IB DP Biology- C3.1 Integration of body systems -FA 2025- IB Style Questions For HL Paper 2

Question

The diagram shows a section through a human heart with the chambers, valves and main blood vessels.

What are the functions of X and Y?

▶️Answer/Explanation

Ans: C

Question

What is the role of the sinoatrial (SA) node?

A. To produce epinephrine in response to vigorous activity

B. To stimulate the contraction of the walls of the atria

C. To send signals from the ventricles to the atria

D. To ensure that the heart rate does not respond to signals from the medulla

▶️Answer/Explanation

Ans: B

Question

What is a function of the pancreas?

A. To control the rate of metabolism by releasing thyroxine when metabolic rate is low

B. To release glucagon when blood glucose levels are low

C. To release insulin when blood glucose levels are low

D. To secrete an endopeptidase which lowers the blood glucose levels

▶️Answer/Explanation

Ans: B

Question

b. Outline the development of axons in immature neurons. [2]

e. State one activity controlled by the medulla oblongata. [1]

▶️Answer/Explanation

Markscheme

a. axon grows from an «immature» neuron

b. chemical stimuli trigger the growth/direction of axon

c. only one axon develops per neuron

d. some axons extend beyond neural tube to reach other parts of body

gut muscles / heart rate/cardiac centre / vasomotor / breathing/ventilation rate / reflex centre of vomiting/coughing/sneezing/swallowing

Question

The drawing shows a vertical section through the brain.

a.i. Label the cerebellum on the diagram. [1]

a.ii. State a function of the cerebellum. [1]

b. On the diagram, label one named structure that produces hormones. [1]

c. Outline one method that can be used to investigate the function of different parts of the brain. [2]

▶️Answer/Explanation

Markscheme

label to cerebellum

a.i.

controls/coordinates (motor) movements/balance

a.ii.

label to pituitary
OR
label to hypothalamus;

Alternative 1:
a. fMRI;

b. scan detects changes in blood flow/oxygen in blood
OR
more active parts of brain receive more blood flow;

Alternative 2:
c. lesions/autopsy;

d. part of the brain damaged
OR
loss of function detected;

Alternative 3:
e. stimulation during open brain surgery;

f. reaction observed;

The “f” must be written for fMRI.

Description must relate to method named.

IB DP Biology- C3.1 Integration of body systems -FA 2025- IB Style Questions For HL Paper 2

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