Theme A Question | Acebiochem7

Theme A Practice Questions

SL Marks: /10
HL Marks: /20
(Updated Monthly)

1. Which of these best explains water's role as a temperature buffer in cells?

A. Low viscosity

B. High latent heat

C. High specific heat capacity

D. High thermal conductivity

Solution

C

2. Which scenario undermines the morphological species concept?

A. Geographical isolation

B. Asexual reproduction

C. Identical morphology across regions

D. Fertile hybrids of morphologically distinct species

Solution

D

3. Which of the following is an example of disruptive selection?

A. Only large or small beaked birds survive

B. Average-sized fish have better survival

C. All tall plants survive

D. Equal selection across all phenotypes

Solution

A

4. Which conservation method best preserves natural interactions?

A. Seed banks

B. Captive breeding

C. In situ reserves

D. Zoo

Solution

C

5. Why do hydrophobic molecules not dissolve in water?

A. They are too large

B. They are non-polar

C. They have high density

D. They form strong ionic bonds

Solution

B

6. The electron micrograph below shows part of a eukaryotic cell, which of the following correctly identifies a non membraned organelle?

Solution

B

7. Freeze-fracture electron microscopy primarily supports which property of membranes?

A.Double membrane

B. Fluidity

C. Hydrophilicity

D. Asymmetry

D

Solution

8. Isolated populations reunite and interbreed producing fertile offspring. What does this suggest?

A. Allopatric speciation

B. Speciation failure

C. No speciation occurred

D. Behavioral isolation

C

Solution

9. Which structural feature is unique to RNA?

A. Thymine base

B. Double Strand

C. Deoxyribose sugar

D. Ribose Sugar

Solution

D

10. An electron micrograph shows a mitochondrion that appears 30 mm long. Its actual size is 3 μm.

What is the magnification?

A. ×1000

B. ×2000

C. ×10000

D. ×20000

Solution

C

11. The graph below shows the results of the Hershey and Chase experiment, which of the following is the most reasonable conclusion based on the data?

A. Only DNA enters the host cell, indicating it is the genetic material.

B. Viral proteins enter the host and carry genetic information.

C. Both DNA and protein enter the host cell equally during infection.

D. Neither DNA nor protein enters the host; both remain extracellular.

Solution

A

Higher Level

12. Which feature ensures the constant diameter of the DNA double helix?

A.Hydrogen bonding

B. Base stacking

C. Purine-pyrimidine pairing

D. Double helix twist

Solution

C

Higher Level

13. Which concept fails to define species in asexually reproducing bacteria?

A. Morphological

B. Biological

C. Ecological

D. Genetic

Solution

B

Higher Level

14. Which virus replication cycle integrates viral DNA into host genome?

I. Lytic

II. Lysogenic

III. Retroviral

A. I only

B. II only

C. I & II

D. II & III

Solution

D

Higher Level

15. What does a node in a cladogram represent?

A. Convergent evolution

B. A Common Ancestor

C. A divergence point

D. A morphological trait

Solution

C

Higher Level

16. Which of the following would most challenge the validity of the Miller-Urey experiment?

A. Abundance of oxygen in early Earth

B. Formation of amino acids

C. Presence of lightning

D. Presence of volcanic gases

Solution

A

Higher Level

17. What condition is not essential for the spontaneous formation of protocells?

A. Catalysis

B. Photosynthesis

C. Self-assembly

D. Compartmentalization

Solution

B

Higher Level

18. The cladogram shows evolutionary relationships among extinct members of the Elephant family. Which of the statements is correct?

A. Palaeoloxodon is more closely related to Elephas maximus than to Loxodonta cyclotis.

B. Loxodonta africana and Loxodonta cyclotis share a more recent common ancestor with each

other than with Palaeoloxodon.

C. Mammuthus and Palaeoloxodon form a sister clade separate from Loxodonta.

D. Loxodonta africana is more closely related to Mammuthus than to Loxodonta cyclotis.

Solution

B

Higher Level

19. Which property of water enables insects to walk on its surface?

A. Adhesion

B. High specific heat

C. Cohesion

D. Universal solvent

Solution

C

Higher Level

20. Which of the following is an example of a eukaryotic cell that lacks a nucleus?

A. Muscle cell

B. Neuron

C. Fungal hypha

D. Sieve tube element

Solution

D

Higher Level

Theme A Practice Questions

SL Marks: /10 HL Marks: /20 (Updated Monthly)

C

D

A

C

B

B

D

C

D

C

A

C

B

D

C

A

B

B

C

D

SL Marks: /10
HL Marks: /20
(Updated Monthly)