Topic 5c - Animal and Plant Hormones Flashcards
(94 cards)
1
Q
What are the 2 types of contraceptive methods?
A
- Hormonal
- Non-hormonal
2
Q
What kind of contraceptives are oral contraceptives/ the pill?
A
Hormonal
3
Q
How do oral contraceptives/ the pill work?
A
Pill taken which contains hormones to inhibit FSB so that an egg does not mature.
4
Q
What are the pros of oral contraceptives/ the pill? (4)
A
- Easily self-administrated.
- Short-term effects.
- Can easily be reversed.
- Very reliable.
5
Q
What are the cons of oral contraceptives/ the pill? (3)
A
- May have mild side effects associated.
- Could lead to pregnancy if missed.
- Does not protect from STIs.
6
Q
What type of contraceptive are injections, implants or skin patches?
A
Hormonal
7
Q
How do injections, implants or skin patches work?
A
Contains progesterone which is slowly released to inhibit the release of eggs for months or even years.
8
Q
What are the pros of injections, implants or skin patches? (3)
A
- Administrated through routine appointment at GP surgery.
- Requires little to no aftercare or maintenance.
- Very reliable.
9
Q
What are the cons of injections, implants or skin patches? (2)
A
- May take some time for effects to be reversed once removed.
- Does not protect from STIs.
10
Q
What kind of contraceptives are condoms/diaphragms?
A
Non-hormonal
11
Q
How do condoms/diaphragms work?
A
Creates a physical barrier to prevent the sperm from reaching the egg.
12
Q
What are the pros of condoms/diaphragms? (4)
A
- Easy to use.
- Short-term effects.
- Very reliable.
- Provides protection from most STIs.
13
Q
What are the cons of condoms/diaphragms? (1)
A
- Can fail.
14
Q
What kind of contraceptive are intrauterine devices/ the coil?
A
Hormonal
15
Q
How does intrauterine devices/ the coil work?
A
The device is attached to the lining of the uterus and releases hormones or prevents the implantation of an embryo.
16
Q
What are the pros of intrauterine devices/ the coil? (2)
A
- Requires little to no aftercare or maintenance.
- Very reliable.
17
Q
What are the cons of intrauterine devices/ the coil? (2)
A
- May take some time for effects to be reversed once removed.
- Does not protect from STIs.
18
Q
What kind of contraceptive are spermicidal agents?
A
Non-hormonal
19
Q
How do spermicidal agents work?
A
Contains chemicals to kill or immobilise sperm cells.
20
Q
What are the pros of spermicidal agents? (2)
A
- Easy to use.
- Short-term effects.
21
Q
What are the cons of spermicidal agents? (2)
A
- Does not protect from STIs.
- Less effective when used as the only method.
22
Q
What kind of contraceptive is abstaining from intercourse around the time of ovulation?
A
Non-hormonal
23
Q
How does abstaining from intercourse around the time of ovulation work?
A
Avoiding sexual intercourse when there is a likelihood of an egg being present in the oviduct.
24
Q
What are the pros of abstaining from intercourse around the time of ovulation? (1)
A
- Inexpensive.
25
What are the cons of abstaining from intercourse around the time of ovulation? (1)
* Not always reliable.
26
What kind of contraceptive is surgery?
Non-hormonal
27
How does surgery work as a form of contraceptive? (3)
* A surgical procedure carried out in men or women.
* In males, the vas deferens tubes are sealed or blocked to prevent the passage of sperm from the testes.
* In females, the fallopian tubes/oviducts are sealed or blocked to prevent the passage of the egg from the ovaries.
28
What are the cons of surgery as a form of contraception? (3)
* Risks associated with surgery (such as infection).
* Difficult to reverse, if at all possible.
* Can take several months to be reliable
29
What do reproductive hormones cause during puberty?
During puberty reproductive hormones cause secondary sex characteristics to develop.
30
What are the secondary sexual characteristics of puberty for boys only? (4)
* Voice breaks
* Hair grown on face and body
* Body becomes more muscular
* Testes start to produce sperm cells
31
What is the main male reproductive hormone?
Testosterone => produced by testes, and stimulates sperm production.
32
What are the secondary sexual characteristics of puberty for girls only? (4)
* Voice deepens gradually
* Hips get wider
* Breasts develop
* Ovaries start to release egg cells => menstruation starts
33
What is the main female reproductive hormone?
Oestrogen => produced by ovaries.
34
What are the secondary sexual characteristics of puberty for girls and boys? (3)
* Pubic hair grows
* Underarm hair grows
* Sexual organs grow and develop
35
What is FSH?
Follicle stimulating hormone
36
What is LH?
Lutenising hormone
37
What is Oestrogen?
A steroid hormone
38
What is progesterone?
A steroid hormone
39
What are the 4 stages of the menstrual cycle?
1. When menstruation starts. Uterus lining breaks down for 4 days.
2. Lining of uterus builds up again, from day 4 to 14, into thick spongy layer full of blood vessels => ready to receive fertilised egg.
3. Egg released from ovary at day 14 => ovulation.
4. Wall maintained for 14 days until day 28. If no fertilised egg landed by day 28, lining starts to break down again, restarting the cycle.
40
What is ovulation? Where?
The release of an egg from a follicle in the ovary.
41
What does the empty follicle do in the menstrual cycle?
Releases progesterone.
42
What does FSH do? Where is it released from?
It is released from the pituitary and it stimulates maturation of the follicle.
43
What does Oestrogen do? Where is it released from?
It is released from the ovary/ developing follicle and it inhibits FSH production, stimulates LH production, and rebuilds the uterus lining.
44
What does LH do? Where is it released from?
It is released from the pituitary and it stimulates ovulation/ the release of an egg.
45
What does Progesterone do? Where is it released from?
It is released from the ovary / corpus luteum (empty follicle) and it inhibits FSH and LH production.
46
What do Oestrogen and Progesterone do more generally?
They maintain the uterus lining in the second half of the cycle.
47
What is the sequence of hormone interactions in the menstrual cycle? (8)
* During first days of cycle FSH from pituitary gland stimulates a follicle to mature.
* FSH stimulates oestrogen from the ovaries.
* Oestrogen causes thickening of the uterus lining (1st half of cycle).
* Oestrogen inhibits FSH but stimulates LH from the pituitary.
* The high levels of LH stimulate ovulation / release of egg on day 14.
* Progesterone is secreted by empty follicle (corpus luteum) after day 14.
* Progesterone maintains lining of uterus in 2nd half as it inhibits FSH and LH.
* Progesterone falls if no pregnancy happens and uterus lining comes away as menstrual blood flow.
48
What is the mini pill? (2)
* A contraceptive that only contains the progesterone hormone.
* Has to be taken at same day each time to prevent pregnancy.
49
Why does missing a dose of the mini-pill reduce the success rate of the mini-pill? (4)
* Missing a dose causes a dip / drop in Progesterone levels.
* Therefore FSH is not inhibited anymore.
* Therefore LH is not inhibited anymore.
* And consequently an egg is matured and released.
50
What is one way that hormones can prevent contraception / pregnancy? (3)
* Inhibiting FSH production.
* This is because FSH, from pituitary, leads to maturing of follicles, which causes pregnancy.
* So by inhibiting FSH, the egg does not mature and the woman can't get pregnant.
51
Why does infertility occur? (2)
* It can be a result of insufficient or too low levels of reproductive hormones affecting the development of egg and sperm cells.
* Or as a result of issues with the reproductive system of the female.
52
When are artificial hormones used to treat infertility?
Artificial hormones are used to treat infertility when the female is not producing enough eggs, usually as a result of the pituitary gland not producing sufficient FSH to cause egg maturation.
53
How are artificial hormones used to treat infertility?
The hormones FSH and LH are given as a ‘fertility drug’ to stimulate egg production.
54
What are the issues with using artificial hormones to treat infertility? (3)
* Several eggs can be released at once so this increases the chance of multiple births (twins or triplets etc).
* It also doesn’t have a particularly high success rate.
* It can be expensive.
55
What is IVF?
In Vitro Fertilisation
56
What is the 8 step process for IVF?
* Test M + F blood tests for hormones and a sperm count. Come to diagnosis.
* Give female high doses of FSH for ovarian stimulation (of follicles). Followed by high dose of LH to release an egg.
* Egg retrieved in fertility clinic via key hole surgery. Try to retrieve up to 10 eggs.
* Sperm retrieval in fertility clinic => ejaculation into vessel.
* Fertilisation in 'glass' => production of zygote.
* Mitosis takes place.
* Embryo transferred into woman's uterus.
57
What is ICSI?
Intra Cytoplasmic Sperm Injection
58
What is the success rate of IVF?
30%
59
How have improvements and advancements in medical technologies helped to improve the success rate of IVF?
Improvements in microscope techniques and micro-tools, which enable single cells to be removed from an embryo for genetic testing to identify if the embryo is healthy or has genetic defaults the couple might want to consider.
60
What are the potential issues of IVF? (5)
* As several embryos are implanted, the risk of multiple births is quite high (which increases the risk of miscarriage or stillbirths).
* The success rate is not very high (although it is increasing); IVF treatment failures can be very emotionally upsetting and physically stressful for couples.
* Some women use IVF to get pregnant at a later age than they would be able to conceive naturally.
* Some people are against IVF as more embryos can be produced than are used; the issue of who owns these embryos and whether they are used in research before eventually being destroyed is contentious (as embryos are a potential life).
* The use of genetic testing is controversial as there is potential it could be misused in choosing characteristics of offspring (this is not allowed).
61
When is adrenaline produced?
In response to stressful or scary situations, the brain triggers the release of adrenaline from the adrenal glands.
62
Where are the adrenal glands?
The adrenal glands are located just above the kidneys.
63
What does adrenaline do?
Adrenaline increases the heart rate and boosts the delivery of oxygen and glucose to the brain and muscles, preparing the body for ‘flight or fight’.
64
How does adrenaline help with 'flight of fight'?
Increased glucose and oxygen are needed by the cells for respiration to release energy; the delivery of more enables more energy to be released (to fuel the muscles to move/run away for example!).
65
What is thyroxine?
Thyroxine is a hormone that is released from the thyroid gland (which is located in the neck).
66
What are 2 of thyroxines main roles in the body?
* It stimulates the basal metabolic rate (BMR); this is the speed at which chemical reactions occur in the body when it is at rest.
* It also stimulates protein synthesis in cells, which is important for growth and development.
67
What is TSH?
Thyroid Stimulating Hormone
68
What are thyroxine levels controlled by?
Thyroxine levels are controlled by negative feedback; with levels of TSH released from the pituitary gland responsible for maintaining normal levels in the bloodstream.
69
What happens if thyroxine levels are too high?
If the level of thyroxine is too high; the release of TSH is inhibited, so less thyroxine is released from the thyroid gland.
70
What happens if thyroxine levels are too low?
If the level of thyroxine falls below a normal level, the release of TSH from the pituitary gland is increased, which stimulates the thyroid to release more thyroxine.
71
What are two conditions relating to the thyroid gland?
* Hyperthyroidism
* Hypothyroidism
72
What is hyperthyroidism?
Hyperthyroidism is caused by an overactive thyroid gland secreting too much thyroxine into the bloodstream resulting in an increase in BMR and protein synthesis.
73
What is hypothyroidism?
Hypothyroidism is caused by an underactive thyroid gland secreting too little thyroxine into the bloodstream which can lead to heart and nerve problems, and death.
74
What are the types of tropisms?
* Phototropism => light
* Gravitropism => gravity
75
How do shoots grow?
The shoots must grow upwards, away from gravity and towards light, so that leaves are able to absorb sunlight – shoots show a positive phototropic response and a negative gravitropic response.
76
How do roots grow?
Roots need to grow downwards into the soil, away from light and towards gravity, in order to anchor the plant and absorb water and minerals from the soil particles - so roots show a negative phototropic response and a positive gravitropic response.
77
Where do auxins come from?
They are mostly made in the tips of growing stems and roots, which are known as apical meristems, and can diffuse to cells behind the tips.
78
How do auxins control the growth of plants?
By promoting cell division and causing elongation in plant cells.
79
How do auxins work in plant stems/ shoots?
In the shoots auxin promotes cell elongation; more auxin = more cell elongation = more growth.
80
How do auxins work in plant roots?
In the roots auxin inhibits cell elongation; more auxin = less cell elongation = less growth.
81
What is the distribution of auxins affected by in the shoots?
Light and gravity
82
What is the distribution of auxins affected by in the roots?
Gravity
83
How does gravity affect the growth of roots and shoots? (3)
* If a shoot or root is placed on its side, auxins will accumulate along the lower side as a result of gravity; so the uppermost side has a lower auxin concentration.
* In the shoots, the lower side grows faster the upper side, so the shoot grows upwards.
* In the roots, the lower side grows slower than the upper side (as auxin inhibits cell elongation and growth in the roots), so the root grows downwards.
84
How does the plant grow if light is all around the tip?
If light shines all around the tip, auxin is distributed evenly throughout and the cells in shoot grow at the same rate.
85
What happens if light is shone on only one side of the plant? (3)
* When light shines on the shoot predominantly from one side, the auxin produced in the tip concentrates on the shaded side.
* This makes the cells on that side elongate and grow faster than the cells on the sunny side.
* This unequal growth on either side of the shoot causes the shoot to bend and grow in the direction of the light.
86
What is a clinostat?
A machine used to investigate gravitropisms.
87
What does a clinostat do?
The clinostat rotates a plant/ seedlings slowly so they do not experience the effects of gravity and the plant/ seedlings will not grow against the force of gravity (negative gravitropism).
88
What are the 3 main uses of auxins?
* As selective weed killers
* As rooting powders
* For promoting growth in tissue culture
89
How are auxins used as selective weed killers?
Auxins negatively effect the growth of broad-leaved plants, which are weeds, in comparison to the narrow- leaved grasses and cereals grown as crops for food production.
90
How are Gibberellins used? (3)
* Important in initiating seed germination => process that occurs when a seed starts to grow.
* Have a role in inducing flowering.
* Promote the growth and development of fruits.
91
How is ethene used in plants?
Ethene is a gas released by plants which controls cell division and ripening of fruits. Therefore when ripening needs to be encouraged, artificially produced ethene gas can be released to speed up the process.
92
What is the apparatus needed for required practical 8 => investigating the effect of light or gravity on the growth of newly germinated seedlings? (5)
• some white mustard seeds
• three Petri dishes
• cotton wool
• a ruler
• water
93
What is the method for required practical 8 => investigating the effect of light or gravity on the growth of newly germinated seedlings? (9)
1. Set up three petri dishes containing cotton wool soaked in equal amounts of water.
2. Put ten mustard seeds in each dish.
3. Put the dishes in a warm place. They must not be disturbed or moved.
4. Allow the mustard seeds to germinate and water daily with equal amounts of water to each dish.
5. Each dish should have the same number of seedlings after the seeds have geminated. Remove excess seedlings from any dish that has too many.
6. Measure the height of each seedling in mm.
7. Move the petri dishes into position.
* Put one on a windowsill in full sunlight.
* Put the second one in partial light.
* Put the third one in darkness.
8. Measure the height of each seedling every day, for at least five consecutive days.
9. Record the heights in a table. Having a table for each position.
94
What is the basic conclusion for required practical 8 => investigating the effect of light or gravity on the growth of newly germinated seedlings?
* Plants grow tallest in darkness => looking for light.
* Grew least in full light.
