Question 1

Which of the following best explains why mitochondria have their own DNA and ribosomes?

Accepted Answer

They originated from a symbiotic relationship with a prokaryotic cell, as described by the endosymbiotic theory.

Question 2

Which of the following statements about the bacterial cell wall is correct?

Accepted Answer

Gram-positive bacteria contain teichoic acids in their cell wall, which contribute to structural strength and antibiotic resistance.

Question 3

Which of the following best describes the function of microtubules in eukaryotic cells?

Accepted Answer

They move cellular components and are involved in the structure of cilia and flagella.

Question 4

Which of the following is a correct description of glycolysis?

Accepted Answer

It converts glucose into two molecules of pyruvate, producing a net gain of 2 ATP and 2 NADH.

Question 5

Which equation correctly represents the conversion of pyruvate to acetyl-CoA?

Accepted Answer

$$\mathrm{Pyruvate} + \mathrm{HSCoA} + \mathrm{NAD}^+ \rightarrow \mathrm{Acetyl{-}CoA} + \mathrm{CO}_2 + \mathrm{NADH}$$

Question 6

During fermentation in muscle cells, what is the primary purpose of converting pyruvate to lactate?

Accepted Answer

To regenerate $$\mathrm{NAD}^+ so $$glycolysis can continue.

Question 7

Which of the following best describes the role of NADH in cellular metabolism?

Accepted Answer

It serves as an electron carrier, storing energy for later use in the electron transport chain.

Question 8

Which of the following statements about enzymes is correct?

Accepted Answer

Enzymes lower the activation energy required for a reaction to proceed.

Question 9

A bacterial cell is found to lack peptidoglycan in its cell wall and is resistant to penicillin. Which type of cell is this most likely to be?

Accepted Answer

Mycoplasma

Question 10

Which of the following best describes the difference between catabolic and anabolic reactions?

Accepted Answer

Catabolic reactions release energy by breaking down molecules, while anabolic reactions use energy to build molecules.

Question 11

Which of the following is true regarding the effect of temperature on enzyme activity?

Accepted Answer

Enzyme activity increases with temperature up to an optimal point, after which the enzyme denatures and activity decreases.

Question 12

Which of the following best describes the function of the glycocalyx in animal cells?

Accepted Answer

It acts as a protective and recognition layer on the cell surface.

Question 13

Which of the following is a correct summary of the net products of glycolysis from one molecule of glucose?

Accepted Answer

$$2$$ pyruvate, $$2$$ ATP (net), $$2$$ NADH

Question 14

Which of the following best explains why mycobacteria are difficult to treat with antibiotics?

Accepted Answer

They have a waxy coating of mycolic acid that prevents antibiotics and nutrients from entering.

Question 15

Which of the following best describes the role of the electron transport chain in cellular respiration?

Accepted Answer

It uses electrons from NADH and FADH$$_2 to $$generate a proton gradient for ATP synthesis.

Question 16

Which of the following is a correct description of a chemoheterotroph?

Accepted Answer

An organism that uses chemicals as an energy source and organic molecules as a carbon source.

Question 17

Which of the following best describes the function of cilia in multicellular organisms?

Accepted Answer

They move substances past the surface of fixed cells.

Question 18

Which of the following is true about the energy of activation in a chemical reaction?

Accepted Answer

It is the energy required to reach the transition state from the reactants.

Question 19

Which of the following best describes the effect of pH on enzyme activity?

Accepted Answer

Enzymes have an optimal pH, and activity decreases if the pH moves away from this optimum.

Cell Structure and Microbial Metabolism: Study Notes

Study Guide - Practice Questions