Introduction to Biochemistry

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Questions and Answers

A researcher is studying a metabolic pathway and observes that a particular reaction has a positive Gibbs free energy change ($ΔG > 0$). What can the researcher conclude about this reaction?

The reaction is spontaneous and releases energy.
The reaction requires an input of energy to proceed. (correct)
The reaction proceeds at an equilibrium state.
The reaction will occur rapidly without any external influence.

During exercise, muscle cells convert chemical energy into mechanical energy. Which molecule is the primary energy currency that facilitates this conversion?

DNA
Enzymes
ATP (correct)
RNA

A scientist is investigating the effect of pH on enzyme activity. They find that an enzyme functions optimally at a pH of 7.4. What would be the most appropriate buffer to use in their experiment?

A buffer that maintains a pH of 10.0
A buffer that maintains a pH of 14.0
A buffer that maintains a pH of 2.0
A buffer that maintains a pH of 7.4 (correct)

A mutation in the coding region of a gene results in a change from one codon to another, but the amino acid sequence of the protein remains the same. Which characteristic of the genetic code explains this observation?

The genetic code is degenerate. (A) Signup and view all the answers

In a biotechnology lab, researchers are using recombinant DNA technology to produce a human protein in bacteria. Which of the following steps is essential for this process?

Introducing the human gene into a bacterial plasmid. (D) Signup and view all the answers

Which of the following best describes the central role of biochemical signaling?

Coordinating communication within and between cells to regulate biological processes. (C) Signup and view all the answers

In the context of biochemistry, how do enzymes catalyze biochemical reactions?

By lowering the activation energy required for the reaction to proceed. (A) Signup and view all the answers

What is the primary role of nucleic acids within a cell?

Storing and transmitting genetic information. (A) Signup and view all the answers

If a scientist is studying the arrangement of multiple polypeptide chains within a protein, which level of protein structure are they investigating?

Quaternary structure (A) Signup and view all the answers

Which of the following is the most accurate description of anabolism?

The synthesis of complex molecules from simpler ones, requiring energy. (B) Signup and view all the answers

What is the crucial role of the electron transport chain in oxidative phosphorylation?

To generate a proton gradient that drives ATP synthase. (A) Signup and view all the answers

Which of the following is a key characteristic of lipids?

They are hydrophobic molecules used for energy storage and as structural components of cell membranes. (A) Signup and view all the answers

During glycolysis, what is the net production of ATP from one molecule of glucose?

2 ATP (C) Signup and view all the answers

How does the specificity of an enzyme contribute to its function?

It ensures that the enzyme only catalyzes reactions involving specific substrates, preventing unwanted side reactions. (D) Signup and view all the answers

Which of the following best describes the role of cofactors in enzyme activity?

They are inorganic ions or coenzymes that are required for the enzyme to function properly. (C) Signup and view all the answers

What distinguishes saturated fatty acids from unsaturated fatty acids?

Unsaturated fatty acids contain one or more carbon-carbon double bonds, while saturated fatty acids do not. (B) Signup and view all the answers

Which of the following is an example of a polysaccharide?

Cellulose (B) Signup and view all the answers

In DNA structure, which nitrogenous base pairs with adenine?

Thymine (A) Signup and view all the answers

Which of the following best describes the citric acid cycle's primary role in cellular metabolism?

The oxidation of acetyl-CoA to produce carbon dioxide, NADH, and FADH2. (D) Signup and view all the answers

A drug that inhibits a specific receptor on a cell surface would directly affect which of the following biochemical processes?

Biochemical signaling (C) Signup and view all the answers

Flashcards

ATP

The main energy currency of the cell, storing energy in its chemical bonds.

Buffer

A substance that resists changes in pH, maintaining a stable environment.