3a - Reproduction Flashcards by Inayah Y

What is the definition of fertilisation?

The fusion of Gamete nuclei

How well did you know this?

Not at all

Perfectly

How many chromosomes in a gamete ?

How well did you know this?

Not at all

Perfectly

What does a zygote have?

46 chromosomes (half from each parent)

- diploid nucleus

How well did you know this?

Not at all

Perfectly

What are advantages to sexual reproduction?

increases genetic variation
species can adapt to new environments
disease is less likely to have effect

How well did you know this?

Not at all

Perfectly

What are disadvantages to sexual reproduction?

takes time and energy to find mates

- difficult for those isolated to reproduce

How well did you know this?

Not at all

Perfectly

What are advantages to Asexual reproduction?

rapid population increase

- more time + energy efficient

How well did you know this?

Not at all

Perfectly

What are disadvantages to Asexual reproduction?

limited genetic variation

- population vulnerable to disease + change in conditions

How well did you know this?

Not at all

Perfectly

What is the function of the sepal ?

Protects unopened flower

How well did you know this?

Not at all

Perfectly

What is the function of the petals ?

Brightly coloured to attract insects

How well did you know this?

Not at all

Perfectly

What is the function of the anther ?

Produces and releases pollen

How well did you know this?

Not at all

Perfectly

What is the function of the stigma ?

Collects pollen grains

How well did you know this?

Not at all

Perfectly

What is the function of the ovary (plants) ?

Produces the female sex cell

How well did you know this?

Not at all

Perfectly

What is the function of the ovule ?

Contains the female sex cells

How well did you know this?

Not at all

Perfectly

What is the male sex cell in a plant ?

Pollen

How well did you know this?

Not at all

Perfectly

What is the male part of the flower and what does it contain?

Stamen - contains anther + filament

How well did you know this?

Not at all

Perfectly

What is the female part of the flower and what does it contain?

Carpel- contains stigma, style + ovary

How well did you know this?

Not at all

Perfectly

What are the conditions required for germination?

moisture, oxygen, warmth

How well did you know this?

Not at all

Perfectly

Describe insect pollination

anthers from a flower deposit pollen onto the insect

- the insect then deposits that pollen onto the stigma of another flower

How well did you know this?

Not at all

Perfectly

Describe wind pollination

when ripe, the anthers open + shed pollen into air

- the pollen is blown by wind onto a flower

How well did you know this?

Not at all

Perfectly

What are features of insect pollinated flowers?

large bright coloured petals
stigma + anther INSIDE flower
larger sticky pollen grains

How well did you know this?

Not at all

Perfectly

What are features of wind pollinated flowers?

small dull petals
anther + stigma OUTSIDE flower
small light pollen grains

How well did you know this?

Not at all

Perfectly

When does cross pollination occur?

When pollen from one plant is transferred to the stigma of another plant of the same species

How well did you know this?

Not at all

Perfectly

What is self pollination?

When pollen from a flower lands on its own stigma or another flower on the same plant.

How well did you know this?

Not at all

Perfectly

What does self pollination reduce?

The genetic variation of offspring

How well did you know this?

Not at all

Perfectly

Describe the role of a pollen tube during fertilisation in a plant

- the nucleus inside the pollen grain moves down the tube as the tube grows down the style towards the ovary - pollen nucleus fuses with ovum nucleus = fertilisation

What is germination ?

The start of growth in the seed

What does a seed contain?

The zygote which divides into cells which develop into the embryo plant

What structure surrounds an embryo (plants) ?

Cotyledons

What does the cotyledon contain ?

Food reserves which provide the seed with energy for germination

How long do the cotyledons provide for?

Until the plant can make its own food via photosynthesis

When does the seed coat (testa) split?

After taking in water

What happens when the seed coat (testa) splits?

The production of the plumule + radicle

What is the function of the prostate gland ?

Produces semen, which provides sperm cells with nutrients

What is the function of the prostate sperm duct?

Sperm passes through it to be mixed with other gland fluids

What is the function of the urethra?

Tube that carries out urine + semen

What is the function of the testis?

Produces sperm + testosterone

What is the function of the scrotum ?

Ensures sperm are kept at the right temperature

What is the function of the oviduct?

- connects ovary to the uterus | - lined with ciliated cells to push ovum down it

What is the function of the ovary?

Contains female gametes

What is the function of the uterus ?

Has soft lining for a foetus to develop

What is the function of the cervix?

Ring of muscle at uterus end to keep the foetus in place during pregnancy

What are the features of a sperm cell ?

- flagellum (tail) - many mitochondria - enzymes

What are the features of an egg cell? (humans)

- cytoplasm to provide energy | - jelly like coating

What is the function of the placenta?

Ensures materials can be exchanged between the blood of the mother + foetus

What is the function of the umbilical cord?

Joins the embryo’s blood supply to the placenta for exchange of materials

What is the function of Amniotic fluid?

protects the embryo during development by cushioning it from bumps

What does the mothers blood absorb?

The baby’s waste products eg CO2 + urea

How do most molecules move across the placenta ?

By diffusion

What does the placenta prevent?

Toxins and pathogens getting into the foetus’ blood

How is the placenta adapted for diffusion?

- large surface area - Villi which increase the surface area - rich supply of maternal blood vessels.

What are secondary sexual characteristics controlled by in females + males?

Females - oestrogen | Males - Testosterone

What are the effects of oestrogen in women?

- breasts develop - menstrual cycle - body hair

What are the effects of testosterone in men?

- facial + body hair grows - voice breaks - muscles develops - testes start to produce sperm

When does ovulation occur?

About halfway through the menstrual cycle (day14)

What is menstruation caused by?

The breakdown of the lining of the uterus

What releases FSH?

Pituitary gland

What releases LH and when?

Pituitary gland when oestrogen levels have reached their peak

What does FSH cause?

- causes egg to start maturing in the ovary | - stimulates the ovaries to release oestrogen

What does LH cause?

Ovulation + stimulates the ovary to produce progesterone

When does progesterone start to rise?

After ovulation (day 14 onwards)

Why does progesterone start to rise?

To cause the uterus lining to thicken further

What happens when progesterone levels fall?

Uterus lining breaks down (menstruation)

When do oestrogen levels rise?

From day 1-14(peak)

What does the rise of oestrogen cause?

- uterus lining thickens | - egg matures

What does oestrogen do after ovulation ?

inhibits FSH + LH production

What hormones does the ovary produce?

Oestrogen + progesterone