Free Animal and Plant Cell MCQs with Answers

41. Which of the following is NOT a characteristic of prokaryotic cells?

• A. Absence of membrane-bound nucleus
• B. Presence of 70S ribosomes
• C. Presence of histone proteins
• D. Circular DNA

Explanation: Prokaryotes lack histone proteins. Their DNA is not organized into nucleosomes with histones, unlike eukaryotes.

42. The fluid mosaic model of cell membrane was proposed by

• A. Robertson
• B. Singer and Nicolson
• C. Gorter and Grendel
• D. Danielli and Davson

Explanation: Singer and Nicolson proposed the fluid mosaic model in 1972, describing the membrane as a fluid lipid bilayer with embedded proteins.

43. Which of the following is TRUE about the Na+/K+ pump?

• A. It moves 2 Na+ out and 3 K+ in
• B. It moves 3 Na+ out and 2 K+ in
• C. It is a passive transport mechanism
• D. It does not require ATP

Explanation: The Na+/K+ ATPase pump moves 3 Na+ out and 2 K+ in against their concentration gradients, using ATP.

44. In osmosis, water moves from

• A. High solute concentration to low solute concentration
• B. Low water potential to high water potential
• C. High water potential to low water potential
• D. Hypertonic to hypotonic solution

Explanation: Water moves from high water potential (dilute, hypotonic) to low water potential (concentrated, hypertonic).

45. A student observed a boundary in both plant and animal cells that controls entry and exit of substances. Which of the following structures is likely being observed?

• A. Mitochondria
• B. Golgi apparatus
• C. Plasma membrane
• D. Cell wall

Explanation: The plasma membrane is present in every cell and is partially permeable, so it decides what enters and leaves, which is exactly the function described. The cell wall is the trap: it is a boundary too, but it occurs only in plants and is fully permeable, so it controls nothing. The words both plant and animal are what rule it out.