Lecture 13 Class: Cell cycle and mitosis
While you wait for class to begin:
Fill in the following diagram with 2n = 4 chromosomes:
Starter:
Phosphodiester bonds are formed during:
A. G1 phase
B. S phase
C. G2 phase
D. M phase
Which of the following does _____________________________ during mitosis?
A. Replication of DNA
B. Separation of sister chromatids
C. Breakdown of the nuclear membrane
Lecture 13 Page 1
Stage
How many
chromosomes?
Cells in G1
46
Chromosomes
look like:
How many
sister
chromatids?
Ploidy?
2n or n
0
2n
In G2
Metaphase of
mitosis
Daughter cells
50
DNA Content
(arbitrary units)
The DNA content of nerve cells at G1, mature sperm, and gut
endothelial cells at G2 have been measured and plotted on the graph
below. Based on the data in the graph, which DNA sample is the nerve
cell?
A. Sample 1
B. Sample 2
C. Sample 3
40
30
20
10
0
1
2
3
Sample
1. homologous chromosomes?
2.
sister chromatids?
3. How many chromosomes before?
4. How many chromosomes after?
Lecture 13 Page 2
In Mitosis, chromosomes line up on the metaphase plate:
A. Where DNA replication occurs
B. As tubulin subunits are removed from the kinetochore microtubules
C. When kinetochore microtubules from opposite poles attach to sister chromatids
D. Before the nuclear membrane fragments
E. Due to transport by dynein motor proteins
Lecture 13 Page 3