Modes of Reproduction

Question 1

Define asexual reproduction

Answer 1

Is the process resulting in the production of genetically identical offspring from one parent without the fusion of gametes

Question 2

Advantages of asexual reproduction

Answer 2

• Only one parent required
• Fusion of gametes not required
• Beneficial qualities passed on
• Faster than sexual repro

Question 3

What is the disadvantage of asexual reproduction

Answer 3

• No genetic variation in offspring, species not well adapted to changes in the environment

Question 4

Define mitosis

Answer 4

Mitosis is a part of cell division which produces two daughter cells that are genetically identical to each other, chromosome number is maintained

Question 5

Name the order of phases in mitosis

Answer 5

Prophase, metaphase, anaphase, telophase

Question 6

Define cytokinesis

Answer 6

The division of the cytoplasm to produce two completely separated daughter cells

Question 7

Describe cytokinesis in animal cells

Answer 7

Cleavage or furrow appears between two nuclei in cytoplasm, deepens until parent cell pinches into two daughter cells, each with complete nucleus and share of organelles

Question 8

Describe cytokinesis in plant cells

Answer 8

A cell plate forms by the fusion of vesicles produced by the Golgi apparatus.

Question 9

State the importance of mitosis

Answer 9

To maintain genetic stability of an organism, meaning two daughter cells formed are genetically identical and contain same number of chromosomes as the parental cell

Question 10

What is maintained in mitosis to be exactly the same

Answer 10

Identical chromosome numbers, exact genetic information and diploid set of chromosomes

Question 11

How does mitosis help growth

Answer 11

Increase in number of cells within the organism (e.g. development of fertilised egg)

Question 12

How does mitosis help repair the organism

Answer 12

Regeneration and replacement of cells and tissues lost in normal processes of wear and tear, aging, damage and disease

Question 13

How does mitosis help in asexual reproduction

Answer 13

Reproduction of an organism without production of gametes

Question 14

Why must cells be genetically identical

Answer 14

So that they can carry out the same function. New cells that replace damaged cells must be exact copies of original cells for tissue to function properly

Question 15

Define haploid

Answer 15

Haploid cells have only one set of chromosomes, where number of chromosomes is represented by n, normally gametes/sex cells

Question 16

Define diploid cells

Answer 16

Those with two sets of chromosomes in the nucleus, number of chromosomes in diploid cell represented by 2n

Question 17

What are somatic cells

Answer 17

Human somatic cells are all body cells except gametes, dividing by mitosis. 46 chromosomes arranged into 23 pairs of homologous chromosomes, one from mother one from father

Question 18

Define sexual reproduction

Answer 18

Sexual reproduction is the process involving the fusion of the haploid nuclei of the male and female gametes to form a zygote.

Question 19

Advantages of sexual reproduction

Answer 19

May inherit beneficial qualities, genetic variation

Question 20

Disadvantages of sexual reproduction

Answer 20

Two parents are usually needed, fusion of gametes needed, slower

Question 21

Similarities between asexual and sexual reproduction

Answer 21

Both processes pass on genetic materials to the offsprings, produce new offspring

Question 22

Define homologous chromosomes

Answer 22

A pair of chromosomes having identical structural features

Question 23

What are some similarities between homologous chromosomes

Answer 23

Same length, size and shape
Same centromere position
Genes for same biological features at corresponding location on the chromosome, thus determine same traits, but may have different alleles

Question 24

What is allele

Answer 24

Allele is alternative form of gene which occupies same location on a pair of homologous chromosomes

Question 25

Define meiosis

Answer 25

A part of cell division that produces genetically dissimilar cells containing half the number of chromosomes as the parent cell

Question 26

Why is chromosome number halved due to separation of homologous chromosomes

Answer 26

To maintain the constancy of number of chromosomes from generation to generation, as when nucleus of two gametes fuse the diploid number for the species will be recovered

Question 27

State importance of meiosis

Answer 27

Produces haploid genes and produces gametes that are genetically dissimilar

Question 28

How does meiosis produce haploid gametes

Answer 28

During meiosis, each pair of homologous chromosomes in parent nucleus separates to form daughter cells, each daughter cell receives one copy, when two gametes fuse diploid number is restored and maintained

Question 29

Why does meiosis produce gametes that are genetically dissimilar

Answer 29

Greater genetic variation, better species is adapted to changes in environment. increases likelihood that at least some individuals would possess desirable traits to adapt to new environment