The Cell Cycle Flashcards
Chapter 3 (13 cards)
1
Q
What are the stages of the cells cycle?
A
- Interphase
- Mitosis (PMAT)
- Cytokinesis
2
Q
Describe interphase
A
- Majority of the cell life cycle
- Four sub-phases:
- G1
- G0
- S
- G2
3
Q
Describe G1 of Interphase
A
Vigorous growth and metabolism
4
Q
Describe G0 of Interphase
A
Cells permanently cease dividing
5
Q
Describe the S phase of Interphase
A
Growth and DNA replication (chromosomes are duplicated)
6
Q
Describe G2 of Interphase
A
Growth and final preparation for cell division
What happens after G2 if cells are not formed properly
7
Q
Describe DNA replication
A
- Occurs during interphase
- Helices untwists the double helix and exposes complementary chains
- DNA polymerase replicates DNA using the “old strand” as a template
- Strands are synthesized in opposite directions
8
Q
Describe the “early phase” of Prophase
A
- Chromosomes become visible (two chromatids joined together at a centromere)
- Centrosomes separate and migrate toward opposite poles
- Mitotic spindle and asters form
9
Q
Describe the “late phase” of prophase
A
- Nuclear envelope fragments
- Kinetochore microtubules attach to centromeres and draw them toward the equator of the cell
10
Q
Describe Metaphase
A
Centromeres of chromosomes = aligned at the equator (metaphase plate)
11
Q
Describe Anaphase
A
- Shortest phase
- Centromeres of chromosomes split simultaneously and each chromatid becomes a chromosome
- Chromosomes are pulled toward the poles by motor proteins of the kinetochores
12
Q
Describe Telophase
A
- Begins when chromosome movement stops
- Two sets of chromosomes uncoil to form chromatin
- New nuclear membrane forms around each chromatin mass
- Nucleoli reappear
- Spindle disappears
13
Q
Describe Cytokinesis
A
- Begins during late anaphase
- Actin microfilaments contract to for cleavage furrow (“draw-string”)
- Two daughter cells are pinched each with a nucleus and identical to the other cell
