IB DP Biology Mock Exam SL Paper 1A Set 5 - 2025 Syllabus

IB DP Biology Mock Exam SL Paper 1A Set 5

Prepare for the IB DP Biology Exam with our comprehensive IB DP Biology Exam Mock Exam SL Paper 1A Set 5. 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

IB DP Biology Mock Tests -All Sets

Question

The photograph shows a pond skater.

Which property of water enables the insect to stand and move across the water’s surface?

A.  Adhesion
B.  Capillarity
C.  Surface tension
D.  Transparency

▶️ Answer/Explanation

Water molecules are strongly cohesive, creating a tight surface film known as surface tension. This allows lightweight insects like pond skaters to stay supported on the water’s surface without sinking.
✅ Answer: (C)

Question

The graph illustrates the energy changes in a reaction, both with an enzyme and without one.

Which statement correctly identifies two of the regions labeled X, Y, and Z on the graph?

(A) X is the activation energy with an enzyme and Z is the net energy released from the reaction.
(B) X is the energy released from the reaction and Y is the activation energy with an enzyme.
(C) Y is the energy released with an enzyme and Z is the energy released when bonds are broken.
(D) Y is the activation energy with an enzyme and Z is the net energy released.

▶️ Answer/Explanation

Detailed solution

In enzyme-catalyzed reaction graphs: X typically represents the activation energy without enzyme, Y represents the lower activation energy with enzyme, and Z represents the net energy released (the difference between reactant and product energy levels). Option D correctly identifies Y as the activation energy with an enzyme and Z as the net energy released.
✅ Answer: (D)

Question

The diagram shows a gel electrophoresis setup used to separate DNA fragments.

What can be inferred from the diagram?

A. X is the smallest DNA fragment.

B. Y is positively charged.

C. X is migrating toward the cathode.

D. Y travels through the gel at the fastest rate.

▶️ Answer/Explanation

In gel electrophoresis, smaller DNA fragments move farther down the gel toward the positive anode. Since X has traveled the greatest distance, it must be the smallest fragment.

✅ Answer: (A)

IB DP Biology Mock Exam SL Paper 1A Set 5 - 2025 Syllabus