Q: Which functional group is present in both peptide bonds and the backbone of proteins, and is responsible for linking amino acids?

Amide group $$\text{R–C(=O)–NH}_2$$

Q: Given the reaction $$\text{glucose} + \text{P}_i \rightarrow \text{glucose 6-phosphate}$$ with $$\Delta G^\circ = +13.8\ \text{kJ/mol}$$ and ATP hydrolysis $$\Delta G^\circ = -30.5\ \text{kJ/mol}$$, what is the net standard free energy change for the coupled reaction $$\text{glucose} + \text{ATP} \rightarrow \text{glucose 6-phosphate} + \text{ADP}$$?

$$\Delta G^\circ = -16.7\ \text{kJ/mol}$$

Question 1

Which of the following statements best explains why cells are limited in size?

Accepted Answer

As cell size increases, the surface area to volume ratio decreases, limiting nutrient entry and waste removal relative to metabolic demand.

Question 2

A scientist isolates a fraction from cell homogenization that is enriched in catalase activity. Which organelle is most likely present in this fraction?

Accepted Answer

Peroxisomes

Question 3

Which functional group is present in both peptide bonds and the backbone of proteins, and is responsible for linking amino acids?

Accepted Answer

Amide group $$	ext{R–C(=O)–NH}_2$$

Question 4

A molecule has two chiral centers and no internal symmetry. How many stereoisomers are possible?

Accepted Answer

$$2^2 = 4$

Question 5

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

Accepted Answer

ATP couples exergonic and endergonic reactions, often through phosphoryl group transfer.

Question 6

Given the reaction $$	ext{glucose} + 	ext{P}_i ightarrow 	ext{glucose 6-phosphate}$$ with $$\Delta G^\circ = +13.8\ 	ext{kJ/mol}$$ and ATP hydrolysis $$\Delta G^\circ = -30.5\ 	ext{kJ/mol}$$, what is the net standard free energy change for the coupled reaction $$	ext{glucose} + 	ext{ATP} ightarrow 	ext{glucose 6-phosphate} + 	ext{ADP}$$?

Accepted Answer

$$\Delta G^\circ = -16.7\ 	ext{kJ/mol}$$

Question 7

Which statement about enzymes is correct?

Accepted Answer

Enzymes lower the activation energy ($$\Delta G^\ddagger) $$but do not change the equilibrium constant ($$K) or $$the overall free energy change ($$\Delta G).$$

Question 8

A cell maintains constant concentrations of a metabolite for several hours. Which statement is most accurate?

Accepted Answer

The cell is likely in a dynamic steady state, with ongoing production and consumption.

Question 9

Which of the following is a correct application of the second law of thermodynamics to living cells?

Accepted Answer

Cells maintain order by exporting entropy to their surroundings, so total entropy increases.

Question 10

Which of the following best describes the relationship between genome, proteome, and metabolome?

Accepted Answer

The proteome and metabolome can change due to regulation and environmental factors without DNA mutation.

Question 11

A mutation replaces glutamate with valine at position 6 of the β-globin chain. Which effect is most likely?

Accepted Answer

The protein's structure and function may change, potentially causing sickle-cell anemia.

Question 12

Which of the following is NOT a major function of the cytoskeleton?

Accepted Answer

Catalyzing metabolic reactions

Question 13

Which of the following best describes the Miller–Urey experiment's significance?

Accepted Answer

It demonstrated that some organic building blocks can form abiotically under simulated early Earth conditions.

Question 14

Which of the following is a correct statement about the RNA world hypothesis?

Accepted Answer

RNA could both store sequence information and catalyze reactions, making it plausible as an early genetic system.

Question 15

Which equation correctly relates Gibbs free energy to enthalpy and entropy?

Accepted Answer

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

Question 16

A reaction has $$K = 0.01 at$$ $$298\ 	ext{K}. $$What is the sign of $$\Delta G^\circ$$?

Accepted Answer

$$\Delta G^\circ \u003e 0$$

Question 17

Which of the following best describes feedback inhibition in metabolic pathways?

Accepted Answer

An end product inhibits an earlier enzyme, preventing unnecessary production and conserving resources.

Question 18

Which of the following is a correct description of semiconservative DNA replication?

Accepted Answer

Each daughter double helix contains one old strand and one new strand.

Question 19

Which of the following is a correct statement about stereospecificity in biological systems?

Accepted Answer

Enzymes, receptors, and antibodies often distinguish between stereoisomers, leading to different biological effects.

Question 20

Which of the following best explains why carbon is central to biomolecular diversity?

Accepted Answer

Carbon can form four stable covalent bonds, allowing chains, branches, rings, and multiple bonds with other elements.

Foundations of Biochemistry: Chapter 1 Study Guide and Practice

Guida di studio - Domande di pratica

Study guide - Flashcard