IB DP Biology Mock Exam HL Paper 1B Set 4 - 2025 Syllabus
IB DP Biology Mock Exam HL Paper 1B Set 4
Prepare for the IB DP Biology Exam with our comprehensive IB DP Biology Exam Mock Exam HL Paper 1B Set 4. Test your knowledge and understanding of key concepts with challenging questions covering all essential topics. Identify areas for improvement and boost your confidence for the real exam
Question
The electron micrograph shows part of a cell including a mitochondrion.
(a) Outline how the structures labelled X and Y are adapted to carry out the function of
the mitochondrion.
X:
Y:
(b) Explain how ATP is generated in mitochondria by chemiosmosis.
Answer/Explanation
Ans:
a)
X: large/increased SA area for ATP production/electron transport/oxidative phosphorylation/proton pumping
OR
X: small/narrow intermembrane space for generating proton gradient (rapidly/steeply);
Y: contains enzymes for Krebs cycle/link reaction;
b)
a. protons pumped across inner membrane of mitochondria/into intermembrane space;
b. using energy released by flow of electrons/by electron transport/by electron carriers;
c. proton gradient established/maintained / proton motive force generated;
d. protons pass/diffuse back through inner membrane/membrane of cristae/to matrix;
e. through ATP synthase;