Mitosis and Meiosis

Question 1

Describe the 4 main components of a chromosome

Answer 1

Telomere - end of the chromosome
Centromere - joins the two chromatids
P Arm - short arm
Q Arm - long arm

Question 2

Name the 4 centromere positions

Answer 2

• Metacentric
• Submetacentric
• Acrocentric
• Telocentric

Question 3

Give 3 characteristics of a homologous chromosome

Answer 3

• A chromosome with maternal and paternal DNA
• Genes can be variants (Alleles)
• Contain sister and non-sister chromatids

Question 4

Name the 5 stages of the Cell Cycle and a brief description of each

Answer 4

G0 - Rest phase
G1 - Cell contents (except chromosomes) are duplicated
S Phase - Each of the 46 chromosomes are duplicated (DNA synthesis)
G2 - Cell checks duplicated chromosomes for any errors
Mitosis - Cell replicates and becomes 2 daughter cells

Question 5

What is the product of Mitosis and why is it important?

Answer 5

• Produces 2 daughter cells with the same chromosomes as the parent cell
• Important in development and replacement of cells

Question 6

What are the 6 stages of Mitosis?

Answer 6

• Prophase
• Prometaphase
• Metaphase
• Anaphase
• Telophase
• Cytokinesis

Question 7

In which phase of Mitosis does the cytoplasm divide?

Answer 7

Cytokinesis

Question 8

In which phase of Mitosis do sister chromatids move to opposite poles?

Answer 8

Anaphase

Question 9

In which phase of Mitosis do the chromosomes condense?

Answer 9

Prometaphase

Question 10

Name 2 differences between Mitosis and Meiosis

Answer 10

• Mitosis produces 2 cells, Meiosis produces 4 cells
• Mitosis produces identical cells, Meiosis produces non-identical cells
• Mitosis involves 1 round of replication and 1 round of division, Meiosis involves 1 round of replication and 2 rounds of division

Question 11

What is the product of Meiosis?

Answer 11

4 haploid cells

Question 12

What process in Meiosis results in genetic diversity?

Answer 12

Recombination

Question 13

Are chromosomes duplicated or unduplicated in Metaphase I and Metaphase II

Answer 13

Metaphase I - Duplicated

Metaphase II - Unduplicated

Question 14

What is Spermatogenesis and how long does it take?

Answer 14

• 1 diploid spermatocyte becomes 4 haploid sperm

- Takes approximately 60 days

Question 15

What is Oogenesis and how long does it take?

Answer 15

• 1 diploid oocyte becomes 1 haploid egg and 3 polar bodies

- Takes 12-50 years

Question 16

What is a Karyotype?

Answer 16

The number and appearance of the chromosomes in the nucleus

Question 17

What is the karyotype of a normal, healthy male?

Answer 17

46, XY

Question 18

What is it called when there is an abnormal number of chromosomes in a cell?

Answer 18

Aneuploidy

Question 19

What causes Mitotic Disjunction?

Answer 19

Monosomy -Presence of only one chromosome is first post-zygotic division

Question 20

What is a non-mosaic karyotype and name a condition in which this occurs

Answer 20

• Presence of 2 or more cell lines caused by first post-zygotic division
• Downs’ Syndrome

Question 21

What is a Mosaic Karyotype ?

Answer 21

Presence of 2 or more cell lines in an individual due to later mitotic divisions

Question 22

When can Meiotic Disjunction occur and what does it result in?

Answer 22

• Can occur in Meiosis I or Meiosis II
• Results in Monosomy or Trisomy
• If it occurs in Meiosis II 50% are normal