Download Cell Respiration Exam - Data Analysis and Essay Markscheme

Cell Respiration Exam – Data Analysis and Essay Markscheme
17.
(a)
(b)
(c)
Q: anaerobic respiration / fermentation;
R: aerobic respiration / Kreb’s (citric acid) cycle;
2
A: pyruvate / 3-oxopropanoate;
D: carbon dioxide;
2
mitochondrion;
1
[5]
18.
(a)
(i)
carbon dioxide and water
Need both to receive the mark.
1
(ii)
heat / energy
1
1
(b)
(c)
starch is broken down transforming into sugar;
chlorophyll is broken down so bananas change from green to yellow;
increase in respiration causes water release and CO2 formation;
2 max
reduce heat of cargo / refrigerate (bananas) to slow respiration rate;
lower oxygen / raise nitrogen / carbon dioxide level in cargo
atmosphere to inhibit respiration rate;
shorten transport distance / time so less time to over ripen;
2 max
[6]
19.
(a)
mitochondria
1 max
(b)
shows membrane of a mitochondrion / chloroplast;
H+ is pumped out across membrane;
more H+ outside (from electron transport chain);
concentration gradient of H+ is formed / potential energy;
H+ movement across membrane through protein channels in ATP
synthetase;
ADP is phosphorylated / picks up phosphate to ATP;
ATP has more energy than ADP;
chemiosmosis;
3 max
[4]
20.
(a)
(i)
A: cristae / inner membrane;
B: matrix;
1
Both needed for [1].
(ii)
A: electron transport / proton transport;
B: Krebs cycle / ATP synthesis;
1
Both needed for [1].
(b)
large surface area of cristae allows electron transport / oxidative phosphorylation
to be very efficient;
matrix provides necessary chemical environment for the Krebs cycle;
small distance between inner and outer membranes allows rapid movement
of molecules between cytosol and matrix;
small space between membranes allows protons to be
accumulated / concentrated;
3 max
[5]
2
Essay 21)
Award [1] for each correct row, up to [5 max].
Aerobic respiration
Anaerobic respiration
occurs in mitochondria
occurs in cytoplasm;
requires O2
occurs without O2;
both produce pyruvate from glucose (glycolysis);
uses fatty acids / lipids / amino
acids
doesn’t use fatty acids;
(Krebs cycle) produces CO2 and
H2O
(fermentation) produces ethanol / CO2
(in yeast);
(Krebs cycle) produces CO2 and
H2O
(fermentation) produces lactate in
animals (humans);
NADH produced in both;
large amount of ATP (36 per
glucose
molecule) produced
small amount of ATP (2 per glucose
molecule) produced;
5 max
Essay 22)
glucose is broken down to pyruvate in the cytoplasm;
with a small yield of ATP / net yield of 2 ATP;
and NADH + H+ / NADH;
aerobic respiration in the presence of oxygen;
pyruvate converted to acetyl CoA;
acetyl CoA enters Krebs cycle;
Krebs cycle yields a small amount of ATP / one ATP per cycle;
and FADH2 / FADH + H+ / NADH / NADH + H+ /
reduced compounds / electron collecting molecules;
these molecules pass electrons to electron transport chain;
oxygen is final electron acceptor / water produced;
electron transport chain linked to creation of an electrochemical gradient;
electrochemical gradient / chemiosmosis powers creation of ATP;
through ATPase;
[8]
3