C - Hormones, plant hormones, menstrual cycle Flashcards
What are hormones?
CHEMICAL messengers which TRAVEL IN THE BLOOD to ACTIVATE TARGET CELLS
What’s the differences between nerves and hormones?
NERVES:
Long lasting
Act for a short time
Act on a precise area
HORMONES:
Slower reaction
Act for a long time
Act in a more general way
Where is FSH and LH produced?
Pituitary gland
Explain the menstrual cycle in detail
- FSH levels stimulates the egg to mature in one of the ovaries.
- This stimulates the production of oestrogen which repairs the uterus wall.
- This stimulates a surge of LH which stops FSH.
- The LH causes ovulation (egg is released and ovaries thicken) from day 14 to 28.
- If egg doesn’t get fertilised the walls of uterus shed at day 28.
What hormone can be used to prevent the release of an egg?
Oestrogen
What is a plant growth hormone?
Auxin
Shoots grow towards ______ and therefore….
Light
The shaded side grows faster causing it to bend and it to grow towards the light
Shoots grow away from…
Gravity
Roots grow towards ______ and ______
Gravity and moisture
Roots grow towards…
Moisture
Name two hormones used in contraceptive pills
Oestrogen
progesterone
Where is oestrogen produced?
Ovaries
Hormones travel through your body at what speed?
The speed of blood
What is the menstrual cycle?
The monthly release of an egg from a woman’s ovaries and the build up and break down of the protective lining in the uterus (womb)
What happens Day 1 of the menstrual cycle?
The bleeding and breakdown of the uterus lining
What happens on day 4 of The menstrual cycle?
Lining of the uterus builds up
What happens on day 14 of the menstrual cycle?
The egg is released
What happens on day 28 of the menstrual cycle?
The cycle starts again (period starts!)
What hormone can be used to stimulate thick cervical mucus which prevents any sperm getting through and reaching an egg?
Progesterone
Name the 2 hormones used as contraception
Progesterone and oestrogen
What two hormones can be injected into women to stimulate egg release in their ovaries?
FSH And LH
What are the two disadvantages of the hormone injection that helps women to get pregnant (2)
- It doesn’t always work
* Too many eggs could be stimulated, resulting in multiple pregnancies (e.g. Twins)
What does IVF involve?
Collecting eggs from the woman’s ovaries and fertilising them in a lab using the mans sperm. Once the embryos are tiny balls of cells, one or two are transferred into the woman’s uterus to improve the chance of pregnancy
What are a couple disadvantages of IVF?
- Some women have strong side effects to the hormones
- Some reports of increased cancer
- Multiple births can occur
Auxin controls the growth of a plant in response to …
Light, gravity, and moisture
Auxin controls the growth of a plant in response to light (__________)
Phototropism
Auxin controls the growth of a plant in response to gravity (__________)
Gravitropism
Auxin is produced in the ___ and and moves backwards to stimulate ______________ which occurs just behind the tips
Tips
Cell elongation
Hormonal weed killers target flat-leaved plants and disrupt their …
Growth patterns which soon kills them but leaves things like grass untouched
What will happen if you add rooting powder to plant cuttings?
They’ll produce roots rapidly and start growing as new clone plants
