Thought i'd write some of my answers i've been unsure of:
2008- Q29C, Q32A
2010- Q28A, Q31D
1998 (lol)- Q49D, no idea about Q 50 and 56
2008.
Q28: C
I agree it is C, lecture 33 slide 9 basically gives you the answer.
Q32: I have no freaking idea... Did we go though this in our lectures??? :S
2010 exam
Q28: A
Yea i remember reading that to increase copy number, reduce size of the plasmid.
Q31: D
I'm not sure about this either!! Wow the questions you've presented so far are pretty hard.....I'm hoping you only picked out the hardest ones

I havne't looked at the whole exam yet.
Maybe Golden can help.
LOL btw i can't find the 1998 exam on the LMS

Will have to search for it later somehow.
But for now, i'm actually enjoying memorising the step of glycolysis!! IT's surprisingly fun haha