Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
48 Cards in this Set
- Front
- Back
|
what happens in the synthesis phase
|
the chromosomes are copied so you have sets of sister chromatin
|
|
|
what does 5' end in
3'? |
5'- phosphate
3'- sugar |
|
|
when the DNA is unzipped which strand is the leading and which strand in the lagging strand
|
lagging- 5' strand
leading- 3' strand |
|
|
how does the leading strand copy itself
|
Helicase unzips the DNA and SSB's help keep the DNA open so it doesn't snap back together
Primase puts down an RNA "primer" on the leading strand (about 10 nucleotides long) DNA polymerase III starts to lay down the matching bases to the DNA and make the other side of the DNA DNA polymerase I turns the RNA primer into DNA so it isnt RNA anymore Ligase attatches the DNA to the DNA made from the RNA |
|
|
how does the lagging strand copy DNA
|
Helicase unzips the DNA
Primase lays down an RNA primer on the 5' side of the strand so the DNA polymerase III knows where to start DNA polymerase III lays down the matching bases and starts to make okazaki fragments of DNA Primase lays down another primer farther along the strand so more okazaki fragments can be made DNA polymerase I turns the RNA primer into DNA Ligase attatches the okazaki fragments together by attatching the DNA made from RNA to the DNA |
|
|
in which direction can DNA polymerase III work?
|
from 5' to 3'
thats why you need to build the DNA backwards on the 5' side (since the strand you are building starts with 3' since DNA is antiparallel) |
|
|
what does Helicase do
|
it unzips the DNA and exposes the bases
|
|
|
what does primase do
|
it lays down an RNA primer so DNA polymerase III knows where to start
on the lagging strand the RNA primer lays down a primer that starts with 5' so the DNA polymerase can work |
|
|
what are okazaki fragments
|
since the lagging strand must be copied backwards (since DNA polymerase can only work from 5' to 3' and the lagging strand starts with 3') it must be copied in fragments---- each fragment of DNA made is called okazaki fragments
|
|
|
what are SSB's
|
Single Strand Binding Proteins
when Helicase is splitting the DNA apart SSB's hold the two strands apart so they won't snap back together |
|
|
what does DNA polymerase III and DNA polymerase I do?
|
DNA polymerase III--- it lays down the matching bases on the new strand of DNA --- it actually copies the bases
DNA polymerase I--- turns the RNA primer into DNA |
|
|
what does Ligase do?
|
it attaches the DNA made by DNA polymerase III to the DNA made from DNA polymerase I
|
|
|
what does semi conservative mean?
|
if when DNA is synthesized and the new DNA has one old strand from the original DNA and one new strand that was made it is called semiconservative
|
|
|
how long does an average cell live (includes mitosis)
|
a day
|
|
|
what is an example of a cell that lives in G0 phase
|
a nerve cell
G0 phase means it doesn't go through mitosis and it simply lives all through its life--- nerve cells never die |
|
|
why do cells divide
|
to replace old cells
growth to create a new organism (in asexual reproduction) |
|
|
what are the phases of the cell cycle
|
interphase--- G1 (growth 1) S (synthesis) G2 (growth 2)
Mitosis---- Prophase, Metaphase, Anaphase, Telephase |
|
|
what is a homolog
|
a set of chromosomes that have 1 chromosome from each parent
|
|
|
what are sister chromatin
|
a chromosome with its exact copy attached to it
|
|
|
what are two chromosomes attached by?
|
a centromere
|
|
|
what do the chromosomes line up along during Mitosis in order for them to be pulled apart
|
spindle fibers
|
|
|
how long is a typical okazaki fragment
|
1-200 nucleotides long
|
|
|
how long is a typical RNA primer?
|
10 nucleotides long
|
|
|
what are body cells known as
|
somatic cells
|
|
|
what is the protein that DNA coils around called?
|
histones
|
|
|
what is cancer
|
abnormally growing and dividing cells
|
|
|
what is a mutation
|
a change in the gentic code of DNA
|
|
|
what is a mutagen
|
any agent that causes a mutation (tobacco, UV radiation)
|
|
|
excision repair
|
process that replaces mismatched bases (profreads the DNA)
|
|
|
how many PAIRS of chromosomes do you have
|
23
|
|
|
what is an autosome
|
a chromosome that codes for your traits (first 22 pairs are autosomes)
|
|
|
what is a sex chromosome
|
the X and Y or X and X
the set of chromosomes that determine your gender (23rd set) |
|
|
what is the difference between chromatin and chromosomes
|
chromatin-- uncondensed form of chromosomes-- unless your going through mitosis the chromosomes are always uncondensed
chromosomes-CONDENSEd form of chromatin----- during mitosis the chromosomes are condensed |
|
|
nucleosome
|
another word for chromosome- DNA wrapped around a histone
|
|
|
cytokinesis
|
the spitting of the cytoplasm (and the cell)--- last step of mitosis
|
|
|
ORDER of MITOSIS and steps and what happens
|
1) Prophase--- chromatin becomes condensed into chromosomes----nuclear envelope disappears-----centrioles move to opposite sides of the cell and spindle fibers start to grow
2) Metaphase---- chromosomes are attached to the spindle fibers and the chromosomes get pushed to the middle--- chromosomes line up along the center (equator) 3) Anaphase--- centromeres split apart and the retracting spindle fibers pull the sister chromosomes apart 4) Telophase and Cytokinesis--- chromosomes reach opposite ends and start to recoil into chromatin--- nuclear membrane and nucleolus is formed--- spindle fibers disappear---cytokinesis happens and the two cells split apart and divide |
|
|
Cleavage furrow
|
when an animal cell goes through cytokinesis it pinches the membrane and pinches into two cells
|
|
|
how does a plant cell go through cytokinesis
|
the cell wall is formed before the cell can split apart
|
|
|
what is p53
|
it prevents excessive cell growth--- it tells the cell to kill itself (end mitosis) if it senses a DNA mutation or if something goes wrong
|
|
|
how many times does meiosis cell go through mitosis
|
2 times - so one meiosis cell ends up in 4 daughter cells
|
|
|
what is a diploid? haploid? examples of each in meiosis
|
diploid- when a cell has all the complete homolog pairs ( you have one chrom. from ur mom and one from ur dad.) the original cell in meiosis is a diploid
haploid- when you don't have both of the chroms. from the original homolog pair---you only have one (moms or dads chrom.) attatched to its sister chrom. ----a meiosis cell that is going through metaphase for the second time is a haploid |
|
|
when do you see tetrads and what are they?
|
tetrads are only seen in the original cell of meiosis---- there are four chromosomes in a tetrad (a side of a homolog and its sister chrom. and the other side of the homolog and its sister chrom)
|
|
|
what is a gemete
|
the result of meiosis (sperm or egg) they are not genetically identical to their parent cell
|
|
|
what is the BIG difference between mitosis and meiosis
|
the resulting cells of meiosis are not genetically identical to their parent cell---this creates genetic diversity for the zygote
in mitosis the whole point is to produce two identical daughter cells that are identical to the parent |
|
|
how many times does the DNA duplicate in meiosis
|
ONCE although it goes through mitosis twice
|
|
|
when is the only time the DNA is copied in meiosis
|
in interphase of the original cell
|
|
|
what is a tetrad
|
homologs with their sister chromatids attatched---there are four chromosomes in a tetrad
|
|
|
what is crossing over
|
when two homologs are in PROPHASE ONE OF MEIOSIS ONLY they exchange info and genetic info (putnit squares)---- this creates genetic variety
|
