paper 2 specification 3

Question 1

what is the calculation for transpiration

Answer 1

distance divided by time

Question 2

how is adrenalin produced by the adrenal glands to prepare the body for fight or flight

Answer 2

-adrenalin binds to specific receptors in the heart. Causes the heart to contract more frequently and with more force-blood pressure/heart rate increases
-increases blood flow and muscles receive more oxygen and glucose for increased respiration
-raised blood sugar levels by stimulating the liver to change glycogen into glucose

Question 3

how does thyroxine regulate metabolism?

Answer 3

-low levels of thyroxine stimulate the production of TRH in the hypothalamus
- this causes a release of TSH from the pituitary gland
-TSH acts on the thyroid to produce thyroxine
- When thyroxine levels are normal thyroxine inhibits the release of TRH and the production of TSH

Question 4

what happens if you have a higher-than-normal thyroxine level

Answer 4

directly inhibits secretion of TSH

Question 5

what happens if you have an underactive thyroid gland

Answer 5

-leads to weight gain due to a metabolic drop
-less glucose is broken down in respiration and is stored as fat

Question 6

what is clomifene therapy?

Answer 6

-a drug that causes more FSH and LH to be released which stimulates egg maturation and ovulation
-by knowing when the woman will be ovulating couples can have sex during this time period

Question 7

what is IVF

Answer 7

collecting eggs from the woman’s ovaries and fertilising them in the lab which is then grown into an embryo which is then transferred into the woman’s uterus.FSH and LH are given before to stimulate egg production.

Question 8

Explain how hormonal contraception influences the menstrual cycle and prevents pregnancy

Answer 8

-oestrogen can be used to prevent the release of an egg if it is used every day, and the level is high, it inhibits the production of FSH
-progesterone can reduce fertility. Stimulates the production of thick cervical mucus which prevents any sperm from getting through to the uterus

Question 9

how can pregnancy be prevented by barrier methods

Answer 9

-condoms and diaphragms (must be used with a spermicide)

Question 10

pros and cons of hormonal contraceptive

Answer 10

-when used correctly is the most effective at preventing pregnancies than barrier methods.Couples don’t have to stop and think about contraception each time
-however hormonal methods can have unpleasant side effects such as headaches acne and mood swings.They don’t protect you from sexual infections-only condoms can