Question 1

Which of the following best describes the role of heterotrophic bacteria in the environment?

Accepted Answer

They decompose organic matter, recycling nutrients back into ecosystems.

Question 2

Peptidoglycan is a key structural component of bacterial cell walls. Which of the following statements about peptidoglycan is correct?

Accepted Answer

It provides rigidity and shape to bacterial cells.

Question 3

A scientist observes a bacterial sample under a microscope and notes the cells are spherical. What is the correct term for this bacterial shape?

Accepted Answer

Coccus

Question 4

Which equation correctly represents the nitrogen fixation reaction catalyzed by nitrogenase in cyanobacteria?

Accepted Answer

$\mathrm{N_2 + 8H^+ + 8e^- \rightarrow 2NH_3 + H_2}$

Question 5

Why is the nitrogenase enzyme in cyanobacteria inhibited by oxygen?

Accepted Answer

Oxygen denatures the enzyme, preventing nitrogen fixation.

Question 6

Which of the following best explains why cyanobacteria are considered photoautotrophs?

Accepted Answer

They use light energy to convert carbon dioxide and water into organic compounds.

Question 7

A student is examining a slide of Oscillatoria under a microscope. Which feature should they look for to identify this genus?

Accepted Answer

Filamentous chains that exhibit a gliding movement.

Question 8

Which of the following statements about Escherichia coli (E. coli) is correct?

Accepted Answer

E. coli is a heterotrophic bacterium commonly found in the human gut.

Question 9

Which of the following best describes the function of heterocysts in cyanobacteria?

Accepted Answer

They are specialized cells for nitrogen fixation.

Question 10

A yogurt sample is examined under a microscope and shows thick, rod-shaped bacteria. Which genus is most likely present?

Accepted Answer

Lactobacillus

Question 11

Which of the following is a correct application of the Compound Microscope when observing bacteria?

Accepted Answer

Start with the 40X objective lens, then switch to higher magnification after focusing.

Question 12

Which of the following best explains why cyanobacteria are important in aquatic ecosystems?

Accepted Answer

They produce oxygen and serve as a primary food source for aquatic organisms.

Question 13

Which bacterial genus is responsible for causing strep throat in humans?

Accepted Answer

Streptococcus

Question 14

Which of the following is a distinguishing feature of the genus Nostoc?

Accepted Answer

It forms large, jelly-like colonies of trichomes with interspersed heterocysts.

Question 15

Which of the following equations represents the process of photosynthesis in cyanobacteria?

Accepted Answer

$\mathrm{6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2}$

Question 16

Which of the following best describes the difference between photoautotrophic and heterotrophic bacteria?

Accepted Answer

Photoautotrophic bacteria use light energy to produce organic compounds, while heterotrophic bacteria obtain energy by consuming organic matter.

Question 17

Which of the following is a common misconception about cyanobacteria?

Accepted Answer

They are eukaryotic algae.

Question 18

A sample from a pond contains bacteria that form chains and taste 'slimy.' Which genus is most likely present?

Accepted Answer

Oscillatoria

Question 19

Which of the following statements about the use of high-power objectives (1000X) in microscopy is correct?

Accepted Answer

It is necessary to use oil immersion to achieve clear images at 1000X.

Prokaryotes: Domain Bacteria and Cyanobacteria – Structure, Function, and Laboratory Identification Lab 11

Study Guide - Practice Questions