Maintaining Internal Environments (OCR GCSE Biology A (Gateway))

Higher Tier only

The diagram shows a kidney tubule (nephron).

(i) What is the name of part X?

[1]

(ii) The hormone ADH affects the permeability of part of the kidney tubule.

Name the part of the tubule affected by ADH.

[1]

The diagram shows the composition of glomerular filtrate and urine.

What evidence is there to suggest that selective reabsorption occurs in the kidney tubule?

Use evidence from the diagram to support your answer.

Higher Tier only

Sports drinks are usually one of three types. Look at the table of information on these types of sports drink.

An athlete is going to run a 10000 metre race. About an hour before the race the athlete drinks a hypertonic sports drink.

The athlete completes the 10000 metre race. After the race the athlete drinks an isotonic sports drink.

Explain how the race causes changes in water, salt and sugar levels in the athlete’s body and explain the athlete’s choice and timing of drinks.

This question is about control and coordination.

The diagrams show a section through the skin in two different conditions.

Which diagram shows the skin in a hot, humid environment?

Explain your answer.

Look at the diagram.

It shows a vertical section through a kidney.

(i) What is the name of part Y?

[1]

(ii) Which liquid flows through the ureter?

[1]

(iii) Draw an arrow in the ureter showing the direction that this liquid flows.

[1]

The kidney is important for water balance.

The table shows the measurements of water balance for two patients in hospital.

(i)Calculate the total output for Patient A and Patient B.

Patient A .......................................
Patient B ....................................... [1]

(ii) Which patient needs treatment for their kidneys?

Explain the reasons for your choice.

[2]

Look at the diagram. It shows a kidney tubule (nephron).

(i) What is the name of part Z?

[1]

(ii)The diagram shows the composition of glomerular filtrate and urine.

What conclusions can be made about what happens between part Z and the collecting duct in the kidney tubule?

Use evidence from the diagram to support your answer.

[3]

Fig. 17.1 shows the mass of urea in the urine plotted against the BMI (Body Mass Index) for nine boys. BMI is a value often used to see if a person is a healthy mass for their height.

Fig. 17.1

(i) What does the graph show about the relationship between BMI and the mass of urea in the urine?

[1]

(ii) A boy has a BMI of 16. He produces 1000cm³ of urine in 24 hours.  Calculate the concentration of urea in the boy’s urine.

Concentration = ....................g/cm³ [2]

(iii)Fig. 17.2 shows the mass of urea in the urine against the BMI for nine different boys.

Fig. 17.2

Give two differences in the relationship between BMI and the mass of urea in the urine shown in Fig. 17.1 and Fig. 17.2.

1 ................................
2 ..................................

[2]

The kidney filters the blood. The fluid produced by filtering the blood passes through kidney tubules.

Each kidney tubule contains a number of different parts.

Put a number (1 to 5) in the boxes to show the order of the parts that the liquid passes through.

The first one has been done for you.

Fig. 20.1 shows a section through the skin on the back of the hand.

Fig. 20.1

(i) Which part of the skin detects something touching the back of the hand?

[1]

(ii) The body responds when something touches the back of the hand.

Complete the sentences to explain how this happens.

The ..................................... receives impulses from the skin along sensory neurones.

These impulses are processed and other impulses are sent along ..................................... neurones to bring about responses.

[2]

The skin on some areas of the body contains hairs. Modern hair shampoos contain cleaning agents. One cleaning agent is made from fatty acids.

Explain how a polymer found in plants and animals can be treated to obtain these fatty acids.

(i) The skin is important for controlling body temperature.
Explain why overheating of the body may stop chemical reactions in cells.

[2]

(ii)Look at Fig. 20.2 which shows two people riding on boards.

Person A is riding a board on sand in a hot desert.
Person B is riding a board on snow.

Fig. 20.2

Explain the different problems of temperature regulation for these two people and give examples of the ways their bodies solve these problems.

[6]

Red blood cells burst when they are placed in a solution with a much higher water potential than the red blood cells. This is called lysis. 

Explain why lysis happens.

Higher Tier only

ADH is a protein hormone made up of amino acids.

(i) Complete the sentences to explain the link between amino acids and proteins.

Large molecules, like proteins, made of smaller molecules are called ............................

The smaller molecules, or amino acids, are called ........................................... .

[2]

(ii) Alcohol inhibits ADH production.

Person A and B both drank one small 100ml drink. Only one of the drinks was high in alcohol.

Look at the diagram of a kidney tubule in person A and B after the drink.

Explain how you can tell from the diagram that person A’s drink contained alcohol.

[2]

(iii) After the alcohol has been removed from person A’s body, control mechanisms will correct the excess loss of water caused by the alcohol.

Describe these control mechanisms.

[2]