BGM1004/L09 Mitosis & Meiosis

Question 1

What are the products of mitosis?

Answer 1

2 genetically identical daughter cells

Question 2

What is mitosis necessary for? (4)

Answer 2

Embryonic development
Replacement of skin cells
Wound healing
Production of reticulocytes

Question 3

What is the result of uncontrolled rounds of mitosis?

Answer 3

Tumour formation

Question 4

Name the 3 phases of interphase.

Answer 4

G1, S & G2

Question 5

What occurs during G1?

Answer 5

Growth phase in which biosynthesis activities increase in preparation for DNA synthesis

Question 6

What occurs during S phase?

Answer 6

DNA replication

Question 7

When does G2 occur?

Answer 7

Lasts until mitosis begins

Question 8

What is a kinetochore? (2)

Answer 8

Protein structure located at centromere
Attachment point for mitotic spindle

Question 9

What are spindle fibres? (2)

Answer 9

Formed from microtubules that run between poles of a cell
Create axis for separation of chromosomes

Question 10

What is a centriole?

Answer 10

Cytoplasmic organelle composed of 9 groups of microtubules serving as foci for mitotic spindle fibre gneration

Question 11

What is a centrosome?

Answer 11

Region of cytoplasm containing pair of centrioles

Question 12

What occurs during G2?

Answer 12

Chromosomes are extended

Question 13

What occurs during Prophase of mitosis?

Answer 13

Chromosomes condense
Centrioles divide and move apart

Question 14

When do chromosomes become recognisable as double structures?

Answer 14

Prometaphase

Question 15

What occurs during prometaphase of mitosis? (2)

Answer 15

Centrioles reach opposite poles
Spindle fibres form and attach to kinetochore

Question 16

What occurs during metaphase of mitosis?

Answer 16

Centromeres align on metaphase plate

Question 17

What occurs during anaphase of mitosis?

Answer 17

Centromeres split
Daughter chromosomes migrate to opposite poles

Question 18

What occurs during telophase of mitosis? (3)

Answer 18

Daughter chromosomes arrive at poles
Chromosomes decondense
Nuclear envelope forms

Question 19

What are the products of meiosis?

Answer 19

4 genetically different gametes

Question 20

Give the 5 stages of Prophase I in meiosis.

Answer 20

Leptonema
Zygonema
Pachenema
Diplonema
Diakinesis

Question 21

What occurs during Leptotene of meiosis?

Answer 21

Duplicated chromosomes start to condense

Question 22

What occurs during Zygotene of meiosis?

Answer 22

Synapsis begins

Question 23

What occurs during Pachytene of meiosis?

Answer 23

Synapsis complete
Crossing over

Question 24

What occurs during Diplotene of meiosis? (2)

Answer 24

Synaptonemal complex disappears
Chiasma visible

Question 25

What occurs during Diakinesis of meiosis?

Answer 25

Bivalent ready for metaphase

Question 26

What is the frequency of crossing over in humans?

Answer 26

Occurs at least once in each chromosome arm

Question 27

What forms between paired homologous chromosomes in meiosis?

Answer 27

Synaptonemal complex (nucleoprotein 'zipper')

Question 28

What occurs during Metaphase I of meiosis?

Answer 28

Alignment of tetrads on metaphase plate

Question 29

What occurs during Anaphase I of meiosis?

Answer 29

Half of tetrad (dyad) migrates to one pole, the other half to opposite pole (disjunction)

Question 30

What occurs during Telophase I of meiosis?

Answer 30

Nuclear membranes form around dyads Cell division

Question 31

What does Meiosis II follow?

Answer 31

Telophase I or short interphase

Question 32

What form do chromosomes take during Prophase II of meiosis?

Answer 32

Each dyad composed of sister chromatids

Question 33

What occurs during Metaphase II of meiosis?

Answer 33

Alignment of dyads on metaphase plate

Question 34

What occurs during Anaphase II of meiosis?

Answer 34

Half of dyad (monads) migrate to opposite poles

Question 35

What occurs during Telophase II of meiosis?

Answer 35

Cytokinesis

Question 36

What is the difference in meiotic divisions between sperm and egg cells?

Answer 36

In oogenesis, meiotic divisions may not be continuous

Question 37

Where does the first division in oogenesis arrest?

Answer 37

Prophase I

Question 38

What is aneuploidy?

Answer 38

Chromosome number is not an exact multiple of haploid number

Question 39

What is trisomy?

Answer 39

When 3 copies of a chromosome are present rather than 2

Question 40

What is trisomy 8?

Answer 40

Warkany syndrome

Question 41

What is trisomy 12?

Answer 41

Chronic Lymphocytic Leukemia

Question 42

What is Trisomy 13?

Answer 42

Patau Syndrome

Question 43

What is trisomy 18?

Answer 43

Edwards Syndrome