Question 1

Which of the following best describes the relationship between a community and an ecosystem?

Accepted Answer

A community is a group of populations of different species living in the same area, while an ecosystem includes the community plus the abiotic environment.

Question 2

A scientist is testing the effect of a new fertilizer on plant growth. She sets up two groups: one receives the fertilizer, and the other does not. Which of the following is the dependent variable in this experiment?

Accepted Answer

The growth of the plants measured over time

Question 3

Which of the following best explains why water is considered a polar molecule?

Accepted Answer

Oxygen is more electronegative than hydrogen, resulting in an unequal sharing of electrons and partial charges on the molecule.

Question 4

Which of the following is a correct statement about the pH scale?

Accepted Answer

A solution with a pH of 7 is neutral because $$[H^+] = [OH^-].$$

Question 5

Which of the following best describes the function of enzymes in biological systems?

Accepted Answer

Enzymes act as catalysts by lowering the activation energy of reactions, increasing the reaction rate.

Question 6

A triglyceride is formed by the condensation (dehydration synthesis) of which molecules?

Accepted Answer

Three fatty acids and one glycerol

Question 7

Which of the following statements about phospholipids is correct?

Accepted Answer

Phospholipids have two fatty acid tails and a phosphate group, making them amphipathic.

Question 8

Which of the following best explains why ice floats on liquid water?

Accepted Answer

Hydrogen bonds in ice create a lattice structure that is less dense than liquid water.

Question 9

A solution has a hydrogen ion concentration of $$1 	imes 10$$^{-5}$$ M. What is the pH of this solution?

Accepted Answer

$$5$$

Question 10

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

Accepted Answer

Nucleic acid – nucleotide

Question 11

A researcher observes that the average distance between sea slugs in a plot increases dramatically at noon and decreases again by midnight. Which of the following is the most plausible explanation for this pattern?

Accepted Answer

Sea slugs spread out at noon to avoid high temperatures or increased sunlight.

Question 12

Which of the following best describes the difference between a saturated and an unsaturated fatty acid?

Accepted Answer

Unsaturated fatty acids have one or more double bonds, causing kinks in the chain, while saturated fatty acids have no double bonds.

Question 13

Which of the following best explains why buffers are important in biological systems?

Accepted Answer

Buffers maintain a stable pH by accepting or donating hydrogen ions as needed.

Question 14

Which of the following is a correct description of a peptide bond?

Accepted Answer

A peptide bond is a covalent bond formed between the amino group of one amino acid and the carboxyl group of another.

Question 15

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

Accepted Answer

The overall structure formed by the association of two or more polypeptide chains.

Question 16

A pineapple enzyme called bromelain is used as a meat tenderizer. If the pH of the fruit is increased from 3.5 to 11, what is the most likely effect on bromelain activity?

Accepted Answer

Bromelain activity will decrease because the enzyme's structure is altered at extreme pH.

Question 17

Which of the following best explains the difference between hydrolysis and condensation (dehydration synthesis) reactions?

Accepted Answer

Condensation joins monomers by removing water, while hydrolysis breaks polymers by adding water.

Question 18

Which of the following is a property shared by all lipids?

Accepted Answer

They are all hydrophobic or nonpolar.

Question 19

Which of the following best describes the role of ATP in cells?

Accepted Answer

ATP stores and transfers energy for cellular processes.

General Biology: Atoms, Molecules, Macromolecules, and Experimental Design

Guida di studio - Domande di pratica

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