Q: A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

$$[H^+] = 1 \times 10$$^{-4}$$ \ M$$

Question 1

Which of the following best describes a negative feedback mechanism in biological systems?

Accepted Answer

A process that reduces the original stimulus, helping maintain homeostasis.

Question 2

A scientist observes that a certain plant grows faster when exposed to blue light. Which step of the scientific method is the scientist performing if they design an experiment to test this observation?

Accepted Answer

Conducting an experiment

Question 3

Which of the following statements about isotopes is correct?

Accepted Answer

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

Question 4

A sodium atom ($$Na) $$loses one electron to become $$Na^+. $$What type of ion is $$Na^+$$ and why?

Accepted Answer

$$Na^+ is a $$cation because it has lost an electron.

Question 5

Which of the following bonds is primarily responsible for the cohesion of water molecules?

Accepted Answer

Hydrogen bonds

Question 6

A solution has a pH of 4. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-4}$$ \ M$$

Question 7

Which functional group is present in all amino acids and acts as a base by accepting $$H^+$$ ions?

Accepted Answer

Amino group ($$-NH_2$)

Question 8

Which of the following macromolecules is NOT formed by the polymerization of monomers?

Accepted Answer

Lipids

Question 9

During the process of protein synthesis, which organelle is responsible for the initial assembly of amino acids into polypeptides?

Accepted Answer

Ribosome

Question 10

A red blood cell is placed in a hypotonic solution. What will most likely happen to the cell?

Accepted Answer

The cell will swell and may burst due to water entering.

Question 11

Which of the following statements about enzymes is correct?

Accepted Answer

Enzymes lower the activation energy and speed up reactions.

Question 12

Which process produces the most ATP during cellular respiration?

Accepted Answer

Chemiosmosis (oxidative phosphorylation)

Question 13

Which of the following best describes the semiconservative model of DNA replication?

Accepted Answer

Each new DNA molecule consists of one old and one new strand.

Question 14

If a DNA template strand has the sequence $$5'	ext{-}ATGCGT-3'$$, what is the sequence of the complementary mRNA strand produced during transcription?

Accepted Answer

$$5'	ext{-}UACGCA-3'$$

Question 15

Which phase of the cell cycle is characterized by DNA replication?

Accepted Answer

S phase

Question 16

Which event during meiosis increases genetic variation among offspring?

Accepted Answer

Crossing over during prophase I

Question 17

A person with genotype $$Aa$$ for a gene is considered:

Accepted Answer

Heterozygous

Question 18

Which type of mutation results in a premature stop codon?

Accepted Answer

Nonsense mutation

Question 19

Which type of RNA carries amino acids to the ribosome during translation?

Accepted Answer

tRNA

Question 20

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

Accepted Answer

Facilitated diffusion moves substances down their concentration gradient without energy input, while active transport moves substances against their gradient using energy.

Comprehensive Study Guide: Foundations of Biology (Chapters 1–17)

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