ALevel Biology Practice Exam

ALEVEL BIOLOGY

PRACTICE EXAM

Question 1: Which structure is present in both eukaryotic and prokaryotic cells?

Choices:

1) Nucleus 2) Mitochondrion 3) Ribosome 4) Endoplasmic reticulum

Correct Answer: Ribosome

Explanation: Ribosomes are present in both cell types, although eukaryotes have 80S ribosomes and prokaryotes have 70S ribosomes.Page 1

Question 2: What is the maximum resolution of a standard light microscope?

Choices:

1) 0.2 nm 2) 2 nm 3) 200 nm 4) 2000 nm

Correct Answer: 200 nm

Explanation: The maximum resolution of a standard light microscope is approximately 200 nm, limited by the wavelength of visible light.Question 3: Which organelle is responsible for the synthesis of lipids and steroids?

Choices:

1) Rough endoplasmic reticulum 2) Smooth endoplasmic reticulum 3) Golgi apparatus 4) Lysosome

Correct Answer: Smooth endoplasmic reticulum

Explanation: The smooth endoplasmic reticulum is responsible for lipid and steroid synthesis, whereas the rough ER synthesizes proteins.Page 2

Question 4: What is the function of the nucleolus?

Choices:

1) To synthesize ATP 2) To assemble ribosomes 3) To break down cellular waste 4) To package proteins for secretion

Correct Answer: To assemble ribosomes

Explanation: The nucleolus is the site within the nucleus where ribosomal RNA (rRNA) is transcribed and ribosome subunits are assembled.

Question 5: Which bond is primarily responsible for maintaining the secondary

structure of a protein?

Choices:

1) Peptide bond 2) Disul�de bond 3) Hydrogen bond 4) Ionic bond

Correct Answer: Hydrogen bond

Explanation: Hydrogen bonds between the backbone amino and carboxyl groups maintain secondary structures like alpha-helices and beta-pleated sheets.Page 3