Food Constituents Chemical structure, classification and functions Part 1
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Question No. 1
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Which of the following is a
reducing monosaccharide
due to a free aldehyde or ketone group?
A.
Amylopectin
B.
Glucose
C.
Sucrose
D.
Cellulose
Question No. 2
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Peptide bond formation between amino acids is best described as:
A.
Phosphorylation of amino group
B.
Condensation (dehydration) forming an amide bond
C.
Hydrolysis of an ester bond
D.
Oxidation-reduction
Question No. 3
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Which vitamin is fat-soluble and essential for calcium homeostasis and bone mineralization?
A.
Vitamin D
B.
Vitamin B6
C.
Vitamin C
D.
Vitamin B12
Question No. 4
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Which statement about triglycerides is correct?
A.
They are esters formed between glycerol and three fatty acids
B.
They are phosphate esters with a charged head group
C.
They are monosaccharides attached to glycerol
D.
They contain peptide bonds linking glycerol and fatty acids
Question No. 5
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Which mineral is the central atom in haem and essential for O2 transport in blood?
A.
Magnesium
B.
Zinc
C.
Calcium
D.
Iron
Question No. 6
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Which of the following is an
essential amino acid
(cannot be synthesized by humans)?
A.
Leucine
B.
Proline
C.
Alanine
D.
Glycine
Question No. 7
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An enzyme increases reaction rate mainly by:
A.
Changing equilibrium constant to favor products
B.
Lowering the activation energy
C.
Providing heat to the reaction
D.
Raising the activation energy
Question No. 8
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Which carbohydrate linkage is present in cellulose and responsible for linear, rigid fibers?
A.
β(1→4) glycosidic linkage
B.
α(1→4) glycosidic linkage
C.
β(1→6) linkage
D.
α(1→6) branch linkage
Question No. 9
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Which vitamin is a coenzyme in carboxylation reactions (e.g., pyruvate carboxylase) and often bound to biotin?
A.
Biotin (B7)
B.
Folate (B9)
C.
Riboflavin (B2)
D.
Niacin (B3)
Question No. 10
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Which type of fatty acid contains one or more double bonds and is typically liquid at room temperature?
A.
Unsaturated fatty acid
B.
Cyclic fatty acid
C.
Saturated fatty acid
D.
Trans fatty acid only
Question No. 11
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What is the primary role of bile salts in fat digestion?
A.
Emulsify large lipid droplets into micelles to increase surface area
B.
Convert saturated fats into unsaturated fats
C.
Act as enzymes to cleave ester bonds
D.
Hydrolyze triglycerides to glycerol and FA
Question No. 12
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Which vitamin deficiency causes scurvy characterized by bleeding gums and poor wound healing?
A.
Vitamin K
B.
Vitamin C
C.
Vitamin A
D.
Vitamin D
Question No. 13
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A protein's
secondary structure
primarily arises from:
A.
Disulfide bonds between cysteines
B.
Peptide bond isomerization
C.
Ionic interactions between side chains
D.
Hydrogen bonds between backbone N-H and C=O groups
Question No. 14
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Which mineral is required as a cofactor for thyroid hormone synthesis and deficiency causes goiter?
A.
Copper
B.
Potassium
C.
Iodine
D.
Selenium
Question No. 15
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In Michaelis-Menten kinetics, an enzyme with a low Km indicates:
A.
That enzyme is inhibited by substrate
B.
Tight (high affinity) binding to substrate
C.
High Vmax
D.
High substrate concentration required to reach half Vmax
Question No. 16
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Which of the following is a disaccharide composed of glucose and fructose?
A.
Sucrose
B.
Maltose
C.
Cellobiose
D.
Lactose
Question No. 17
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Which vitamin functions as a methyl group donor in one-carbon metabolism (important for DNA synthesis)?
A.
Vitamin C
B.
Vitamin B12 (cobalamin) and Folate (B9)
C.
Vitamin E
D.
Vitamin K
Question No. 18
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Which type of bond stabilizes a protein's tertiary structure most directly?
A.
Phosphodiester bonds
B.
Peptide bonds between residues
C.
Hydrogen bonds, ionic interactions, hydrophobic packing and disulfide bonds
D.
Glycosidic bonds
Question No. 19
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Which statement about omega-3 fatty acids is correct?
A.
They are saturated fats
B.
They cannot be obtained from diet
C.
They have first double bond at the third carbon from the methyl end and are anti-inflammatory
D.
They are always trans fats
Question No. 20
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Which enzyme class catalyzes transfer of phosphate groups from ATP to substrates?
A.
Isomerases
B.
Hydrolases
C.
Lyases
D.
Kinases (transferases)
Question No. 21
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A person with prolonged fat malabsorption is likely to be deficient in which vitamin first?
A.
Vitamin C
B.
Vitamin B1 (thiamine)
C.
Vitamin B9 (folate)
D.
Vitamin A (fat-soluble)
Question No. 22
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Which polysaccharide is the major storage form of glucose in animals?
A.
Starch (amylose/amylopectin)
B.
Chitin
C.
Cellulose
D.
Glycogen
Question No. 23
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Which statement about essential fatty acids is true?
A.
Linoleic (ω-6) and alpha-linolenic (ω-3) acids are essential and must be obtained from diet
B.
All saturated fatty acids are essential
C.
Humans can synthesize linoleic and alpha-linolenic acid de novo
D.
Trans fats are essential nutrients
Question No. 24
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Which enzyme secreted in saliva initiates carbohydrate digestion by cleaving α(1→4) glycosidic bonds?
A.
Trypsin
B.
Pepsin
C.
Lipase
D.
Salivary amylase (ptyalin)
Question No. 25
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Which vitamin is required for blood clotting because it participates in γ-carboxylation of glutamate residues in clotting factors?
A.
Vitamin B12
B.
Vitamin A
C.
Vitamin D
D.
Vitamin K
Question No. 26
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Which of the following best describes HDL's primary function?
A.
Storage of cholesterol in adipose tissue
B.
Reverse cholesterol transport from tissues to liver
C.
Transport of dietary triglycerides to adipose tissue
D.
Hydrolysis of triglycerides in circulation
Question No. 27
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Which amino acid side chain can form a covalent disulfide bond stabilizing protein structure?
A.
Cysteine
B.
Aspartate
C.
Serine
D.
Lysine
Question No. 28
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Which trace element is a component of the antioxidant enzyme glutathione peroxidase?
A.
Magnesium (Mg)
B.
Iron (Fe)
C.
Calcium (Ca)
D.
Selenium (Se)
Question No. 29
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Which statement about vitamins is correct?
A.
Water-soluble vitamins (B and C) are not stored and excess is often excreted in urine
B.
Fat-soluble vitamins cannot be toxic even in large doses
C.
All vitamins are synthesized in adequate amounts by the human body
D.
Fat-soluble vitamins are excreted rapidly in urine and need daily intake
Question No. 30
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Which of the following best describes enzyme inhibition where an inhibitor binds the active site competing with substrate?
A.
Competitive inhibition
B.
Allosteric activation
C.
Uncompetitive inhibition
D.
Non-competitive inhibition
Question No. 31
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A diet deficient in iodine during pregnancy most likely causes:
A.
Scurvy in the newborn
B.
Congenital hypothyroidism (cretinism) and developmental delay
C.
Sickle cell anemia in the fetus
D.
Rickets in the newborn
Question No. 32
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Which biochemical group is present in all phospholipids and gives them amphipathic properties?
A.
Only saturated fatty acids
B.
A polar phosphate-containing head group attached to glycerol or sphingosine
C.
Three fatty acids without head group
D.
Glycerol backbone only
Question No. 33
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Which of the following is the simplest form of carbohydrate?
A.
Polysaccharide
B.
Disaccharide
C.
Monosaccharide
D.
Oligosaccharide
Question No. 34
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Carbohydrates are generally composed of which elements?
A.
Carbon, Hydrogen, Oxygen
B.
Carbon, Nitrogen, Oxygen
C.
Nitrogen, Oxygen, Sulphur
D.
Hydrogen, Phosphorus, Oxygen
Question No. 35
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Which carbohydrate is commonly known as milk sugar?
A.
Glucose
B.
Sucrose
C.
Maltose
D.
Lactose
Question No. 36
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Which of the following is a polysaccharide?
A.
Glucose
B.
Starch
C.
Fructose
D.
Sucrose
Question No. 37
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The general formula of carbohydrate is:
A.
CH4
B.
C2H5OH
C.
C6H12O6
D.
Cn(H2O)n
Question No. 38
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Which of the following is not a reducing sugar?
A.
Lactose
B.
Maltose
C.
Sucrose
D.
Glucose
Question No. 39
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Cellulose is mainly found in:
A.
Stomach lining
B.
Animal cell membranes
C.
Plant cell walls
D.
Blood plasma
Question No. 40
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Glycogen is the storage form of carbohydrate in:
A.
Fungi
B.
Animals
C.
Plants
D.
Bacteria
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