1.
B
2.
C
3.
D
4.
B
5.
B
6.
C
7. A
8. E
9. B
10. C
11. B
12. A
13. D.
1 (a) Award [1] for each structure clearly drawn and correctly labelled.
1. Z lines;
2. actin filaments;
3. myosin filaments with heads;
4. light bands and dark bands;
(b)
1. Ca2+ ions released when a nerve impulse arrives at the muscle;
2. Ca2+ ions are released from the sarcoplasmic reticulum;
3. The binding sites for myosin heads are exposed on the actin protein;
4. The exposure of the binding sites on actin allow for a cross-bridges between myosin and
actin to form;
2.
(a)
(i)
(ii)
biceps and triceps correctly labelled;
(biceps = muscle on right, triceps = muscle on left)
Both needed for mark.
1
(cartilage is hard but flexible) able to absorb mechanical shocks /
allows bones to pivot or move smoothly
1
(b)
1. ATP binds to myosin heads, and the ATP is hydrolyzed to ADP + Pi;
2. ATP broken down/hydrolysed to ADP + Pi, causing myosin heads to become energized
3. ADP + Pi is released causing the myosin heads to push actin filament along its length
towards the center of the sacromere, this push is called the power stroke occurs;
4. ATP binds to the myosin head and causes the actin + myosin cross bridges to break and
the myosin heads detach from binding site;
5. If calcium is still present in the sarcomere, the myosin heads attach to another binding
sites on actin filament further along sarcomere;
IB Questionbank Biology
1
3.
Award [1] for each of the following structures of the kidney clearly drawn and correctly
labelled.
cortex shown at the edge of kidney;
medulla shown inside the cortex with pyramids;
pelvis shown on the concave side of the kidney;
ureter shown connected to the pelvis on the concave side;
renal artery and vein shown originating from the concave side;
calyx/papilla; [4 max]
(b)
1.
2.
3.
4.
5.
6.
7.
8.
9.
ultrafiltration of high pressure blood occurs in the glomerulus;
glomerular filtrate (from ultrafiltration) is produced in Bowman’s capsule;
This filtrate flows into proximal convoluted tubule;
80% of water is reabsorbed in from the filtrate in the proximal convoluted tubule;
filtrate leaves the proximal convoluted tubule and enters the descending limb loop of Henle;
The descending limb of Henle is permeable to water and water drawn out by osmosis;
The ascending limb of Henle pumps sodium into the tissue of the medulla;
The ascending limb of Henle ascending limb impermeable to water;
The concentration of soluted decreases in the ascending limb of Henle, because sodium
ions are actively pumped out.
10. The filtrate solute concentration in distal convoluted tubule equals solute concentration in
proximal convoluted tubule;
11. If the blood plasma has a high solute concentration ADH released/ ADH controls water
balance in the blood;
12. ADH makes collecting duct water permeable to water;
13. ADH allows water to move from the urine in the collecting ducts into tissues and blood
plasma. This movement causes the urine is more concentrated; [9 max]
14.
(a)
(b)
positive/direct correlation / as mitochondrial concentration increases so
does HAD activity
fur seal has greater mitochondrial concentration / vice versa;
fur seal has greater HAD activity / vice versa;
lowest value of HAD for fur seal equal to/slightly above highest sea lion
value/ no overlap of data points;
IB Questionbank Biology
1
2 max
2
(c)
1. swimming muscle has a greater mitochondrial concentration than
non-swimming muscle;
2. the range in HAD activity is similar in both, but non-swimming has slightly
larger range;
3. mitochondrial concentration overlaps in the middle range of values for both swimming
and non-swimming muscles / low mitochondrial concentration only in non-swimming
muscle / highest mitochondrial concentration only in swimming muscle;
2
(d)
1. Products of fatty acid oxidation could be used in respiration
so hypothesis could be supported;
2. If there is an increase in HAD activity would mean an increase in fatty acid
oxidation;
3. There was little/no increase in HAD activity in swimming muscles so
hypothesis not supported;
4. During diving low oxygen/hypoxic conditions so high HAD activity and
mitochondrial concentration allows aerobic metabolism to continue so hypothesis could
be supported;;
5. more mitochondria means more aerobic respiration;
6. There are more mitochondria in swimming muscles so there will be more ATP production
and more aerobic respiration in these muscles;
IB Questionbank Biology
3
IB Questionbank Biology
4