exam Q's

Question 1

which part of the nephron corresponds to each statement:
1.walls are impermeable to water
2. glucose is reabsorbed into the blood
3.ADH acts on the walls
4. contains podocytes
5. most of the water is reabsorbed into the blood

Answer 1

1. ascending limb of loop on henle
   2.PCT
2. DCT, collecting duct
3. Bowmans capsule
4. PCT

Question 2

explain the role of the loop of henle in the production of urine

Answer 2

1. role of loop of henle= to cause a decrease in water potential in/ establish water potential gradient going down medulla
   2.in ascending limb active transport outwards of sodium and chloride ions
   3.walls of descending limb are permeable to water
2. water removed from descending limb
3. water potential of tissues surrounding collecting duct is lower than fluid inside it
4. water removed from filtrate/ urine (in collecting duct)

Question 3

in addition to deamination, liver cells also use amino acids for protein synthesis, suggest one other use of amino acids in liver cell metabolism

Answer 3

-conversion to lipids/ fatty acids
-used for respiration
-transamination
-convert to glucose

Question 4

explain how each of the following adaptations help the animal to control its body temperature

1. elephants have large thin ears that they move backwards and forwards when hot

2.penguines live in cold climates have shunt blood vessels, which link arterioles carrying blood towards feet with small veins that carry blood away from the feet

Answer 4

1. -large surface area to lose heat
   -thin so blood vessels are close to skin surface to lose heat
   -increased air movement over skin to lose heat
2. blood loses less heat because less blood flows to feet/ less blood flow to feet so core body temp maintained

Question 5

explain the effect that sweating will have on the body

Answer 5

1. evaporation will have a cooling effect/ reduce body temp
   2.heat from the blood is used for evaporation / evaporation uses latent heat
2. water has a high latent heat of vapourisation

Question 6

suggest why shivering occurs during fever

Answer 6

to increase body temperature as it is lower than the new set point (normal body temp is higher than normal due to fever)

Question 7

suggest why lactate is converted into pyruvate by the hepatocytes rather than by the respiring cells in which it is produced

Answer 7

hepatocytes can tolerate lactate/ low pH which would otherwise be toxic

Question 8

describe the features of the glomerulus and bowmans capsule that allow them to perform their function effectively

Answer 8

-ultrafiltration
-afferent arteriole is wider than efferent arteriole
-high blood pressure in glomerulus
-endothelium has gaps to allow passage of substances
-basement membrane stops large molecules/ cells
-podocytes finger like projections = allow gaps to ensure passage of substances

Question 9

explain the need for close matching of the donated kidney to the recipient

Answer 9

-donated kidney will be recognized as foreign/ non-self
-antigens will be different
-causing rejection
-by immune system
-use of immuno-suppressant drugs

Question 10

explain how the stick detects the pregnancy hormone

Answer 10

-testing for hCG
-hormone small so can pass from blood into filtrate at bowmans capsule
-monoclonal/ immobilised atibodies on stick
-antibodies attached to marker/ dye
-hormone binds/ complementary to antibody
-triggers appearance of line