The Student Room Group
Reply 1
asianangel86
couple of questions for you guys.... i'm panicking hard.

1)give an advantage of lactase and other digestive enzymes being located in the plasma membranes of the cells lining the small intestine rather than being secreed into the lumen of the small intestine.

2) the absorption of galactose from the small intestine is reduced if the absorbing cells are treated with a respiratory inhibitor, such as cyanide. suggets an explanation for this.


Don't panic!

1 - enzymes can be adsorbed onto on the surface of cells lining the small intestine as this means the products of digestion can be right next to the cells that will absorb them. this means a faster rate of absorption as the molecules have a very short distance to diffuse.

2 - (this ones a bit of a guess!) cyanide is a competitive inhibitor so will block the carrier proteins in the plasma membrane. Hence galactose won't be able to cross the plasma membranes through these proteins so the rate of absorption would be reduced.
Reply 2
Good luck for tomorrow ppl!!
xxx
Reply 3
thank you!! if i had any left i'd rep you!
We're all going to fail. Yay. [I hope not]
Reply 5
ahhh we'll be fine. if nothing else, we can join the army together! yay!
Polygenic Inheritance? Polyploidy? Gah.
Reply 7
The respiratory inhibitor one is to do with galactose etc. being taken up by active transport. No respiration = no ATP, and we all know what that means :biggrin:

Sorry if this was too late for you, I'm on my usual cram schedule. (cram-get distracted-cram-distract-cram-oh, look, it's 3am...*collapse*)
I can't believe this was 14 years ago wow
I've only just started my a levels
:colondollar:
same