have more hydrogen bonds to break
The melting point (Tm) is ...
the temp at which 50% of the DNA is single stranded
Spectrophotometry helps us to see ...
if the DNA is double or single stranded
How does it do this
it measure the amount of light absorbed by the DNA
Which kind of DNA absorbs the most light?
ssDNA
what is this called (that ssDNA absorbs more light)
hyperchromicity
why does ssDNA absorb light better?
dsDNA has base stacking so the light cannot get to it as well.
what do Topoisomerases do
they break DNA strands to help unwind them
Does Topo 1 require ATP, and how many cuts doe it make
YEs
1
Does Topo 2 require ATP, and how many cuts does it make
No
2
Topos main job is to do what to the DNA
Unwind its supercoil
Topo 1 is monomeric meaning
only one protein is needed to grab a strand
Topo 2 is different because
it grabs two strands so it need between 2-4 subunits to grab the strands
Order of fastest to slowest which DNA moves in the elctrophoresis
Supercoiled
Linear
Relaxed, nicked circular
LECTURE 6
LECTURE 6
Diploid cells have
two copies of 'Homologs' of each chromosome
The larger the Genome size
the more complex the organism
The lower the gene density
the more complex the organism
what does gene density mean, and how does it relate to complexity
- the less genes you have per stretch of DNA, the more complex the organism. these genes get larger in complex organisms
Only eukarotic genes contain coding and non coding sequences called
exons
introns
which ones are spliced out of the mRNA
introns
This results in a ? mRNA
shorter
DNA replication begins at ? on the ?
Origin of Replication (ORI)
chromosome
Telomeres are are found where
the end of the chromosome
The Telomeres have two jobs
- Proteins on the Telomeres end allows the ends of chromosomes to be distinguished from ds breaks
- Telomeres allow the ends of the chromosomes to be relicated
What is a kinetochore
it is located on the centromere and it is responsible for grabbing the spindle fibers
what is a centromere
where the kinetochore is
How many centromeres does one Chromosome have
1
What if the chromosome had two centromeres?
the chromosome wouldbreak in half
The larger the centromere
the more complex the organism
Two stages of the cell cycle
Interphase
mitosis
interphase is composed of three phases
G1
S
G2
in G1 phase
cells undergo growth and metabolism
in S phase
Cells replicated their DNA
How does this happen
a double stranded chromosome is replicated.
what is this result
we have two pairs of chromosomes, each having one old and one new strand
These pairs are held together by
cohesion
The two pairs are called
sister chromatids
The single pairs are referred to as
homologs
During Mitosis
sister chromatids separate
Mitosis: Prophase
DNA begins to condense
Mitosis: Metaphase
Chromosomes line up along the middle
Mitosis: Anaphase
Sister chromatids are pulled towards opposite ends
Mitosis: Telophase
The parental cell begins to separate
Mitosis: Cytokinesis
When the two daughter cells separate
Meiosis is different then mitosis because it undergoes
meiotic interphase
what is that
where crossing over is doen
Meiosis 1: metaphase 1
the homologs (not sisters) are pulled to opposite sides
meiosis 1: Anaphase 1
The homologs are pulled away more
meiosis II: Metaphase II
the sister chromatids are separated
Meiosis II: Anaphase II
the sister chromatids are more separated
Meiosis is the process by which a ? cell gives rise to a ? cell
Diploid
Haploid