Question 1

Which of the following best explains why water is considered a 'temperature buffer' in living organisms?

Accepted Answer

Water's high specific heat due to strong hydrogen bonding requires more energy to change its temperature.

Question 2

A sodium atom (Na) has 11 protons and 11 electrons. If it loses one electron to form an ion, what is the resulting charge and what is this ion called?

Accepted Answer

The ion has a charge of $$+1$$ and is called a cation.

Question 3

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with the same number of protons but different numbers of neutrons.

Question 4

Which of the following equations correctly represents a synthesis (anabolic) reaction?

Accepted Answer

$$A + B \rightarrow AB$$

Question 5

A scientist is studying the breakdown of starch into glucose molecules in bacteria. Which type of reaction is this, and what is its biological significance?

Accepted Answer

Decomposition (catabolic) reaction; it releases energy for cellular processes.

Question 6

Which property of water allows it to dissolve ionic compounds like sodium chloride (NaCl)?

Accepted Answer

Its polarity, which allows water molecules to surround and separate ions.

Question 7

Which of the following best describes the role of ATP in microbial cells?

Accepted Answer

ATP stores and releases energy required for cellular activities.

Question 8

A solution has a high concentration of $$H^+$$ ions. Which of the following statements is true about this solution?

Accepted Answer

It is acidic and has a low pH.

Question 9

Which of the following is a correct statement about macromolecules in cells?

Accepted Answer

Proteins, carbohydrates, lipids, and nucleic acids are all formed by dehydration synthesis reactions.

Question 10

Which functional group is responsible for the acidic properties of organic acids?

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 11

A reversible reaction is represented as $$A + B \leftrightarrow AB. $$What does this indicate about the reaction?

Accepted Answer

The reaction can proceed in both the forward and reverse directions depending on conditions.

Question 12

Which of the following best explains why ice floats on water and why this is important for aquatic life?

Accepted Answer

Hydrogen bonding causes ice to be less dense than liquid water, insulating aquatic environments.

Question 13

Which of the following is an example of an exchange reaction?

Accepted Answer

$$AB + CD \rightarrow AD + CB$$

Question 14

Which statement best describes the difference between organic and inorganic compounds?

Accepted Answer

Organic compounds always contain carbon and hydrogen, while inorganic compounds do not necessarily contain both.

Question 15

A patient is given a radioactive isotope of iodine for thyroid imaging. Which property of isotopes makes this possible?

Accepted Answer

Isotopes have the same chemical properties but different atomic masses, allowing for tracking in biological systems.

Question 16

Which of the following best describes the role of lipids in microbial cells?

Accepted Answer

They form the structural basis of cell membranes and serve as energy reserves.

Question 17

Which of the following statements about hydrogen bonds is correct?

Accepted Answer

Hydrogen bonds are weak attractions between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom.

Question 18

Which of the following best explains why carbon is central to the structure of organic molecules?

Accepted Answer

Carbon can form four covalent bonds, allowing for diverse and complex molecular structures.

Question 19

A microbiologist adds sodium hydroxide (NaOH) to a bacterial culture. What effect does this have on the solution?

Accepted Answer

It increases the concentration of $$OH^-$$ ions, making the solution more basic.

Question 20

Which of the following best describes the process of dehydration synthesis in the formation of macromolecules?

Accepted Answer

Monomers are joined together by removing a molecule of water to form polymers.

Chapter 2: Chemical Principles – Foundations for Microbial Life

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