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

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

b.

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

e.

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;

b.

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.

c.
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