1
Q
What happens when blood glucose levels are too high?
A
- a high blood sugar is detected by the pancreas, which then releases a hormone called insulin into the blood
- the insulin tells the liver to remove the glucose from the blood and convert it to glycogen
2
Q
What happens when blood glucose levels are too low?
A
- the pancreas detects a low blood sugar and releases glucagon into the blood.
- glucagon tells the liver to convert the glycogen to glucose and release it into the blood
3
Q
What is Type 1 diabetes and how is it treated?
A
- the pancreas produces little or no insulin
- insulin therapy is used to treat it
- insulin is injected several times a day (often at meal times).
- this makes sure the glucose is removed from the blood quickly once food has been digested.
4
Q
What is Type 2 diabetes and how is it treated?
A
- the body becomes resistant to insulin
- treated by limiting the intake of foods rich in simple sugars
5
Q
What is auxin?
A
-auxins are plant hormones which control growth at the tips of the shoots and the roots
6
Q
How does auxin grow plants?
A
- auxin is produced in the tips and diffuses backwards to stimulate the cell elongation process which occurs just behind the tips
- auxin promotes growth in the shoots
- auxin inhibits growth in the roots
7
Q
How are shoots positively phototropic?
A
- shoots grow towards the light
- when a shoot tip is exposed to light, more auxin accumulates on the shaded side
- the cells grow (elongate) faster on the shaded side, so the shoot bends towards the light
8
Q
How are shoots negatively geotropic?
A
- shoots grow away from gravity
- when a shoot is growing sideways, gravity produces an unequal distribution of auxin in the tip, with more on the lower side
- the lower side grows faster, bending the shoot upwards
9
Q
How are root positively geotropic?
A
- roots grow towards gravity
- roots growing sideways have more auxin on the lower side
- auxin inhibits growth in roots
- the cells on top elongate faster, and the root bends downwards
10
Q
How are roots negatively geotropic?
A
- roots grow away from light
- if the root is exposed to light, more auxin accumulates on the shaded side
- cell elongation is inhibited on the shaded side, so the shoot bends downwards
11
Q
What experiment shows auxins are produced in the tip of a plant?
A
- three plants
- leave on uncovered, put a cover to keep light out on the tip of one and halfway on another
- the plant that is covered at the tip is the only one that doesn’t bend
12
Q
What experiment shows auxins cause bending by building up on the shaded side if the root?
A
- a shoot tip is removed and placed on agar jelly to soak up the auxin from the tip
- agar is placed on one side of the tip-less shoot (in darkness)
- shoot bends away from side with auxin
