Question 1

Which of the following best describes the atmosphere of early Earth?

Accepted Answer

Anoxic, high temperature, and abundant volcanic gases such as $$CO_2$$, $$N_2$$, $$H_2$$, $$CH_4$$, $$NH_3$$

Question 2

The first life forms on Earth were most likely:

Accepted Answer

Anaerobic chemolithoautotrophs using $$H_2 as $$electron donor and $$CO_2 as $$carbon source

Question 3

Which concept is illustrated by the universal tree of life?

Accepted Answer

All life shares a common ancestor known as LUCA

Question 4

According to the endosymbiotic hypothesis, mitochondria originated from:

Accepted Answer

A bacterium capable of aerobic respiration

Question 5

Which statement about the formation of eukaryotic cells is correct?

Accepted Answer

Eukaryotes have information-processing genes similar to Archaea and metabolic genes similar to Bacteria

Question 6

Which type of mutation results in an amino acid substitution in the protein sequence?

Accepted Answer

Missense mutation

Question 7

A nonsense mutation is best described as:

Accepted Answer

A mutation that substitutes a stop codon for an amino acid

Question 8

Which process can cause evolutionary change in a population in the absence of natural selection?

Accepted Answer

Genetic drift

Question 9

What is the main energy-generating mechanism for lactic acid bacteria?

Accepted Answer

Substrate-level phosphorylation during fermentation

Question 10

Which bacterial genus is responsible for the holes and flavor in Swiss cheese due to $$CO_2$$ and propionic acid production?

Accepted Answer

Propionibacterium

Question 11

Which group of bacteria is the largest and most metabolically diverse phylum, containing all gram-negative species?

Accepted Answer

Proteobacteria

Question 12

Which of the following is a major component of the microbial community in the human gut and can cause bacteremia?

Accepted Answer

Bacteroides (Bacteroidetes)

Question 13

Which statement about cyanobacteria is correct?

Accepted Answer

They perform oxygenic photosynthesis and contain chlorophyll a

Question 14

Which archaeal group includes both methanogens and extreme halophiles?

Accepted Answer

Euryarchaeota

Question 15

What is the function of bacteriorhodopsin in certain haloarchaea?

Accepted Answer

Catalyzes light-driven synthesis of ATP

Question 16

Which mutation type is most likely to result in a frameshift?

Accepted Answer

Insertion or deletion

Question 17

Which of the following is NOT a characteristic of Firmicutes?

Accepted Answer

Gram-negative cell wall

Question 18

Which of the following best explains why endosymbiotic mitochondria were beneficial to early eukaryotic cells?

Accepted Answer

They increased the cell's respiratory capacity

Question 19

Which process is defined by the ability of an organism to produce progeny and contribute to the genetic makeup of future generations?

Accepted Answer

Fitness (as used in selection)

Question 20

Which of the following is true about the evolutionary process?

Accepted Answer

Evolution is a change in allele frequencies in a population over time

Microbial Evolution and Diversity: Structured Study Notes

Study Guide - Practice Questions