B11.5 - B11.10 - Hormonal Coordination (set B)✔️

Question 1

What is the menstrual cycle?

Answer 1

Once a girls has gone through puberty - each month, eggs begin to mature in the ovary and uetrus lining thickens (in prepiration for pregnancy) - every 28 days a mature egg is released (called ovulation) if egg is not fertilised arrund 14 days later the lining of the uterus is shed along with egg - cycle repeats

Question 2

Function of the hormone FSH?

Answer 2

Follicle stimulating hormone is secreated by the pituitary gland - makes eggs mature in their follicles in the ovaries - also stimulates ovaries to produce hormones including oestrogen

Question 3

Function of oestrogen?

Answer 3

Oestrogen Is made and secreted by the ovaries in response to FSH - stimulates lining of uetrus to grow again after mensturation

Question 4

What is the response to high levels of oestrogen?

Answer 4

Inhibts the prouction of more FSH and stimulate the release of LH (lutenising hormone) from the pituitary gland

Question 5

Function of luteinsing hormone (LH)?

Answer 5

Released by pituitary gland and stimulates the release of a mature egg from the ovary - once ovulation has taken place, LH levels fall again

Question 6

Function of Progesteron?

Answer 6

Secreted by the empty egg follicle in the ovary after ovulation - helps maintain a pregnancy if the egg is fertelised - inhibits both FSH and LH and it maintains the lining of the uterus in the second half of the cycle so it is ready to recieve a developing embryo (if egg is fertelised)

Question 7

How do hormones act to control what happens in the menstural cycle?

Answer 7

Hormones produced by the pituitary gland and ovary act together - as the oestrogen levels rise, they inhibit the production of FSH and encourage the production of LH which when LH levels reach a peak in the middle of the cycle, stimulate the release of a mature egg

Question 8

What is testostrone and its role?

Answer 8

Main male reproductive hormone produced in the testes and it stimulates sperm production

Question 9

What is oestrogen and its role?

Answer 9

Female reproductive hormone produced in the ovary - at puberty eggs begin to mature and one is released approximately every 28 days this is called ovulation

Question 10

4 Examples of different types of contraception?

Answer 10

• surgical methods
• oral contraceptives
• injections
• barrier methods

Question 11

How do oral contraceptives work?

Answer 11

Use femal hormones to prevent pregnancy - pill contains low doeses of oestrogen along with progesterone which inhibits the production and release of FSH - affecting the ovaries so no eggs mature

Question 12

How do contraceptives like injections/implants/skin patch’s work?

Answer 12

Slow release of progesterone to inhibit the maturation and release of eggs for a number of months or years

Question 13

How do barrier contraceptives work?

Answer 13

Examples such as condoms and diaphragms prevent the sperm reaching an egg

Question 14

How do spermicidal agents work as contraceptives?

Answer 14

Kills or disables sperm to prevent pregnancys

Question 15

How can FSH and LH help treat infertility?

Answer 15

Both hormones can be used to stimulate ovulation in women with low FSH levels - it stimulates the eggs in the ovary to mature and also triggers oestrogen production

Question 16

Explain the fertility treatment vitro fertelisation (IVF)?

Answer 16

IVF is form of fertility treatment used if the oviducts have been damaged or blocked by infection - in some cases where a man produces very few sperm or the sperm do not mature - individual sperm are injected into an egg during IVF process

Question 17

Explain fully the process of IVF treatment?

Answer 17

1) mother given synthetic FSH to stimulate maturation of eggs , followed by LH to bring eggs to point of ovulation
2) eggs collected and fertelised with fathers sperm in lab
3) fertelised eggs kept in warm special conditions to develop into embryos
4) when they are just balls of cells the embryos are inserted back into the uterus of the mother

Question 18

3 Disadvantages of IVF?

Answer 18

• not always successful - low success rates
• process is emotionally and physically stressful
• often results in a multiple births

Question 19

Advantage of IVF?

Answer 19

• allows couples who cant have children the chance

Question 20

Why do plants produce hormones?

Answer 20

To coordinate and control growth and response to light (phototropism) and gravity (gravitopism or geotropism)

Question 21

What causes unequal growth rates in plant roots and shoots?

Answer 21

Unequal distribution of auxin

Question 22

Explain what auxin is and its function?

Answer 22

Plant hormone which stimulates growth and cell division in plants - used as weed killers and rooting powders - extra auxin can send a plant into rapid, uncontrolled growth, killing them

Question 23

What is ethene used for in plants?

Answer 23

Used to control the ripening of fruits - unriped fruit is stored in warmer temperatures with ethene added which causes it to ripen rapidly for sale when needed

Question 24

What are gibberellians and what are there use?

Answer 24

Important for initiating seed germination and are used to promote flowering and increase the size of fruit

Question 25

What are tropisms?

Answer 25

The response of plants roots and shoots to gravity and light - phototropism is the plants response to light - gravitropism is the plants response to gravity result of the uneven distribution of auxin

Question 26

Which direction do roots grow in?

Answer 26

Grow in the direction of the force of gravity (gravitropism)

Question 27

Which direction do shoots grow in?

Answer 27

Grow towards light and against the force of gravity (phototopism)

Question 28

Three things auxins are used for?

Answer 28

• weed killer
• as rooting powders
• promoting growth in tissue culture

Question 29

Three things gibberellians can be used to do?

Answer 29

• end seed dormancy
• promote flowering
• increase fruit size