Phototropism - Auxins are prduced into the tip of the shoot they defuse down the the shoot and the side at which is facing the sun, there auxins are broken down. The shady side auxins stimulate growth causing the shoot to bend towards the light.
Gravitropism - roots produce auxins which are sensitive to gravity, the auxins build up at the side at which gravity pulls down. This stimulated growth on the opposite side of the plant causing it to grow down
Q what are the advantages and disadvantages of gm 6 marks
Advantages: You can produce useful substances (insulin) which can be used to treat human diseases. Has the potential for solving many problems. An example of this is that people who live in developing countries often lack nutrients in their diet and GM crops could provide them with the nutrients they're missing. Can make genetically modified crops that are resistance to viruses, herbicides, insects etc which will increase the yield of crops.
Disadvantages: Genetically modified crops could reduce biodiversity. There are concerns about the long term effects.
(And i would write it all in full sentences, not bullet points as such)
Q. Why is antibiotic resistance becoming more common?
1. message travels across neurone as electrical impulse 2. when impulse reaches the synapse the neurone releases a chemical impulse 3. the chemicals diffuse across the synapse gap (junction) 4. chemicals are detected by receptors on target neurone, triggering an electrical impulse
1. message travels across neurone as electrical impulse 2. when impulse reaches the synapse the neurone releases a chemical impulse 3. the chemicals diffuse across the synapse gap (junction) 4. chemicals are detected by receptors on target neurone, triggering an electrical impulse
Steps in drug trialling: Firstly, the drug is discovered (not sure if optional). Then lab research is done on it. Next, it is tested on animals, then cells/ tissues, then on human volunteers. Penultimately the drug is evaluated by researchers before it is finally sold to doctors.
Q: How does vaccine make someone immune to a disease (3 marks)
A vaccine contains a dead/inactive pathogen of the disease. This allows your white blood cells to produce antibodies that can lock onto the antigens. Your body then remembers these antibodies and when you get the real disease these antibodies can reproduce rapidly, killing the disease before you get ill
This forum post is actually a really good revision resource for me personally. Seeing how people answer questions is helping me develop my answers :P Just gonna skim over it all a few times. Thanks everyone for your contribution!
How would I anwer a 6 marker on homeostasis? Help?!
It depends on the question but I would guess you would talk about how the ion content is regulated (kidneys), how water content is regulated (how it gets in and is removed from your body) and how the body temperature is regulated, or something along those lines hope this helps
Q. Explain the role of FSH, Oestrogen and LH in the menstrual cycle.
FSH --> produced in the pituitary gland, causes an egg to mature and stimulates the production of oestrogen
Oestrogen --> produced in the ovaries, inhibits the production of FSH, stimulates the production of LH and stimulates the thickening of the uterus lining
LH --> produced in the pituitary gland, causes the release of a mature egg
--> Describe how to take and grow an uncontaminated culture (6 marks) <--