DP Biology (first assessment 2025)

Test builder »

Question 19N.1B.SL.TZ0.23

Select a Test
Date November 2019 Marks available [Maximum mark: 6] Reference code 19N.1B.SL.TZ0.23
Level SL Paper 1B Time zone TZ0
Command term Explain Question number 23 Adapted from N/A
23.
[Maximum mark: 6]
19N.1B.SL.TZ0.23

Explain how ventilation rate is changed during vigorous physical exercise.

[6]

Markscheme

a. exercise increases the rate of cellular respiration ✔

b. increases production of CO2 ✔

c.  increased CO2 causes increased acidity in blood
OR
decrease pH ✔

d. chemoreceptors in aorta/carotid artery/medulla oblongata detect change in pH ✔

e. impulse/signal/message to breathing centre
OR
impulse/signal/message to medulla oblongata ✔

f. impulse/signal/message to to diaphragm for more frequent contraction
OR
impulse/signal/message to intercostal muscles for more frequent contraction ✔

g. increase ventilation rate for more gas exchange ✔

h. long term effects of increased lung surface area
OR
vital capacity ✔

i. training decreases ventilation rate over time ✔

Syllabus sections