Biomolecules are organic compounds essential for
A industrial processes
B laboratory reactions
C life processes
D combustion
Biomolecules are fundamental to structure and function of living organisms.
Which of the following is NOT a biomolecule
A carbohydrates
B proteins
C polymers
D nucleic acids
Polymers are macromolecules but not all are biomolecules.
Carbohydrates are polyhydroxy
A ketones only
B aldehydes only
C aldehydes or ketones
D acids
Carbohydrates contain multiple –OH groups and an aldehyde/ketone group.
General formula of carbohydrates is
A CₙH₂ₙ
B CₙH₂ₙ₊₂
C Cₓ(H₂O)ᵧ
D CₙHₙ
Carbohydrates are hydrates of carbon.
Glucose is an example of
A disaccharide
B polysaccharide
C monosaccharide
D oligosaccharide
Glucose is the simplest sugar unit.
Glucose is classified as
A ketohexose
B aldohexose
C aldopentose
D ketopentose
Glucose has an aldehyde group and six carbon atoms.
Fructose is a
A aldohexose
B ketohexose
C aldopentose
D ketopentose
Fructose contains a ketone group.
Which sugar is called fruit sugar
A glucose
B sucrose
C fructose
D lactose
Fructose is naturally present in fruits.
Sucrose is composed of
A glucose + glucose
B glucose + fructose
C glucose + galactose
D fructose + galactose
Sucrose is a disaccharide.
Lactose is found in
A fruits
B sugarcane
C milk
D honey
Lactose is known as milk sugar.
Maltose consists of
A glucose + fructose
B fructose + fructose
C glucose + glucose
D glucose + galactose
Maltose is a disaccharide of glucose units.
Which carbohydrate is non-reducing
A glucose
B fructose
C sucrose
D maltose
No free aldehyde or ketone group.
Reducing sugars reduce
A Fehling’s solution
B NaOH
C NaCl
D HCl
Presence of free carbonyl group.
Starch is a polymer of
A fructose
B galactose
C glucose
D sucrose
Starch consists of α-glucose units.
Cellulose is composed of
A α-glucose
B β-glucose
C fructose
D sucrose
β-linkages give fibrous structure.
Humans cannot digest cellulose because
A it is insoluble
B lack of cellulase enzyme
C high molecular mass
D presence of ketone group
Humans lack enzyme to break β-glycosidic bonds.
Proteins are polymers of
A nucleotides
B monosaccharides
C amino acids
D fatty acids
Proteins are polypeptides.
Amino acids contain which functional groups
A –OH and –COOH
B –NH₂ and –COOH
C –CHO and –NH₂
D –COOH only
Both groups are present on same carbon.
Amino acids exist in solution mainly as
A neutral molecules
B cations
C anions
D zwitter ions
Internal salt formation occurs.
Peptide bond is formed between
A two amino groups
B two carboxyl groups
C amino and carboxyl group
D two side chains
–CO–NH– linkage is formed.
Peptide bond formation is an example of
A oxidation
B reduction
C condensation
D hydrolysis
Water molecule is eliminated.
Primary structure of protein refers to
A α-helix
B β-pleated sheet
C sequence of amino acids
D folding of polypeptide
Determined by peptide bonds.
Secondary structure of protein is stabilised by
A covalent bonds
B hydrogen bonds
C ionic bonds
D disulphide bonds
Occur between peptide groups.
Tertiary structure of protein is stabilised by
A hydrogen bonds only
B peptide bonds
C disulphide bonds
D glycosidic bonds
Strong covalent S–S bonds.
Denaturation of protein causes
A breakage of peptide bonds
B loss of biological activity
C change in primary structure
D formation of new protein
Secondary/tertiary structure is destroyed.
Enzymes are
A carbohydrates
B lipids
C proteins
D vitamins
Enzymes act as biological catalysts.
Enzymes speed up reactions by
A increasing activation energy
B decreasing activation energy
C increasing temperature
D increasing concentration
They provide an alternate pathway.
The site where substrate binds is called
A active site
B allosteric site
C inhibitor site
D binding pocket
Specific region of enzyme.
Lock-and-key model explains
A enzyme denaturation
B enzyme specificity
C enzyme inhibition
D enzyme synthesis
Shape complementarity.
Enzyme action is maximum at
A very high temperature
B very low temperature
C optimum temperature
D zero temperature
High or low temperature denatures enzyme.
Vitamins are
A energy sources
B catalysts
C essential organic compounds
D polymers
Required in small amounts.
Vitamin C deficiency causes
A rickets
B scurvy
C night blindness
D beriberi
Vitamin C is ascorbic acid.
Vitamin A deficiency leads to
A rickets
B anaemia
C night blindness
D pellagra
Vitamin A is essential for vision.
Fat-soluble vitamins are
A B and C
B C and D
C A, D, E, K
D B₁, B₂, B₆
Stored in body fats.
Water-soluble vitamins are
A A and D
B B and C
C E and K
D A and K
Excess excreted in urine.
Nucleic acids are polymers of
A amino acids
B nucleotides
C sugars
D fatty acids
DNA and RNA are polynucleotides.
DNA contains sugar
A ribose
B deoxyribose
C glucose
D fructose
Hence called deoxyribonucleic acid.
RNA contains base
A thymine
B uracil
C cytosine only
D adenine only
Thymine is absent in RNA.
Base pairing in DNA is
A A–C, G–T
B A–T, G–C
C A–G, T–C
D A–U, G–C
Hydrogen bonding determines pairing.
DNA has structure described as
A single helix
B triple helix
C double helix
D planar
Watson–Crick model.
Which biomolecule stores genetic information
A proteins
B carbohydrates
C lipids
D nucleic acids
DNA and RNA carry genetic code.
Glycosidic bond is present in
A proteins
B lipids
C carbohydrates
D nucleic acids
Connects monosaccharide units.
Phosphodiester bond is found in
A proteins
B carbohydrates
C nucleic acids
D lipids
Links nucleotides.
Enzymes are highly specific due to
A large size
B active site shape
C protein nature
D solubility
Specific fit with substrate.
Which molecule acts as energy currency
A DNA
B RNA
C ATP
D glucose
Adenosine triphosphate stores energy.
Hydrolysis of sucrose gives
A glucose only
B fructose only
C glucose + fructose
D glucose + galactose
Acid or enzyme hydrolysis.
Which protein is fibrous
A haemoglobin
B insulin
C keratin
D albumin
Structural protein.
Which protein is globular
A keratin
B collagen
C haemoglobin
D silk
Soluble and functional protein.
Enzymes are not consumed because they
A are very large
B are regenerated after reaction
C have high molecular mass
D are stable
Catalyst property.
Correct statement is
A Proteins are reducing sugars
B Vitamins provide energy
C Enzymes are proteins
D DNA is water soluble vitamin
Fundamental concept of biochemistry