Question 1

Which of the following best describes the chemical reaction used to synthesize polymers such as proteins and polysaccharides in cells?

Accepted Answer

Dehydration synthesis, which removes a water molecule to form a bond between monomers.

Question 2

Which of the following statements about the structure of DNA is correct?

Accepted Answer

The backbone of DNA is composed of alternating phosphate and deoxyribose groups.

Question 3

A patient is diagnosed with a genetic disorder caused by a single amino acid substitution in a protein. At which level of protein structure does this change directly occur, and why is it significant?

Accepted Answer

Primary structure, because the sequence of amino acids determines all higher levels of structure.

Question 4

Which of the following best distinguishes saturated fatty acids from unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have no double bonds between carbon atoms, resulting in straight chains that pack tightly.

Question 5

Which of the following is a correct pairing of a polymer and its specific monomer?

Accepted Answer

Glycogen – alpha glucose

Question 6

A scientist isolates a molecule composed of a nitrogenous base, a five-carbon sugar, and a phosphate group. This molecule is best described as:

Accepted Answer

A nucleotide

Question 7

Which of the following organelles is primarily responsible for the synthesis of lipids and detoxification of drugs in eukaryotic cells?

Accepted Answer

Smooth endoplasmic reticulum

Question 8

Which of the following statements about the plasma membrane is correct?

Accepted Answer

The plasma membrane is selectively permeable, allowing some substances to cross more easily than others.

Question 9

A red blood cell is placed in a hypertonic solution. What will most likely happen to the cell, and why?

Accepted Answer

It will shrink because water leaves the cell to balance solute concentrations.

Question 10

Which of the following best describes the function of microtubules in eukaryotic cells?

Accepted Answer

They serve as tracks for motor proteins and are essential for chromosome movement during cell division.

Question 11

Which of the following best explains why steroid hormones can bind to intracellular receptors?

Accepted Answer

Steroid hormones are nonpolar and can diffuse through the lipid bilayer of the plasma membrane.

Question 12

Which of the following is a function of the electrogenic pump in animal cells?

Accepted Answer

It pumps sodium ions (Na$$^+) $$out and potassium ions (K$$^+) $$into the cell, generating a membrane potential.

Question 13

Which of the following best describes the role of kinases in cell signaling pathways?

Accepted Answer

Kinases add phosphate groups to proteins, often activating or deactivating them.

Question 14

A mutation prevents the formation of disulfide bonds in a protein. Which amino acid is most likely affected, and at which level of protein structure would this have the greatest impact?

Accepted Answer

Cysteine; tertiary structure

Question 15

Which of the following scenarios best illustrates the concept of selective permeability of the plasma membrane?

Accepted Answer

Oxygen (O$$_2) $$diffuses rapidly across the membrane, while glucose requires a transport protein.

Question 16

Which of the following best describes the difference between a G protein-coupled receptor (GPCR) and a ligand-gated ion channel?

Accepted Answer

A GPCR activates a G protein, which then triggers a signaling cascade, while a ligand-gated ion channel opens to allow ions to flow across the membrane.

Question 17

Which of the following best explains why the sequence of amino acids in a protein is important?

Accepted Answer

It dictates the protein's three-dimensional structure and function.

Question 18

Which of the following is a correct description of the flow of information in a eukaryotic cell from gene to functional protein?

Accepted Answer

DNA is transcribed to RNA, which is translated to protein, which is then transported to its destination.

Question 19

Which of the following best describes the function of cAMP in cell signaling?

Accepted Answer

It acts as a second messenger that amplifies the signal inside the cell.

Question 20

A plant cell is placed in a hypotonic solution. What is the most likely outcome, and why?

Accepted Answer

The cell will become turgid as water enters, but the cell wall prevents bursting.

Study Guide: Biomolecules, Cell Structure, Membranes, and Cell Signaling

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