Question 1

Which functional group is most likely to increase the solubility of a molecule in water due to its ability to form hydrogen bonds?

Accepted Answer

Hydroxyl group ($$-\mathrm{OH})$$

Question 2

Amino acids contain both an amino group and a carboxyl group. Which of the following correctly represents the chemical structure of the carboxyl group?

Accepted Answer

$$-\mathrm{COOH}$$

Question 3

Which functional group is responsible for the acidic properties of organic molecules such as fatty acids and amino acids?

Accepted Answer

Carboxyl group ($$-\mathrm{COOH})$$

Question 4

Which of the following groups is most likely to participate in the formation of disulfide bridges, which stabilize protein structure?

Accepted Answer

Sulfhydryl group ($$-\mathrm{SH})$$

Question 5

A molecule contains a $$\u003e\mathrm{C}=\mathrm{O}$$ group. Which type of functional group does this represent, and what is its significance in sugars?

Accepted Answer

Carbonyl group; it determines whether a sugar is an aldose or ketose

Question 6

Which functional group is commonly found in ATP and is directly involved in energy transfer within cells?

Accepted Answer

Phosphate group ($$-\mathrm{OPO}_3$$^{2-}$$)

Question 7

Which of the following functional groups is nonpolar and tends to decrease the solubility of organic molecules in water?

Accepted Answer

Methyl group ($$-\mathrm{CH}_3)$$

Question 8

A mutation causes a cysteine residue in a protein to be replaced by a serine residue. Which functional group is lost, and what effect might this have on protein structure?

Accepted Answer

Loss of a sulfhydryl group ($$-\mathrm{SH}$$); possible loss of disulfide bridges

Question 9

Which functional group can act as a base by accepting a hydrogen ion ($$\mathrm{H}^+) in $$aqueous solution?

Accepted Answer

Amino group ($$-\mathrm{NH}_2)$$

Question 10

Which of the following best describes the role of the phosphate group in nucleic acids such as DNA and RNA?

Accepted Answer

It links nucleotides together via phosphodiester bonds

Question 11

A researcher is studying a molecule with the formula $$\mathrm{C}_2\mathrm{H}_6\mathrm{O}. $$Which functional group is most likely present, and what property does it confer?

Accepted Answer

Hydroxyl group ($$-\mathrm{OH}$$); increases solubility in water

Question 12

Which functional group is most likely to be found in fatty acids and is responsible for their acidic nature?

Accepted Answer

Carboxyl group ($$-\mathrm{COOH})$$

Question 13

Which of the following functional groups is most likely to be involved in the transfer of genetic information and cellular signaling due to its high-energy bonds?

Accepted Answer

Phosphate group ($$-\mathrm{OPO}_3$$^{2-}$$)

Question 14

Which functional group is present in both aldehydes and ketones, and how does its position affect the classification of the molecule?

Accepted Answer

Carbonyl group ($$\u003e\mathrm{C}=\mathrm{O}$$); terminal position forms aldehydes, internal position forms ketones

Question 15

A molecule with the structure $$-\mathrm{CH}_3 is $$added to DNA. What is the likely effect of this methylation?

Accepted Answer

It decreases gene expression by making DNA less accessible

Question 16

Which functional group is most likely to be found in the side chain of the amino acid methionine, and what property does it confer?

Accepted Answer

Methyl group ($$-\mathrm{CH}_3$$); increases hydrophobicity

Question 17

Which of the following functional groups is most likely to be ionized at physiological pH, contributing to the negative charge of molecules such as DNA and phospholipids?

Accepted Answer

Phosphate group ($$-\mathrm{OPO}_3$$^{2-}$$)

Question 18

A biochemist is analyzing a molecule that can act as both an acid and a base. Which two functional groups must be present for this property?

Accepted Answer

Carboxyl group ($$-\mathrm{COOH}) $$and amino group ($$-\mathrm{NH}_2)$$

Question 19

Which functional group is most likely to be found in alcohols, and what is its chemical formula?

Accepted Answer

Hydroxyl group ($$-\mathrm{OH})$$

Biologically Important Chemical Groups

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