WEAKNESSES - Reproduction and inheritance

how many possible codons are there?

64

describe mitosis

• prophase - duplicate chromosomes, nucleus membrane breaks down

• metaphase - align in the middle of the cell

• anaphase - spindle fibres pull the chromosomes apart

• telophase - two nuclei membranes form around the chromosomes, cytoplasm divides

what is produced when the two gametes fuse

zygote

what forms when the zygote divides

embryo

describe meiosis

• chromosomes duplicate

• similar chromosomes line up

• genes get swapped

• chromosome pairs separate

• chromosomes are pulled apart by spindle fibres

compare mitosis and meiosis

• one parent vs two parents

• genetically identical offspring vs genetic variation in offspring

• diploid vs haploid

• 2 daughter cells vs four daughter cells

where does meiosis happed

ovaries, testes

examples of mitosis (3)

• growth

• repair

• cloning

name for male reproductive part in flowers

stamen

name for female reproductive part in flowers

carpel

anther function

contain pollen grains which produce male gametes

filament function

supports anther

stigma function

pollen grains attach to

style function

supports stigma

ovary function

contains ovum within ovules

define pollination

transfer of pollen from an anther to a stigma

features of insect pollinated plants (5)

• big colourful petals

• scented flowers

• nectaries

• large sticky pollen grains

• sticky stigma

features of wind pollinated plants (5)

• small dull petals

• no scent

• no nectary

• small and light pollen grains

• large feathery stigma

what does a fertilised female gamete form

seed

what does the fertilised ovary become

fruit

why do seeds need water to germinate

• activate enzymes to break down food reserves

why do seeds need oxygen to germinate

respiration to release energy for growth

why do seeds need warmth to germinate

temperature for enzymes to work

how do plants reproduce asexually naturally

runners

how do plants reproduce asexually artificially

cloning from cuttings

advantages of cuttings (3)

• quick

• cheap

• genetically identical

what is semen made from

sperm

seminal fluid

urethra function

carries sperm and urine through the penis

erectile tissue function

swells when filled with blood to make the penis erect

testes function

produce sperm

seminal vesicle function

produces seminal fluid to make semen

vas deferens function

carries sperm from epididymis to urethra

epididymis function

stores, matures and transports sperm from testes to vas deferens

scrotum function

contains testes

vagina function

where the sperm are deposited

uterus function

where the embryo implants into

cervix function

neck of uterus which connects the vagina to the uterus

ovary function

produces oestrogen and egg cells

fallopian tube function

carries the egg from the ovary to the uterus

order of hormones

FSH, oestrogen, LH, progesterone

functions of placenta/what is gives the foetus (4)

• oxygen and glucose for respiration

• amino acids for protein synthesis

• antibodies for short term immunity

• remove metabolic waste (CO2 and urea)

adaptations of the placenta

• large surface area (placental villi) for diffusion

• thin walls of blood vessels = short diffusion distances

• good blood supply - maintains high concentration gradient for diffusion

function of amniotic sac

• contains amniotic fluid

• protects the foetus against knocks and bumps

• provides a constant temperature for the foetus