Reproduction

Question 1

What is reproduction?

Answer 1

Reproduction is the process by which members of a species produce offspring.

Question 2

What is sexual reproduction?

Answer 2

Sexual reproduction involves the fusion of gametes (sex cells) during a process called fertilisation.

Question 3

In multicellular animals and plants are body cells diploid or haploid?

Answer 3

In multicellular animals and plants, all body cells (except sex cells) are diploid. This means they contain two sets of chromosomes.

Question 4

Are sex cells haploid or diploid?

Answer 4

Sex cells, known as gametes, are haploid. Therefore, each gamete contains only one set of chromosomes.

Question 5

In humans what is the chromosome complement for each body (non-sex) cell and the chromosome complement for each gamete?

Answer 5

In humans the chromosome complement for each body (non-sex) cell is 46 therefore the chromosome complement for each gamete is 23.

Question 6

Describe the sperm gamete production in males.

Answer 6

The sperm gamete is produced in the testis. There are many gametes produced and they are relatively small in size.

Question 7

Describe the egg gamete production in mammals.

Answer 7

The egg gamete is produced in the ovaries. There are few gametes produced and they are relatively big in size.

Question 8

Where are sperms in males produced?

Answer 8

In males, sperm are produced in the testis

Question 9

How do sperm get to the penis?

Answer 9

Sperm travel along the sperm duct to the penis. The sperm travel down the urethra of the penis.

Question 10

Where are eggs in the females produced?

Answer 10

Inside the female, an egg is released from the ovaries.

Question 11

How do eggs travel along the oviduct?

Answer 11

The eggs travel along the oviduct, being wafted along by tiny hairs.

Question 12

How does fertilisation occur?

Answer 12

When inserted into the vagina of the female, the penis releases sperm. Sperm swim up through the uterus into the oviduct. If the sperm meets the egg here then fertilisation may occur. During fertilisation the haploid male gamete nucleus and the haploid female gamete nucleus must fuse.

Question 13

Is the fertilised egg diploid or haploid?

Answer 13

The fertilised egg that is formed is diploid (has two sets of chromosomes).

Question 14

What is the fertilised egg called?

Answer 14

The cell is called a zygote.

Question 15

What does the zygote contain?

Answer 15

The fertilised egg that is formed (zygote) contains genetic information from both parents.

Question 16

How many sperm can fertilise the egg?

Answer 16

Only one sperm fertilises the egg.

Question 17

Where does fertilisation occur in mammals?

Answer 17

In mammals, fertilisation takes place in the oviduct.

Question 18

How is an embryo formed?

Answer 18

During its journey from the oviduct to the uterus, the fertilised egg (zygote) divides by the process of mitosis to form a small ball of cells called an embryo.

Question 19

Where does the embryo develop until birth?

Answer 19

The embryo will attach and become embedded in the uterus lining. This is where the embryo will develop over the next 9 months until birth.

Question 20

By which process do flowering plants reproduce?

Answer 20

Flowering plants also reproduce by sexual reproduction.

Question 21

Describe gamete production in plants that are female.

Answer 21

The female plant gamete is called an ovule and it is produced in the ovary.

Question 22

Describe gamete production in plants that are male.

Answer 22

The male plant gamete is called pollen and is produced in the anther.

Question 23

What is the definition of pollination?

Answer 23

Pollination is the transfer of pollen grains from an anther to a stigma.

Question 24

How does pollination occur?

Answer 24

The transfer may occur due to wind or insects.

Question 25

Where does pollen grain get its energy from and why?

Answer 25

Once the pollen grain has landed on a stigma it uses sugar as an energy source to form a pollen tube that grows down through the style.

Question 26

How does the pollen grain come into contact with the female gamete?

Answer 26

The pollen grain’s nucleus divides into two male gametes in the region behind the tip. When the tip of the tube reaches an ovule, it enters through a tiny hole and comes into contact with a tiny sac containing the female gamete.

Question 27

How do gametes enter the sac containing the female gamete?

Answer 27

The top of the pollen tube bursts and 2 haploid gametes enter the sac.

Question 28

How is a diploid zygote in plants formed?

Answer 28

one male gamete fuses with the haploid egg to form a diploid zygote ( the other fuses with a second nucleus in the ovule sac to form a cell that becomes the food store in the seed).

Question 29

What happens to the fertilised egg? (plants)

Answer 29

The fertilised egg becomes a seed.

Question 30

What happens to the ovary wall? (plant)

Answer 30

The ovary wall becomes a fruit.

Question 31

Why has fertilisation of plants evolved?

Answer 31

These have evolved for the dispersal of seeds.