Reproduction 15/3/18

Question 1

What’s asexual reproduction?

Answer 1

Asexual reproduction involves only one parent. The offspring have identical genes to the parent - so there’s no variation between parent and offspring.

Question 2

What are natural methods of asexual reproduction?

Answer 2

Strawberry plants send out runners(fast growing stems) that grow sideways just above the ground
These runners take root at various points(a short distance away) and new plants start to grow
The new plants are clones of the parent strawberry plant so there’s no genetic variation between them

Question 3

What are artificial methods of asexual reproduction?

Answer 3

Gardeners have used cuttings for many years
They take cuttings from good plants, and then plant them to produce genetically identical copies(clones) of the parent plant
This can be done quickly and cheaply

Question 4

What is sexual reproduction?

Answer 4

Sexual reproduction involves the fusion of male and female gametes. Because there are two parents, the offspring contains a mixture of their parents’ genes.

Question 5

What is the sexual organ of a plant?

Answer 5

The flower-it contains both male and female gametes

Question 6

What’s the male reproductive parts of a flower and what is it made up of?

Answer 6

Stamen-Male reproductive parts

• anther(contains pollen grains[male gametes])
• filament(it is the stalk that supports the anther)

Question 7

What’s the female reproductive parts of a flower and what is it made up of?

Answer 7

Carpel-Female reproductive parts

• stigma(the bit that the pollen grain attaches to)
• style(rod like section that supports the stigma)
• ovary(contains the eggs[female gametes] inside the ovule)

Question 8

What is pollination?

Answer 8

Pollination is the transfer of pollen from an anther to a stigma, so that the male gametes can fertilise the female gametes in sexual reproduction.

Question 9

What is cross-pollination?

Answer 9

Cross-pollination is a type of sexual reproduction where pollen is transferred from the anther of one plant to the stigma of another.

Question 10

How do plants cross-pollinate?

Answer 10

They rely on things like insects or the wind to help them pollinate.

Question 11

What are gametes?

Answer 11

Gametes are sperm and egg cells.

Gametes are haploid(this means they contain half the number of chromosomes of a normal cell, they have 23 chromosomes)

Question 12

What’s fertilisation?

Answer 12

Fertilisation is when a male gamete fuses with a female gamete to form a zygote. The zygote ends up with a full set of chromosomes. The zygote then undergoes cell division and develops into an embryo.

Question 13

How are some plants adapted for insect pollination?

Answer 13

• brightly coloured petals(to attract insects)
• scented flowers and nectaries(glands that produce nectar) to attract insects
• make big, sticky pollen grains(the grains stick to insects as they go from plant to plant)
• stigma is sticky so that pollen from insects sticks to the stigma

Question 14

How are some plants adapted for wind pollination?

Answer 14

• small, dull petals(don’t need to attract insects)
• no nectaries or strong scents
• a lot of small, light pollen grains(so they can be easily carried by the wind)
• long filaments hang the anther outside of the flower(so lots of pollen gets blown away)
• large, feathery stigma(to catch pollen from the wind)

Question 15

What is the process of plant fertilisation?

Answer 15

1) pollen grain lands on stigma
2) pollen tube grows out of the pollen grain down into the ovule
3) a nucleus from the male gamete moves down the tube to join with the female gamete in the ovule
4) the two nuclei then fuse together(fertilisation)
5) the fertilised female gamete forms a seed, the ovary develops into a fruit around the seed

Question 16

What is germination?

Answer 16

Germination is when a seed starts to grow

Question 17

What conditions are required for a seed to germinate?

Answer 17

A seed will often lie dormant until the conditions are right.

• water(to activate the enzymes that break down food reserves in the seed)
• oxygen(for respiration which transfers the energy from food for growth)
• suitable temperature(for the enzymes)

Question 18

What happens when a seed germinates?

Answer 18

1) seed takes in water and starts to grow using its store of energy
2) first root starts to grow down into the soil
3) shoot grows up
4) extra roots grow and the first green leaves appear

Question 19

Where do germinating seeds get their energy from?

Answer 19

A developed seed contains an embryo and a store of food reserves, wrapped in a hard seed coat.
When a seed starts to germinate, it gets glucose for respiration from its own food source
Once a plant has grown enough to produce green leaves it then uses photosynthesis

Question 20

What’s an experiment to investigate the conditions needed for germination?

Answer 20

1) take four boiling tubes with cotton wool and 10 seeds in each
2) tube 1-water, oxygen, room temperature_tube 2-oxygen, room temperature_tube 3-water, oxygen, low temperature_tube 4-boiled water and oil, room temperature
3) leave the tubes for a few days and observe what has happened, you should only see germination in tube 1

Question 21

What do the male reproductive parts make, and how is this used?

Answer 21

Make sperm(male gametes), made in the testes all the time after puberty
-sperm mix with a liquid to make semen, which is ejaculated from the penis into the vagina during sexual intercourse

Question 22

What is the urethra and where is it?

Answer 22

Urethra-a tube which carries sperm through the penis during ejaculation, urine also passes through the urethra to exit the body
-it’s the tube down the inside of the penis

Question 23

What’s the glands and where are they located?

Answer 23

Glands-produce a liquid that’s added to sperm to make semen

-at the base of the penis

Question 24

What’s vas deferens and where is it located?

Answer 24

Vas deferens(sperm duct)-muscular tube that carries sperm from the testis towards the urethra
-they are the tubes that lead to the testis

Question 25

What’s the scrotal sac and where is it located?

Answer 25

Scrotal sac(scrotum)-hangs behind the penis and contains the testes

Question 26

What is erectile tissue?

Answer 26

Erectile tissue-swells when filled with blood to make the penis erect

Question 27

What is a testis?

Answer 27

Where sperm are made

Question 28

What does the female reproductive system make?

Answer 28

Ova(eggs), one is produced every 28 days

Question 29

What is a Fallopian tube?

Answer 29

Fallopian tube(oviduct)- a muscular tube that carries the ovum from the ovary to the uterus

Question 30

What is an ovary?

Answer 30

Ovary-the organ that produces ova and sex hormones

Question 31

What is the endometrium?

Answer 31

Endometrium(lining of the uterus)-has a good blood supply for implantation of an embryo

Question 32

What’s the uterus?

Answer 32

Uterus(womb)-where the embryo grows

Question 33

What is the cervix?

Answer 33

Cervix-neck of the uterus

Question 34

What is the hormone and secondary characteristics in men?

Answer 34

Hormone-testosterone
Characteristics-extra hair on face and body, muscles to develop, penis and testicles enlarge, sperm production, deepening of voice

Question 35

What is the hormone and secondary characteristics in women?

Answer 35

Hormone-Oestrogen
Characteristics-extra hair on underarms and pubic area, hips to widen, development of breasts, ovum release and start of periods

Question 36

What are the four stages of the menstrual cycle?

Answer 36

Stage1-menstruation starts(uterus lining breaks down for 4 days)
Stage2-uterus lining builds up again day 4-14, into a thick, spongy layer full of blood vessels, ready to receive a fertilised egg
Stage3-egg developers and is released day 14(ovulation)
Stage4-wall is maintained day 14-28, if no fertilised egg has implanted the lining breaks down and the cycle starts again

Question 37

What are the four hormones that control the menstrual cycle?

Answer 37

FSH
Oestrogen
LH
Progesterone

Question 38

Where is FSH produced and what’s its function?

Answer 38

• produced in the pituitary gland
• causes ova to mature in one of the ovaries in a follicle
• stimulates the ovaries to produce oestrogen
• oestrogen then inhibits the release of FSH

Question 39

Where is Oestrogen produced and what’s its function?

Answer 39

• produced in the ovaries
• cause the lining of the uterus to grow
• stimulates the release of LH

Question 40

Where is LH produced and what’s its function?

Answer 40

• produced by the pituitary gland

- stimulate the release of an egg on day 14

Question 41

Where is Progesterone produced and what’s its function?

Answer 41

• produced in the ovaries by the remains of the follicle after ovulation
• maintains the lining of the uterus during the second half of the cycle, when levels fall the lining breaks down
• inhibits the release of LH and FSH

Question 42

When does an embryo become a foetus?

Answer 42

After 8 weeks of development

Question 43

What’s the point in the amniotic sac(amnion membrane)?

Answer 43

It produces amniotic fluid and protects the developing embryo from knocks and bumps

Question 44

When does the placenta develop and what’s the purpose of the placenta?

Answer 44

The placenta develops once the embryo has implanted
-materials pass by diffusion
Materials that diffuse from the mother to the embryo:oxygen, glucose, amino acids, nutrients such as vitamins and minerals
Materials the diffuse from the embryo to the mother:carbon dioxide, urea