Question 1

Which of the following statements best explains why phospholipids form bilayers in aqueous environments?

Accepted Answer

Phospholipids are amphipathic, with hydrophilic heads that interact with water and hydrophobic tails that avoid water, leading to bilayer formation.

Question 2

A scientist isolates a nucleic acid strand with the following sequence: 5′-AUGCCGAU-3′. Which of the following statements is correct about this molecule?

Accepted Answer

It is RNA because it contains uracil and ribose.

Question 3

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

Accepted Answer

Enzymes lower the activation energy required for a reaction, increasing the reaction rate.

Question 4

A red blood cell is placed in a solution and begins to swell and eventually bursts. Which of the following best describes the tonicity of the solution relative to the cell?

Accepted Answer

The solution is hypotonic to the cell.

Question 5

Which of the following changes would most likely increase the fluidity and permeability of a cell membrane at room temperature?

Accepted Answer

Increasing the proportion of phospholipids with short, unsaturated fatty acid tails.

Question 6

A protein is found to consist of two separate polypeptide chains that interact to form a functional unit. This level of protein structure is known as:

Accepted Answer

Quaternary structure

Question 7

Which of the following best explains why DNA polymerization always proceeds in the 5′ to 3′ direction?

Accepted Answer

New nucleotides are added to the 3′ hydroxyl group of the growing strand.

Question 8

A mutation causes a single amino acid substitution in the active site of an enzyme. Which of the following is the most likely consequence?

Accepted Answer

The enzyme's ability to bind its substrate or catalyze the reaction may be altered, potentially reducing or eliminating activity.

Question 9

Which of the following best distinguishes prokaryotic cells from eukaryotic cells?

Accepted Answer

Eukaryotic cells contain a nucleus and membrane-bound organelles; prokaryotic cells do not.

Question 10

A cell is observed to have a large central vacuole, chloroplasts, and a rigid cell wall. Which type of cell is this most likely to be?

Accepted Answer

Plant cell

Question 11

Which of the following best describes the function of the Golgi apparatus in eukaryotic cells?

Accepted Answer

It modifies, sorts, and packages proteins and other materials for transport.

Question 12

A solution contains a higher concentration of solute than the cytoplasm of a cell placed in it. What will happen to the cell, and what is the term for this type of solution?

Accepted Answer

The cell will lose water and shrink; the solution is hypertonic.

Question 13

Which of the following is a function of the cytoskeleton in eukaryotic cells?

Accepted Answer

Providing structural support, maintaining cell shape, and enabling intracellular transport.

Question 14

Which of the following best describes the difference between simple diffusion and facilitated diffusion across a cell membrane?

Accepted Answer

Facilitated diffusion requires membrane proteins, while simple diffusion does not.

Question 15

A scientist is studying a protein that is secreted from the cell. Which of the following best describes the pathway this protein takes from synthesis to secretion?

Accepted Answer

Rough ER → Golgi apparatus → transport vesicle → plasma membrane

Question 16

Which of the following statements about the 9 + 2 arrangement of microtubules is correct?

Accepted Answer

It is found in the axoneme of eukaryotic cilia and flagella and is essential for their movement.

Question 17

Which of the following best explains why RNA is more functionally versatile than DNA?

Accepted Answer

RNA can fold into complex three-dimensional structures and can act as a catalyst (ribozyme).

Question 18

Which of the following is true regarding the movement of water across a selectively permeable membrane?

Accepted Answer

Water moves from areas of low solute concentration to areas of high solute concentration by osmosis.

Question 19

Which of the following best describes a peptide bond?

Accepted Answer

A covalent bond formed between the carboxyl group of one amino acid and the amino group of another, releasing water.

Biology 1 Exam 2 Study Guide: Nucleic Acids, Proteins, Membranes, and Cellular Organization

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