Help with some biology questions?

Question

I was going through past biology papers and came across a few questions i found difficult. I'd appreciate any help...
1)Suggest why treating diabetics with insulin made by genetically engineered bacteria may be better than with insulin made by pigs/cattle.
2) How do decomposers break down carbon-containing compounds from dead remains of plants?
3) Why isn't starch digested in the stomach?

ooh i forgot one more:
The nerve pathway linking a heat receptor in the hand with arm muscle is about 1.5m long. It would take a nervous impulse 0.02s to travel this dist. along a neurone, yet it takes 0.5s for the arm to start moving during a reflex response to heat. Explain why.

Regarding qu 2...the question said "suggest why..." which we've been told means it's not necessarily something we've learnt - just what we have to think about. Plus its 2 reasons...sorry for not making that clear.

Answer 1

1. The insulin made by genetic engineering is made using the human insulin gene. Use of pig and bovine insulin will eventually result in an immune response against the foreign insulin, and it will no longer work. Human insulin will not produce an immune response in the diabetic person.

2. The metabolize all of the organic molecules just as you metabolize the stuff that you eat.

3. Starch isn't digested in the stomach because there is no enzyme in the stomach that degrades starch. Amylase enzymes are found in saliva and in the small intestine.

Answer 2

Hello there - good luck in the biology exam

1) bacteria release a lot of extracellular enzymes but with cattle you would have to extract it.
they produce a lot of enzyme relative to their ratio.
they are easy to control and manipulate (genetically) - not proding them ... lol

2) They release extracellular enzymes that breakdown the molecules and then the beacteria engulf it

3) In the stomach the conditions are too acidic for amylase
Instead it happens in the duodenum and mouth.