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194 Cards in this Set
- Front
- Back
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LECTURE 1
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LECTURE 1
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Three pioneers of evolution
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Darwin
Wallace Huxley |
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Darwin Wallace and Huxley believed in
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gradualism - gradual and continual evolution
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Who promoted catastrophism and what is it
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Agassiz
creation after catastrophic events |
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Evolution is based off of what concept
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heredity
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what is heredity
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passing down of traits
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what is the study of heredity
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genetics
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Who is the father of modern genetics
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Mendel
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where did Mendel study genetics
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in peas
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Mendel's 1st law
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Law of Independent Segregation
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What does the law of Independent Segregation deal with
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alleles of the same gene
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The law says that
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dominate and recessive alleles segrate independently
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Mendel's 2nd law
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Law of Independent Assortment
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Law of independent Assorment deals with
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alleles from different genes
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The law says that
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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
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ASK FOR HELP ON THE CROSSES
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ASK FOR HELP ON THE CROSSES
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Incomplete dominance means
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allels of the same gene are not completely dominant or recessive
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Polygenic traits means
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More than one gene can contribute to a single trait
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LECTURE 2
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LECTURE 2
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What did Sutton postulate
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That the units of heredity (genes) reside of chromosomes
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Who proved Suttons theory that genes were on chromosomes
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Morgan
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How did Morgan observe this
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By looking at the eye color of drosphilla
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how do Genes on different chromosomes behave during meiosis
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independantly
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how do genes on the same chromosome assort?
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not independently
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These genes that do not undergo random assortment are called
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linked genes
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During meiosis , genes on homologous chromosomes
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cross over
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What is the result of crossing over
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the two chromatids break at the points of contact and fuse a portion of the other
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This whole process of crossing over is known as
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recombination
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Genes located close together on a chromosome will
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assort with one another more regularly
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Genes located close together on a chromosme have a
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high recombination frequency
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Who was the first describe this process of crossing over?
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Janssens
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Who accuatlly proved Janssens hypothesis of crossing over ?
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McClintock and Creighton
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How did McClintock and Creighton show that Chromosomes actually break and rejoin
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they used visible tags (knob and extrachromosomal material) in maize to confirm meiotic crossing over
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The order of people for Heredity
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Sutton (theory genes are on chromosome)
Janssens (theory- genes cross over) Morgan et al (theory- Genes close together assort more) McClintock&Creighton (proof- maize) |
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LECTURE 3
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LECTURE 3
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3 reasons why they use model organisms
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- simple (easy to maintain, short generation time)
- accessible - Genetically manipulatable |
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Bacteriophage is useful as a model organism because
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viruses play a big role in disease
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Two ways bacteriophage reproduce
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Lysogenic and lytic cycle
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During the lysogenic cycle what happen
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The phage incorporates instelf into the genome
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once it has incorporated itself into the genome what happens
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it is replicated passively
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What are the daughter cells then called
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lysogens
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What happens in the lytic stage
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The bacteria is expressed and produces more phage
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once there is a lot of phage in the cell what happens
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the cell lysis and releases more phage
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four things bacteriophage has been used to study
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1- recombination
2- cell attachment 3- lytic/lysogenic infections 4- DNA transfer |
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Yeast as a model organism: who discovered that yeast is responsible for fermentation
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Pasteur
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Why is yeast useful?
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it has many stages of life, so it is useful to study mechanism that control each stage of the life cycle
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What is homologous recombination?
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crossing over
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Where should homologous recombination be done?
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haploid cells
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How were homologous recombination methods used in yeast as a MO
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ANy region of the yeast genome can be exchanged with a DNA sequence of choice
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Yeast cells do not split, they
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bud
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Yeast cells are not ideal for ? studies beause they are ?
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Developmental
Unicellular organisms |
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Yeast are also good for studding
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aging
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Two things that make Arabidopsis useful as a MO
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- Diploid, simple to manipulate for small studies
- Thousands in small area |
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Arabidopsis is the MO of choice for
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Plant biologist
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Nematodes were used as a MO mainly to study
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differentiated cell types (cells that actually gain function)
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What about the nematodes made this conveinient?
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They have transparent cells so you can directly observe them develop
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What is unique about nematodes?
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They have hermaphroditic reproduction
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what does hermaphroditic reproduction mean
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they have both male and femal sex organs and can creat a lot of self progeny
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In the C. elegans, the entire genome is
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sequenced
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Three things that are readily studied in C elegans
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Pain
Locomotion Cell Death |
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In Dorsphillia , Balancer chromosomes are
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chromosome that contain all of the same genes as the normal chromosomes, but they contain several regions where the genes are flipped
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Why are they important
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- 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 |
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Mice as a MO, easy to produce
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Transgenic mice
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Easy to isolate and work with mice
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stem cells
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What did Grittith do that helped show DNA is a hereditary material
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Heat killed S strain bacteria (Pathogenic)
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After he heat killed the S strain bacteria he
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Injected the S strain int the R strain (non pathogenic)
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What did he do with this S/R strain hybrid/
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Injected it inot mice
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what happened
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mice died
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this showed
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something changed non pathogenic bacteria to pathogenic bacteria
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The thing that changed the non pathogenic bacteria to pathogenic bacterim was called a
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transformation factor
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What did Avery do?
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He altered Griffiths experiment
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How did he alter the experiment
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he isolated the DNA from the heat killed S strain
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after he isolated the DNA from the heat killed S strain, what did he do
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He mixed the heat killed DNA with R strain and injected it into the mice
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what happened
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mice died
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this shows what
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that DNA is the transforming factor
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What did Hershey and Chase do?
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Proved that DNA was the transforming factor
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How did they prove this?
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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
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What did this do?
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Confirm that DNA is the hereditary material
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LECTURE 4
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LECTURE 4
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Who obtained the first diffraction pictures of DNA?
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Franklin and Wilkins
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How did they obtain these?
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X-ray crystallography
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Who used these diffraction pictures
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Watson and Crick
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what did Watson and Crick do with those images
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dtermined the double helix structure of DNA
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Three things DNA is composed of
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- Sugar
-phospahte -Base (A,G/C,T) |
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Each DNA nucleotide can be joined into a chain of nucleotides by its
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Phosphodiester bond
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How do these nucleotides combine
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The 3'C of one nucleotide binds to the 5'C of the next nucleotide
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DNA posses a ? backbone
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sugar-phosphate
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what helps form this sugar-phosphate back bone?
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phosphodiester bonds
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There are 4 bases which fall into which two categories?
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Purines
Pyrimidines |
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Purines are
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A and G
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Purines are ? rings
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2
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Pyrimidines are
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T and C
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pyrimadines have ? rings
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1
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What did Chargaff experimentally determine
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that the ratio of A:T is about 1 &
the ratio of C:G is about 1 |
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A forms how many hydrogen bonds with T?
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2 (AT2)
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C forms how many hydrogen bonds with G?
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3 (GC3)
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Why doesn't A form 3 H bonds with T?
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Because one of As hydrogens is attached to a carbon and C is not electronegative enough
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DNA is double straned, and the two strands are
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anti-parallel
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Three things you need for DNA synthesis
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DNA template
Nucleotides DNA Pol I |
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When trying to determine what DNA replication is, distributive strands had a
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mix of old and new DNA
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When put into the centrafuge, where did the Distributive DNA go?
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in the bottom with the heavey (N15) nitrogen
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What is the Semi-conservative strands made of
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had new (daughter) on top of old (mother) strands
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what happened when semi-conservative strands were put into the centrifuge
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there was a hybrid between heavy (N15) and light N(14)
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what is the conservative strands made of
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separate old and new double helixs
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what happend when the conservative strands were spun in the centrifuge
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There was nitrogen in the medium and high parts of the tube
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This shows that DNA replication is
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Semi-conservative
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2 difference between RNA and DNA
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-RNA has an extra OH group
-RNA associates with Uracil, DNA associates with Thymine |
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Another difference is that RNA is ? stranded and can ? on itself
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single
fold |
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DNA is read in the ? direction
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5'-3'
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DNA is called the ? strand
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sense
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What helps make RNA, and how does it do it
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- RNA Pol
- by using a strand of DNA as the template |
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this RNA that is formed from the DNA is called the ? strand
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Anti-sense
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RNA synthesis occurs in the
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5'-3'
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What are the steps of the central dogma?
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DNA-Transcripes-RNA-Translates-Protein
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3 types of RNA
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mRNA
tRNA rRNA |
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mRNA serves as
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the template for protein synthesis
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tRNA does what
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RNA adaptor that links mRNA to growing polypeptide
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? on the tRNA pairs with the ? on the mRNA
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Anticodon on the tRNA pairs with the codon on the mRNA
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rRNA is what
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Ribosomal RNA
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rRNA contains how many different subunits and whats unique about them
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2 and they are different sized
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What is the most abundent form of RNA
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rRNA
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what is the least abundent form of RNA
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mRNA
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Can mRNA vary in length
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mRNA can vary in length depending on the size of the gene that encodes it
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The sense strand is what? and it reads in what direction?
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DNA
5'-3' |
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The anti-sense strand is what? and it reads in the
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mRNA
3'-5' |
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Which DNA strand codes for the mRNA
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sense strand
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LECTURE 5
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LECTURE 5
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a codon is
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a group of 3 nucleotides
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nluceoltides are
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A C G U
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the codons encode for
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Amino acids
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how many codons are stop codons
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3
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DNA double helix is held together but these two forces
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Hydrogen bonds
plannar stacking |
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Proper base pairing only occurs when the purines are in the ? form and the pyrimidines are in the ? form
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amino
keto |
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purines need to be in the
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amino
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pyrimidines need to be in the
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keto
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opposite of amino is the
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imino
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opposite of keto is the
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enol
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two ways that DNA bonding is flexible
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-base flipping
- strand can separate and reassociate |
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what does base flipping do
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bases can flip out to allow modification
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how does the strands being able to separate and re associate make bonding flexible?
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you can denature (heat,strong acid,strong base) and break the H bonds of the DNA allowing it to form with different strands
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Melting temperature of DNA depends on 2 factors
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G:C content
salt concentration of the solution |
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Why does G:C content matter more than A:T content?
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There is more hydrogen bonding it G:C
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The more G:C content..
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the higher the boiling point because you have more hydrogen bonds to break
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The melting point (Tm) is ...
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the temp at which 50% of the DNA is single stranded
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Spectrophotometry helps us to see ...
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if the DNA is double or single stranded
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How does it do this
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it measure the amount of light absorbed by the DNA
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Which kind of DNA absorbs the most light?
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ssDNA
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what is this called (that ssDNA absorbs more light)
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hyperchromicity
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why does ssDNA absorb light better?
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dsDNA has base stacking so the light cannot get to it as well.
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what do Topoisomerases do
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they break DNA strands to help unwind them
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Does Topo 1 require ATP, and how many cuts doe it make
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YEs
1 |
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Does Topo 2 require ATP, and how many cuts does it make
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No
2 |
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Topos main job is to do what to the DNA
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Unwind its supercoil
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Topo 1 is monomeric meaning
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only one protein is needed to grab a strand
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Topo 2 is different because
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it grabs two strands so it need between 2-4 subunits to grab the strands
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Order of fastest to slowest which DNA moves in the elctrophoresis
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Supercoiled
Linear Relaxed, nicked circular |
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LECTURE 6
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LECTURE 6
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Diploid cells have
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two copies of 'Homologs' of each chromosome
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The larger the Genome size
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the more complex the organism
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The lower the gene density
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the more complex the organism
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what does gene density mean, and how does it relate to complexity
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- the less genes you have per stretch of DNA, the more complex the organism. these genes get larger in complex organisms
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Only eukarotic genes contain coding and non coding sequences called
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exons
introns |
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which ones are spliced out of the mRNA
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introns
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This results in a ? mRNA
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shorter
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DNA replication begins at ? on the ?
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Origin of Replication (ORI)
chromosome |
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Telomeres are are found where
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the end of the chromosome
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The Telomeres have two jobs
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- 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 |
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What is a kinetochore
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it is located on the centromere and it is responsible for grabbing the spindle fibers
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what is a centromere
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where the kinetochore is
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How many centromeres does one Chromosome have
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1
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What if the chromosome had two centromeres?
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the chromosome wouldbreak in half
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The larger the centromere
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the more complex the organism
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Two stages of the cell cycle
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Interphase
mitosis |
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interphase is composed of three phases
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G1
S G2 |
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in G1 phase
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cells undergo growth and metabolism
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in S phase
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Cells replicated their DNA
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How does this happen
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a double stranded chromosome is replicated.
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what is this result
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we have two pairs of chromosomes, each having one old and one new strand
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These pairs are held together by
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cohesion
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The two pairs are called
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sister chromatids
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The single pairs are referred to as
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homologs
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During Mitosis
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sister chromatids separate
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Mitosis: Prophase
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DNA begins to condense
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Mitosis: Metaphase
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Chromosomes line up along the middle
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Mitosis: Anaphase
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Sister chromatids are pulled towards opposite ends
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Mitosis: Telophase
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The parental cell begins to separate
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Mitosis: Cytokinesis
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When the two daughter cells separate
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Meiosis is different then mitosis because it undergoes
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meiotic interphase
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what is that
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where crossing over is doen
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Meiosis 1: metaphase 1
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the homologs (not sisters) are pulled to opposite sides
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meiosis 1: Anaphase 1
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The homologs are pulled away more
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meiosis II: Metaphase II
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the sister chromatids are separated
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Meiosis II: Anaphase II
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the sister chromatids are more separated
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Meiosis is the process by which a ? cell gives rise to a ? cell
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Diploid
Haploid |
