REPRODUCTION OF LIVING THINGS

Question 1

What is meant by sex? (2)

Answer 1

The sex of an organism has a genetic basis. In mammals, it depends on the absence or presence of an activated gene, SRY, located on the Y chromosome.

Question 2

What is a zygote? (1)

Answer 2

Cell that is produced from the fusion of two gametes.

Question 3

What are the differences between oogenesis and spermatogenesis? (7)

Answer 3

-time of arrival
-development
-timing
-number of gametes
-release
-process of meiosis
-structure

Question 4

What is fertilisation? (1)

Answer 4

The fusion of two haploid nuclei to form the nucleus of a zygote and contains the chromosomes from both gametes.

Question 5

What is the karyotype of a female? (1)

Answer 5

XX

Question 6

How oogenesis and spermatogenesis is different, in terms of timing? (3)

Answer 6

Oogenesis- from puberty till menopause a few primary oocytes undergo meiosis 1 to become secondary oocytes only one of these forms a Graafian follicle, the others degenerate.
Spermatogenesis- millions of sperm are formed daily.

Question 7

How are spermatogenesis and oogenesis different, in terms of the process by meiosis? (2)

Answer 7

Oogenesis- meiosis 2 stops at prophase until fertilisation occurs with the haploid nucleus of the sperm cell, then it undergoes the rest of meiosis 2.
Spermatogenesis- sperm cells undergo both meiosis 1 and meiosis 2 in sperm production.

Question 8

How are oogenesis and spermatogenesis different, in terms of the number of gametes? (1)

Answer 8

Oogenesis- one ovum is produced from each oogonium.
Spermatogenesis- 4 spermatozoa are produced from each spermatogonium.

Question 9

What is a gamete? (1)

Answer 9

Cells containing half the number of chromosomes.

Question 10

How are oogenesis and spermatogenesis different, in terms of release? (2)

Answer 10

Oogenesis-the Graafian follicle releases a secondary oocytes into the oviduct at ovulation.
Spermatogenesis- sperm are released from the body by ejaculation.

Question 11

How are oogenesis and spermatogenesis different, in terms of development? (3)

Answer 11

Oogenesis- oogonia become surrounded by follicle cells forming tiny primary follicles that remain dormant in the oviduct. Most fail to develop further, they degenerate.
Spermatogenesis- all spermatozoa become sperm cells they are nurtured by the somatic cell and the fibrous tubules of the testes.

Question 12

How are oogenesis and spermatogenesis different, in terms of time of arrival? (2)

Answer 12

Oogenesis- oogonia formed in the embryonic ovaries, long before birth.
Spermatogenesis- spermatogonia form from the time of puberty throughout adult life.

Question 13

What occurs during the first round of meiosis in spermatogenesis? (1)

Answer 13

The primary spermatocytes develop into secondary spermatocytes. They are the same size.

Question 14

What occurs during the second round of meiosis in spermatogenesis? (1)

Answer 14

Secondary spermatocytes undergo meiosis 2 and develop into 4 haploid spermatids.

Question 15

What occurs during the first round of meiosis in oogenesis? (1)

Answer 15

Primary oocytes develops into a secondary oocytes and the first polar body that degenerates

Question 16

What is meant by maturation in terms of the process of gametogenesis? (1)

Answer 16

Involves meiosis and the production of haploid gametes

Question 17

What is meant by proliferation, in terms of the process of gametogenesis? (2)

Answer 17

In which cells present in a layer called the germinal epithelium divide by mitotic cell division. This division is repeated to reproduce cells capable of becoming gametes.

Question 18

What happens in the growth stage, in terms of spermatogenesis? (1)

Answer 18

The spermatogonia develop into primary spermatocytes.

Question 19

What occurs in the second round of meiosis in oogenesis? (1)

Answer 19

Second oocytes develop into develop into a large ovum and a secondary polar body which is lost.

Question 20

What happens in the growth stage of oogenesis? (1)

Answer 20

Oogonium develop into primary oocytes.

Question 21

What is the germinal epithelium? (1)

Answer 21

A layer of cells that undergoes continues cell division.

Question 22

What are the sequences of both the male and female processes of gametogenesis? (3)

Answer 22

-maturation (proliferation)
-growth
-multiplication

Question 23

What is a gonad? (1)

Answer 23

A reproductive organ that produces gametes.

Question 24

What are the female gonads? (2)

Answer 24

The ovaries that produce ova.

Question 25

What are the male gonads? (1)

Answer 25

The testes that produce spermatids.

Question 26

What process are sperm cells produced by? (1)

Answer 26

Spermatogenesis.