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WorksheetsFunctional Groups and Biochemistry Quiz
Total questions: 20
Worksheet time: 7mins
Which functional group is represented by -OH?
A. Amino group
B. Hydroxyl group
C. Carboxyl group
D. Carbonyl group
The carboxyl functional group has the general formula:
A. -NH₂
B. -COOH
C. -CHO
D. -SH
Which functional group is present in thiols?
A. Hydroxyl group
B. Sulfhydryl group
C. Carbonyl group
D. Phosphate group
The two forms of stereoisomers in biochemistry, often seen in sugars and amino acids, are called:
A. Alpha and Beta
B. Cis and Trans
C. D and L
D. R and S
The configuration of double bonds in unsaturated fatty acids can be either:
A. D and L
B. Cis and Trans
C. Alpha and Beta
D. R and S
Why is the hydroxyl group important in biochemical molecules?
A. It provides a source of nitrogen.
B. It increases solubility of molecules in water.
C. It stabilizes proteins through disulfide bonds.
D. It stores energy in the form of ATP.
What is the difference between an aldehyde and a ketone?
A. Aldehydes contain -COOH, while ketones contain -OH.
B. Aldehydes have a carbonyl group at the end of the chain, while ketones have it in the middle.
C. Aldehydes are nonpolar, while ketones are polar.
D. Aldehydes contain sulfur, while ketones contain nitrogen.
Why does the cis configuration in fatty acids affect membrane fluidity?
A. Cis bonds create kinks that prevent tight packing of fatty acids.
B. Cis bonds increase hydrogen bonding between fatty acids.
C. Cis bonds allow fatty acids to align more closely.
D. Cis bonds make fatty acids completely hydrophobic.
What distinguishes D- and L- configurations in amino acids?
A. Their ability to dissolve in water.
B. The position of the amino group around the central carbon atom.
C. The length of their carbon chains.
D. The presence or absence of a double bond.
Why are phosphate groups essential in biological molecules like ATP?
A. They form peptide bonds between amino acids.
B. They store and transfer energy through high-energy bonds.
C. They provide hydrophobic interactions in membranes.
D. They act as reducing agents in metabolism.
Which statement best explains why molecules containing hydroxyl groups are soluble in water?
A. They form covalent bonds with water.
B. They form hydrogen bonds with water molecules.
C. They decrease polarity of water.
D. They react with water to form ionic compounds.
A compound has the formula CH₃-C=O-CH₃. Which functional group is present, and why?
A. Aldehyde, because the carbonyl group is at the end.
B. Ketone, because the carbonyl group is between two carbons.
C. Alcohol, because it contains oxygen.
D. Ester, because it has a C=O bond.
Which structural feature explains why cis fatty acids are usually liquid at room temperature, unlike trans fatty acids?
A. Cis double bonds cause linear alignment.
B. Cis double bonds create kinks preventing tight packing.
C. Trans bonds weaken van der Waals forces.
D. Trans fatty acids contain fewer carbons.
A sugar molecule rotates polarized light to the right. Which configuration does this suggest?
A. Cis configuration
B. Trans configuration
C. D-configuration
D. L-configuration
Why are thiol groups important in protein structure?
A. They increase protein solubility in water.
B. They form disulfide bonds that stabilize protein shape.
C. They provide energy storage.
D. They act as carriers of genetic information.
A molecule contains both amino (-NH₂) and carboxyl (-COOH) groups. Which statement best explains its behavior in solution?
A. It cannot ionize because both groups are neutral.
B. It can act as both an acid and a base (amphoteric).
C. It dissolves only in nonpolar solvents.
D. It functions only as an acid.
If a mutation changes a cis double bond in a fatty acid to a trans double bond, how would this affect the cell membrane?
A. Increase membrane fluidity
B. Decrease membrane fluidity
C. Increase hydrogen bonding
D. No effect on membrane properties
Which reasoning explains why phosphate groups are used in energy molecules like ATP rather than carboxyl groups?
A. Phosphate bonds release more energy when hydrolyzed.
B. Carboxyl groups are unstable in water.
C. Phosphate groups are hydrophobic.
D. Carboxyl groups cannot form covalent bonds.
Which functional group difference allows esters to be distinguished from ethers?
A. Esters have a carbonyl group adjacent to oxygen, ethers do not.
B. Ethers contain nitrogen, esters do not.
C. Ethers have hydroxyl groups, esters do not.
D. Esters are nonpolar, ethers are polar.
Which explanation best accounts for the chirality of amino acids?
A. They contain two identical groups around the central carbon.
B. The central carbon (α-carbon) is bonded to four different groups.
C. The amino group always appears on the left side.
D. Only the R-group determines chirality.
