AQA BIOL2 Biology Unit 2 Exam - 26th May 2011

Reply 1180

zimmobug

what did you put for the frog eggs one?

Reply 1181

ThEStArE

Original post by zimmobug

what did you put for the frog eggs one?

The answer was that frog eggs are small and have a high surface area: volume ratio, which means that nutrients oxygen and what not can diffuse across it's body surface. As a result, so does the water containing pesticides, which kills the eggs

Reply 1182

sunnybacon

12

Original post by zimmobug

what did you put for the frog eggs one?

I put pesticides enter the eggs (by osmosis, which is wrong, I should have put diffusion) and may cause harm to the developing tadpoles.
One of my friends put the small eggs have a large SA:vol ratio so a lot of pesticide diffuses in which sounds better than my answer :tongue:

Another one of my friends put that pesticide lowers the water potential of the surrounding water, and so water is drawn out of the eggs by osmosis.

Reply 1183

CrazyDaisy123

Original post by thestare

percentage i got 35.7% i did

(14-9)/14 x 100.

Which is wrong, the answer is 55%

(14-9)/9 x 100

but i'm going to assume you get a mark for doing 14-9 = 5

wahoo i got 55%

Reply 1184

NutterFrutter

I think I'm going to get a B. :frown:

Reply 1185

ThEStArE

For the 6 marker at the end, what did we have to say? I know about vertical and horizontal gene transmission, but selection? What did we have to say for that?

Reply 1186

liviaaa

Original post by ThEStArE

The answer was that frog eggs are small and have a high surface area: volume ratio, which means that nutrients oxygen and what not can diffuse across it's body surface. As a result, so does the water containing pesticides, which kills the eggs

Original post by sunnybacon

I put pesticides enter the eggs (by osmosis, which is wrong, I should have put diffusion) and may cause harm to the developing tadpoles.
One of my friends put the small eggs have a large SA:vol ratio so a lot of pesticide diffuses in which sounds better than my answer :tongue:

Another one of my friends put that pesticide lowers the water potential of the surrounding water, and so water is drawn out of the eggs by osmosis.

Yay I put large s.area: volume ratio!

Reply 1187

ThEStArE

Original post by NutterFrutter

I think I'm going to get a B. :frown:

If I don't get an A in this paper there's no hope for me haha, I'll shoot myself! I'm sure you'll do better than you think!

Reply 1188

liviaaa

How did you work out the time for the cell cycle?

I got 774? You had to times the minutes by 3, from what I've seen in questions I've done off the old spec.

Reply 1189

sunnybacon

12

Original post by ThEStArE

For the 6 marker at the end, what did we have to say? I know about vertical and horizontal gene transmission, but selection? What did we have to say for that?

Basically, the bacteria with the advantageous mutation that results in them being resistant to the antibiotic are the ones more likely to survive, and thus more likely to reproduce. This is essentially natural selection - biological traits become more or less common in a population due to the increased chance of survival having those traits - in this case, antibiotic resistance. :smile:

Reply 1190

liviaaa

Original post by swiftylol

Err I thought i finished till I found out I missed 2 pages :colonhash:

Btw what did you guys put for the athlete question?

They have more red blood cells, so more haemologlobin, so can load more oxygen. Oxygen is needed for aerobic respiration during excercise. So more oxygen allows more aerobic respiration in muscles. :smile:

Reply 1191

NutterFrutter

Horizontal, vertical gene transmission, natural selection leads to resistant bacteria survivng and further reproducing asexually.

Further expansion of that for 6 marks.

Reply 1192

ChemistryProNOT

Original post by CrazyDaisy123

wahoo i got 55%

I must have read the graph wrong because I didn't get 9 at 1996 I read it around 9.6, so got a percentage of 45.8%. Ah well that'll teach me for rushing.

Reply 1193

zimmobug

Original post by liviaaa

How did you work out the time for the cell cycle?

I got 774? You had to times the minutes by 3, from what I've seen in questions I've done off the old spec.

i swear you have to times the minutes by 4 to get 8 eggs? because 3 divisions makes 7 eggs

Reply 1194

ChessMister

12

Anybody who cares about or values their worry free state of mind leave this thread now, as there will be a lot of conjecture! I am going in five minutes...maybe 6

Reply 1195

ThEStArE

Original post by liviaaa

Yay I put large s.area: volume ratio!

I think i wrote small surface area to volume ratio!!!! i was rushing and wasn't thinking and when i saw the word small eggs it made me write down small AHHH haha only 1 mark, i got the second mark but that's pretty stupid thing to do :P

Reply 1196

sunnybacon

12

Now it's my turn to ask a question :tongue:

What did you guys put for the second part of the frog eggs question, about what effect evaporation of water had? I put the concentration of pesticide increased....
And also, what about the question asking why ten leaves were used in the experiment, measuring water loss in milligrams? For that, I put because the change in mass of one leaf is too small to measure, so ten leaves allows a significant change to be measured.

...or similar words to that effect :biggrin:

Reply 1197

NutterFrutter

Horizontal, vertical gene transmission, natural selection leads to resistant bacteria survivng and further reproducing asexually.

Further expansion of that for 6 marks.