Question 1

Which statement best describes the cell theory as currently accepted in biology?

Accepted Answer

All living organisms are composed of cells, and all cells come from preexisting cells.

Question 2

Which of the following is NOT a property of water that is crucial for life?

Accepted Answer

Water is a poor solvent for polar and charged molecules.

Question 3

A scientist is studying a population of finches and observes that some individuals have larger beaks, which allow them to eat tougher seeds. According to the theory of evolution by natural selection, what must be true for the population to evolve larger beaks over time?

Accepted Answer

Beak size must be heritable and individuals with larger beaks must have higher reproductive success.

Question 4

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by sharing electrons between atoms.

Question 5

Given the electronegativity scale: O \u003e N \u003e C ≈ H, which bond is most polar?

Accepted Answer

$$\mathrm{O-H}$$

Question 6

Which of the following statements about biological polymers is correct?

Accepted Answer

Condensation reactions join monomers into polymers and release water.

Question 7

A mutation causes the hemoglobin protein to have a valine instead of a glutamate at a specific position. What is the most likely consequence of this change?

Accepted Answer

Hemoglobin will bind to other nonpolar parts of other hemoglobin molecules, leading to sickle cell disease.

Question 8

Which of the following best explains why enzymes speed up chemical reactions?

Accepted Answer

Enzymes lower the activation energy required for the reaction.

Question 9

Which of the following is true about the sodium-potassium pump?

Accepted Answer

It uses ATP to move sodium out of the cell and potassium into the cell against their concentration gradients.

Question 10

Which of the following is a correct description of a nonpolar covalent bond?

Accepted Answer

Electrons are shared equally between atoms, resulting in no partial charges.

Question 11

Which property of water allows insects to walk on its surface?

Accepted Answer

Cohesion due to hydrogen bonding

Question 12

A protein loses its function after being exposed to high temperature and extreme pH. What is the most likely explanation?

Accepted Answer

The protein was denatured, disrupting its tertiary and quaternary structure.

Question 13

Which of the following is true about phospholipids in biological membranes?

Accepted Answer

They form a bilayer with hydrophilic heads facing outward and hydrophobic tails facing inward.

Question 14

Which of the following would increase the permeability of a cell membrane?

Accepted Answer

Increasing the proportion of unsaturated fatty acids in the membrane.

Question 15

Which of the following is a function of competitive inhibitors in enzyme activity?

Accepted Answer

They bind to the active site and block substrate binding.

Question 16

Which of the following best describes the secondary structure of a protein?

Accepted Answer

The folding of the polypeptide chain into alpha helices and beta sheets stabilized by hydrogen bonds.

Question 17

Which of the following is true about the process of diffusion across a cell membrane?

Accepted Answer

It moves molecules from high concentration to low concentration until equilibrium is reached.

Question 18

Which of the following is a correct statement about the quaternary structure of proteins?

Accepted Answer

It involves the interaction of multiple polypeptide chains.

Question 19

Which of the following is true about the change in free energy ($$\Delta G) in a $$spontaneous reaction?

Accepted Answer

$$\Delta G is $$negative and energy is released.

Question 20

Which of the following is a correct description of an ionic bond?

Accepted Answer

A bond formed by the attraction between oppositely charged ions.

General Biology: Core Concepts and Molecular Foundations

Guida di studio - Domande di pratica

Study guide - Flashcard