Chromosome Segregation

Question 1

Are germ cells haploid or diploid?

Answer 1

Haploid, 23 chromosomes

Question 2

Are somatic cells haploid or diploid?

Answer 2

Diploid, 46 chromosomes

Question 3

Basic phases in cell cycle

Answer 3

1. Interphase
2. M phase (mitosis)

Question 4

What happens in interphase?

Answer 4

Replication, where homologous chromosomes that are very similar to one another, replicate

Question 5

Main processes of prophase?

Answer 5

• chromosomes condense
• nucleolus disappears
• centrioles move to poles
• spindles begin to form
  -nuclear membrane breaks down

Question 6

Late prophase/ prometaphase

Answer 6

Movement of chromosomes to center of cell

Question 7

During which phase of the cell cycle does chromosomal DNA replicate?

Answer 7

Interphase

Question 8

Main processes of metaphase?

Answer 8

chromosomes align at equatorial plane of the cell, mitotic spindle formation

Question 9

Main processes of anaphase?

Answer 9

Sister chromatids split.
- chromosomes move to poles of cell
- cell begins to elongate
- cleavage furious starts

Question 10

Main processes of telophase?

Answer 10

Chromosomes reach poles.
- nuclear membrane reforms
-chromosomes de condense
-nucleoli reform
-spindle fibers disappear
-cleavage furrow continues

Question 11

Main processes of cytokinesis?

Answer 11

Completion of cleavage furrow and production of 2 cells

Question 12

During which phase do chromosomes condense as part of the cell cycle?

Answer 12

Prophase

Question 13

Chromosomes align at equatorial plane of the cell during telophase T/F?

Answer 13

False

Question 14

Difference between mitosis and meiosis?

Answer 14

Meiosis only occurs in germ cells, produces gametes, involves two sequential cells divisions without DNA replication

Question 15

Meiosis I

Answer 15

Reduction division, segregation of homologous chromosomes. 2n –> n

Question 16

Meiosis II

Answer 16

Equational division. Same as mitosis EXCEPT going to 1N

Question 17

Meiosis Prophase I Stages

Answer 17

• leptotene
• zygotene
• pachytene
• diplotene
  diakinesis

Question 18

Leptotene

Answer 18

• Chromosomes begin to condense and become visible
• Thickened regions (chromosomes) appear

Question 19

Zygotene

Answer 19

• Chromosomes continue to condense and there is active pairing of chromosome threads between non-sister chromatids

Question 20

Pachytene

Answer 20

-Chromosomes become fully aligned

Question 21

Diplotene

Answer 21

• Aligned homologous pairs become less tightly aligned
• Chiasmata become apparent

Question 22

Chiasmata

Answer 22

point in chromosomes that cross over and share genetic info

Question 23

Diakinesis

Answer 23

• Compaction is completed and chromosomes are ready to be segregated

Question 24

Bivalent chromosomes

Answer 24

pair of connected homologous chromosomes

Question 25

What is the importance of meiosis?

Answer 25

1. Production of haploid cells by meiosis is critical for sexual reproduction.
2. Independent assortment of chromosomes during meiosis I produces diversity in offspring.
3. Recombination increases diversity by shuffling genetic information between chromosomes

Question 26

How many possible combinations can occur from 23 pairs of chromosomes?

Answer 26

8,324,608

Question 27

At the end of meiosis, the daughter cells contain diploid genome T/F?

Answer 27

False

Question 28

Meiosis can occur in sperm cells T/F?

Answer 28

True