2009 Biology Unit 3 Exam Suggested Solutions

[polky]

I have no idea how you got C for 5 because the largest component should be on the bottom. ! so how will you retrieve the nucleus first?

Because the nucleus is pretty big?  You can see it in a light microscope.

[lukeperry91]

For the final question, were students expected to talk about increased conformity to the active site of the enzyme that binds cdl-2 and chemical four?

[shinny]

I have no idea how you got C for 5 because the largest component should be on the bottom. ! so how will you retrieve the nucleus first?

Isn't that the point? The nucleus is the largest chunk, so after the first centrifuging it'll be the pellet at the bottom which you extract. Then you take the left over fluid, and spin it again at a higher speed and so forth. Remember that they're listing in order of the PELLETS, not supernatant (leftover) fluid.

[lukeperry91]

By the way guys in case anyone was wondering, last year you could lose 25 marks out of 150 marks, and still get an A+, and this year's exame is relatively harder compared to '08, so an A+ cutoff is probably more than 25 marks

[mmmmm]

For 3b.
can you put CO2?

[polky]

For 3b.
can you put CO2?

I think that should be accepted.

[Pumpkinator]

can tRNA be found in the ribosomes , as it carries the amino acids there for protein synthesis?

[lukeperry91]

I think they wanted in the area surrounding the ribosomes

[Pumpkinator]

it just says 'where is tRNA found in the cell'

[hard]

wait i dont get 17, 18 and 25 of MC? can someone explain please?!

[shinny]

For 3b.
can you put CO2?

Yep. I'll add that in.

can tRNA be found in the ribosomes , as it carries the amino acids there for protein synthesis?

Stuff can't be 'in' the ribosomes. They're simply made of two protein/nucleic acid complexes and aren't really membrane-bound organelles so yeh.

it just says 'where is tRNA found in the cell'

But ribosomes aren't the only place. The cytoplasm is the more correct answer by far.

[Pumpkinator]

ahh ok 

[hard]

For 3b.
can you put CO2?

Yep. I'll add that in.

can tRNA be found in the ribosomes , as it carries the amino acids there for protein synthesis?

Stuff can't be 'in' the ribosomes. They're simply made of two protein/nucleic acid complexes and aren't really membrane-bound organelles so yeh.

it just says 'where is tRNA found in the cell'

But ribosomes aren't the only place. The cytoplasm is the more correct answer by far.

could they accept the cytoplasm and ribosomes?

[Pumpkinator]

i hope so  :2funny:

[shinny]

could they accept the cytoplasm and ribosomes?

They always 'could', but I'd say the chances are really low. It's incorrect for the two reasons I've stated above.