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

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

Question 1

Which of the following best describes the relationship between an atom, a molecule, and a cell in the hierarchy of biological organization?

Accepted Answer

An atom is the basic unit of matter, molecules are made of atoms, and cells are made of molecules.

Question 2

A scientist is studying 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 independent variable in this experiment?

Accepted Answer

The application of the new fertilizer

Question 3

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

Accepted Answer

Water has a bent shape and unequal sharing of electrons, resulting in partial charges.

Question 4

Which of the following equations correctly represents the process of photosynthesis?

Accepted Answer

$$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6$ + 6O_2$$

Question 5

A triglyceride is formed by the condensation of three fatty acids and one glycerol molecule. What type of bond is formed between the glycerol and fatty acids?

Accepted Answer

Ester bond

Question 6

Which of the following statements about enzymes is correct?

Accepted Answer

Enzymes lower the activation energy required for a reaction to occur.

Question 7

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}$$ 	ext{ M}$$

Question 8

Which of the following best describes the difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have no double bonds between carbon atoms; unsaturated fatty acids have one or more double bonds.

Question 9

Which of the following is a correct description of a buffer system in biological fluids?

Accepted Answer

A buffer system minimizes changes in pH by accepting or donating hydrogen ions.

Question 10

A student observes that the average distance between slugs in a plot increases dramatically at noon and 4 PM, then decreases by midnight. Which of the following is the most plausible explanation for this pattern?

Accepted Answer

Slugs are more active and spread out during the hottest parts of the day to avoid dehydration.

Question 11

Which of the following best explains why phospholipids are well-suited to form cell membranes?

Accepted Answer

Phospholipids have both hydrophilic heads and hydrophobic tails, allowing them to form bilayers in aqueous environments.

Question 12

Which of the following is the correct sequence of protein structure levels from simplest to most complex?

Accepted Answer

Primary, secondary, tertiary, quaternary

Question 13

Which of the following best describes a hydrolysis reaction?

Accepted Answer

A reaction that breaks a polymer into monomers by adding a water molecule.

Question 14

A pineapple enzyme called bromelain is used to prevent browning in cut fruits. Bromelain is most likely which type of macromolecule?

Accepted Answer

Protein

Question 15

Which of the following best explains why enzymes are specific to their substrates?

Accepted Answer

Enzymes have active sites with shapes that fit only specific substrates.

Question 16

If the pH of a solution changes from 7 to 5, how does the hydrogen ion concentration change?

Accepted Answer

It increases by 100 times.

Question 17

Which of the following is a correct example of a monomer-polymer pair?

Accepted Answer

Amino acid - protein

Question 18

Which of the following best describes the function of a buffer in human blood?

Accepted Answer

Buffers maintain the pH of blood by neutralizing excess acids or bases.

Question 19

Which of the following statements about the structure of DNA is correct?

Accepted Answer

DNA is a double helix composed of nucleotide monomers.

Question 20

A student adds hydrochloric acid (HCl) to a solution, causing the pH to drop from 7 to 2. By how many times did the hydrogen ion concentration increase?

Accepted Answer

100,000 times

General Biology: Core Concepts, Macromolecules, and Experimental Design

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