HKDSE · DSE Biology

DSE Biology: Cells and Molecules of Life — Practice Questions & Answers

The chemical building blocks of life, the structure of cells, how materials cross membranes, and the energy-handling processes of enzymes, photosynthesis and respiration.

750 practice questions available for this topic — here are 10 with full answers and explanations.

Start an interactive quiz on Cells and Molecules of Life →

Practice questions with answers

1 Multiple choice · Easy

Which of the following tissue types has the greatest number of mitochondria?

Tap an answer to check it.

WhyCells doing intense active transport, such as the absorbing wall of the small intestine, have the most mitochondria.
2 Multiple choice · Medium

A large number of mitochondria in the lining cells of the small intestine is an adaptation for

Tap an answer to check it.

WhyActive absorption of digested food needs ATP from many mitochondria.
3 Multiple choice · Hard

Which observation best indicates that a cell carries out a high rate of aerobic respiration?

Tap an answer to check it.

WhyNumerous mitochondria reflect a high rate of aerobic respiration.
4 Fill in the blank · Medium

The organelle that is the main site of aerobic respiration is the .

Answer: mitochondrion / mitochondria

WhyMitochondria are the site of aerobic respiration.
5 Fill in the blank · Medium

A cell with a high energy requirement contains a large number of .

Answer: mitochondria / mitochondrion

WhyActive cells have many mitochondria.
6 Fill in the blank · Medium

Energy released during aerobic respiration in the mitochondria is used to synthesise .

Answer: ATP / adenosine triphosphate

WhyATP is the immediate energy store made in respiration.
7 Multiple choice · Easy

Which describes a role of light in photosynthesis?

Tap an answer to check it.

WhyLight activates chlorophyll, providing high-energy electrons.
8 Multiple choice · Medium

Which roles of light in photosynthesis are correct? (1) activation of chlorophyll provides high-energy electrons (2) photolysis of water releases oxygen (3) photolysis of water releases hydrogen for the formation of NADPH

Tap an answer to check it.

WhyAll three are correct roles of light in the light reactions.
9 Multiple choice · Hard

The oxygen given off during photosynthesis is produced by the

Tap an answer to check it.

WhyOxygen comes from the photolysis of water.
10 Fill in the blank · Medium

The splitting of water molecules by light energy during photosynthesis is called .

Answer: photolysis

WhyPhotolysis splits water.

Ready to test yourself?

Practise Cells and Molecules of Life with instant marking and per-topic score tracking.

Start the Cells and Molecules of Life quiz →

Key terms in Cells and Molecules of Life

Cell: The basic structural and functional unit of all living organisms.
Cell membrane: A partially permeable layer of phospholipids and proteins that controls the movement of substances into and out of a cell.
Nucleus: The cell organelle that contains the genetic material and controls the cell's activities.
Mitochondrion: The organelle in which aerobic respiration occurs to release energy as ATP.
Chloroplast: The organelle in plant cells containing chlorophyll where photosynthesis takes place.
Enzyme: A protein that acts as a biological catalyst, speeding up a specific reaction without being used up.
Substrate: The specific reactant molecule on which an enzyme acts.
Active site: The region of an enzyme with a specific shape that binds the substrate during a reaction.

See the full study notes and flashcards for this topic.

Practise other DSE Biology topics

Topic B: Genetics and Evolution Topic C: Organisms and Environment Topic D: Health and Disease Topic E: Human Physiology: Regulation and Control (Elective) Topic F: Applied Ecology (Elective) Topic G: Microorganisms and Humans (Elective) Topic H: Biotechnology (Elective)