Question 1

Which of the following is a feature common to all cellular life forms but absent in acellular microbes such as viruses and prions?

Accepted Answer

Cytoplasm

Question 2

Which statement best explains why prokaryotic cells rely on diffusion for intracellular transport, while eukaryotic cells use compartmentalization and transport mechanisms?

Accepted Answer

Prokaryotic cells are much smaller in diameter, typically $$0.1-5\ \mu m$$, making diffusion sufficient for material movement.

Question 3

Which of the following best describes the genetic material found in prions?

Accepted Answer

No genetic material; prions are misfolded proteins.

Question 4

How is the bacterial chromosome compacted within the nucleoid?

Accepted Answer

By cations, small positively charged proteins, and topoisomerase enzymes

Question 5

Which of the following statements about ribosomes is correct?

Accepted Answer

Prokaryotic ribosomes are 70S, while eukaryotic ribosomes are 80S.

Question 6

Which of the following is a function of proteins in the plasma membrane of both prokaryotes and eukaryotes?

Accepted Answer

Transport of molecules across the membrane

Question 7

Which lipid acts as a 'fluidity buffer' in the plasma membrane of many eukaryotes?

Accepted Answer

Cholesterol

Question 8

Why are antibiotics that target the 70S ribosome effective against bacteria but not human cells?

Accepted Answer

Human cells have 80S ribosomes, which differ structurally from bacterial 70S ribosomes.

Question 9

Which of the following best describes the plasma membrane structure found in archaea?

Accepted Answer

It can be a monolayer or bilayer of unique phospholipids.

Question 10

A scientist discovers a microbe with a membrane-bound nucleus, 80S ribosomes, and chromosomes compacted by histones. To which domain does this organism most likely belong?

Accepted Answer

Eukarya

Question 11

Which of the following is NOT a function of the plasma membrane in prokaryotes?

Accepted Answer

Compartmentalization of organelles

Question 12

Which of the following best explains why viruses are considered acellular?

Accepted Answer

They lack cytoplasm, ribosomes, and a plasma membrane.

Question 13

Which of the following statements about the genetic material of viruses is correct?

Accepted Answer

Viruses may have either DNA or RNA as their genetic material.

Question 14

Which of the following is a real-world consequence of the difference in ribosome size between prokaryotes and eukaryotes?

Accepted Answer

Selective toxicity of antibiotics such as tetracycline, which inhibits 70S ribosomes but not 80S ribosomes.

Question 15

Which of the following best describes the role of histones in eukaryotic cells?

Accepted Answer

They compact DNA within the nucleus.

Question 16

Which of the following is true regarding the number of genes in different biological entities?

Accepted Answer

Prokaryotes have approximately 5,000 genes, while viruses have about 10-20 genes.

Question 17

Which of the following is a correct comparison between the plasma membranes of bacteria and fungi?

Accepted Answer

Bacteria use hopanoids, while fungi use ergosterol as fluidity buffers.

Question 18

A patient is infected with an organism that lacks a membrane-bound nucleus, has histones for DNA compaction, and possesses a plasma membrane. Which domain does this organism most likely belong to?

Accepted Answer

Archaea

Question 19

Which of the following best explains why energy generation (respiration and photosynthesis) occurs at the plasma membrane in prokaryotes but not in eukaryotes?

Accepted Answer

Eukaryotes have specialized organelles (mitochondria and chloroplasts) for energy generation.

Cellular and Acellular Organization of Microbes: Structure and Function of Common Features

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