Biological Molecules: Structure, Function, and Exam Preparation

Question 1

Which characteristic is unique to quaternary protein structure?

Accepted Answer

Interaction of multiple protein subunits

Answer

Determination by amino acid composition

Answer

Formation of alpha-helices and beta-sheets

Answer

Covalent bonding between amino acids

Question 2

Which characteristic is NOT a property of polysaccharides?

Accepted Answer

Highly soluble in water

Answer

Composed of numerous monosaccharide subunits

Answer

Function as an energy reserve in organisms

Answer

Can be broken down through hydrolysis

Question 3

Are lipids classified as nucleic acids or non-nucleic acids?

Accepted Answer

Non-nucleic acid

Answer

Nucleic acid

Question 4

Which of the following accurately describes the structure of polysaccharides?

Accepted Answer

Branched polymers of monosaccharides

Answer

Unbranched polymers of monosaccharides

Answer

Composed solely of glucose molecules

Answer

Insoluble in water

Question 5

Carbohydrates, a class of biological molecules, play essential roles in various biological processes. Which of the following is NOT a function of carbohydrates in living organisms?

Accepted Answer

Membrane stabilization

Answer

Energy source

Answer

Energy storage

Answer

Structural component

Question 6

Which of the following is not a type of biomolecule?

Accepted Answer

Electrons

Answer

Carbohydrates

Answer

Proteins

Answer

Lipids

Question 7

Which level of protein structure does NOT describe the arrangement of its components?

Accepted Answer

Quaternary

Answer

Primary

Answer

Secondary

Answer

Tertiary

Question 8

Which of the following is NOT a recognized level of protein structure?

Accepted Answer

Quinary

Answer

Primary

Answer

Secondary

Answer

Tertiary

Question 9

Identify the disaccharide among the following molecules:

Accepted Answer

Sucrose

Answer

Glucose

Answer

Fructose

Question 10

Which of the following is NOT a naturally occurring type of fatty acid?

Accepted Answer

Trans

Answer

Saturated

Answer

Unsaturated

Answer

Polyunsaturated

Question 11

How does hydrogen bonding contribute to the structure of a DNA double helix?

Accepted Answer

It holds together the two DNA strands.

Answer

It connects nitrogenous bases within a single DNA strand.

Answer

It is stronger between A-T base pairs than G-C base pairs.

Answer

It is essential for RNA function but not DNA function.

Question 12

In transcription, which DNA strand serves as the template for RNA synthesis, and how does the resulting RNA molecule compare to the template strand?

Accepted Answer

The coding strand is the template, and the RNA molecule is complementary to the template strand.

Answer

The non-coding strand is the template, and the RNA molecule is identical to the template strand.

Answer

The non-coding strand is the template, and the RNA molecule is complementary to the coding strand.

Answer

The coding strand is the template, and the RNA molecule is identical to the template strand.

Question 13

Which structural feature of glycogen enables it to function as a readily accessible energy source in animal cells?

Accepted Answer

Branched chain of glucose molecules linked by α-1,4- and α-1,6-glycosidic bonds

Answer

Linear chain of glucose molecules linked by α-1,4-glycosidic bonds

Answer

Helical chain of glucose molecules linked by β-1,4-glycosidic bonds

Answer

Cyclic chain of glucose molecules linked by α-1,4-glycosidic bonds

Question 14

Which lipid class is characterized by a four-ring structure and includes molecules like cholesterol and hormones?

Accepted Answer

Steroids

Answer

Phospholipids

Answer

Glycolipids

Question 15

What is the correct description of the structure of nucleic acids?

Accepted Answer

Two antiparallel polynucleotide chains held together by complementary nitrogenous base pairing

Answer

A single polynucleotide chain linked by phosphodiester bonds

Answer

A double helix structure with the sugar-phosphate backbone exposed to the exterior

Answer

A triple helix structure containing only two types of nucleotides

Question 16

Which biopolymer exhibits a rigid structure because of the specific arrangement of its repeating sugar units?

Accepted Answer

Cellulose

Answer

Starch

Answer

Glycogen

Question 17

Which enzyme is responsible for synthesizing messenger RNA (mRNA) during transcription?

Accepted Answer

RNA polymerase

Answer

Ligase

Answer

Helicase

Answer

Primase

Question 18

Which biomolecule is made up of a chain of amino acids?

Accepted Answer

Protein

Answer

Starch

Answer

Lipids

Answer

Nucleic Acid

Question 19

In addition to their roles in catalyzing reactions and transporting molecules, which of the following is **NOT** a function of proteins in living organisms?

Accepted Answer

Storing genetic information

Answer

Providing structural support and protection

Answer

Regulating gene expression

Answer

Hormonal signaling

Question 20

Which of the following describes a key characteristic of carbohydrates?

Accepted Answer

Carbohydrates exist as monomers, dimers, or polymers

Answer

Carbohydrates store genetic information

Answer

RNA is a carbohydrate involved in protein synthesis

Answer

Carbohydrates only provide energy for cells

Question 21

Identify the pentose sugar, a type of monosaccharide with five carbon atoms in its structure:

Accepted Answer

Ribose

Answer

Glucose

Answer

Fructose

Answer

Sucrose

Question 22

In a protein, which structure is determined first, followed by the second and third structures?

Accepted Answer

Primary, secondary, tertiary

Answer

Tertiary, secondary, primary

Answer

All structures are determined independently

Question 23

What defines the primary structure of a protein?

Accepted Answer

Sequence of amino acids

Answer

3D arrangement of amino acids

Answer

Polypeptide chains linked by disulfide bonds

Question 24

Which component is NOT found in a nucleotide?

Accepted Answer

Amino acid

Answer

Deoxyribose or ribose

Answer

Phosphate group

Answer

Nitrogenous base

Question 25

Which of the following accurately describes the structure of a triglyceride molecule?

Accepted Answer

Three fatty acids bonded to a glycerol molecule

Answer

A glycerol molecule bonded to two fatty acids and one phosphate group

Answer

Two fatty acids bonded to a glycerol molecule and one amino acid

Answer

A fatty acid bonded to a glycerol molecule and two phosphate groups

Question 26

Which bond type is primarily responsible for maintaining the quaternary structure of a protein?

Accepted Answer

Disulfide bonds

Answer

Hydrogen bonds

Answer

Ionic bonds

Answer

Covalent bonds

Question 27

Explain the role of chaperone proteins in assisting the folding and assembly of other proteins within cells.

Accepted Answer

Chaperone proteins prevent misfolding and aggregation of newly synthesized proteins, ensuring their correct folding and assembly.

Answer

Chaperone proteins act as enzymes, catalyzing the formation of peptide bonds during protein synthesis.

Answer

Chaperone proteins are only required for the folding of large and complex proteins, while smaller proteins can fold independently.

Question 28

Compare and contrast the mechanisms of DNA replication and transcription, identifying their similarities and differences.

Accepted Answer

Both processes involve unwinding the DNA double helix.

Accepted Answer

Transcription uses RNA polymerase, while DNA replication uses DNA polymerase.

Accepted Answer

Replication produces two identical daughter DNA molecules, while transcription produces a single RNA molecule.

Answer

Only DNA replication requires a primer.

Question 29

Beyond temperature and substrate concentration, which factor significantly impacts the rate of enzymatic reactions?

Accepted Answer

Cofactors

Answer

Reaction medium molarity

Answer

Reaction environment pressure

Answer

Gravitational field strength

Question 30

What is the basic structural unit of a phospholipid molecule?

Accepted Answer

Glycerol, fatty acid, and phosphate

Answer

Glycerol and fatty acid

Answer

Glycerol and phosphate

Answer

Fatty acid and phosphate

Question 31

What type of bond forms between adjacent amino acids in a polypeptide chain?

Accepted Answer

Peptide bond

Answer

Phosphodiester bond

Answer

Glycosidic bond

Answer

Ester bond

Question 32

Which of the following nitrogenous bases is NOT present in DNA molecules?

Accepted Answer

Uracil

Answer

Adenine

Answer

Cytosine

Answer

Guanine

Question 33

What is the primary role of ribosomes in protein synthesis?

Accepted Answer

Translation of mRNA into amino acid sequences

Answer

Transcription of genetic information

Answer

Synthesis of amino acids

Answer

Polymerization of nucleic acids

Question 34

What factor determines the primary structure of a protein molecule?

Accepted Answer

Sequence of amino acids

Answer

Interactions between amino acid side chains

Answer

Folding patterns

Answer

Presence of disulfide bonds

Question 35

Which enzyme type catalyzes the hydrolysis of fats and oils?

Accepted Answer

Lipase

Answer

Protease

Answer

Amylase

Answer

Nuclease

Question 36

What is the main role of tRNA molecules in protein synthesis?

Accepted Answer

Transporting specific amino acids to the ribosome

Answer

Polymerizing nucleotides into mRNA strands

Answer

Binding to promoter sequences on DNA

Answer

Catalyzing the formation of peptide bonds

Question 37

In the gene editing technique CRISPR-Cas9, which biological molecule is primarily targeted for modification?

Accepted Answer

Nucleic acids (DNA)

Answer

Carbohydrates

Answer

Lipids

Answer

Proteins

Question 38

What is gene regulation and how does it influence the expression of genes at the molecular level?

Accepted Answer

Gene regulation controls the timing and amount of protein production, allowing cells to adapt to their environment.

Answer

Gene regulation only affects the start of transcription.

Answer

Gene regulation is not essential for cell growth and function.

Question 39

How does protein denaturation affect a protein's ability to function?

Accepted Answer

Denaturation exposes reactive groups that can interact with other molecules, altering protein function.

Answer

Denaturation enhances functionality by strengthening hydrogen bonds.

Answer

Denaturation stabilizes protein structure through stronger hydrophobic interactions, preserving functionality.

Answer

Denaturation has no impact on protein structure or function.

Question 40

How do biological molecules play a key role in passing on traits and creating variation?

Accepted Answer

They store and transmit genetic instructions.

Answer

They provide energy for life processes.

Answer

They help chemical reactions happen in cells.

Question 41

Which enzyme is responsible for the chemical reaction that combines glucose and fructose to form the disaccharide sucrose?

Accepted Answer

Sucrose synthase

Answer

Lipase

Answer

Sucrase

Answer

Amylase

Question 42

Which of the following biomolecules is a structural polysaccharide found in plants?

Accepted Answer

Starch

Answer

Glucose

Answer

Glycine

Answer

Glycogen

Question 43

What is the primary role of phospholipids in biological membranes?

Accepted Answer

To provide structural support and regulate membrane permeability

Answer

To transport molecules across the membrane

Answer

To catalyze chemical reactions

Answer

To store genetic information

Question 44

What is the primary function of RNA polymerase during DNA transcription?

Accepted Answer

To synthesize a complementary mRNA strand using the DNA template

Answer

To unwind and separate the two strands of DNA

Answer

To catalyze the formation of peptide bonds

Answer

To replicate DNA into RNA

Question 45

Which of the following metabolic pathways involves the breakdown of complex molecules into simpler ones, releasing energy?

Accepted Answer

Catabolism

Answer

Anabolism

Answer

Gluconeogenesis

Answer

Glycolysis

Question 46

What is the process by which plants utilize light energy to convert carbon dioxide and water into glucose and oxygen?

Accepted Answer

Photosynthesis

Answer

Respiration

Answer

Chemosynthesis

Answer

Glycolysis

Question 47

What is the term for the process by which a cell divides, resulting in two genetically identical daughter cells?

Accepted Answer

Mitosis

Answer

Meiosis

Answer

Citogenesis

Answer

Karyokinesis

Question 48

How do hormones function in cell signaling?

Accepted Answer

Hormones bind to receptors on target cells, triggering intracellular events.

Answer

Hormones cross the cell membrane and directly change gene expression.

Answer

Hormones are only made by endocrine glands.

Answer

Hormones always block cellular processes.

Question 49

Which of the following is NOT a primary function of carbohydrates in living organisms?

Accepted Answer

Hormonal signaling

Answer

Energy storage

Answer

Structural support

Question 50

Which type of bond joins the amino acid subunits of a polypeptide chain?

Accepted Answer

Peptide bond

Answer

Glycosidic bond

Question 51

In DNA, which base pairs with adenine?

Accepted Answer

Thymine

Answer

Guanine-guanine

Question 52

Which of the following describes the function of ribosomes?

Accepted Answer

Translation of mRNA into protein

Answer

Transcription of DNA into RNA

Question 53

How does a covalent bond differ from an ionic bond?

Accepted Answer

Covalent bonds involve electron sharing, while ionic bonds involve electron transfer

Answer

Ionic bonds involve electron sharing, while covalent bonds involve electron transfer

Question 54

Which molecule is hydrophilic?

Accepted Answer

Glucose

Answer

Cholesterol

Question 55

Which statement best describes how biological molecules contribute to cell communication?

Accepted Answer

Certain molecules, like hormones, act as signals. They bind to cell surface receptors, triggering responses within the cell.

Answer

Biological molecules are only involved in metabolism and energy production, playing no part in cell communication.

Answer

Signal transduction only involves transferring signals across the nuclear membrane.

Question 56

In eukaryotic cells, how does the compartmentalization of biological molecules into organelles enhance cellular efficiency?

Accepted Answer

It enables the coordinated execution of biochemical reactions, preventing interference and optimizing cellular function.

Answer

Organelles synthesize all biological molecules, ensuring their availability within the cell.

Answer

Compartmentalization is not essential in eukaryotic cells, as all processes can occur simultaneously in the cytoplasm.

Question 57

Whose research was instrumental in Watson and Crick's discovery of DNA's double helix structure?

Accepted Answer

Rosalind Franklin

Answer

Frederick Griffith

Answer

James Watson

Question 58

How do mutations in a DNA sequence affect the resulting protein's structure and function?

Accepted Answer

Silent mutations don't change the encoded protein.

Accepted Answer

Missense mutations change the amino acid at a specific codon.

Accepted Answer

Nonsense mutations create a stop codon, shortening the protein.

Question 59

Diagnostic tests often rely on biological molecules. What is their key role in this context?

Accepted Answer

Detecting and quantifying specific molecules that indicate disease

Answer

Measuring protein synthesis directly in the body

Answer

Providing a complete analysis of all biological processes in the body

Question 60

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

Accepted Answer

Glucose

Answer

Starch

Answer

Glycogen

Answer

Cellulose

Question 61

What type of bond links amino acids together to form proteins?

Accepted Answer

Peptide bond

Answer

Hydrogen bond

Answer

Glycosidic bond

Answer

Ionic bond

Question 62

Which enzyme is primarily responsible for synthesizing new DNA strands during DNA replication?

Accepted Answer

DNA polymerase

Answer

Ligase

Answer

Helicase

Question 63

What is the primary structure of a protein, referring to its basic molecular arrangement?

Accepted Answer

The linear sequence of amino acids

Answer

The glycosylation of the protein

Answer

The presence of disulfide bonds

Answer

The three-dimensional folding of the protein

Question 64

Which of the following molecules is nonpolar, meaning it lacks a net electrical charge?

Accepted Answer

Ethane

Answer

Methanol

Answer

Water

Answer

Ammonia