Answer Scheme

No 1) a)

2) a) i)

Expected answer Go to 2 Go to 5 Gymnopis multiplicata Go to 3 Triturus cristatus Go to 4 Necturus maculosus Ambystoma tigrinum Go to 6 Oreophrynella quelchii Polypedates leucomystax Rana temporaria MP1 A cytoplasm ;

b)

Guideline

B C D G E F A

MP2 B nucleus ; ii) MP1 forms a barrier between the cell and its surroundings ; MP2 keeps contents of cell inside ; MP3 allows / controls /(movement of) substances, into/ out, of the cell/ across membrane ; iii) Irregular shape/rounded shape/not columnar/ not cylindrical/ not rectangular/ no

3) a) i)

Mark [ 6]

specific shape ; MP1 large surface area ; MP2 more surface for respiration ; MP3 allows, increased/ faster/ efficient, respiration ; MP1 passive/ does not require energy ; MP2 substances move down a concentration gradient ; MP3 does not have to occur across a membrane ; MP4 occurs with gases ; MP5 no need for protein, carrier/ channels /pumps ; two marks for the correct answer – if no answer, an incorrect answer or

[2]

[1]

[1]

[1] A moresurface area for enzymes

an answer without the minus sign award one mark for the correct working MP1 183 – 175 = 8 ;

c) i) ii) d)

MP2 8/183 × 100 = – 4.4 ; MP3 transfer the answer on the table line finished to - 4.4/A ecf from (b)(i) MP1 44 ± 1 ; MP2 gdm–3 ; MP1 movement of water ; MP2 by osmosis ; MP3 through partially permeable membrane(s) ; MP4 gain – onion has lower water potential/ solution has higher water potential ; MP5 loss – onion has higher water potential/ solution has lower water potential ;

A: - 4.3 [3] [1]

R extrapolation past 200 gdm–3

[2] A ‘down a water potential gradient’ if direction is correct and clear ignore references to ‘concentrations of water’ [4]