Name:
.
6.6/11.2/11.3/11.4 Reproduction/ Kidneys/ Muscles
1. D
2. B
3. A
4. C
5. A
6. A
7. B
8. C
9. A
10. D
11. C
12. C
13. D
14. D
15. C
16. A
1
(a) I.
II.
III.
thick filament / myosin;
Z line;
A/dark band;
2.Award [1] for each of the following clearly drawn and correctly labelled.
1. loop of Henle;
2. ascending and descending;
3. proximal convoluted tubule; (shown with convolutions)
4. Bowman’s capsule; (shown as a continuation of proximal convoluted tubule)
5. afferent arteriole;
6. efferent arteriole; (with smaller diameter than afferent)
7. distal convoluted tubule; (shown with convolutions)
8. collecting duct; (shown with branches)
9. fenestrated capillaries; (shown as an enlarged diagram)
3
4 max
3.
1.
2.
3.
4.
It is important that some products of digestion not lost during the excretion process;
Products in the blood stream are filtered out of the blood in the glomerulus;
This filtration process is called ultrafiltration ;
Capillaries in the glomerulus are fenestrated/ porous, which allow substances to leave the blood. These
capillaries are supported by cells called podocytes;
5. The capillaries in the glomerulus has a basement membrane that acts as the filter;
6. This basement membrane prevents large proteins and red bloods to pass through because they are too
large;
7. Filtrate from the blood will exit the glomerulus and enter the proximal convoluted tubule (PCT) via the
bowman’s capsule for reabsorption;
8. In the PCT salts / glucose / ions / other named substance are reabsorbed ;
9. The cells of the PCT have microvilli, which increase surface area from reabsorption;
10. The cell membrance of the PCT have protein pumps and many mitochondria so it can actively transport
materials from the lumen of the PCT back to the blood plasma;
11. Water is reabsorbed in the PCT and the descending loop of henle via osmosis.
12. In the ascending limb of loop of henle, salt is actively transported into the medulla of the kidney
creating high solute concentration so water will leave the filtrate via osmosis and return back to the
blood.
4.
1. After a nerve impulse reaches the muscle cells, calcium ions are released from the
sarcoplasmic reticulum (inside the muscle cells);
2. This calcium exposes the myosin binding sites on actin by causing the movement of
blocking molecules/troponin;
3. Once the myosin binding sites are exposed a cross-bridges form between actin and
myosin molecules;
4. ATP provides energy to the myosin head for the cross bridge to form. ATP is attached
to the myosin head and is hydrolyzed to ADP + P. The energy in the original ATP
molecule is transferred to the myosin head;
5. The ADP + P will be released from the myosin head, causing a change in position of
the myosin head, the change results in the “power stroke” causing the actin filaments
to slide over the myosin filaments towards the center of the sacromere;
6. ATP provides energy to release myosin from binding site on actin;
7. This entire action can be repeated further along the actin molecule;
5 max
5.
1. oogenesis is process by which female gametes/eggs are produced;
2. oogenesis begins during fetal development;
2a. oogonia/large number of cells formed by mitosis;
3. oogonia/cells enlarge/undergo cell growth/become primary oocytes via mitosis;
4. primary oocytes begin first meiotic division but stop in Prophase I;
5. primary oocytes stay in Prophase I until puberty;
5a. (at puberty) some follicles develop each month in response to FSH;
6. Once a month after puberty, a primary oocyte will complete its first meiotic division;
7. The result of meiosis I are two cells of different/unequal sizes / unequal distribution
of
cytoplasm;
8. One of these cells created during meiosis I is a polar body;
9. This polar body formed from Meiosis I will eventually degenerates;
10. The larger cell/secondary oocyte formed from Meiosis I proceeds to meiosis II;
11. The secondary oocyte stops at prophase II;
12. The secondary oocyte will complete meiosis II if cell is fertilized;
13. The products of meiosis II are an ovum and second polar body;
8 max
6.
To award full marks, discussion must contain both pro and con
considerations.
pros/positive considerations (3 max):
1. chance for infertile couples to have children;
2. decision to have children is clearly a conscious one due to difficulty of
becoming
pregnant;
3. genetic screening of embryos could decrease suffering from genetic diseases;
4. spare embryos can safely be stored for future pregnancies/used for
stem cell research;
To award full marks, discussion must contain both pro and con
considerations.
cons/negative considerations:
1. IVF is expensive and might not be equally accessible;
2. success rate is low therefore it is stressful for the couple;
3. it is not natural/cultural/religious objections;
4. could lead to eugenics/gender choice;
5. could lead to (unwanted) multiple pregnancies with associated risks;
6. production and storage of unused embryos / associated legal issues /
extra embryos may be used
for (stem cell) research;
7. inherited forms of infertility might be passed on to children;
Accept any other reasonable answers.
7. (a) Award [1] for each structure clearly drawn and correctly labelled.
1. ovary — shown adjacent to but not joined to oviduct/fallopian tube;
2. oviduct/fallopian tube — shown as a tube leading into a uterus;
3. uterus —shown with a thicker wall than oviduct/fallopian tube;
4. vagina — shown leading from the uterus, connected to the cervix;
5. cervix —shown as a constriction between the vagina and uterus;
6. endometrium — shown as inner lining of uterus;
4 max
8.
1. FSH stimulates the follicles to develop and secrete estrogen;
2. Initially a (rapid) increase in estrogen stimulates FSH/LH production;
3. Estrogen also stimulates repair/thickening of endometrium/uterus lining;
4. LH causes follicle to produce more progesterone because it turns the follicle into the corpus
luteum;
5. The corpus luteum secretes both estrogen/progesterone;
6. progesterone maintains/stimulates thickening of endometrium/uterus lining;
7. Both estrogen/progesterone inhibit FSH/LH secretion;
8. estrogen/progesterone levels fall after day 21–24 if no embryo/fertilization;
9. This lower concentration of estrogen/progesterone allows disintegration of endometrium/uterus
lining / menstruation occurs;
9.
1. The placenta is a disc shaped organ
2. It is formed by fetal tissue invading the uterine lining of the mother
3. It is connected to the fetus through an umbilical cord
4. The function of the placenta is to transfer of foods/nutrients/glucose/ antibodies/hormones from
mother to fetus;
5. The placenta is also involved in fetal gas exchange/transfer of oxygen from mother to fetus;
6. The placenta also transfers of excretory products/CO2 from fetus to mother;
7. The placenta has several structures that allow it to easily exchange material between the fetus and
mother . It has placental villi increase the surface area for exchange;
8. These placental villi contain fetal capillaries (which carries the fetus’s blood).
9. The fetal capillaries are in close proximity to the intervillus space; The intervillus space contains
the mother’s blood.
10. The barrier / chorion between the mother and fetal blood is only one cell thick so there is a small
distance from material to travel during exchange.
11. At approximately 12 weeks / when ovary/corpus luteum stops secretion of estrogen and
progesterone;
12. At this time (12 weeks) the placenta starts to secrete of estrogen/progesterone;