Topic 14 - Human Reproduction

Question 1

Sexual reproduction

Answer 1

Involves fusion of two gametes (fertilisation). Offspring produced will be genetically unique.

Question 2

Asexual reproduction

Answer 2

When offspring (clones) are produced from one parent through the mitosis of body cells

Question 3

Gamete

Answer 3

A sex cell

Question 4

Diploid

Answer 4

Cells that have the full number of chromosomes in homologous pairs (body cells)

Question 5

Haploid

Answer 5

Cells that have half the normal number of chromosomes (gametes)

Question 6

Fertilisation

Answer 6

The fusing of the nuclei of a male and female gamete

Question 7

Zygote

Answer 7

The diploid cell produced following fertilisation

Question 8

Embryo

Answer 8

A cluster of cells formed after the zygote divides several times – the earliest stage of an organism’s development (first 8 weeks for humans)

Question 9

Fetus

Answer 9

An unborn organism but with recognisable features of the species (from 8 weeks for humans)

Question 10

Placenta

Answer 10

An organ that connects a fetus with the uterus wall. It allows essential, nutrient-rich substances to be exchanged between mother and child

Question 11

Amnion

Answer 11

The membrane that encloses the developing foetus

Question 12

Amniotic fluid

Answer 12

The fluid secreted by the amnion that protects the fetus from jolts and bumps

Question 13

Pituitary gland

Answer 13

The gland at the base of the brain that produces FSH, LH and ADH

Question 14

Oestrogen

Answer 14

A female sex hormone that promotes the development of secondary sexual characteristics. It also repairs the lining of the uterus

Question 15

Progesterone

Answer 15

Maintains uterus lining

Question 16

Testosterone

Answer 16

The male sex hormone that promotes the development of secondary sexual characteristics and sperm production

Question 17

FSH

Answer 17

A hormone released from the pituitary gland that is involved with the production of sperm cells in males and the development of eggs in females.

Question 18

LH

Answer 18

A hormone released from the pituitary gland that causes the testes to produce sperm in males and ovulation in females.

Question 19

Glands

Answer 19

Where the liquid component of semen is made

Question 20

Urethra

Answer 20

A tube through which urine and semen exit the body

Question 21

Scrotum

Answer 21

Provides insulation for the testes

Question 22

Penis

Answer 22

The part inserted into the vagina during sexual reproduction

Question 23

Testes

Answer 23

Where sperm cells and testosterone are found and created

Question 24

Sperm duct (vas deferens)

Answer 24

A long muscular tube through which sperm travels from the testes to the penis

Question 25

Foreskin

Answer 25

Protective layer of skin that covers the glans of the penis

Question 26

Acrosome

Answer 26

An organelle that releases digestive enzymes during fertilisation

Question 27

Haploid nucleus

Answer 27

Contains half of the genetic information

Question 28

Flagellum

Answer 28

A slender threadlike structure that allows the sperm to travel towards the egg cell. Its pointed shape allows it to be streamlined.

Question 29

Oviduct

Answer 29

Where the egg cell travels through to be fertilised in

Question 30

Ovary

Answer 30

Where egg cells, progesterone, and oestrogen are produced

Question 31

Cervix

Answer 31

A ring of muscle that holds to fetus in place during pregnancy

Question 32

Uterus

Answer 32

The location of fetal development

Question 33

Endometrium

Answer 33

To provide a nutrient rich and thick, blood-filled space for fetal development

Question 34

Vagina

Answer 34

Where the penis is inserted into during sexual reproduction

Question 35

Cortical reaction

Answer 35

A process that prevents polyspermy. Only one sperm can enter the egg cell. The egg cell then seals itself

Question 36

Placenta adaptations

Answer 36

- villi are present to increase surface area - the blood vessels of the mother and fetus are very close together to provide short diffusion distance - steep concentration gradient for efficient diffusion - umbilical cord for delivery of nutrients by diffusion - many blood vessels - amniotic fluid and sac to protect the developing fetus by acting as shock absorbers

Question 37

Effects of smoking during pregnancy

Answer 37

CO diffuses unto the fetal blood and binds to haemoglobin. This causes lack of oxygen to be delivered to cells. Respiration rate is reduced, resulting in a lack of energy released. This can cause premature birth and low birth weight.

Question 38

Drinking

Answer 38

Conc. of alcohol would be high in fetal blood, which can cause early miscarriages. Later stages of pregnancy: fetal alcohol syndrome can develop, which can cause learning delays and physical abnormalities due to the effect on the brain.

Question 40

Puberty

Answer 40

A time period where bodily changes occur to make an individual reproductively ready. It is caused by the hormones oestrogen and testosterone.

Question 41

Hormones

Answer 41

Chemical messengers released from glands that travel through the bloodstream to a target organ. The release is slow and effects are long-lasting.