Question 1

Which of the following best describes a nucleotide and its role in the structure of DNA?

Accepted Answer

A nucleotide is composed of a phosphate group, a sugar, and a nitrogenous base, and it links with other nucleotides to form the double helix structure of DNA.

Question 2

Which of the following equations correctly represents the relationship between pH and hydrogen ion concentration $$[H^+]$$?

Accepted Answer

$$pH = -\log_{10}([H^+])$$

Question 3

Which of the following is an example of a positive feedback loop in biology?

Accepted Answer

Blood clotting, where the presence of a clotting factor accelerates the production of more clotting factors.

Question 4

Which of the following is NOT one of the seven properties of life?

Accepted Answer

Ability to photosynthesize

Question 5

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

Accepted Answer

Eukaryotic cells have a nucleus, while prokaryotic cells lack a nucleus.

Question 6

Which of the following best explains how natural selection leads to evolution?

Accepted Answer

Individuals with advantageous traits are more likely to survive and reproduce, passing those traits to the next generation.

Question 7

Given the electron configuration $$1s^2$$ $$2s^2$$ $$2p^6$$ $$3s^2$$ $$3p^5$$, which element is this and how many valence electrons does it have?

Accepted Answer

Chlorine, with 7 valence electrons.

Question 8

Which of the following bonds is most likely to be nonpolar covalent?

Accepted Answer

A bond between two identical oxygen atoms ($$O_2).$$

Question 9

Which of the following best explains why water is an excellent solvent for ionic compounds?

Accepted Answer

Water is polar, allowing it to surround and separate ions due to its partial charges.

Question 10

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 11

Which of the following best describes how carbon dating works?

Accepted Answer

It measures the ratio of $$^{14}C to$$ $$^{12}C in a $$sample to estimate the time since the organism died.

Question 12

Which of the following best explains why sodium chloride ($$NaCl) $$dissolves in water?

Accepted Answer

The polar water molecules stabilize the $$Na^+$$ and $$Cl^-$$ ions by forming hydration shells around them.

Question 13

Which of the following is a correct statement about the carbonic acid-bicarbonate buffer system in blood?

Accepted Answer

It maintains blood pH by converting $$CO_2$$ and $$H_2O$$ into $$H_2CO_3$$, which can dissociate into $$HCO_3$$^-$$ and H$$^+$$.

Question 14

Which of the following best describes the difference between alpha and beta glucose in polysaccharide formation?

Accepted Answer

Alpha glucose forms starch, while beta glucose forms cellulose due to the orientation of the hydroxyl group on carbon 1.

Question 15

Which of the following best explains why carbon is so important for life on Earth?

Accepted Answer

Carbon can form up to four covalent bonds, allowing for a diversity of stable organic molecules.

Question 16

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

Accepted Answer

Enzymes lower the activation energy, speeding up chemical reactions without being consumed.

Question 17

Which of the following best explains the difference between chemical bonds and intermolecular forces?

Accepted Answer

Chemical bonds involve sharing or transfer of electrons between atoms, while intermolecular forces are attractions between molecules.

Question 18

Which of the following is a correct example of a functional group and its possible chemical bond?

Accepted Answer

A carboxyl group ($$-COOH) $$can form hydrogen bonds with water molecules.

Question 19

Which of the following best explains how the structure of fatty acids affects their function in temperature regulation?

Accepted Answer

Unsaturated fatty acids have double bonds that create kinks, increasing membrane fluidity and helping organisms adapt to cold environments.

Question 20

Which of the following best describes the four classes of biomolecules and their monomers?

Accepted Answer

Carbohydrates (monosaccharides), proteins (amino acids), lipids (fatty acids and glycerol), nucleic acids (nucleotides).

General Biology: Core Concepts and Practice Questions

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