L9 Mitosis and Meiosis

Question 1

Chromosome act as the vehicles that must…

Answer 1

Pass on genetic information accurately

Question 2

Mitosis produces…

Answer 2

2 genetically identical daughter cells

Question 3

Mitosis is the basis for asexual reproduction in…

Answer 3

Single-celled eukaryotes

Question 4

In humans mitosis plays an important part in (4)…

Answer 4

• Embryonic development
• Skin cells
• Wound healing
• Reticulocytes (immature red blood cells)

Question 5

Uncontrolled mitosis can lead to…

Answer 5

Tumor formation

Question 6

In mitosis a cell goes from Xn to Yn which divides to form two Xn cells.

Answer 6

X = 2
Y = 4

Question 7

The 5 phases of mitosis are:

Answer 7

1. Prophase
2. Prometaphase
3. Metaphase
4. Anaphase
5. Telophase

Question 8

The kinetochore is…

Answer 8

The protein at the centromere, which serves as an attachment point for the mitotic spindles

Question 9

Spindle fibres are…

Answer 9

Microtubules running between the two poles of the cell, creating the axis for separation of the chromosomes

Question 10

The centriole generates spindle fibres and has a (structure)…

Answer 10

9 triplet microtubule structure

Question 11

Interphase is divided into 4 possible phases…

Answer 11

• G0
• G1
• S
• G2

Question 12

Meiosis is the cell division which produces…

Answer 12

Gametes (sperm, egg cells, spores, pollen)

Question 13

Unlike mitosis, meiosis results in (2)…

Answer 13

Haploid gametes (1n) and genetic variability

Question 14

During meiosis I, genetic reassortment occurs through (2)…

Answer 14

‘Crossing-over’ and independent assortment

Question 15

The chiasma is the…

Answer 15

Physical connection between non-sister chromatids during meiosis I

Question 16

During interphase between meiosis I & II DNA replication ( occurs / does not occur / sometimes occurs )

Answer 16

Does not occur ❌

Question 17

Meiosis prophase I can be subdivided into 5 phases, these are…

Answer 17

1. Leptonema (Leptotene)
2. Zygonema (Zygotene)
3. Pachynema (Pachytene)
4. Diplonema (Diplotene)
5. Diakinesis

Question 18

Meiosis I, prophase I - 1. Leptotene

Answer 18

Duplicated chromosome starts to condense

Question 19

Meiosis I, prophase I - 2. Zygotene

Answer 19

Synapsis begins. Synaptonemal complex forms, forming a ‘bivalent’ (a.k.a ‘tetrad’)

Question 20

Meiosis I, prophase I - 3. Pachytene

Answer 20

Synapsis completed. Crossing over occurs

Question 21

Meiosis I, prophase I - 4. Diplotene

Answer 21

Chiasma becomes visible. Synaptonemal complex begins to disappear

Question 22

Meiosis I, prophase I - 5. Diakinesis

Answer 22

The nuclear envelope fragments

Question 23

Meiosis II is similar to…

Answer 23

Mitosis

Question 24

The production of male gametes is continuous. In contrast, oogenesis pauses at prophase I in the embryo, resuming…

Answer 24

Prior to ovulation (years later)

Question 25

Aneuploidy

Answer 25

Chromosome number is not an exact multiple of the haploid number

Question 26

Non-disjunction results in aneuploid gametes. Non-disjunction is…

Answer 26

The failure of chromosome pairs to separate

Question 27

Trisomy is a polysomy with…

Answer 27

Three chromosomes 3️⃣

Question 28

Trisomy 21 results in…

Answer 28

Down Syndrome

Question 29

The centrosome is comprised of…

Answer 29

A pair of centrioles

Question 30

When does crossing over occur?

Answer 30

Prophase I

Question 31

Why is crossing over important?

Answer 31

To increase genetic diversity