hormonal control (required practical) Flashcards
what are hormones?
chemical molecules produced in endocrine glands that control things in organs and cells that need constant adjustment.
what does the pituitary gland do?
what does the thyroid release?
what do the ovaries release?
what does the adrenal gland release?
what do the testes release?
what does the pancreas release?
pituitary gland - ‘master gland’ hormones control other glands.
thyroid - thyroxine → metabolism, heart rate, temperature.
ovaries - oestrogen → menstrual cycle.
adrenal gland - adrenaline → fight or flight response.
testes - testosterone → puberty, sperm production.
pancreas - insulin → blood glucose level.
what are the differences between nerves and hormones?
nerves - fast, act for a short time, act on a precise area.
hormones - slow, act for a long time, act in a general way.
what is insulin?
a hormone that tells the liver to make glucose into glycogen.
what is glucagon?
a hormone that tells the liver to make glycogen into glucose.
what is diabetes and what are the 2 types?
diabetes - a condition that affects the ability to control blood sugar level.
type 1 - the pancreas doesn’t make enough insulin so glucose levels are too high. (insulin injection)
type 2 - cells don’t respond to insulin. (exercise and controlled carbohydrates)
what are the sex hormones in men and women?
testosterone - produced by the testes for sperm production.
oestrogen - produces by the ovaries for physical change and menstrual cycle.
what are the 4 stages of the menstrual cycle?
stage 1 - uterus lining breaks down. (4 days)
stage 2 - uterus lining builds again. (day 4 - 14)
stage 3 - an egg develops and is released from the ovary. (ovulation)
stage 4 - the wall is maintained. (day 14 - 28)
what does FSH do?
what does oestrogen do?
what does LH do?
what does progesterone do?
FSH - pituitary gland - mature an egg - make ovaries produce oestrogen.
oestrogen - ovaries - grow uterus lining - stimulate release of LH.
LH - pituitary gland - release of egg. (ovulation)
progesterone - ovaries - maintain uterus lining - stops LH FSH release.
how can oestrogen be used to prevent pregnancy?
if the oestrogen level is always high FSH cannot be produced and egg development and production is stopped.
how do barriers stop pregnancy?
they stop the sperm from reaching the egg. (condom, diaphragm, spermicide)
how can hormones increase fertility?
fertility drugs contain FSH and LH to stimulate ovulation.
what is IVF?
collecting eggs and sperm and fertilising in a lab. (incubated and once embryos are balls of cells are transferred to the uterus)
what are the pros and cons of IVF?
can give infertile people a baby.
low success rate.
stressful.
multiple births.
what is auxin?
a plant hormone that controls growth at the tip of shoots and roots. (in response to light and gravity)
how do shoots grow towards light?
- when a shoot tip is exposed to light auxin goes to the shaded side.
- auxin makes the cells grow faster and the plant bends towards the light.
how do shoots grow away from gravity and roots towards gravity?
shoots.
1. when a shoot is growing sideways auxin falls to the low side.
2. auxin makes the low cells grow faster and the plant bends upwards.
roots.
1. when a root is growing sideways auxin falls to the low side.
2. however auxin in roots stops growth compared to causing growth in shoots.
3. auxin makes the low cells grow slower and the plant bends downwards.
how do you investigate the effect of light on plant growth? (required practical)
- set up 3 labelled petri dishes lined with moist filter paper. (label the dishes)
- put 10 cress seeds in each.
- shine a light onto one dish from above, and the other 2 from different directions.
- leave the cress seeds for a week.
- observe the direction of the cress seeds.
what are 3 things auxins are used for? (except plant growth)
- killing weeds
- growing from cuttings with rooting powder
- growing cells in tissue culture
what is gibberellin?
a plant hormone that stimulates seed germination, stem growth and flowering.
what is ethene?
a gas that controls cell division and stimulates enzymes that cause fruit to ripen. (release by again parts of a plant)
