Homeosatis And Response- Paper 2 Flashcards
What hormones can you use to increase fertility (2) and why with pros and cons? 2 cons
1)women levels of FSH and LH too low to cause their eggs to mature. no eggs are released, women can’t get pregnant.
2) hormones FSH and LH can be given to women in a fertility drug to stimulate ovulation.
CONS
It doesn’t always work - so repeat=expensive.
Too many eggs could be stimulated=unexpected multiple pregnancies
What is IVF and how does it work?
IVF (“in vitro fertilisation”). involves collecting eggs from the woman’s ovaries and fertilising them in a lab using the man’s sperm.
How does IVF work and pros + cons? 4, 1 pro and 4 cons
1) FSH and LH are given before egg collection to stimulate several eggs to mature
2) Sperm Injection sperm is injected directly into an egg. useful for very low sperm count.
3) fertilised eggs are then grown into embryos in a laboratory incubator.
4) Once embryos are tiny balls of cells, one or two transferred to the woman’s uterus to improve the chance of pregnancy.
CONS
.Multiple births
.miscarriage, stillbirth
.success rate low=upsetting
.strong reaction to hormones
What 3 Advances in microscope techniques have helped IVF?
1.Specialised micro-tools have been developed to use on the eggs and sperm under the microscope.
2.remove single cells from the embryo for genetic testing (to check that it is healthy)
3.time-lapse imaging growth of the embryos can be monitored to help identify those likely to result successful pregnancy.
What are 2 reasons People Are Against IVF?
- process of IVF results in unused embryos destroyed. unethical embryo is a potential human life.
2.genetic testing of embryos before implantation ethical issues could lead selection of preferred characteristics.
What does adrenaline do where is it released and what is it?
.Adrenaline=hormone
.released by the adrenal glands, above the kidneys
.response to stressful Situations
How does adrenaline work
what is negative feedback?
1.triggering mechanisms increase supply of oxygen and glucose to cells Brain and muscles.
2.control the levels of hormones in blood using negative feedback.
what is Thyroxine job, where is it made, how does it do its job?
1.Regulates Metabolism
2.made in the thyroid gland.
3.regulates metabolic rate - speed chemical reactions and process in the body occur while the body is at rest
Negative feedback with thyroxine? 3
high
1.thyroxine in the blood is higher than normal
2.secretion of Tyorid Stimulating Hormone from pituitary gland is inhibited reduces the amount of thyroxine released from thyroid gland
3.level in the blood falls back towards normal.
What is a Auxin location where it controls growth, and what are the responses to light and gravity called?
.Auxin plant hormone controls growth near the tips of shoots and roots.
.response to light (phototropism) and gravity (gravitropism)
Where is Auxins produced and how does it work where does it occur in the tips?
.Auxin is produced in tips
-moves backwards to stimulate cell elongation
-process occurs in the cells behind the tips.
What happens when the tip of a plant is removed and what does extra auxin do?
.no auxin is available shoot stop growing.
.Extra auxin promotes growth in the shoot but inhibits growth in the root
what is Phototropism? how does it work? 2
Shoots grow towards light
1) shoot tip is exposed light, more auxin accumulates
side that’s in shade
2)cells grow (elongate) faster on the shaded side,
so the shoot bends towards the light.
Method of Investigate effect of light on Plant Growth Responses? 3
1)Put 10 cress seeds into three different Petri dishes, each lined with moist filter paper.(label A, B, C.)
2) Shine a light onto one of the dishes from above and two of the dishes from different directions.
3) Leave cress seeds a week until you can observe their responses -seedlings grow towards light
Variables of The experiment (light effect on seeds) and how to control them? 5
.
How to investigate gravity in plants? 3
- place four seedlings on damp cotton wool in a Petri dish,
2.roots pointing in a different direction
3.. store the Petri dish vertically for a week in dark. =roots of each seedling grow downwards.
What are the 3 uses of Auxins?
1) KILLING WEEDS -
weeds broad-leaved, opposite cereals narrow leaves.
-only affect the broad-leaved plants. disrupting growth patterns= kills them crops untouched.
2) GROWING FROM CUTTINGS WITH ROOTING POWDER -
produce roots rapidly and start growing as new plants. enables growers to produce lots of clones really good plant quickly.
3) GROWING CELLS IN TISSUE CULTURE -
auxins added to the growth medium stimulate the cells to divide form both roots and shoots.
What is gibberellin, what is the 3 things it does?
Gibberellin is another type of plant growth hormone. It stimulates seed germination, stem growth and flowering.
What are the 3 uses for gibberellin?
1) CONTROLLING DORMANCY -
germinate certain conditions
gibberellin make them germinate all the seeds in a batch germinate at the same time.
2) INDUCING FLOWERING -
gibberellin, they will flower without any change in environment. grow bigger flowers.
3) GROWING LARGER FRUIT -
Seedless do not grow as large as seeded fruit. gibberellin grow larger
How does Ethene Stimulates Ripening of Fruit and how can this be used (3)?
HOW:growth controlling cell division. stimulates enzymes that cause fruit to ripen.
1)speed up the ripening of fruits
transport to the shops.
2) picked unripe firmer,less easily damaged
3)Ripening delayed fruit is in storage preserved by adding chemicals that block ethene’s effect
What is homozygous and heterozygous?
homozygous for a particular gene means you inherited two identical versions.
It’s the opposite of a heterozygous genotype, where the alleles are different.
What two things can you interpret form a family tree?
- allele for a disorder is a dominant because family members carry it not the disorder
- You can work out percentages by who are carriers unaffected and who has it
What is cystic fibrosis, and how do you get it and where 2 places does it occur? 2
Genetic disorder of the membranes which causes mucus in the air passages and in the pancreas.
1. Allele is recessive, only one copy won’t cause it=Carrier
2. Both parents have it means you have it.
What is polydactyl? 2
Genetic disorder when are babies born with an extra finger or toes
1. always Dominant allele, causes it, only one parent need to have it.
2. defective allele which can be inherited