PRELIMINARY STAGE 2024
ROUND 4 - TRUE OR FALSE
SECOND SET OF QUESTIONS
PREAMBLE
The given type of molecule is produced from dehydration reactions.
1. Protein
ANSWER: TRUE
EXPLANATION:
Proteins are formed when amino acids are joined together by peptide bonds, which involve a dehydration (condensation) reaction.
2. Triglyceride
ANSWER: TRUE
EXPLANATION:
Triglycerides are formed when glycerol and fatty acids join via ester bonds in a dehydration reaction.
3. Polysaccharide
ANSWER: TRUE
EXPLANATION:
Polysaccharides are formed when monosaccharides are linked together by glycosidic bonds, which are also formed by dehydration reactions.
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PRACTICE QUESTIONS
PREAMBLE 1
The given molecule is produced from a dehydration (condensation) reaction:
1. Maltose.
ANSWER: TRUE
EXPLANATION:
Two glucose molecules join and release water.
2. Glycogen.
ANSWER: TRUE
EXPLANATION:
Many glucose units are joined by glycosidic bonds.
3. Glucose.
ANSWER: FALSE
EXPLANATION:
Glucose is a monosaccharide, a single unit.
PREAMBLE 2
The given bond is formed by a condensation reaction:
1. Phosphodiester bond in DNA.
ANSWER: TRUE
EXPLANATION:
It links nucleotides and releases water.
2. Peptide bond.
ANSWER: TRUE
EXPLANATION:
It joins two amino acids.
3. Hydrogen bond between DNA bases.
ANSWER: FALSE
EXPLANATION:
Hydrogen bonds are weak attractions, not formed by condensation.
PREAMBLE 3
Hydrolysis:
1. Breaks bonds by adding water.
ANSWER: TRUE
EXPLANATION:
It is the reverse of condensation.
2. Takes place when starch is digested.
ANSWER: TRUE
EXPLANATION:
Amylase hydrolyses starch to maltose.
3. Joins monomers to form polymers.
ANSWER: FALSE
EXPLANATION:
Condensation joins monomers; hydrolysis splits polymers.