Question 1

Which of the following statements best describes the 'directionality' of a nucleic acid polymer?

Accepted Answer

Nucleic acids have chemically distinct 5' phosphate and 3' hydroxyl termini, giving them directionality.

Question 2

Which functional group is characteristic of amino acids and is responsible for their acidic properties?

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 3

A reaction has $$\Delta H = -50\ \mathrm{kJ/mol}$$ and $$\Delta S = -100\ \mathrm{J/(mol\cdot K)} at$$ $$T = 298\ \mathrm{K}. $$What is the value of $$\Delta G$$ and is the reaction spontaneous?

Accepted Answer

$$\Delta G = -20.2\ \mathrm{kJ/mol}$$; the reaction is spontaneous

Question 4

Which of the following best explains why living organisms are considered open systems in thermodynamics?

Accepted Answer

They exchange both energy and matter with their surroundings.

Question 5

Which of the following is NOT a correct pairing of monomer and its corresponding polymer?

Accepted Answer

Monosaccharides — Lipids

Question 6

Given the following reaction: $$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P_i}$$, with $$\Delta G^\circ = -30.5\ \mathrm{kJ/mol}$$, what does the negative $$\Delta G$$ indicate?

Accepted Answer

The reaction is spontaneous and releases free energy.

Question 7

Which of the following elements is much more abundant in living organisms than in the universe as a whole, relative to carbon?

Accepted Answer

Oxygen

Question 8

Which of the following best describes the difference between prokaryotic and eukaryotic cells?

Accepted Answer

Eukaryotic cells have a nucleus, while prokaryotic cells lack a nucleus.

Question 9

Which of the following functional groups is found in both nucleic acids and phospholipids and is essential for their function?

Accepted Answer

Phosphate group ($$-PO_4$^{2-})$$

Question 10

A biochemical reaction has $$\Delta H \u003e 0$$ and $$\Delta S \u003e 0. $$Under what temperature conditions will this reaction be spontaneous?

Accepted Answer

At high temperatures

Question 11

Which of the following statements about entropy ($$S) is $$correct?

Accepted Answer

An increase in entropy ($$\Delta S \u003e 0) $$means the system has become more random.

Question 12

Which of the following best describes the role of enzymes in biochemical reactions?

Accepted Answer

Enzymes decrease the activation energy ($$E_a) $$required for a reaction.

Question 13

Which of the following is a correct statement about the primary structure of proteins?

Accepted Answer

It is determined by the sequence of amino acids from the N-terminus to the C-terminus.

Question 14

Which of the following best describes an exothermic reaction?

Accepted Answer

$$\Delta H \u003c 0$$; heat flows from the system to the surroundings.

Question 15

Which of the following is a correct example of a closed thermodynamic system?

Accepted Answer

A sealed beaker that allows heat transfer but not matter exchange.

Question 16

Which of the following statements about the evolution from the RNA-world to the protein-world is correct?

Accepted Answer

RNA molecules are thought to have acted as both genetic material and catalysts before proteins evolved.

Question 17

Which of the following best explains why the abundance of phosphorus in organisms is much higher than in the universe relative to carbon?

Accepted Answer

Phosphorus is essential for nucleic acids and energy transfer molecules like ATP.

Question 18

Which of the following best describes the relationship between $$\Delta G$$, $$\Delta H$$, and $$\Delta S in a $$biochemical reaction?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 19

Which of the following is a correct statement about spontaneous reactions?

Accepted Answer

A spontaneous reaction has $$\Delta G \u003c 0.$$

Question 20

Which of the following best describes the chemical structure of a triglyceride (a type of lipid)?

Accepted Answer

A molecule formed from glycerol and three fatty acids.

Introduction to Biochemical Macromolecules and Thermodynamics in Microbiology

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