Master Biological Molecules: A Comprehensive Guide for Medical Students

Question 1

Which of the following is **not** considered a biological molecule?

Accepted Answer

Sodium chloride

Answer

Carbohydrates

Answer

Lipids

Answer

Proteins

Question 2

Identify the monosaccharide among the following options:

Accepted Answer

Glucose

Answer

Starch

Answer

Glycogen

Answer

Cellulose

Question 3

Which of the following best describes the primary function of proteins?

Accepted Answer

Providing structural support

Answer

Storing energy

Answer

Regulating hormones

Answer

Defending against pathogens

Question 4

Which type of nucleic acid is represented by mRNA?

Accepted Answer

Messenger RNA

Answer

Deoxyribonucleic acid

Answer

Adenosine triphosphate

Answer

Glycogen

Question 5

What is the primary function of lipids in biological systems?

Accepted Answer

Storing energy

Answer

Regulating hormones

Answer

Maintaining acid-base balance

Answer

Synthesizing proteins

Question 6

Which characteristic is unique to DNA?

Accepted Answer

Contains deoxyribose

Answer

Double-stranded helix structure

Answer

Presence of uracil

Answer

Linear structure

Question 7

Describe the primary role of tRNA in protein synthesis:

Accepted Answer

Delivers specific amino acids to the ribosome

Answer

Initiates protein synthesis

Answer

Terminates protein synthesis

Answer

Catalyzes peptide bond formation

Question 8

Which of the following is NOT a primary biological molecule?

Accepted Answer

Vitamins

Answer

Carbohydrates

Answer

Proteins

Answer

Lipids

Question 9

Which of the following statements accurately describes the relationship between monosaccharides and polysaccharides?

Accepted Answer

Monosaccharides are the fundamental units that combine to form polysaccharides.

Answer

Polysaccharides are the fundamental units that combine to form monosaccharides.

Answer

Monosaccharides and polysaccharides are distinct types of carbohydrates with unrelated structures.

Question 10

Which of the following defines a monosaccharide?

Accepted Answer

A carbohydrate with the simplest structure.

Answer

A carbohydrate that cannot be further broken down.

Answer

A carbohydrate composed of multiple sugar units.

Answer

A carbohydrate that is insoluble in water.

Question 11

What is the main function of lipids in living organisms?

Accepted Answer

Energy storage and insulation

Answer

Hormone synthesis and regulation

Answer

Nucleic acid replication and repair

Answer

Protein synthesis and catalysis

Question 12

Which of the following amino acids is required for human nutrition and cannot be synthesized by the body?

Accepted Answer

Lysine

Answer

Alanine

Answer

Glycine

Answer

Serine

Question 13

Which nitrogenous base is present in RNA but not in DNA?

Accepted Answer

Uracil

Answer

Adenine

Answer

Cytosine

Answer

Guanine

Question 14

What type of chemical bond forms the backbone of polysaccharides?

Accepted Answer

Glycosidic bonds

Answer

Phosphodiester bonds

Answer

Peptide bonds

Answer

Hydrogen bonds

Question 15

What is the primary role of enzymes in biochemical reactions?

Accepted Answer

To lower the activation energy required for the reaction to occur

Answer

To increase the activation energy required for the reaction to occur

Answer

To supply the energy needed for the reaction to proceed

Answer

To remove the products formed in the reaction

Question 16

Which amino acid is classified as nonpolar?

Accepted Answer

Leucine

Answer

Asparagine

Answer

Glutamic acid

Answer

Tyrosine

Question 17

Glycosylation, phosphorylation, and acetylation are examples of what type of biochemical process?

Accepted Answer

Post-translational modifications

Answer

Protein degradation

Answer

Nucleotide synthesis

Answer

Gene regulation

Question 18

What is the primary function of hormones in biological systems?

Accepted Answer

Transmitting signals between cells

Answer

Regulating gene expression

Answer

Providing energy to cells

Answer

Defending against pathogens

Question 19

Which of the following is a monosaccharide, the simplest form of carbohydrate?

Accepted Answer

Glucose

Answer

Starch

Answer

Cellulose

Answer

Glycogen

Question 20

The primary structure of a protein refers to its:

Accepted Answer

Sequence of amino acids

Answer

Interactions between amino acid side chains

Answer

Folding of the polypeptide chain

Answer

Presence of disulfide bonds

Question 21

Which of the following is not characteristic of lipids?

Accepted Answer

Carbohydrates

Answer

Fatty acids

Answer

Phospholipids

Answer

Steroids

Question 22

According to Watson-Crick base pairing rules, which nitrogenous bases form a complementary pair?

Accepted Answer

A with T, and C with G

Answer

A with G, and C with T

Answer

T with G, and C with A

Answer

G with C, and T with A

Question 23

In which cellular compartment does glycolysis, the first step of cellular respiration, occur?

Accepted Answer

Cytoplasm

Answer

Mitochondria

Answer

Nucleus

Answer

Endoplasmic reticulum

Question 24

Which of the following is a secondary messenger involved in signal transduction?

Accepted Answer

Cyclic AMP

Answer

Glucose

Answer

Amino acids

Answer

Fatty acids

Question 25

The genetic code is considered degenerate because:

Accepted Answer

Multiple codons can code for the same amino acid

Answer

Different amino acids can be coded by the same codon

Answer

The genetic code is not universal across all organisms

Answer

The genetic code changes over time

Question 26

Phosphoglyceride is a type of lipid. Which category does it belong to?

Accepted Answer

Complex lipid

Answer

Simple lipid

Answer

Neutral lipid

Answer

Steroid lipid

Question 27

Which amino acid side chain has a positive charge under physiological conditions (pH 7)?

Accepted Answer

Lysine

Answer

Aspartic acid

Answer

Glutamic acid

Answer

Serine

Question 28

What is the primary role of nucleic acids in biological systems?

Accepted Answer

Storing and transmitting genetic information

Answer

Providing energy

Answer

Regulating cellular processes

Answer

Forming cell membranes

Question 29

Which of the following is a purine base found in both DNA and RNA?

Accepted Answer

Adenine

Answer

Thymine

Answer

Uracil

Answer

Cytosine

Question 30

Which lipid class serves as the body's primary energy reserve?

Accepted Answer

Triglycerides

Answer

Phospholipids

Answer

Glycolipids

Answer

Steroids

Question 31

What is the primary function of hemoglobin in the human body?

Accepted Answer

Oxygen transport

Answer

Glucose transport

Answer

Hormone secretion

Answer

Immune response

Question 32

Which technique separates proteins based on their electrical charge?

Accepted Answer

Gel electrophoresis

Answer

Chromatography

Answer

Spectrophotometry

Answer

Mass spectrometry

Question 33

Which of the following is NOT a classification of carbohydrates?

Accepted Answer

Peptides

Answer

Monosaccharides

Answer

Polysaccharides

Answer

Glycosaminoglycans

Question 34

Which of the following amino acids is essential for human health?

Accepted Answer

Lysine

Answer

Alanine

Answer

Glycine

Answer

Proline

Question 35

Which enzyme class is responsible for catalyzing the breakdown of peptide bonds?

Accepted Answer

Proteases

Answer

Amylases

Answer

Lipases

Answer

Nucleases

Question 36

What is the significance of the hydrophobic effect in protein folding?

Accepted Answer

It drives the folding of proteins into their specific conformations.

Answer

It promotes the formation of disulfide bonds.

Answer

It stabilizes the interactions between protein subunits.

Answer

It has no effect on protein folding.

Question 37

Which metabolic pathway is responsible for the breakdown of glucose?

Accepted Answer

Glycolysis

Answer

Gluconeogenesis

Answer

Glycogenolysis

Answer

Lipogenesis

Question 38

What is the primary role of ATP in biological systems?

Accepted Answer

Energy currency for cellular processes

Answer

Building block for RNA synthesis

Answer

Cofactor for enzyme reactions

Answer

Precursor for lipid synthesis

Question 39

Which of the following is **not** a function of carbohydrates in the body?

Accepted Answer

Regulating gene expression

Answer

Providing energy

Answer

Storing energy

Answer

Forming structural components

Question 40

Which of the following **phospholipids** is a major component of cell membranes?

Accepted Answer

Phosphatidylcholine

Answer

Triglycerides

Answer

Waxes

Answer

Steroids

Question 41

Which of the following amino acids is **essential** for humans?

Accepted Answer

Lysine

Answer

Alanine

Answer

Glutamic acid

Answer

Asparagine

Question 42

Which of the following is the **primary structure** of DNA?

Accepted Answer

A sequence of nucleotides linked by phosphodiester bonds

Answer

A double helix with antiparallel strands

Answer

A triple helix with complementary strands

Answer

A branched structure with multiple sequences

Question 43

Which of the following bonds is responsible for maintaining the **secondary structure** of proteins?

Accepted Answer

Hydrogen bonds

Answer

Ionic bonds

Answer

Disulfide bonds

Answer

Covalent bonds

Question 44

Which of the following is the main function of **ribosomes** in the cell?

Accepted Answer

Protein synthesis

Answer

RNA synthesis

Answer

DNA synthesis

Answer

Lipid synthesis

Question 45

Which level of protein structure is primarily determined by interactions between amino acid side chains?

Accepted Answer

Tertiary Structure

Answer

Primary Structure

Answer

Secondary Structure

Answer

Quaternary Structure

Question 46

Translate this mRNA sequence into the corresponding amino acid sequence: AUG-CCU-GGA-UUC

Accepted Answer

Methionine - Proline - Glycine - Phenylalanine

Answer

Alanine - Leucine - Arginine - Isoleucine

Answer

Tryptophan - Valine - Glutamic acid - Serine

Answer

Glycine - Asparagine - Alanine - Histidine

Question 47

Which metabolic pathway initiates the breakdown of carbohydrates?

Accepted Answer

Glycolysis

Answer

Gluconeogenesis

Answer

Citric acid cycle (Krebs cycle)

Answer

Oxidative phosphorylation

Question 48

Which of the following is NOT a key step in fatty acid oxidation?

Accepted Answer

Glycolysis

Answer

Activation

Answer

Dehydrogenation

Question 49

Which of the following is NOT a monosaccharide?

Accepted Answer

Starch

Answer

Ribose

Answer

Glucose

Answer

Fructose

Question 50

Which functional group(s) are characteristic of amino acids?

Accepted Answer

Amine and carboxylic acid

Answer

Ether and ketone

Answer

Hydroxyl and carbonyl

Answer

Phosphate and sugar

Question 51

What determines the primary structure of a protein?

Accepted Answer

Sequence of amino acids

Answer

Shape of the protein

Answer

pH of the surrounding environment

Answer

Presence of disulfide bonds

Question 52

What is the primary function of a promoter in DNA?

Accepted Answer

Initiate transcription

Answer

Protect DNA from damage

Answer

Terminate transcription

Answer

Encode genetic information

Question 53

Which type of bond links nucleotides together in a polynucleotide chain?

Accepted Answer

Phosphodiester bond

Answer

Hydrogen bond

Answer

Peptide bond

Answer

Glycosidic bond

Question 54

What is the primary role of enzymes in biological reactions?

Accepted Answer

Catalyze and increase the rate of reactions

Answer

Transport molecules across membranes

Answer

Inhibit and slow down reactions

Answer

Provide energy for reactions

Question 55

Which of the following characteristics **does not** apply to biological membranes?

Accepted Answer

Rigid and impermeable

Answer

Contain lipids

Answer

Fluid and semi-permeable

Answer

Asymmetrical