Question 1

The kidneys of a healthy individual filter 178 dm3 day-1 of fluid from the glomeruli into the renal capsules. However, only 1.5 dm3 day-1 of urine is produced.

What percentage of the filtrate is reabsorbed back into the blood?

  A  

176.5%

  B  

0.8%

  C  

11.8%

  D  

99.2%

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Question 2

The image below shows the structure of the nucleotide base guanine.

Bird droppings are known as guano because they contain a high proportion of guanine. Unlike mammals, birds excrete nitrogenous waste as guanine instead of urea. Guanine is synthesised from ammonia in the liver.

The statements below relate to guanine, which of the statements correctly explains why birds excrete guanine?

1 - ammonia is more toxic than guanine

2 - urea is more soluble in water than guanine

3 - guanine has a high proportion of nitrogen

  A  

1, 2, and 3

  B  

only 1 and 2

  C  

only 2 and 3

  D  

only 1

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Question 3

Damage to the hypothalamus results in lower water potential of the blood.

What explains these observations?

  A  

ADH release increases the water potential of blood

  B  

mineralocorticoids affect cells in the loop of Henle

  C  

fewer water channels are inserted into the cell-surface membranes of the collecting duct

  D  

the anterior pituitary releases hormones into the blood


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Question 4

Antidiuretic hormone (ADH) is required for osmoregulation.

What is a region of the nephron that is responsive to ADH?

  A  

Bowman’s capsule

  B  

collecting duct


  C  

loop of Henle

  D  

proximal convoluted tubule

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Question 5

The diagram below shows the structure of an amino acid. Four regions are labelled A to D.

Which region is removed from the amino acid to produce urea?

  A  
  B  
  C  
  D  

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Question 6

What process occurs at the proximal convoluted tubule (PCT)?

  A  

reabsorption of glucose and amino acids

  B  

filtration of blood

  C  

secretion of hormones

  D  

production of urine

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Question 7

Which substance is not normally found in urine due to being reabsorbed in the nephrons?

  A  

water

  B  

salts

  C  

urea

  D  

glucose

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Question 8

What effect does dehydration have on urine concentration?

  A  

urine becomes more dilute

  B  

urine becomes more concentrated

  C  

urine volume increases

  D  

urine pH increases

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Question 9

What is the outcome when the blood ADH level is high?

  A  

the bladder is relaxed

  B  

more water is reabsorbed into the blood

  C  

urine production is increased

  D  

blood glucose level is reduced

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Question 10

What triggers the release of ADH from the posterior pituitary gland?

  A  

high blood pressure

  B  

low water potential in the blood

  C  

high glucose levels in the blood

  D  

low sodium levels in the blood

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Question 11

What does the loop of Henle establish in the medulla to aid water reabsorption?

  A  

high glucose concentration

  B  

high urea concentration

  C  

low protein concentration

  D  

high ion concentration

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Question 12

Excess amino acids are metabolised in the liver. What is this process called?

  A  

amination

  B  

gluconeogenesis

  C  

deamination

  D  

transamination

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Question 13

What is a primary waste product of metabolism that the liver is responsible for processing?

  A  

oxygen

  B  

glucose

  C  

ammonia

  D  

carbon dioxide

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