iGCSE Biology (0610)-9.1 Circulatory systems - iGCSE Style Questions Paper 3

Question

(a)(i) The boxes on the left show some of the components of blood. The boxes on the right show the functions of the components. Draw lines to link each component with its function or functions. Draw four lines.

(ii) Plasma is also a component of blood. Describe the function of plasma.

(b)

Fig. 1.1 is a photomicrograph of one component of blood.

(i) State the name of the component of blood shown in Fig. 1.1.

(ii) Identify structures A, B, and C shown in Fig. 1.1.

(iii) Describe one function of the cytoplasm.

▶️ Answer/Explanation

Solution

(a)(i) The correct matching is as follows:

Explanation: Red blood cells transport oxygen, platelets help in clotting, white blood cells defend against pathogens, and plasma proteins maintain osmotic balance.

(a)(ii) Plasma functions to transport substances such as blood cells, nutrients (e.g., glucose), hormones (e.g., insulin), and waste products (e.g., carbon dioxide, urea).

(b)(i) The component shown is a white blood cell (e.g., lymphocyte or phagocyte).

(b)(ii) Structures identified:
A: Cell membrane
B: Nucleus
C: Mitochondrion

(b)(iii) The cytoplasm functions as the site of metabolic reactions (e.g., glycolysis) and provides a medium for organelles to operate efficiently.

Question

(a) Complete the sentences about the circulatory system.

The heart …… blood around the body.

Blood is carried away from the heart in blood vessels called …… .

Blood is carried to the heart in blood vessels called …… .

Nutrients are delivered to cells by blood vessels called …… .

One-way flow of blood is ensured by the presence of …… .

(b) Fig. 4.1 shows ECG traces of the activity of a student’s heart.

An ECG trace was produced while the student was at rest and while the student was exercising.

The ECG trace shows the number of heart beats in 2.8 seconds.

There were four heart beats in 2.8 seconds at rest.

(i) State the number of heart beats in 2.8 seconds during exercise.

(ii) Calculate the percentage increase in heart beats between at rest and during exercise.

Describe other ways of reducing a person’s risk of developing coronary heart disease.

(d) Fig. 4.2 shows a stethoscope which is used to listen to the heart.

State the cause of the heart sounds detected by the stethoscope.

▶️ Answer/Explanation

Solution

(a)

The heart pumps blood around the body.

Blood is carried away from the heart in blood vessels called arteries.

Blood is carried to the heart in blood vessels called veins.

Nutrients are delivered to cells by blood vessels called capillaries.

One-way flow of blood is ensured by the presence of valves.

Explanation: The circulatory system is a closed system where the heart acts as a pump. Arteries carry oxygenated blood away from the heart (except pulmonary artery), while veins return deoxygenated blood back to the heart (except pulmonary vein). Capillaries are tiny vessels where exchange of nutrients and gases occurs. Valves prevent backflow of blood, especially in veins and between heart chambers.

(b)(i) 6 beats

Explanation: By counting the peaks in the ECG trace during exercise, we can observe there are 6 complete heartbeats in the same 2.8 second period.

(b)(ii) 50%

Explanation: The calculation is done as follows:
At rest: 4 beats in 2.8 seconds
During exercise: 6 beats in 2.8 seconds
Increase = 6 – 4 = 2 beats
Percentage increase = (Increase/Original) × 100 = (2/4) × 100 = 50%

(c) Any three from:
– Maintaining a balanced diet
– Reducing consumption of saturated fats
– Reducing salt intake
– Maintaining healthy body weight
– Avoiding smoking
– Managing stress levels
– Getting adequate sleep

Explanation: Coronary heart disease is often caused by lifestyle factors. A balanced diet helps maintain healthy cholesterol levels. Reducing saturated fats prevents plaque buildup in arteries. Salt reduction helps control blood pressure. Healthy weight reduces strain on the heart. Smoking damages blood vessels. Stress management and proper sleep contribute to overall cardiovascular health.

(d) (Heart) valves closing

Explanation: The characteristic “lub-dub” sounds heard through a stethoscope are caused by the closing of heart valves. The “lub” sound occurs when the atrioventricular valves close at the start of ventricular contraction (systole). The “dub” sound occurs when the semilunar valves close at the end of ventricular contraction.

iGCSE Biology (0610)-9.1 Circulatory systems – iGCSE Style Questions Paper 3

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