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 arise from preexisting cells.

Question 2

Which of the following best explains why water has a high surface tension?

Accepted Answer

Water molecules form hydrogen bonds, resulting in strong cohesive forces.

Question 3

A scientist observes that sickle cell disease is caused by a mutation that replaces a glutamate with a valine in hemoglobin. What is the most direct effect of this mutation on the hemoglobin protein?

Accepted Answer

It introduces a nonpolar side chain, causing hemoglobin to bind to other nonpolar parts and aggregate.

Question 4

Which of the following is true about the difference between ionic and covalent bonds?

Accepted Answer

Ionic bonds involve attraction between oppositely charged ions, while covalent bonds involve sharing electrons.

Question 5

Which property of water allows it to moderate temperature changes in living organisms?

Accepted Answer

High heat of vaporization

Question 6

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

Accepted Answer

$$O-H$$

Question 7

Which of the following best describes the process of natural selection?

Accepted Answer

Individuals with heritable differences that are better suited for reproduction are more likely to survive and pass on their genes.

Question 8

A protein is exposed to high temperature and extreme pH. What is the most likely effect on the protein?

Accepted Answer

It will denature, losing its tertiary and possibly secondary structure.

Question 9

Which of the following is a function of enzymes in biological reactions?

Accepted Answer

Enzymes lower the activation energy, speeding up the reaction.

Question 10

Which statement about the structure of amino acids is correct?

Accepted Answer

Amino acids have a central carbon bonded to an amino group, a carboxyl group, a hydrogen atom, and a variable side chain.

Question 11

Which of the following best explains why lipid bilayers with unsaturated tails have higher permeability than those with saturated tails?

Accepted Answer

Unsaturated tails have kinks that prevent tight packing, increasing membrane fluidity.

Question 12

A sodium-potassium pump moves sodium ions out of the cell and potassium ions into the cell. Which type of transport is this and what is required for it to occur?

Accepted Answer

Active transport; requires ATP

Question 13

Which of the following is true about nonpolar covalent bonds?

Accepted Answer

Electrons are shared equally between atoms.

Question 14

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

Accepted Answer

Low heat of vaporization

Question 15

Which level of protein structure is primarily determined by hydrogen bonds between backbone atoms, forming shapes like alpha helices and beta sheets?

Accepted Answer

Secondary structure

Question 16

A mutation causes a protein to lose its ability to bind to a substrate at its active site, but it can still bind at a different site. What type of regulation is most likely occurring?

Accepted Answer

Allosteric regulation

Question 17

Which of the following statements about biological polymers is correct?

Accepted Answer

Condensation reactions join monomers to form polymers, releasing water.

Question 18

Which of the following is a correct description of facilitated diffusion?

Accepted Answer

Movement of molecules down their concentration gradient through a membrane protein.

Question 19

Which class of biological molecule is NOT correctly matched with its function?

Accepted Answer

Carbohydrates - genetic information storage

Question 20

Which of the following best explains why enzymes do not change the $$	riangle G of a $$reaction?

Accepted Answer

Enzymes only change the activation energy, not the overall energy difference between reactants and products.

General Biology: Foundations, Cell Structure, Water, Macromolecules, and Enzymes

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