Question 1

Which of the following best describes the difference between covalent and non-covalent bonds in biological molecules?

Accepted Answer

Covalent bonds involve the sharing of electron pairs between atoms, while non-covalent bonds include interactions such as hydrogen bonds, ionic bonds, and van der Waals forces that do not involve electron sharing.

Question 2

A protein's tertiary structure is most directly determined by which of the following?

Accepted Answer

The sequence of amino acids in its primary structure.

Question 3

Which of the following scenarios best illustrates the role of non-covalent bonds in the three-dimensional structure of a protein?

Accepted Answer

Hydrogen bonds and ionic interactions between side chains stabilizing the folding of the protein.

Question 4

A cell is placed in a solution with a higher solute concentration than the cytoplasm. Which process will most likely occur, and what is the underlying mechanism?

Accepted Answer

Water will move out of the cell by osmosis, because the solution is hypertonic to the cell.

Question 5

Which of the following best describes an electrochemical gradient?

Accepted Answer

A difference in both the concentration of ions and the electrical charge across a membrane.

Question 6

A reaction has a negative $$\Delta G. $$What does this indicate about the reaction?

Accepted Answer

The reaction is spontaneous and can proceed without an input of energy.

Question 7

Which of the following is a correct statement about enzymes?

Accepted Answer

Enzymes lower the activation energy of a reaction without changing the overall $$\Delta G.$$

Question 8

Which of the following is an example of active transport in a biological membrane?

Accepted Answer

Uptake of glucose into a cell against its concentration gradient using ATP.

Question 9

A ligand binds to a protein's binding site, causing a conformational change. What is the most likely result of this event?

Accepted Answer

The protein's ability to interact with other molecules may be increased or decreased.

Question 10

Which of the following best describes the function of activated carriers such as ATP or NADH in cellular metabolism?

Accepted Answer

They store and transfer energy or chemical groups between molecules.

Question 11

A patient is given an intravenous solution that is hypotonic relative to their blood plasma. What is the most likely effect on their red blood cells?

Accepted Answer

Red blood cells will swell and may burst due to water influx.

Question 12

Which of the following is a function of junctional complexes in animal tissues?

Accepted Answer

They facilitate communication and adhesion between adjacent cells.

Question 13

During endocytosis, which of the following occurs?

Accepted Answer

The cell engulfs external materials by forming vesicles from the plasma membrane.

Question 14

Which of the following best explains why non-covalent interactions are essential for the function of biological macromolecules?

Accepted Answer

They allow for dynamic interactions and reversible changes in structure necessary for biological activity.

Question 15

A cell needs to import a large, polar molecule that cannot diffuse through the lipid bilayer. Which transport mechanism is most likely used?

Accepted Answer

Facilitated diffusion through a specific transporter protein.

Question 16

Which of the following statements about exocytosis is correct?

Accepted Answer

Exocytosis is the process by which cells secrete substances by vesicle fusion with the plasma membrane.

Question 17

If a reaction has $$\Delta G = 0$$, what does this indicate about the reaction?

Accepted Answer

The reaction is at equilibrium and no net change will occur.

Question 18

Which of the following best describes the relationship between a protein's primary structure and its function?

Accepted Answer

The primary structure determines the folding and final 3D shape, which is critical for function.

Question 19

A scientist observes that a certain reaction in a cell only occurs when ATP is hydrolyzed. What type of transport or reaction is most likely involved?

Accepted Answer

Active transport.

Question 20

Which of the following is a real-life example of a process driven by an electrochemical gradient?

Accepted Answer

The movement of sodium ions into a neuron during an action potential.

Biol 203 Exam 1 Study Guide: Molecular and Cellular Foundations

Study Guide - Practice Questions

Study Guide - Flashcards