Exam 3 Flashcards
(41 cards)
During mitosis, when do the sister chromatids become daughter chromosomes?
Anaphase. During anaphase, centromeres split, and sister chromatids are pulled by the spindle fibers toward opposite poles of the cell to become daughter chromosomes.
Which is the first checkpoint in the cell cycle where a cell will be caused to exit the cycle if this point is not passed?
G1 checkpoint. It would need to make sure that there is enough nutrients, big enough cell size, social signals are present, DNA is undamaged for it to pass. If it does not pass, it goes to G0 state (like mature cells).
What stage of cell replication will be affected by a drug inhibiting shortening of microtubules?
Anaphase. ***
Why do neurons and some other specialized cells divide infrequently?
Stuck in G0 phase for a while because they are differentiated (due to cell signals)***
During which process does independent assortment of chromosomes occur?
Metaphase 1 sets up crossing over where it separates at Anaphase 1
When does the nuclear membrane disappear during cell division?
Prophase
Which protein moves chromosomes following their attachment of spindle microtubules?
kinetechores
How is metaphase characterized?
Sister chromosomes lining up in the at the metaphase plate and all the spindle fibers are lined up there
Which cytoskeletal proteins are involved in animal cell cytokinesis?
Actin and Myosin( pinches cell and creates cleavage furrow)
What happens to MPF once a cell completes mitosis?
During anaphase, an enzyme complex begins degrading MPF’s cyclin
subunit. MPF triggers a chain of events that leads to its own destruction. Phosphates wont be attached after mitosis completes so concentration decreases.
If M-phase checkpoint fails to happen, in which stage of mitosis would the cells be most
Metaphase
What happens to cell cycle progression if a cell has accumulated DNA damage?
If the DNA is physically damaged, the p53 protein either pauses the cell cycle(G1), or initiates apoptosis; programmed cell death
What are tumor suppressor proteins?
p53 is an example of a tumor suppressor; intitates apoptosis and makes sure destorys damaged cells. Damage to the p53 gene can
lead to uncontrolled cell division
What are haploidy and diploidy?
haploidy (n) is the amount of distinct chromosomes that one person is supposed to have while diploidy (2n) is two times the amount of each chromosomes present.
What is aneuploidy?
It is an abnormal amount of chromosomes that a person has (humans have 46 but aneuploidy has 43)
When chromosome crossover takes place?
Late Prophase 1
When does the synaptonemal complex disappear during meiosis?
late prophase of meiosis I
What are homologous chromosomes?
4 non sister chromatids (2 X) attached to each other. Two chromosomes that have the same sequence of genes.
When do the sister chromatids separate from each other?
Anaphase 2
At what stage of meiosis does DNA replication take place?
Doesnt happen in mitosis/meiosis. Happens in S phase (interphase)
Why the offspring of sexually-reproducing animals are genetically different from their parents?
Because of crossing over and independent assortment and they get half the genetic information from each parent so it not going to be exactly the same as one parent.
What is karyotyping
a test to examine chromosomes in a sample of cells. This test can help identify genetic problems as the cause of a disorder or disease.
Why does the MPF activity decline at the end of mitosis?
Enzyme complex breaks it down **
At which stage independent assortment of chromosomes occurs?
Metaphase 1
