3/25 Mitosis and Meiosis Flashcards
are homologous chromosomes identical
no, they are not due to allelic variation
are sister chromatids identical in mitosis?
yes
What is the G1 phase of the cell cycle
this is where the cell acts normally and undergoes gene expression
what is important about chromosomes at S phase?
this is where the DNA content will double since sister chromatids develop
what are sister chromatids connected by
kinetochore proteins
how can the number of kinetochores be used for determining number of chromosomes
for every kinetochore that connects a sister chromatid, you have one chromosome
if a cell enters S phase with 2n DNA content, what will be it’s DNA content at the end of S phase
it will be 4n since the DNA content doubles
what happens to chromosome count at S-phase?
the chromosome number does not change, the DNA content will double
at what phase in mitosis does the DNA content change from 4n to 2n?
at telophase when the cell divides
what is the overall goal of mitosis
to produce exact copies of itself where all subsequent cells have identical genetic information
true or false, at the end of S phase, a cell has twice as many chromatids as thee are chromosomes in the G1 phase
true
if a human has 46 chromosomes in G1, how many chromosomes, chromatids, and pairs of chromatids are there at the end of S phase
there will be 46 chromosomes
92 chromatids
46 pairs of chromatids
in G1 and late M phase, what is one chromosome referred to
it means one chromatid
in G2 or early M phase, what does one chromosome refer to
it means one pair of sister chromatids
if you have 2n=4, how many chromosomes do you have and what is the haploid amount of chromosomes
you have 4 chromosomes total and the haploid amount is n=2
at G2, what happens to the centrioles/centrosomes?
they double
what is a microtubule organizing center
it is a region where the mitotic spindle will form and the mitotic spindle will attach to the kinetochore proteins on the chromatids
what is the role of the MTOC in pro-metaphase
the microtubules will attach to the sister chromatids on either side of the kinetochore and move the chromatids to the center plate
what is prometaphase defined by
the movement of chromosomes towards the center line
what is the kinetochore DNA made of?
repetitive DNA
what do the kinetochore microtubules not connect to?
they do not connect to the DNA, they will connect to proteins that surround the centromere and make up the kinetochore
when a microtubule connects with.a kinteochore at either side, what will occur
the chromosomes will be pulled to the metaphase plate
if 2n=6, how many pairs of sister chromatids will there be?
6
when comparing pre-metaphase in mitosis and meiosis, what is the key difference in how the chromosomes will align on the plate
in mitosis, the chromosomes will not line up exactly but in meiosis they will line up in an organized fashion
