Q: Which of the following best describes the role of buffers in biological systems?

Buffers minimize changes in $$\text{pH} by $$absorbing or releasing $$\text{H}^+$$ ions as needed.

Q: Which of the following functional groups is correctly matched with its property?

$$-\text{COOH} ($$carboxyl): acidic, donates $$\text{H}^+$$

Question 1

Which of the following best explains why saturated fats are solid at room temperature while unsaturated fats are typically liquid?

Accepted Answer

Saturated fats have only single C–C bonds, allowing their molecules to pack closely together, resulting in a higher melting point.

Question 2

A scientist discovers a new single-celled organism that lacks a nucleus and membrane-bound organelles. To which domain does this organism most likely belong?

Accepted Answer

Either Bacteria or Archaea

Question 3

Which of the following statements about hydrogen bonds is CORRECT?

Accepted Answer

Hydrogen bonds are weak attractions between a partially positive hydrogen atom in a polar molecule and an electronegative atom in another molecule.

Question 4

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

Accepted Answer

Buffers minimize changes in $$	ext{pH} by $$absorbing or releasing $$	ext{H}^+$$ ions as needed.

Question 5

A DNA sample is found to contain 35% adenine (A). According to Chargaff’s rules, what percentage of the bases are cytosine (C)?

Accepted Answer

$$15\%$$

Question 6

Which of the following functional groups is correctly matched with its property?

Accepted Answer

$$-	ext{COOH} ($$carboxyl): acidic, donates $$	ext{H}^+$$

Question 7

Which of the following best describes the difference between a hypothesis and a scientific theory?

Accepted Answer

A hypothesis is a testable explanation for a specific observation, while a theory is a broad explanation supported by a large body of evidence.

Question 8

Which of the following molecules is most likely to be amphipathic?

Accepted Answer

A phospholipid with a hydrophilic head and two hydrophobic tails

Question 9

A solution has a $$[	ext{H}^+]$$ concentration of $$10^{-5}$$\ 	ext{M}$$. What is its $$	ext{pH}$$?

Accepted Answer

$$5$$

Question 10

Which of the following best explains why water is an excellent solvent for many biological molecules?

Accepted Answer

Water is a polar molecule, allowing it to dissolve ionic and other polar substances.

Question 11

Which of the following best describes the process of hydrolysis?

Accepted Answer

A water molecule is added to break a bond in a polymer, releasing a monomer.

Question 12

Which of the following is a correct example of binomial nomenclature?

Accepted Answer

Homo sapiens

Question 13

Which of the following best describes the difference between an ionic bond and a covalent bond?

Accepted Answer

An ionic bond involves the transfer of electrons, while a covalent bond involves the sharing of electrons.

Question 14

A protein’s function is most directly determined by its:

Accepted Answer

Three-dimensional structure (tertiary and quaternary levels)

Question 15

Which of the following best explains why cellulose cannot be digested by most animals, while starch can?

Accepted Answer

Cellulose has a different glycosidic linkage than starch, which most animals lack the enzyme to break.

Question 16

Which of the following best describes the relationship between the genome and the proteome?

Accepted Answer

The genome stores genetic information, while the proteome consists of all proteins expressed and determines cellular structure and function.

Question 17

Which of the following is a real-world example of horizontal gene transfer?

Accepted Answer

A bacterium acquiring antibiotic resistance from another species via a plasmid.

Question 18

Which of the following best explains why noble gases such as helium are chemically unreactive?

Accepted Answer

Their outermost electron shell is completely filled.

Question 19

A solution is made by dissolving 36 g of glucose ($$	ext{C}_6	ext{H}_{12}	ext{O}_6$$, molecular mass $$=180\ 	ext{g/mol}) in $$enough water to make $$0.2\ 	ext{L} of $$solution. What is the molarity of the solution?

Accepted Answer

$$1.0\ 	ext{M}$$

Question 20

Which of the following best describes the process of artificial selection?

Accepted Answer

Humans selectively breed organisms to promote desirable traits over generations.

Foundations of Organic Chemistry: Atomic Structure, Bonding, and Biological Macromolecules

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