Biology Unit 3 Questions Megathread

[shinny]

Answer is B

Doubt they would ask that on exam as it is very indepth knowledge, but it could be one of the harder MC on there

Quite possible IMO. They gave you all the information you needed regarding chaperone proteins as you're not expected to know about them. What you were meant to know about was the word 'folding', which is essentially a tertiary structure process.

[HERculina]

okie. i got b too but i was quite tempted to choose a. this was on one of teh A+ practice tests on enzymes and proteins.
what is a reason for eliminating A?

[shinny]

Because folding of proteins is a tertiary structure process as I said above. Primary structure is only dictated by the order of the amino acids which isn't affected if folding was faulty.

[HERculina]

i dont get it (sorry, im a bit slow in processing things)
are the chaperone proteins helping the protein fold into its tertiary structure. if so, wouldnt the folding part of the q. be irrelevant to how chaperone protein is defective.
thats why i sort of just thought of it as wat makes a protein not work. if the proteins amino sequence was altered it wouldnt even be able to become chaperone = defective chaperone

OH AND DOES ANYONE HAVE THE SOLUTIONS TO A+ PRACTICE TESTS?

[shinny]

It's asking what the effect of defective chaperone proteins on other proteins being synthesised would be - not the chaperone protein itself. That is, if a cell didn't have chaperone proteins to ensure correct folding of other proteins being synthesised, then their tertiary structure wouldn't be correct.

[HERculina]

OHHHHHH ok i get it now! i must read q.s more carefully next time
its totally B then.
ok thanks shinny, cleared up that confusion for me a lot!

[HERculina]

for teh following graph,
The variable being investigated in these two samples was most probably
a)amount of substrate
b)amount of reactant
c)concentration of enzyme
d)pH

[Truck]

I'd probably go for (a), amount of substrate.

[dooodyo]

I think A is wrong since the concentration of product is the same for both haha the answer would most likely be C.
Because sample 1 arrives at its destnatino much quicker than sample 2.

[Russ]

Secondary structures are nowhere near as variable as tertiary structures. Google "Ramachandran Plot" and you'll see what I mean. As such, they don't require chaperone proteins to control their folding.

[Truck]

yeah oops it's C

[HERculina]

okie kewl thats wat i put down.
If ONE amino acid of haemoglobin changed due to mutation, wat structural level (primary/secondary/tertiary/quaternary) would definitely be changed and wat structural level MIGHT change? explain.

[Truck]

OK, the primary structure definitely changed because the primary structure is the sequence of amino acids, and the amino acid has mutated meaning it is different.

Secondary structure MIGHT change, but I'm not really sure how to put that into words except for really saying that there is no longer the same type of bond? So an alpha helix MIGHT become a random coil due to the different bond.

[HERculina]

ok thanks.
i get the first part but for the second part of the q., could it be tertiary as well?

[shinny]

Yeh, secondary, tertiary and quaternary consequently might change. Primary by definition must change.