B1g

Question 1

What happens when blood glucose levels are too high?

Answer 1

• 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

Question 2

What happens when blood glucose levels are too low?

Answer 2

• 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

Question 3

What is Type 1 diabetes and how is it treated?

Answer 3

• 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.

Question 4

What is Type 2 diabetes and how is it treated?

Answer 4

• the body becomes resistant to insulin

- treated by limiting the intake of foods rich in simple sugars

Question 5

What is auxin?

Answer 5

-auxins are plant hormones which control growth at the tips of the shoots and the roots

Question 6

How does auxin grow plants?

Answer 6

• 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

Question 7

How are shoots positively phototropic?

Answer 7

• 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

Question 8

How are shoots negatively geotropic?

Answer 8

• 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

Question 9

How are root positively geotropic?

Answer 9

• 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

Question 10

How are roots negatively geotropic?

Answer 10

• 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

Question 11

What experiment shows auxins are produced in the tip of a plant?

Answer 11

• 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

Question 12

What experiment shows auxins cause bending by building up on the shaded side if the root?

Answer 12

• 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