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

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

Question 1

Which property of water allows it to moderate Earth's climate by absorbing and releasing large amounts of heat with only slight changes in its own temperature?

Accepted Answer

High specific heat capacity

Question 2

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}$$ \ \mathrm{M}$$

Question 3

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

Accepted Answer

Hydrogen bonds in ice create a lattice that spaces water molecules farther apart.

Question 4

Which functional group is present in all amino acids and is responsible for their basic properties?

Accepted Answer

Amino group ($$-NH_2$)

Question 5

Which of the following best describes the difference between cis and trans isomers?

Accepted Answer

Cis isomers have functional groups on the same side of a double bond, while trans isomers have them on opposite sides.

Question 6

Which macromolecule is primarily responsible for catalyzing biochemical reactions in cells?

Accepted Answer

Proteins

Question 7

A patient is diagnosed with sickle cell anemia, a disease caused by a single amino acid substitution in hemoglobin. This is an example of a:

Accepted Answer

Mutation

Question 8

Which of the following best describes the relationship between DNA and RNA?

Accepted Answer

DNA stores genetic information, while RNA helps in protein synthesis.

Question 9

Which of the following is a correct description of a dehydration synthesis reaction?

Accepted Answer

A reaction that joins monomers to form polymers by removing a water molecule.

Question 10

Which of the following best explains the role of buffers in biological systems?

Accepted Answer

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

Question 11

Which of the following is a common feature shared by all macromolecules (carbohydrates, lipids, proteins, nucleic acids)?

Accepted Answer

They are all formed by dehydration synthesis reactions.

Question 12

A protein's tertiary structure is primarily stabilized by which of the following interactions?

Accepted Answer

Interactions between R groups (side chains) of amino acids

Question 13

Which of the following best describes the structure of a nucleotide found in DNA?

Accepted Answer

A phosphate group, a deoxyribose sugar, and a nitrogenous base

Question 14

Which of the following functional groups is found in both nucleic acids and phospholipids?

Accepted Answer

Phosphate group ($$-PO_4$^{2-})$$

Question 15

A scientist is comparing the structures of glucose and fructose. Both have the same molecular formula ($$C_6H_{12}O_6$) but different structures. These molecules are:

Accepted Answer

Structural isomers

Question 16

Which of the following best explains why phospholipids form bilayers in water?

Accepted Answer

Their hydrophobic tails avoid water while hydrophilic heads interact with water.

Question 17

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

Accepted Answer

The sequence of amino acids in a polypeptide chain

Question 18

A researcher adds a strong acid to a buffered solution and observes only a small change in pH. Which equation best represents the buffer's action?

Accepted Answer

$$HA \rightleftharpoons H^+ + A^-$$

Question 19

Which of the following statements about enantiomers is correct?

Accepted Answer

Enantiomers are mirror images of each other and may have different biological activity.

Question 20

Which of the following best describes the process of hydrolysis in biological systems?

Accepted Answer

The breakdown of polymers into monomers by adding water

Study Guide: Chemistry of Life (Chapters 3-5) – General Biology

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