Exam 4 part 4

Question 1

What does the G1 checkpoint check for

Answer 1

Is the cell size is adequate
Nutrients are sufficient
Social signals are present
DNA is undamaged

Question 2

What does the G2 checkpoint check for

Answer 2

Chromosomes have replicated successfully
DNA is undamaged
Activated MPF is present

Question 3

How many M-phase checkpoints are there and what do they check for

Answer 3

2 checkpoints
1 checks that the chromosomes have attached to the spindle apparatus
the other checks that the chromosomes have properly segregated and MPF is absent

Question 4

Mature cells get permanently stuck in the G1 phase. What is this arrested state called

Answer 4

G0
Mature cells are nondividing cells
Cell stops dividing permanently

Question 5

What about cell cycles can vary among different cell types

Answer 5

The length of the cell cycle

Variation in the length of G1 phase is responsible for differences

Question 6

In the simplest way possible, how would you describe to someone what cancer is

Answer 6

Out of control cell division due to cell cycle checkpoints failing (usually G1)

Question 7

What two types of defects can cancerous cells have

Answer 7

Defects that make the proteins required for cell growth active when they should not be
Defects that prevent tumor suppressor genes from shutting down the cell cycle

Question 8

what is the difference between homologs and sister chromatids

Answer 8

Homologs consist of 1 paternal chromosome and 1 maternal chromosome (1 from mom and 1 from dad) that are similar in size, shape and gene content
Sister chromatids are two identical chromatid copies in a replicated chromosome

Question 9

what is a bivalent (or tetrad)

Answer 9

Homologous replicated chromosomes that are joined together during prophase I and metaphase I of meiosis

Question 10

At the end of Meiosis I, are we left with 2 diploid or haploid cells

Answer 10

haploid

Question 11

At the end of Meiosis II, are we left with 4 diploid or haploid cells?
Haploid

Answer 11

haploid