CMB EXAM 1 QUESTIONS AND ANSWERS LATEST UPDATE 2025-2026
Biochemistry - Answers Biochemistry is the intersection of biology and chemistry. It studies
biomolecules (proteins, nucleic acids, carbs, lipids), their structures, and processes like
metabolism, catabolism, anabolism, energy production, and information transfer.
Proteins - Answers Proteins → enzymes, structure, transport, signaling.
Nucleic acids - Answers Nucleic acids → DNA (information storage), RNA (information
expression).
Carbohydrates - Answers Carbohydrates → energy + structural support.
Lipids - Answers Lipids → membranes, long-term energy storage, signaling.
Catabolism - Answers Catabolism → breakdown reactions, release energy (ATP).
Anabolism - Answers Anabolism → building reactions, consume energy (ATP).
3 domains of life - Answers Archaea: single-celled, no nucleus, extreme environments. Bacteria:
single-celled, no nucleus, huge diversity. Eukarya: nucleus + organelles, includes plants, animals,
fungi.
Jacques Monod's statement - Answers Because biochemistry is conserved across life. Core
proteins and pathways are shared (example: thioredoxin in bacteria and humans).
Key characteristics of living things - Answers Complex and organized, extract/use energy,
remove waste, self-replicate, self-assemble.
Central Dogma of Biology - Answers DNA → RNA → Protein. Catabolism provides energy and
precursors for anabolism. Mutations can disrupt this process and lead to disease.
Most abundant elements in life - Answers C, H, O, N (most abundant), S and P (essential but
less abundant). Also ions like Na⁺, K⁺, Ca²⁺, Cl⁻.
Miller-Urey experiment - Answers That amino acids, nucleic acid bases, and sugars (building
blocks of life) can form spontaneously under early Earth conditions.
Amino acids - Answers The building blocks of proteins. Each has an amino group (-NH₂), a
carboxyl group (-COOH), a hydrogen, and a variable R-group side chain.
Standard amino acids - Answers 20 standard amino acids used to build proteins in humans.
General structure of an amino acid - Answers Central α-carbon bonded to: amino group,
carboxyl group, hydrogen atom, and an R-group (side chain that defines the amino acid).
R-group in amino acids - Answers The variable side chain that determines chemical properties
(polar, nonpolar, charged, aromatic, etc.).
, Chiral amino acids - Answers Most amino acids have two mirror-image forms (L and D).
Proteins in humans are built from L-amino acids only.
Bonds connecting amino acids - Answers Peptide bonds, formed by condensation (removing
water) between the carboxyl group of one amino acid and the amino group of another.
Levels of protein structure - Answers 1. Primary → sequence of amino acids. 2. Secondary →
local folding (α-helices, β-sheets). 3. Tertiary → 3D folding of the polypeptide. 4. Quaternary →
interactions between multiple polypeptide chains.
Forces stabilizing tertiary protein structure - Answers Hydrogen bonds, ionic bonds, hydrophobic
interactions, disulfide bridges.
Protein denaturation - Answers Loss of native structure due to heat, pH, or chemicals. Function
is usually lost because structure = function.
Enzymes - Answers Proteins that act as biological catalysts, speeding up reactions by lowering
activation energy.
Active site - Answers The specific region on an enzyme where the substrate binds and reaction
occurs.
Lock and key vs induced fit model - Answers Lock & key → substrate fits enzyme active site
exactly. Induced fit → enzyme changes shape slightly to fit substrate better.
Factors affecting enzyme activity - Answers Temperature, pH, substrate concentration,
inhibitors, and cofactors/coenzymes.
Cofactors - Answers Inorganic ions (e.g., Mg²⁺, Zn²⁺) required for enzyme activity.
Coenzymes - Answers Organic molecules (often vitamins) that assist enzymes.
Primary structure of a protein - Answers The unique linear sequence of amino acids linked by
peptide bonds.
Final 3D structure of a protein - Answers Determined by its primary sequence of amino acids,
since interactions between side chains dictate folding.
Secondary structure of a protein - Answers Local folding into α-helices or β-pleated sheets
stabilized by hydrogen bonds between backbone atoms.
α-helix - Answers A right-handed coil stabilized by hydrogen bonds between every 4th amino
acid. Side chains extend outward.
β-pleated sheet - Answers Extended strands of amino acids that lie side-by-side, connected by
hydrogen bonds. Can be parallel or antiparallel.
Biochemistry - Answers Biochemistry is the intersection of biology and chemistry. It studies
biomolecules (proteins, nucleic acids, carbs, lipids), their structures, and processes like
metabolism, catabolism, anabolism, energy production, and information transfer.
Proteins - Answers Proteins → enzymes, structure, transport, signaling.
Nucleic acids - Answers Nucleic acids → DNA (information storage), RNA (information
expression).
Carbohydrates - Answers Carbohydrates → energy + structural support.
Lipids - Answers Lipids → membranes, long-term energy storage, signaling.
Catabolism - Answers Catabolism → breakdown reactions, release energy (ATP).
Anabolism - Answers Anabolism → building reactions, consume energy (ATP).
3 domains of life - Answers Archaea: single-celled, no nucleus, extreme environments. Bacteria:
single-celled, no nucleus, huge diversity. Eukarya: nucleus + organelles, includes plants, animals,
fungi.
Jacques Monod's statement - Answers Because biochemistry is conserved across life. Core
proteins and pathways are shared (example: thioredoxin in bacteria and humans).
Key characteristics of living things - Answers Complex and organized, extract/use energy,
remove waste, self-replicate, self-assemble.
Central Dogma of Biology - Answers DNA → RNA → Protein. Catabolism provides energy and
precursors for anabolism. Mutations can disrupt this process and lead to disease.
Most abundant elements in life - Answers C, H, O, N (most abundant), S and P (essential but
less abundant). Also ions like Na⁺, K⁺, Ca²⁺, Cl⁻.
Miller-Urey experiment - Answers That amino acids, nucleic acid bases, and sugars (building
blocks of life) can form spontaneously under early Earth conditions.
Amino acids - Answers The building blocks of proteins. Each has an amino group (-NH₂), a
carboxyl group (-COOH), a hydrogen, and a variable R-group side chain.
Standard amino acids - Answers 20 standard amino acids used to build proteins in humans.
General structure of an amino acid - Answers Central α-carbon bonded to: amino group,
carboxyl group, hydrogen atom, and an R-group (side chain that defines the amino acid).
R-group in amino acids - Answers The variable side chain that determines chemical properties
(polar, nonpolar, charged, aromatic, etc.).
, Chiral amino acids - Answers Most amino acids have two mirror-image forms (L and D).
Proteins in humans are built from L-amino acids only.
Bonds connecting amino acids - Answers Peptide bonds, formed by condensation (removing
water) between the carboxyl group of one amino acid and the amino group of another.
Levels of protein structure - Answers 1. Primary → sequence of amino acids. 2. Secondary →
local folding (α-helices, β-sheets). 3. Tertiary → 3D folding of the polypeptide. 4. Quaternary →
interactions between multiple polypeptide chains.
Forces stabilizing tertiary protein structure - Answers Hydrogen bonds, ionic bonds, hydrophobic
interactions, disulfide bridges.
Protein denaturation - Answers Loss of native structure due to heat, pH, or chemicals. Function
is usually lost because structure = function.
Enzymes - Answers Proteins that act as biological catalysts, speeding up reactions by lowering
activation energy.
Active site - Answers The specific region on an enzyme where the substrate binds and reaction
occurs.
Lock and key vs induced fit model - Answers Lock & key → substrate fits enzyme active site
exactly. Induced fit → enzyme changes shape slightly to fit substrate better.
Factors affecting enzyme activity - Answers Temperature, pH, substrate concentration,
inhibitors, and cofactors/coenzymes.
Cofactors - Answers Inorganic ions (e.g., Mg²⁺, Zn²⁺) required for enzyme activity.
Coenzymes - Answers Organic molecules (often vitamins) that assist enzymes.
Primary structure of a protein - Answers The unique linear sequence of amino acids linked by
peptide bonds.
Final 3D structure of a protein - Answers Determined by its primary sequence of amino acids,
since interactions between side chains dictate folding.
Secondary structure of a protein - Answers Local folding into α-helices or β-pleated sheets
stabilized by hydrogen bonds between backbone atoms.
α-helix - Answers A right-handed coil stabilized by hydrogen bonds between every 4th amino
acid. Side chains extend outward.
β-pleated sheet - Answers Extended strands of amino acids that lie side-by-side, connected by
hydrogen bonds. Can be parallel or antiparallel.
