pH 2; $$[H^+] = 1 \times 10$$^{-2}$$ M

Question 1

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

Accepted Answer

A decrease of 1 pH unit represents a 10-fold increase in $$[H^+].$$

Question 2

Which pH value would most likely correspond to a strong acid, and what is the approximate $$[H^+]$$ concentration at that pH?

Accepted Answer

pH 2; $$[H^+] = 1 	imes 10$$^{-2}$$ M

Question 3

Buffers are important in biological systems because they:

Accepted Answer

Maintain a stable pH by neutralizing excess acids or bases.

Question 4

How does increased atmospheric $$CO_2$$ contribute to ocean acidification, and what is a potential consequence for marine life?

Accepted Answer

It forms carbonic acid in water, lowering pH and reducing calcium carbonate availability for shell-forming organisms.

Question 5

Why is carbon considered the backbone of biological molecules?

Accepted Answer

Carbon can form up to four covalent bonds, allowing for complex and diverse molecular structures.

Question 6

Which of the following is a functional group commonly found in amino acids, and what is its biological significance?

Accepted Answer

Carboxyl group ($$-COOH$$); acts as an acid and participates in peptide bond formation.

Question 7

What is meant by 'isomers' in organic chemistry?

Accepted Answer

Molecules with the same molecular formula but different structural arrangements.

Question 8

Which statement best describes the difference between monomers and polymers?

Accepted Answer

Monomers are small molecules that can join together to form larger molecules called polymers.

Question 9

Which reaction type is responsible for joining two monosaccharides to form a disaccharide, and what is the byproduct?

Accepted Answer

Dehydration synthesis; water ($$H_2O) is $$produced.

Question 10

Which polysaccharide is primarily used for energy storage in animals, and what is its monomer?

Accepted Answer

Glycogen; glucose

Question 11

Which statement about lipids is correct?

Accepted Answer

Phospholipids have both hydrophilic and hydrophobic regions, making them essential for cell membrane structure.

Question 12

What does the 'R' group in an amino acid represent?

Accepted Answer

A variable side chain that determines the properties and identity of the amino acid.

Question 13

How many different amino acids are commonly found in nature?

Accepted Answer

20

Question 14

What type of bond forms between the carboxyl group of one amino acid and the amino group of another?

Accepted Answer

Peptide bond

Question 15

Which level of protein structure is most directly affected if there is a mutation in the DNA sequence coding for a protein?

Accepted Answer

Primary structure

Question 16

Why are hydrogen bonds important for protein structure?

Accepted Answer

They stabilize secondary structures such as alpha helices and beta sheets.

Question 17

Sickle-cell disease is caused by a mutation in the gene for hemoglobin. What is the molecular consequence of this mutation?

Accepted Answer

A single amino acid substitution alters the protein's shape, causing red blood cells to become rigid and sickle-shaped.

Question 18

Which of the following correctly matches a nucleic acid with its sugar component?

Accepted Answer

DNA; deoxyribose

Question 19

Which part of a nucleotide is responsible for its acidic properties?

Accepted Answer

Phosphate group

Question 20

Which of the following is NOT a difference between DNA and RNA?

Accepted Answer

DNA can act as an enzyme, while RNA cannot.

Core Concepts in General Biology: Chemistry of Life, Macromolecules, and Biological Molecules

Study Guide - Practice Questions