5th yr Flashcards
(68 cards)
what is asexual reproduction
where offspring is produced from one organism
what does asexual reprodcution not include
gametes or fertilisation
what are advantages of asexual reproduction
quick efficient and provides lots of production
what is sexual reproduction
where an nuclei of two gametes merch to form a zygote
what are the advantages of sexual reproduction
allows for variation in population
what are disadvantages of sexual reproduction
slow process
what are the features of a wind pollinated plant
- dull petals
- scent and nectar not produced
- long filaments
- large surface area
- Exposed stigma
what are the features of insect pollinated plants
- colourful to attract
- sweet scent
- sticky pollen
how do wind pollinated plants work
- as the wind blows past the plant the pollen is picked up easily as the anther hangs outside of the plant
- The pollen then lands on another plant of the same species (female) and reproduction occurs
how do insect pollinated plants work
- when an insect land on the plant the pollen sticks to body
- when the insect visits another plant it brushes past the stigma and the pollen from the original plant is deposited and reproduction occurs
how does fertilisation in plants work
- the pollen lands on the stigma
- the pollen tube grows down the style towards the ovary
- the pollen nucleus travels down the pollen tube to the egg and fertilises it
what are the conditions needed for germination
water
oxygen
warmth
what is fertilisation in human
the fusion of a male and female gamete to produce zygote
what are the parts of the male reproductive system
. bladder - stores urine
. glands
. sperm duct - sperm passes through here
. urethra - carries urine
. testis - produces sperm
. scrotum - supports testes
. penis- passes urine out of body
what are the parts of the female reproductive system
.oviducts- connects ovary to uterus fertilisation occurs here
.ovaries- contains ova that develop and releases hormones
.uterus - soft lining where fertilised egg is implanted to develop
.cervix- keeps foetus in place in pregnancy
. vagina - sperm is deposited here
what is the menstrual cycle stages
days 1-4 : mensuration occurs, breaking down and release of uterus lining AKA period
day 4-14 : uterus lining repairs ready for embryo
day 14 : ovulation, release of egg from ovary
day 14-28 : maintaining of the egg and cycle repeats if egg is not fertilised
what are the 4 hormones within the menstrual cycle
. Oestrogen- causes uterus wall to thick stimulates LH
. LH- produced in pituitary gland stimulates release of egg
. FSH - also produced in the pituitary gland
causes egg to mature, stimulates release of oestrogen
. progesterone - produced in the ovaries maintains thickness of uterus lining
what is the role of the placenta
exchange of substance between mothers blood foetus
gives : oxygen and nutrients
takes : carbon dioxide and urea
how is the placenta adapted for diffusion
. large surface area
. thin wall for efficiency
what is the amnionic fluid
protects the embryo during development by cushioning it from bumps by absorbing impact
what is a genome
then entire DNA of an organism
what is a gene
a section of a molecule of DNA that codes for a specific protein
what is located in the nucleus
chromosmes which encode gentic material
what is chromosome
a thread like structure made of DNA, tightly coiled into a double helix