Biochemistry Quizzes: Test Your Understanding of Biomolecules and Metabolism

Question 1

How do transcription factors and chromatin structure interact to regulate gene expression? Explain the role of epigenetic modifications in shaping cellular differentiation and development.

Accepted Answer

Transcription factors bind to specific DNA sequences and modify chromatin structure, influencing gene accessibility.

Answer

Epigenetic modifications, like DNA methylation and histone acetylation, do not affect gene accessibility or cellular differentiation.

Answer

Cellular differentiation occurs randomly, independent of transcription factor activity or chromatin structure.

Answer

Epigenetic modifications are exclusive to embryonic stem cells and absent in specialized tissues.

Question 2

Which technique is NOT typically used to study protein-protein interactions?

Accepted Answer

Polymerase chain reaction (PCR)

Answer

Co-immunoprecipitation

Answer

Fluorescence resonance energy transfer (FRET)

Answer

Cross-linking

Question 3

Which of the following is NOT a characteristic of enzymes?

Accepted Answer

They form covalent bonds with their substrates.

Answer

They exhibit high specificity for their substrates.

Answer

They accelerate chemical reactions.

Answer

They can be used in industrial applications.

Question 4

Which type of bond contributes primarily to the primary structure of a protein?

Accepted Answer

Covalent bond

Answer

Hydrogen bond

Answer

Ionic bond

Answer

Van der Waals force

Question 5

What is ATP's primary role in cellular processes?

Accepted Answer

Energy currency

Answer

Genetic material

Answer

Structural component

Answer

Hormone

Question 6

What is the fundamental principle of molecular biology known as the central dogma?

Accepted Answer

DNA → RNA → Protein

Answer

RNA → DNA → Protein

Answer

Protein → RNA → DNA

Answer

DNA → Protein → RNA

Question 7

In DNA replication, which enzyme is responsible for synthesizing new DNA strands?

Accepted Answer

DNA polymerase

Answer

RNA polymerase

Answer

Ligase

Answer

Helicase

Question 8

What is the primary function of ribosomes within cells?

Accepted Answer

Translation of mRNA into proteins

Answer

RNA synthesis

Answer

DNA replication

Answer

Molecular transport

Question 9

Which of the following describes a competitive enzyme inhibitor?

Accepted Answer

Competes with the substrate for the active site

Answer

Binds irreversibly to the enzyme

Answer

Enhances enzyme activity

Answer

Binds non-covalently to the enzyme

Question 10

What is the primary role of the Krebs cycle in cellular respiration?

Accepted Answer

Production of NADH and FADH2

Answer

ATP generation

Answer

Glucose breakdown

Answer

Carbon dioxide release

Question 11

Which of the following is NOT considered a type of biomolecule?

Accepted Answer

Water

Answer

Carbohydrates

Answer

Lipids

Answer

Proteins

Question 12

The primary structure of a protein refers to which aspect?

Accepted Answer

The linear sequence of amino acids

Answer

The three-dimensional folding of the protein

Answer

The chemical bonds that hold the protein together

Answer

The biological function of the protein

Question 13

Which type of enzyme is responsible for breaking down peptide bonds?

Accepted Answer

Proteases

Answer

Lipases

Answer

Amylases

Answer

Nucleases

Question 14

In which organelle does the citric acid cycle take place?

Accepted Answer

Mitochondria

Answer

Cytoplasm

Answer

Nucleus

Answer

Ribosomes

Question 15

Which type of bond is primarily responsible for maintaining the secondary structure of proteins?

Accepted Answer

Hydrogen bonds

Answer

Ionic bonds

Answer

Disulfide bonds

Answer

Covalent bonds

Question 16

What was the primary goal of the Human Genome Project?

Accepted Answer

To sequence the entire human genome

Answer

To identify all the genes in the human genome

Answer

To understand the function of every gene in the human genome

Answer

To develop new treatments for genetic diseases

Question 17

Which of the following is NOT classified as a biomolecule?

Accepted Answer

Sodium ions

Answer

Carbohydrates

Answer

Lipids

Answer

Proteins

Question 18

The primary structure of a protein refers to:

Accepted Answer

The linear sequence of amino acids

Answer

The folding pattern of the polypeptide chain

Answer

The three-dimensional structure of the protein

Answer

The interactions between the protein and other molecules

Question 19

Which enzyme is responsible for hydrolysing peptide bonds in proteins?

Accepted Answer

Protease

Answer

Amylase

Answer

Lipase

Answer

Nuclease

Question 20

The initial step of cellular respiration, where glucose is broken down, is known as:

Accepted Answer

Glycolysis

Answer

Citric acid cycle

Answer

Electron transport chain

Answer

Oxidative phosphorylation

Question 21

The double helix structure of DNA is maintained primarily by:

Accepted Answer

Hydrogen bonds

Answer

Covalent bonds

Answer

Ionic bonds

Answer

Van der Waals forces

Question 22

The process by which cells control the expression of specific genes is called:

Accepted Answer

Gene regulation

Answer

Transcription

Answer

Translation

Answer

Epigenetics

Question 23

The enzyme responsible for catalysing the synthesis of new DNA strands during replication is:

Accepted Answer

Polymerase

Answer

Helicase

Answer

Ligase

Answer

Primase

Question 24

Which of the following is NOT considered a primary biomolecule in biochemistry?

Accepted Answer

Vitamins

Answer

Carbohydrates

Answer

Lipids

Answer

Proteins

Question 25

Which type of non-covalent interaction is the strongest among biomolecules?

Accepted Answer

Ionic bond

Answer

Hydrogen bond

Answer

van der Waals force

Answer

Hydrophobic interaction

Question 26

Which enzyme is responsible for breaking down starch into smaller molecules?

Accepted Answer

Amylase

Answer

Protease

Answer

Lipase

Answer

Nuclease

Question 27

The pH at which a protein carries no net electrical charge is known as its:

Accepted Answer

Isoelectric point (pI)

Answer

Melting point

Answer

Boiling point

Answer

Neutralization point

Question 28

Which of the following is an example of a buffer solution?

Accepted Answer

A mixture of 0.1 M acetic acid and 0.1 M sodium acetate

Answer

Pure water

Answer

0.1 M HCl

Answer

0.1 M NaOH

Question 29

Which of the following elements is a crucial cofactor in many redox reactions?

Accepted Answer

Iron (Fe)

Answer

Calcium (Ca)

Answer

Magnesium (Mg)

Answer

Potassium (K)

Question 30

Which type of chemical reaction is involved in the formation of DNA?

Accepted Answer

Dehydration synthesis

Answer

Hydrolysis

Answer

Oxidation-reduction

Answer

Phosphorylation

Question 31

Which characteristic is a defining feature of proteins with a quaternary structure?

Accepted Answer

Multiple polypeptide chains

Answer

Identical subunits

Answer

Single polypeptide chain

Answer

Absence of a defined shape

Question 32

What is the foundational architectural level of a protein known as?

Accepted Answer

Primary structure

Answer

Secondary structure

Answer

Tertiary structure

Answer

Quaternary structure

Question 33

In the reaction where ATP hydrolyzes to ADP, what is the nature of the free energy change (ΔG)?

Accepted Answer

Negative

Answer

Positive

Answer

Zero

Answer

Impossible to determine

Question 34

In protein stabilization, which type of interaction is non-covalent?

Accepted Answer

Hydrogen bonding

Answer

Ionic bonding

Answer

Covalent bonding

Answer

Disulfide bonding

Question 35

What is the main function of the Krebs cycle, also called the citric acid cycle?

Accepted Answer

Formation of NADH and FADH2

Answer

ATP production

Answer

Glucose breakdown

Answer

Release of carbon dioxide

Question 36

In the genetic code, which characteristic applies to all living organisms?

Accepted Answer

Universality

Answer

Prokaryotic specificity

Answer

Eukaryotic specificity

Answer

Varies across species

Question 37

What primary function does the cell membrane serve?

Accepted Answer

Regulating substance exchange with the surroundings

Answer

Providing structural support

Answer

Generating ATP

Answer

Storing genetic information

Question 38

Which of the following is NOT classified as a biomolecule?

Accepted Answer

Minerals

Answer

Carbohydrates

Answer

Lipids

Answer

Proteins

Question 39

What aspect of a protein's structure is determined by its sequence of amino acids?

Accepted Answer

Primary structure

Answer

Secondary structure

Answer

Tertiary structure

Answer

Quaternary structure

Question 40

Which of the following enzymes catalyzes the first step in glycolysis?

Accepted Answer

Hexokinase

Answer

Phosphoglycerate kinase

Answer

Pyruvate kinase

Answer

Lactate dehydrogenase

Question 41

What is the primary function of a buffer system?

Accepted Answer

Maintain a stable pH

Answer

Increase the acidity of a solution

Answer

Decrease the acidity of a solution

Answer

Provide energy for metabolic processes

Question 42

Which of the following is a characteristic of a spontaneous chemical reaction?

Accepted Answer

Negative ΔG

Answer

Positive ΔG

Answer

ΔG = 0

Answer

Requires an external energy input

Question 43

What is the primary role of NAD+ in cellular respiration?

Accepted Answer

Electron carrier

Answer

Energy currency

Answer

Enzyme cofactor

Answer

Hormonal regulator

Question 44

What does the Michaelis-Menten constant (Km) represent?

Accepted Answer

Substrate concentration at half-maximal velocity

Answer

Enzyme concentration at half-maximal velocity

Answer

Maximum reaction velocity

Answer

Inhibition constant

Question 45

What is the main purpose of the citric acid cycle in living cells?

Accepted Answer

Energy production

Answer

Electron transfer

Answer

Carbon dioxide release

Answer

Amino acid synthesis

Question 46

Which type of bond is responsible for linking amino acids?

Accepted Answer

Covalent bond

Answer

Hydrogen bond

Answer

Ionic bond

Answer

Van der Waals force

Question 47

What is the primary role of enzymes in biochemical reactions?

Accepted Answer

Accelerate the rate of reactions

Answer

Provide energy for reactions

Answer

Synthesize new molecules

Answer

Transport molecules across membranes

Question 48

What is the primary function of ribosomes in protein synthesis?

Accepted Answer

Translate genetic code into amino acids

Answer

Assemble amino acids into proteins

Answer

Initiate protein synthesis

Answer

Modify proteins after synthesis

Question 49

Identify the type of pathway that includes glycolysis, the citric acid cycle, and the electron transport chain:

Accepted Answer

Metabolic pathway

Answer

Catabolic pathway

Answer

Anabolic pathway

Answer

Signal transduction pathway

Question 50

What is the primary function of the cell membrane?

Accepted Answer

Regulate substance exchange

Answer

Generate energy

Answer

Synthesize proteins

Answer

Store genetic information

Question 51

What is the purpose of gel electrophoresis in molecular biology?

Accepted Answer

Separate nucleic acids or proteins based on size

Answer

Amplify DNA

Answer

Quantify gene expression

Answer

Identify mutations

Question 52

Which of the following is NOT a class of biomolecules?

Accepted Answer

Inorganic compounds

Answer

Carbohydrates

Answer

Lipids

Answer

Proteins

Question 53

The primary structure of a protein refers to its:

Accepted Answer

Linear sequence of amino acids

Answer

Three-dimensional conformation

Answer

Hydrogen bonding pattern

Answer

Interaction with other molecules

Question 54

Which type of enzyme catalyses the hydrolysis of peptide bonds specifically?

Accepted Answer

Protease

Answer

Ligase

Answer

Polymerase

Answer

Nuclease

Question 55

What is the term for the metabolic process of breaking down glucose in the presence of oxygen?

Accepted Answer

Cellular respiration

Answer

Glycolysis

Answer

Gluconeogenesis

Answer

Photosynthesis

Question 56

Which of the following amino acids is non-polar?

Accepted Answer

Alanine

Answer

Serine

Answer

Glutamic acid

Answer

Asparagine

Question 57

Which field of study focuses specifically on the chemical reactions occurring in living organisms?

Accepted Answer

Biochemistry

Answer

Metabolism

Answer

Physiology

Answer

Genetics

Question 58

Which of the following is NOT considered a major class of biomolecules?

Accepted Answer

Vitamins

Answer

Carbohydrates

Answer

Lipids

Answer

Proteins

Question 59

The primary structure of a protein refers to:

Accepted Answer

The linear sequence of amino acid residues

Answer

The folding of the polypeptide chain into a specific three-dimensional conformation

Answer

The assembly of multiple polypeptide chains into a functional complex

Answer

The presence of non-amino acid components, such as carbohydrates or lipids

Question 60

Which enzyme group is responsible for catalyzing the hydrolysis of peptide bonds?

Accepted Answer

Proteases

Answer

Amylases

Answer

Lipases

Answer

Nucleases

Question 61

The pH optimum of an enzyme refers to:

Accepted Answer

The pH at which the enzyme exhibits its максимальный activity

Answer

The pH at which the enzyme is least active

Answer

The pH at which the enzyme is denatured

Answer

The pH at which the enzyme is synthesized

Question 62

In eukaryotic cells, the citric acid cycle occurs within which organelle?

Accepted Answer

Mitochondria

Answer

Cytoplasm

Answer

Endoplasmic reticulum

Answer

Lysosomes

Question 63

Lipids perform a wide range of biological functions. Which of the following is NOT a major function of lipids?

Accepted Answer

Protein synthesis

Answer

Energy storage

Answer

Hormone synthesis

Answer

Cell signaling

Question 64

The process by which a complementary RNA molecule is synthesized from a DNA template is known as:

Accepted Answer

Transcription

Answer

Replication

Answer

Translation

Answer

Mutation