(c)
inhibitor binds (to the enzyme) away from the active site /
at allosteric site;
shape / (intramolecular) bonding / conformation of the protein /
enzyme is altered;
shape / properties of active site altered;
substrate no longer fits the active site /
no enzyme-substrate / ES complex formed;
no enzyme activity /
works more slowly (until the inhibitor dissociates);
3 max
Award [1 max] if competitive inhibition is described.
[10]
15.
(a)
liver stores excess glucose as glycogen / releases glucose from glycogen
(as levels drop);
liver breaks down red blood cells / hemoglobin and stores iron;
liver stores fat soluble vitamins / vitamin A / vitamin D / vitamin B12 /
folic acid;
2 max
(b)
lipids are hydrophobic / not water soluble;
bile helps to break up lipid droplets / bile emulsifies fats / increases
surface area of lipid droplets for lipase attack;
lipids more accessible to lipase / lipase breaks down lipids;
pancreatic juices brings up pH as optimal pH for lipase is alkaline / pH8;
2 max
[4]
(c)
inhibitor binds (to the enzyme) away from the active site /
at allosteric site;
shape / (intramolecular) bonding / conformation of the protein /
enzyme is altered;
shape / properties of active site altered;
substrate no longer fits the active site /
no enzyme-substrate / ES complex formed;
no enzyme activity /
works more slowly (until the inhibitor dissociates);
3 max
Award [1 max] if competitive inhibition is described.
[10]
16.
(a)
Two of the following needed for [1].
pancreatic;
salivary;
gastric pits / gastric glands;
glands in intestinal wall / krypts / Brunner’s gland;
liver
1 max