Grade 11 Biology Quiz: Biomolecules (Set 1)

Question 1

Which of the following biomolecules is classified as a secondary metabolite in plants?

Accepted Answer

C) Morphine

Answer

A) Glucose

Answer

B) Glutamic acid

Answer

D) Ribose

Question 2

A peptide bond is formed between which two functional groups of adjacent amino acids?

Accepted Answer

A) $-	ext{COOH}$ group of one amino acid and $-	ext{NH}_2$ group of another

Answer

B) Two hydroxyl ($-	ext{OH}$) groups

Answer

C) Two carboxyl ($-	ext{COOH}$) groups

Answer

D) $-	ext{CHO}$ group and $-	ext{NH}_2$ group

Question 3

Which nitrogenous base is present exclusively in RNA and is absent in DNA?

Accepted Answer

B) Uracil

Answer

A) Adenine

Answer

C) Thymine

Answer

D) Cytosine

Question 4

The formation of a glycosidic bond between two monosaccharide units involves which chemical process?

Accepted Answer

B) Dehydration synthesis (elimination of water)

Answer

A) Decarboxylation

Answer

C) Deamination

Answer

D) Addition of water (hydrolysis)

Question 5

In competitive enzyme inhibition, how are the Michaelis constant ($K_m$) and maximum velocity ($V_{max}$) affected?

Accepted Answer

C) $K_m$ increases and $V_{max}$ remains unchanged

Answer

A) $K_m$ increases and $V_{max}$ decreases

Answer

B) $K_m$ remains unchanged and $V_{max}$ decreases

Answer

D) Both $K_m$ and $V_{max}$ decrease

Question 6

Chitin, a complex polysaccharide found in fungal cell walls and arthropod exoskeletons, is a homopolymer of:

Accepted Answer

B) N-acetylglucosamine

Answer

A) D-Glucose

Answer

C) D-Fructose

Answer

D) D-Galactose

Question 7

Which structural level of a protein is defined purely by the linear sequence of amino acids linked by covalent peptide bonds?

Accepted Answer

A) Primary structure

Answer

B) Secondary structure

Answer

C) Tertiary structure

Answer

D) Quaternary structure

Question 8

An amino acid exists in a zwitterionic state when:

Accepted Answer

C) The amino group is positively charged ($-	ext{NH}_3^+$) and the carboxyl group is negatively charged ($-	ext{COO}^-$)

Answer

A) Both amino and carboxyl groups are uncharged

Answer

B) Both amino and carboxyl groups carry net negative charges

Answer

D) Only the side chain (R group) is ionized

Question 9

In a single strand of nucleic acid, adjacent nucleotides are joined together by phosphodiester bonds formed between:

Accepted Answer

A) 3'-carbon of one sugar and 5'-carbon of the next sugar

Answer

B) 1'-carbon of sugar and nitrogenous base

Answer

C) 2'-carbon of sugar and phosphate group

Answer

D) 5'-carbon of one sugar and 5'-carbon of adjacent sugar

Question 10

An enzyme that catalyzes the transfer of a functional group (such as a phosphate group) from a donor substrate to an acceptor substrate belongs to which class?

Accepted Answer

B) Transferases

Answer

A) Oxidoreductases

Answer

C) Hydrolases

Answer

D) Isomerases

Question 11

Glycerol, a component of neutral fats and phospholipids, is chemically identified as:

Accepted Answer

A) Trihydroxy propane

Answer

B) Dihydroxy acetone

Answer

C) Tetrahydroxy butane

Answer

D) Monohydroxy ethane

Question 12

Which of the following disaccharides is a non-reducing sugar because both anomeric carbons participate in the glycosidic bond?

Accepted Answer

C) Sucrose

Answer

A) Maltose

Answer

B) Lactose

Answer

D) Cellobiose

Question 13

A non-protein organic cofactor that is tightly and permanently bound to an apoenzyme to render it catalytically active is called a:

Accepted Answer

C) Prosthetic group

Answer

A) Coenzyme

Answer

B) Activator ion

Answer

D) Isoenzyme

Question 14

How does a nucleoside structurally differ from a complete nucleotide?

Accepted Answer

B) A nucleoside lacks a phosphate group.

Answer

A) A nucleoside lacks a nitrogenous base.

Answer

C) A nucleoside lacks a pentose sugar.

Answer

D) A nucleoside contains amino acids instead of sugars.

Question 15

Which type of bond or interaction is NOT involved in maintaining the three-dimensional tertiary structure of globular proteins?

Accepted Answer

D) Phosphodiester bonds

Answer

A) Hydrogen bonds

Answer

B) Ionic interactions / Salt bridges

Answer

C) Disulfide linkages

Question 16

Secondary Metabolites & Examples:
1. Alkaloid: Morphine
2. Essential Oil: Lemon grass oil
3. Toxin: Abrin
4. Lectin: Concanavalin A

Which of the pairs listed in the table above correctly match the secondary metabolite category with its biological example?

Accepted Answer

D) 1, 2, 3, and 4

Answer

A) 1 and 2 only

Answer

B) 1, 2, and 3 only

Answer

C) 3 and 4 only

Question 17

Malonate acts as a competitive inhibitor of succinate dehydrogenase because malonate:

Accepted Answer

B) Closely resembles succinate in chemical structure and competes for the active site

Answer

A) Binds to an allosteric site causing a conformational change

Answer

C) Irreversibly oxidizes the active site amino acids

Answer

D) Cleaves the substrate into inactive subunits

Question 18

According to Chargaff's rules for double-stranded DNA, if adenine accounts for 30% of total nitrogenous bases, what percentage of bases will be cytosine?

Accepted Answer

A) 20%

Answer

B) 30%

Answer

C) 40%

Answer

D) 60%

Question 19

Enzymes increase the rate of chemical reactions primarily by:

Accepted Answer

B) Lowering the activation energy barrier of the reaction

Answer

A) Increasing the activation energy required for the transition state

Answer

C) Altering the equilibrium constant ($K_{eq}$) toward product formation

Answer

D) Increasing the overall thermal energy of reactant molecules

Question 20

The primary storage carbohydrate (polysaccharide) in animal cells is:

Accepted Answer

C) Glycogen

Answer

A) Starch

Answer

B) Cellulose

Answer

D) Inulin

Grade 11 : Biology - Biomolecules (Set 1)

Grade 11 : Biology - Biomolecules (Set 1)

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Grade 11 : Biology - Biomolecules (Set 1)

Grade 11 : Biology - Biomolecules (Set 1)

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