a) Reproduction

Difference between sexual and asexual reproduction?

Asexual involves one parent and the offspring has identical genes to parent.

Sexual involves two parent, a fusion between male and female gametes and the offspring contains a mixture of their parent’s genes.

What happens in fertilisation?

Two nuclei fuse together to make a zygote. This then divides by mitosis to form an embryo.

How are insect-pollinate flowers adapted for pollination?

1. Brightly coloured petals to attract insects.

2. Scented flowers and nectaries to attract insects.

3. Make big, sticky pollen grains to stick onto insect.

4. Stigma is sticky so pollen from insect will stick to stigma.

How are wind-pollinated flowers adapted for pollination?

1. Small, dull petals

2. No nectaries or strong scents

3. Lots of pollen grains as they’re small and lightweight so can be carried by wind.

4. Long filaments that hang anthers outside flower so lots of pollens gets blown by wind.

5. Large feathery stigma to catch pollen blown past it.

How does a seed and fruit formation appear in a plant?

Pollen lands on stigma.

Pollen tube grows out pollen grain and down through style into ovary and into ovule.

Nucleus from male gamete joins female gamete in ovule.

Fertilisation takes place.

Each fertilised female gamete forms a seed and the ovary develops into fruit around seed.

How to investigate a practical for conditions needed for germination?

1. Put cotton wool on the bottom of 4 boiling tubes.

2. Put 10 seeds on top of cotton wool in each tube.

3. Tube 1 should have water, oxygen, room temperature

4. Tube 2 should have no water, oxygen, room temperature

5. Tube 3 should have water, oxygen, low temperature

6. Tube 4 should have water, no oxygen, room temperature

How do germinating seeds use food reserves until i can carry out photosynthesis?

When seeds germinate they get glucose for respiration from their food store. This transfers energy to grow. Once plant produces green leaves it can get food from photosynthesis.

How can plants reproduce asexually using runners?

Plant send runners that grow sideways.

Runners take root at various points and new plants grow.

New plants is clone and no genetic variation.

How can plants reproduce asexually using cuttings?

Gardeners take cutting of parent plant and then plant them to produce genetically identical copies of parent plant.

Function of male reproductive system?

Make sperm.

Structure of of male reproductive system?

Urethra

Erectile tissues

Testis

Scrotal sac(scrotum)

Foreskin

Head of penis

Vas deferens(sperm duct)

Glands

Function of urethra?

Tube that carries sperm through pie is during ejaculation.

Urine passes through here to exit body.

Function of erectile tissue?

Swells when filled with blood, to make penis erect.

Function of testis?

Where sperm is made.

Function of glands?

Produce the liquid that’s added to sperm to make semen.

Function of vas deferents(sperm duct)?

Muscular tube that caries sperm from tests towards urethra.

Function of scrotal sac(scrotum)?

Hangs behind the penis and contains testes.

Function of female reproductive system?

Make ova(eggs).

Structure of female reproduce system?

Muscular uterus wall

Fallopian tube

Uterus(womb)

Vulva

Ovary

Endometrium

Cervix

Vagina

Function of fallopian tube?

Muscular tube that carries ovum from ovary to uterus.

Function of uterus(womb)?

Organ where an embryo grows.

Function of ovary?

The organ that produces ova and sex hormones.

Function of endometrium(lining of uterus)?

Has a good blood supply for implantation of an embryo.

Function of cervix?

The neck of uterus.

Fucntion of vagina?

Where the sperm is deposited.

Roles of oestrogen in menstrual cycle and where they’re produced?

Produced in ovaries

Causes uterus lining to grow.

Inhibits FSH

Stimulates release of LH

Roles of progesterone in menstrual cycle and where they’re produced?

Produces in ovaries.

Maintains thickness of uterus lining for pregnancy.

Inhibits release of LH and FSH.

Role of placenta in the nutrition of the developing embryo?

Allows blood of embryo and mother get very close to exchange food, oxygen and waste.

Function of amnion?

Thin membrane that surrounds developing embryo and secretes amniotic fluid.

How does amniotic fluid protect a developing embryo?

Acts as a shock absorber so it protects it against knocks and bumps.

Function of umbilical cord?

Join fetus to placenta.

What secondary sexual characteristics does oestrogen cause in women?

Extra hair on underarms ad public area

Hips widen

Breasts develop

Ovum release and start of periods

What secondary sexual characteristics does testosterone cause in men?

Extra hair on face and body

Muscle develop

Penis and testicles enlarge

Sperm production

Deepening of voice