Q.1 Which of the following best describes a gene?
A sequence of DNA that codes for a protein or RNA
A type of cell in the immune system
An organelle that stores energy
A protein that repairs DNA
Explanation - A gene is a defined segment of DNA that contains the instructions to make a protein or functional RNA molecule.
Correct answer is: A sequence of DNA that codes for a protein or RNA
Q.2 What does the term 'genome' refer to?
All the genes in a species
The entire set of genetic material in a cell
A single chromosome
A protein that regulates genes
Explanation - The genome is the complete DNA content of a cell, including all genes and noncoding sequences.
Correct answer is: The entire set of genetic material in a cell
Q.3 Which technique is commonly used to determine the order of nucleotides in DNA?
Sanger sequencing
Microscopy
Mass spectrometry
X-ray crystallography
Explanation - Sanger sequencing is a classic method that reads DNA sequences by incorporating chain-terminating nucleotides.
Correct answer is: Sanger sequencing
Q.4 What does BLAST stand for in bioinformatics?
Basic Local Alignment Search Tool
Biological Logic Analysis System Tool
Base Line Analysis Sequencing Tool
Binary Linear Algorithm Search Test
Explanation - BLAST is a fast algorithm that compares a query sequence against a database to find regions of similarity.
Correct answer is: Basic Local Alignment Search Tool
Q.5 In a gene regulatory network, what is an 'activator'?
A molecule that increases gene expression
A molecule that decreases gene expression
A type of protein that degrades mRNA
A DNA repair enzyme
Explanation - An activator binds to DNA and facilitates the recruitment of RNA polymerase, boosting transcription.
Correct answer is: A molecule that increases gene expression
Q.6 Which of the following represents a common feedback mechanism in cellular signaling?
Positive feedback where a product amplifies its own production
Negative feedback where a product inhibits its own production
Random diffusion of molecules
Passive transport through a membrane
Explanation - Negative feedback maintains homeostasis by reducing the output when a product reaches a threshold.
Correct answer is: Negative feedback where a product inhibits its own production
Q.7 What is the primary purpose of a 'control system' in engineering?
To automate the design of DNA sequences
To maintain a desired state of a system despite disturbances
To sequence proteins from mRNA
To amplify genetic signals
Explanation - Control systems adjust inputs to keep a system's output close to a setpoint, counteracting external changes.
Correct answer is: To maintain a desired state of a system despite disturbances
Q.8 Which model is used to describe the dynamics of a metabolic pathway?
Ordinary differential equations (ODEs)
Linear regression
Finite element method
Monte Carlo simulation
Explanation - ODEs capture time-dependent concentrations of metabolites in a pathway.
Correct answer is: Ordinary differential equations (ODEs)
Q.9 In systems biology, what does a 'Boolean network' represent?
Genes that can be on or off, with logical interactions
Continuous concentration levels of metabolites
Spatial distribution of proteins in a cell
The physical folding of DNA strands
Explanation - Boolean networks simplify gene regulation by using binary states and logical rules to predict behavior.
Correct answer is: Genes that can be on or off, with logical interactions
Q.10 Which mathematical concept from electrical engineering is often applied to analyze signal propagation in neuronal networks?
Fourier transform
Resistor-capacitor (RC) circuit model
Magnetic flux quantization
Quantum tunneling
Explanation - Neuronal membranes act like RC circuits, affecting voltage changes over time during signal transmission.
Correct answer is: Resistor-capacitor (RC) circuit model
Q.11 What role does 'noise' play in gene expression?
It always destabilizes cellular processes
It introduces variability that can be beneficial for adaptation
It is eliminated by cellular mechanisms
It refers to background electromagnetic interference
Explanation - Stochastic fluctuations can help populations explore new phenotypes, aiding evolution and adaptation.
Correct answer is: It introduces variability that can be beneficial for adaptation
Q.12 Which algorithm is commonly used for aligning multiple sequences simultaneously?
Dynamic programming with Smith‑Waterman
Hidden Markov Models (HMM)
Multiple sequence alignment via MUSCLE
K-means clustering
Explanation - MUSCLE is a fast, accurate algorithm for aligning many sequences to identify conserved regions.
Correct answer is: Multiple sequence alignment via MUSCLE
Q.13 In the context of gene regulatory networks, what is a 'regulatory motif'?
A specific arrangement of nucleotides that is functionally insignificant
A recurring pattern of connections that performs a specific function
A motif in the protein structure of transcription factors
A type of DNA repair mechanism
Explanation - Regulatory motifs are small network substructures, like feed‑forward loops, that confer robustness.
Correct answer is: A recurring pattern of connections that performs a specific function
Q.14 Which of the following is a key difference between a 'signal transduction pathway' and a 'metabolic pathway'?
Signal transduction uses ATP; metabolic does not
Metabolic pathways produce metabolites; signal pathways transmit information
Signal pathways are linear; metabolic are cyclical
Metabolic pathways involve genes; signal pathways do not
Explanation - Metabolic pathways transform substrates into products, whereas signal pathways relay information via post‑translational modifications.
Correct answer is: Metabolic pathways produce metabolites; signal pathways transmit information
Q.15 What is the purpose of a 'control gene' in synthetic biology circuits?
To serve as a reference for expression levels
To degrade unwanted proteins
To amplify signals automatically
To inhibit all other genes
Explanation - Control genes provide baseline expression to normalize the activity of other genes in the circuit.
Correct answer is: To serve as a reference for expression levels
Q.16 Which of these is an example of a 'stochastic differential equation' used in modeling biological noise?
dx/dt = -x
dx/dt = -x + η(t)
dx/dt = x^2
dx/dt = 0
Explanation - The term η(t) represents a random noise component, turning the ODE into a stochastic differential equation.
Correct answer is: dx/dt = -x + η(t)
Q.17 What is the main advantage of using 'graph theory' in systems biology?
It allows modeling of electrical circuits only
It provides a framework to analyze interactions and network motifs
It is used exclusively for genome sequencing
It simplifies proteins to single nodes
Explanation - Graph theory represents biological components as nodes and interactions as edges, revealing structural properties.
Correct answer is: It provides a framework to analyze interactions and network motifs
Q.18 Which of the following best describes 'flux balance analysis' (FBA)?
An approach to simulate the electrical potential across cell membranes
A method to predict metabolic fluxes under steady‑state conditions
A technique for visualizing DNA double helices
A way to measure protein concentration in vivo
Explanation - FBA uses linear programming to estimate flux distributions that maximize growth or other objectives.
Correct answer is: A method to predict metabolic fluxes under steady‑state conditions
Q.19 What is the 'central dogma' of molecular biology?
DNA → RNA → Protein
Protein → RNA → DNA
RNA → DNA → Protein
Protein → DNA → RNA
Explanation - The central dogma describes the flow of genetic information from DNA to RNA to protein.
Correct answer is: DNA → RNA → Protein
Q.20 Which of these best describes 'epigenetics'?
Changes in DNA sequence that alter gene function
Modifications to DNA or histones that affect gene expression without changing sequence
The study of ancient genomes
The process of DNA replication during cell division
Explanation - Epigenetic marks can turn genes on or off in response to environmental cues.
Correct answer is: Modifications to DNA or histones that affect gene expression without changing sequence
Q.21 What does 'RNA‑seq' measure?
Protein‑protein interactions
The quantity of RNA transcripts in a sample
DNA methylation levels
Metabolite concentrations
Explanation - RNA‑seq uses high‑throughput sequencing to quantify transcript abundance across the genome.
Correct answer is: The quantity of RNA transcripts in a sample
Q.22 Which of the following best exemplifies a 'synthetic gene circuit'?
A naturally occurring operon in bacteria
A designed set of genes that produce a light‑responsive output
A viral genome used for vaccines
A ribosome assembly line
Explanation - Synthetic gene circuits are engineered to respond to inputs with predictable outputs, such as fluorescence.
Correct answer is: A designed set of genes that produce a light‑responsive output
Q.23 In a Boolean gene network, if gene A is active only when gene B is inactive, what type of regulation is this?
Positive regulation
Negative regulation
Co‑activation
Co‑repression
Explanation - When the activity of one gene suppresses another, it is negative regulation.
Correct answer is: Negative regulation
Q.24 Which term refers to the small, non‑coding RNAs that regulate gene expression by binding messenger RNA?
tRNA
siRNA
rRNA
mRNA
Explanation - Small interfering RNAs (siRNAs) guide the RNA‑induced silencing complex to degrade target mRNAs.
Correct answer is: siRNA
Q.25 In systems biology, what does a 'state variable' represent?
A constant parameter in a model
The current value of a dynamic component, such as metabolite concentration
The initial condition of the system
A measure of noise intensity
Explanation - State variables capture the system’s current condition, changing over time as dictated by equations.
Correct answer is: The current value of a dynamic component, such as metabolite concentration
Q.26 Which of the following is NOT typically considered part of the central dogma?
DNA replication
Transcription
Translation
RNA‑editing
Explanation - The central dogma focuses on the flow from DNA to RNA to protein; DNA replication is separate.
Correct answer is: DNA replication
Q.27 What is a 'transcription factor'?
An enzyme that cuts DNA
A protein that binds DNA to regulate transcription
A small RNA molecule
A lipid that stabilizes membranes
Explanation - Transcription factors bind specific DNA sequences, influencing the initiation of transcription.
Correct answer is: A protein that binds DNA to regulate transcription
Q.28 Which mathematical tool is used to find the steady‑state solutions of a system of ODEs?
Fourier analysis
Setting the derivatives to zero and solving the algebraic equations
Eigenvalue decomposition only
Monte Carlo simulation
Explanation - Steady‑state occurs when dX/dt = 0 for all variables; solving these equations yields constant values.
Correct answer is: Setting the derivatives to zero and solving the algebraic equations
Q.29 Which of the following best represents a 'feed‑forward loop' in gene networks?
Gene A regulates Gene B, and Gene B regulates Gene A
Gene A activates Gene B and also directly activates Gene C
Gene A inhibits Gene B, which in turn inhibits Gene C
Gene A directly controls the cell cycle
Explanation - A feed‑forward loop occurs when an upstream regulator influences a downstream target both directly and indirectly via an intermediate.
Correct answer is: Gene A activates Gene B and also directly activates Gene C
Q.30 Which of the following best describes 'gene knockout'?
Overexpressing a gene to increase its activity
Deleting or disabling a gene to study its function
Sequencing the gene's mRNA
Adding a new gene into the genome
Explanation - Knockout experiments remove a gene to observe resulting phenotypic changes, revealing its role.
Correct answer is: Deleting or disabling a gene to study its function
Q.31 What is the main purpose of a 'time‑delay' element in a biological control system?
To provide a quick response to stimuli
To introduce a lag that can stabilize oscillations
To increase the amplitude of output signals
To eliminate noise completely
Explanation - Delays can create oscillatory dynamics and help a system avoid runaway behavior.
Correct answer is: To introduce a lag that can stabilize oscillations
Q.32 Which of these best captures the concept of 'systems pharmacology'?
Studying drugs only on isolated proteins
Integrating drug action into network models to predict side effects
Testing drugs in animal models only
Focusing on single‑target drug design
Explanation - Systems pharmacology uses network analysis to understand drug effects on complex biological systems.
Correct answer is: Integrating drug action into network models to predict side effects
Q.33 In electrophysiology, what does a 'patch clamp' record?
Protein–protein interactions
Ion currents across a single cell membrane patch
Metabolic fluxes
Gene expression levels
Explanation - The patch clamp technique measures electrical currents through individual ion channels.
Correct answer is: Ion currents across a single cell membrane patch
Q.34 Which of the following is a key difference between a 'static' and a 'dynamic' gene regulatory network model?
Static models assume constant parameter values, dynamic models allow time‑dependent changes
Static models are always linear; dynamic models are non‑linear
Static models include noise; dynamic models do not
Dynamic models cannot be simulated computationally
Explanation - Dynamic models capture how network states evolve over time, whereas static models analyze fixed points or patterns.
Correct answer is: Static models assume constant parameter values, dynamic models allow time‑dependent changes
Q.35 What does 'CRISPR‑Cas9' primarily enable in genome editing?
Random mutation of DNA
Targeted cutting of specific DNA sequences
Amplification of DNA fragments
Sequencing of genomes
Explanation - CRISPR‑Cas9 uses guide RNA to direct the Cas9 enzyme to a precise genomic location for cleavage.
Correct answer is: Targeted cutting of specific DNA sequences
Q.36 Which of the following best describes a 'metabolic switch'?
A change in environmental pH
A genetic mutation that disables an enzyme
An enzyme that regulates the flow between metabolic pathways depending on substrate availability
A type of DNA replication mechanism
Explanation - Metabolic switches divert fluxes between pathways to adapt to changing conditions.
Correct answer is: An enzyme that regulates the flow between metabolic pathways depending on substrate availability
Q.37 What is the purpose of 'parameter estimation' in systems biology models?
To choose the initial state of a system
To infer unknown numerical values that best fit experimental data
To determine the number of genes in an organism
To visualize network diagrams
Explanation - Parameter estimation calibrates model variables like reaction rates to match observed dynamics.
Correct answer is: To infer unknown numerical values that best fit experimental data
Q.38 Which of the following describes a 'bifurcation' in a biological system?
A point where a single output splits into multiple inputs
A change in system behavior due to variation of a parameter, leading to qualitative differences
The division of a cell into two daughter cells
The duplication of a chromosome during replication
Explanation - Bifurcations occur when small parameter changes produce new steady states or oscillations.
Correct answer is: A change in system behavior due to variation of a parameter, leading to qualitative differences
Q.39 What does the 'Hill coefficient' indicate in ligand‑binding kinetics?
The number of ligands that bind to a receptor
The cooperativity of ligand binding
The rate of ligand degradation
The size of the ligand
Explanation - A Hill coefficient >1 indicates positive cooperativity; <1 indicates negative cooperativity.
Correct answer is: The cooperativity of ligand binding
Q.40 Which of the following best explains 'cross‑validation' in bioinformatics?
Splitting data to train and test models to avoid overfitting
Validating the physical integrity of DNA samples
Confirming gene expression levels with two methods
Ensuring cross‑linking in protein interactions
Explanation - Cross‑validation partitions data to assess model generalizability.
Correct answer is: Splitting data to train and test models to avoid overfitting
Q.41 In a gene network, what is an 'oscillator'?
A gene that only expresses once per cell cycle
A system that produces rhythmic oscillations in gene expression
A mechanism that permanently shuts down gene activity
A protein that binds DNA repeatedly
Explanation - Oscillators generate periodic outputs, such as the circadian clock.
Correct answer is: A system that produces rhythmic oscillations in gene expression
Q.42 Which of these is a commonly used 'control' in a genetic circuit to produce a switch‑like response?
Positive feedback loop
Negative feedback loop
Random noise injection
Signal degradation
Explanation - Positive feedback can create bistability, enabling a genetic switch.
Correct answer is: Positive feedback loop
Q.43 What role does a 'kinetic rate constant' play in modeling a biochemical reaction?
It determines the direction of diffusion
It quantifies the speed at which reactants convert to products
It is unrelated to reaction speed
It defines the final concentration of products
Explanation - Rate constants are parameters in kinetic equations that control reaction rates.
Correct answer is: It quantifies the speed at which reactants convert to products
Q.44 Which of the following best describes 'systems resilience' in biology?
The ability of a system to recover from perturbations
The resistance of a system to any change
The speed of cell division
The robustness of a gene’s sequence
Explanation - Resilience refers to how a system returns to a stable state after disruption.
Correct answer is: The ability of a system to recover from perturbations
Q.45 What is a 'signal transduction cascade'?
A series of sequential chemical reactions that propagate a signal inside a cell
A chain of proteins that transport electrons across membranes
A method to sequence DNA strands
A technique for measuring gene expression noise
Explanation - Cascades amplify and modulate signals through a network of enzymes and intermediates.
Correct answer is: A series of sequential chemical reactions that propagate a signal inside a cell
Q.46 Which of the following best describes a 'linear programming' approach in FBA?
Maximizing a linear objective subject to linear constraints
Minimizing the number of reactions in a pathway
Simulating stochastic fluctuations
Determining the kinetic parameters of enzymes
Explanation - FBA uses linear programming to find optimal flux distributions that satisfy stoichiometric constraints.
Correct answer is: Maximizing a linear objective subject to linear constraints
Q.47 Which of the following best defines 'homeostasis' in biological systems?
The ability to maintain a constant internal environment
The process of DNA replication
The breakdown of proteins into amino acids
The synthesis of RNA from DNA
Explanation - Homeostasis ensures stable physiological conditions despite external changes.
Correct answer is: The ability to maintain a constant internal environment
Q.48 In a Boolean gene network, what does the expression 'A AND B' imply?
Gene A is expressed if either A or B is expressed
Gene A is expressed if both A and B are expressed
Gene A is repressed when B is active
Gene B is activated regardless of A
Explanation - The AND logical operator requires both operands to be true for the output to be true.
Correct answer is: Gene A is expressed if both A and B are expressed
Q.49 Which of the following is NOT a typical step in next‑generation sequencing data analysis?
Base calling
Read alignment
Protein folding prediction
Variant calling
Explanation - Protein folding prediction is a separate computational biology task, not part of sequencing pipeline.
Correct answer is: Protein folding prediction
Q.50 What is the main benefit of using 'deep learning' for gene expression prediction?
It always uses fewer parameters
It can capture complex nonlinear relationships in large datasets
It requires no training data
It is limited to linear relationships only
Explanation - Deep learning models learn hierarchical representations that can model intricate gene expression patterns.
Correct answer is: It can capture complex nonlinear relationships in large datasets
Q.51 In the context of systems biology, what does 'model reduction' aim to achieve?
Add more variables to improve accuracy
Simplify models while preserving essential dynamics
Increase computational cost
Eliminate all noise from data
Explanation - Model reduction reduces complexity to make analysis tractable without losing critical behavior.
Correct answer is: Simplify models while preserving essential dynamics
Q.52 Which of these is a characteristic of a 'stochastic model' in biology?
Deterministic equations with fixed outcomes
Inclusion of random variables to capture noise
No parameters involved
Only linear interactions
Explanation - Stochastic models incorporate randomness to reflect inherent biological variability.
Correct answer is: Inclusion of random variables to capture noise
Q.53 Which of the following best describes a 'circuit' in synthetic biology?
A set of genes arranged to produce a desired output, analogous to an electronic circuit
A protein that forms a ring
An electronic device used in the lab
A type of DNA sequencing platform
Explanation - Biological circuits function like electronic circuits, with inputs, processing units, and outputs.
Correct answer is: A set of genes arranged to produce a desired output, analogous to an electronic circuit
Q.54 What is the purpose of 'normalization' in RNA‑seq data?
To remove all biological variation
To adjust for sequencing depth and technical biases
To sequence the genome faster
To convert RNA to DNA
Explanation - Normalization ensures that read counts are comparable across samples by correcting for library size differences.
Correct answer is: To adjust for sequencing depth and technical biases
Q.55 Which of the following best exemplifies a 'feedback inhibition' loop?
A product of a pathway activates the first enzyme of that pathway
A product of a pathway inhibits the last enzyme of that pathway
A product of a pathway activates a different pathway
A product of a pathway is degraded by a protease
Explanation - Feedback inhibition reduces pathway flux when end‑product concentration rises.
Correct answer is: A product of a pathway inhibits the last enzyme of that pathway
Q.56 Which term refers to a network that maps protein–protein interactions?
Interaction map
Gene regulatory network
Metabolic network
Protein interaction network
Explanation - Protein interaction networks show how proteins physically associate with each other.
Correct answer is: Protein interaction network
Q.57 What is a 'time‑series analysis' used for in genomics?
Analyzing static gene expression levels
Studying how gene expression changes over time under various conditions
Determining the physical structure of DNA
Identifying DNA mutations only
Explanation - Time‑series data reveals dynamic regulatory patterns and responses to stimuli.
Correct answer is: Studying how gene expression changes over time under various conditions
Q.58 Which of the following is an example of a 'biosensor'?
A device that detects light intensity
A genetically engineered cell that emits fluorescence in response to a metabolite
A mass spectrometer
A microscope objective lens
Explanation - Biosensors convert biological signals into measurable outputs like fluorescence.
Correct answer is: A genetically engineered cell that emits fluorescence in response to a metabolite
Q.59 Which of these best describes 'parameter identifiability'?
The ability to uniquely determine parameter values from experimental data
The ability to change parameters arbitrarily
The lack of any influence of parameters on the model
The process of measuring gene expression levels
Explanation - Identifiability ensures that model parameters can be estimated reliably.
Correct answer is: The ability to uniquely determine parameter values from experimental data
Q.60 In a genetic toggle switch, what is the role of the 'repressors'?
They activate gene expression
They inhibit gene expression to create bistability
They degrade mRNA
They produce fluorescent proteins
Explanation - Repressors bind to promoters, preventing transcription and allowing two stable states.
Correct answer is: They inhibit gene expression to create bistability
Q.61 Which of the following best describes a 'gene‑drive' system?
A system that speeds up DNA replication
A genetic element that biases inheritance to spread through a population
A method to drive electrons across membranes
A type of computer algorithm for DNA sequencing
Explanation - Gene drives manipulate inheritance patterns to propagate desired genes.
Correct answer is: A genetic element that biases inheritance to spread through a population
Q.62 What does 'entropy' measure in a biological data set?
The amount of disorder or randomness in the data
The average gene length
The number of proteins expressed
The stability of a protein structure
Explanation - Entropy quantifies uncertainty; higher entropy indicates more variability.
Correct answer is: The amount of disorder or randomness in the data
Q.63 Which of the following describes a 'synthetic promoter'?
A naturally occurring promoter
A designer DNA sequence engineered to have specific expression characteristics
A promoter that cannot bind transcription factors
A promoter that is only active in prokaryotes
Explanation - Synthetic promoters allow precise control over gene expression levels and timing.
Correct answer is: A designer DNA sequence engineered to have specific expression characteristics
Q.64 What is the main idea behind 'multi‑omics integration'?
Using one type of omics data exclusively
Combining diverse omics datasets (genomics, proteomics, metabolomics) to gain holistic insights
Sequencing DNA at higher depth
Ignoring protein data in favor of RNA data
Explanation - Multi‑omics provides complementary perspectives on biological systems.
Correct answer is: Combining diverse omics datasets (genomics, proteomics, metabolomics) to gain holistic insights
Q.65 Which of the following best describes 'synthetic lethality' in cancer therapy?
A gene knockout that is lethal in isolation
A combination of two non‑lethal gene perturbations that together kill a cancer cell
A mutation that increases cell viability
A technique to make cells more resilient
Explanation - Targeting synthetic lethal pairs can selectively kill cancer cells while sparing normal cells.
Correct answer is: A combination of two non‑lethal gene perturbations that together kill a cancer cell
Q.66 Which mathematical concept is often used to analyze the stability of fixed points in dynamic systems?
Eigenvalue analysis of the Jacobian matrix
Fourier transform
Histogram plotting
Linear interpolation
Explanation - Eigenvalues determine whether perturbations grow or decay around a steady state.
Correct answer is: Eigenvalue analysis of the Jacobian matrix
Q.67 In a Boolean model, what does a 'stable motif' represent?
A transient state that quickly decays
A subset of nodes whose states are self‑sustaining under network dynamics
A motif that appears only once
A motif that cannot be perturbed
Explanation - Stable motifs are attractors that maintain a particular pattern of activity.
Correct answer is: A subset of nodes whose states are self‑sustaining under network dynamics
Q.68 What does 'phasing' refer to in genomics?
Aligning reads to a reference genome
Determining which alleles are on the same chromosome copy
Measuring gene expression levels
Sequencing only one strand of DNA
Explanation - Phasing resolves the haplotype structure of an individual’s genome.
Correct answer is: Determining which alleles are on the same chromosome copy
Q.69 Which of the following best captures the concept of a 'signal‑to‑noise ratio (SNR)' in bioinformatics?
The ratio of signal intensity to background noise in a measurement
The number of genes expressed in a cell
The ratio of DNA to RNA in a sample
The speed of data transfer in sequencing machines
Explanation - High SNR means the true signal stands out clearly from random noise.
Correct answer is: The ratio of signal intensity to background noise in a measurement
Q.70 What is 'horizontal gene transfer'?
Genes transferred between species rather than inherited vertically
Genes transmitted from parent to offspring
Genes duplicated within the same genome
Genes that encode horizontal muscles
Explanation - Horizontal gene transfer spreads genetic material across organisms, contributing to evolution.
Correct answer is: Genes transferred between species rather than inherited vertically
Q.71 Which of the following best describes a 'phosphorelay' system?
A signal transduction system involving sequential phosphorylation events
A mechanism that transfers photons across membranes
A type of gene duplication
An enzyme that dephosphorylates proteins
Explanation - Phosphorelays propagate signals through a cascade of phosphorylation and dephosphorylation.
Correct answer is: A signal transduction system involving sequential phosphorylation events
Q.72 In the context of metabolic engineering, what is a 'flux balance'?
The equilibrium between input and output metabolites in a pathway
The average speed of all metabolic reactions
The rate of gene transcription
The balance of light absorption in photosynthesis
Explanation - Flux balance refers to the steady‑state condition where production and consumption of metabolites are equal.
Correct answer is: The equilibrium between input and output metabolites in a pathway
Q.73 Which of the following best illustrates a 'multi‑state switch' in synthetic biology?
A system that can occupy more than two distinct stable states
A system that toggles between on and off only
A simple oscillator
A gene that is always expressed
Explanation - Multi‑state switches can encode more complex logic by having multiple stable outputs.
Correct answer is: A system that can occupy more than two distinct stable states
Q.74 What does the term 'allele frequency' describe?
The number of alleles in a gene pool
The proportion of a particular allele among all alleles of that gene in a population
The size of an allele in base pairs
The speed at which alleles mutate
Explanation - Allele frequency quantifies how common an allele is within a population.
Correct answer is: The proportion of a particular allele among all alleles of that gene in a population
Q.75 In a metabolic network, what is a 'bottleneck enzyme'?
An enzyme that catalyzes many reactions simultaneously
An enzyme that controls a critical pathway step and limits the overall flux
An enzyme that is not expressed in any tissue
An enzyme that degrades all metabolites
Explanation - Bottleneck enzymes are rate‑limiting steps; their activity determines pathway throughput.
Correct answer is: An enzyme that controls a critical pathway step and limits the overall flux
Q.76 Which of these best describes 'RNA‑based therapeutics'?
Therapies that use DNA to treat diseases
Treatments employing small RNAs or mRNAs to modulate gene expression
Vaccines that are purely protein‑based
Therapies that rely on electrical stimulation of cells
Explanation - RNA‑based drugs like siRNA and mRNA vaccines alter gene expression without modifying DNA.
Correct answer is: Treatments employing small RNAs or mRNAs to modulate gene expression
Q.77 What is 'allelic dropout' in single‑cell sequencing?
Loss of an allele during DNA replication
Failure to amplify one allele from a heterozygous locus, leading to apparent homozygosity
Deletion of an allele in the genome
The natural loss of alleles over evolutionary time
Explanation - Allelic dropout arises from stochastic amplification inefficiencies in single‑cell protocols.
Correct answer is: Failure to amplify one allele from a heterozygous locus, leading to apparent homozygosity
Q.78 Which of the following best describes a 'gene cluster'?
A set of genes that encode unrelated proteins
Adjacent genes in a genome that are co‑expressed and often share regulatory mechanisms
A single gene duplicated many times
Genes that are located on different chromosomes
Explanation - Gene clusters often encode proteins in a shared metabolic pathway.
Correct answer is: Adjacent genes in a genome that are co‑expressed and often share regulatory mechanisms
Q.79 In the context of CRISPR‑Cas systems, what does 'off‑target effect' refer to?
The desired gene editing outcome
Unintended cleavage or modification at genomic sites other than the target
The activation of Cas9 protein
The delivery of CRISPR components into cells
Explanation - Off‑target effects can lead to unwanted mutations, compromising safety.
Correct answer is: Unintended cleavage or modification at genomic sites other than the target
Q.80 What is a 'steady state' in a biochemical network?
When all concentrations are zero
When the concentration of each species remains constant over time
When the network oscillates infinitely
When the network is in equilibrium with its environment
Explanation - In steady state, production and consumption rates are balanced, keeping concentrations unchanged.
Correct answer is: When the concentration of each species remains constant over time
Q.81 Which of the following best captures the idea of 'network modularity'?
The degree to which a network can be divided into relatively independent subunits
The overall size of a network
The number of edges in a network
The average path length in a network
Explanation - Modularity allows functional compartmentalization and robustness.
Correct answer is: The degree to which a network can be divided into relatively independent subunits
Q.82 What does 'dynamic range' refer to in the context of biosensors?
The maximum number of molecules a sensor can detect
The difference between the lowest and highest signal a sensor can measure reliably
The time it takes for a sensor to respond
The size of the sensor device
Explanation - A larger dynamic range allows accurate detection across a broader concentration spectrum.
Correct answer is: The difference between the lowest and highest signal a sensor can measure reliably
Q.83 Which of these is NOT a typical component of a genetic circuit?
Promoter
RBS (ribosome binding site)
Transcription factor
Cytoskeleton
Explanation - Genetic circuits involve DNA regulatory elements, not cellular structural components like the cytoskeleton.
Correct answer is: Cytoskeleton
Q.84 What is the main purpose of 'differential expression analysis'?
To find genes that have the same expression level across all conditions
To identify genes whose expression levels differ significantly between conditions
To measure protein folding kinetics
To sequence DNA fragments
Explanation - Differential expression highlights genes that respond to experimental perturbations.
Correct answer is: To identify genes whose expression levels differ significantly between conditions
Q.85 Which of the following best describes an 'enzyme kinetic parameter' K_m?
The maximum velocity of an enzyme
The substrate concentration at which the reaction rate is half of V_max
The activation energy of a reaction
The enzyme's molecular weight
Explanation - K_m indicates the affinity of an enzyme for its substrate.
Correct answer is: The substrate concentration at which the reaction rate is half of V_max
Q.86 Which of these best characterizes a 'feed‑forward loop' in a gene regulatory network?
A gene regulating itself indirectly through an intermediate
A gene that both activates and represses another gene simultaneously
A gene that regulates two downstream targets, one of which also regulates the second target
A loop where a gene is only regulated by itself
Explanation - This structure can create filtering or pulse‑generation behavior.
Correct answer is: A gene that regulates two downstream targets, one of which also regulates the second target
Q.87 Which of the following describes a 'negative feedback loop' in a cellular pathway?
A pathway that amplifies its own signal
A pathway where the final product inhibits an upstream component
A pathway that has no regulatory mechanisms
A pathway that only operates during development
Explanation - Negative feedback reduces output when product concentration is high, maintaining balance.
Correct answer is: A pathway where the final product inhibits an upstream component
Q.88 In systems biology, what does a 'steady‑state flux vector' represent?
The direction of energy flow in a cell
The set of all reaction rates that satisfy steady‑state constraints
The concentration of metabolites at equilibrium
The list of genes expressed in a tissue
Explanation - A flux vector details the rate at which each reaction proceeds in steady state.
Correct answer is: The set of all reaction rates that satisfy steady‑state constraints
Q.89 Which of the following best describes the 'central dogma' of molecular biology?
DNA → RNA → Protein
Protein → RNA → DNA
RNA → Protein → DNA
DNA → Protein → RNA
Explanation - This flow of genetic information is the foundational concept of molecular biology.
Correct answer is: DNA → RNA → Protein
Q.90 What is the primary function of a 'transcription factor'?
To cleave DNA strands during replication
To bind DNA and regulate transcription initiation
To synthesize RNA polymerase
To degrade mRNA molecules
Explanation - Transcription factors bind specific DNA sequences to activate or repress gene transcription.
Correct answer is: To bind DNA and regulate transcription initiation
Q.91 Which technique is used to determine the sequence of nucleotides in a DNA fragment?
PCR
Western blot
Sanger sequencing
Electron microscopy
Explanation - Sanger sequencing uses chain‑terminating dideoxynucleotides to read DNA sequences.
Correct answer is: Sanger sequencing
Q.92 What does 'gene expression' refer to?
The process of transcribing DNA into RNA and translating RNA into protein
The mutation rate of a gene
The number of times a gene is present in the genome
The physical shape of a gene on a chromosome
Explanation - Gene expression encompasses transcription and translation to produce functional proteins.
Correct answer is: The process of transcribing DNA into RNA and translating RNA into protein
Q.93 Which of the following best describes 'epigenetics'?
Changes in the DNA sequence itself
Chemical modifications to DNA or histone proteins that affect gene activity without altering the sequence
The study of ancient genomes
The replication of DNA during cell division
Explanation - Epigenetic marks such as methylation control gene expression without changing the DNA code.
Correct answer is: Chemical modifications to DNA or histone proteins that affect gene activity without altering the sequence
Q.94 Which of the following best describes a 'microRNA'?
A large coding RNA molecule
A small non‑coding RNA that regulates gene expression by binding to mRNA
An enzyme that cuts DNA
A type of DNA polymerase
Explanation - MicroRNAs typically bind to complementary sites on mRNA, inhibiting translation or promoting degradation.
Correct answer is: A small non‑coding RNA that regulates gene expression by binding to mRNA
Q.95 Which of these is an example of a 'gene knockout' experiment?
Overexpressing a gene to increase its activity
Deleting a gene so it is no longer expressed
Inserting a fluorescent marker into a gene
Measuring mRNA levels by qPCR
Explanation - Gene knockouts involve removing or disabling a gene to study its function.
Correct answer is: Deleting a gene so it is no longer expressed
Q.96 What is 'RNA‑seq' used for?
Sequencing DNA genomes
Quantifying RNA molecules in a sample
Measuring protein concentrations
Analyzing lipid composition
Explanation - RNA‑seq measures transcript abundance by sequencing RNA fragments.
Correct answer is: Quantifying RNA molecules in a sample
Q.97 Which of the following best describes a 'feedback loop' in biology?
A linear pathway with no regulatory elements
A situation where the output of a process influences its own input
A one‑way signal transmission
A mechanism that only occurs during development
Explanation - Feedback loops can be positive or negative, regulating processes like hormone secretion.
Correct answer is: A situation where the output of a process influences its own input
Q.98 Which of these best describes a 'metabolic pathway'?
A series of enzymes that convert a substrate into a product through a chain of reactions
A chain of genes located on the same chromosome
The sequence of events in DNA replication
The process of protein folding
Explanation - Metabolic pathways involve coordinated enzymatic steps to produce or consume metabolites.
Correct answer is: A series of enzymes that convert a substrate into a product through a chain of reactions
Q.99 What is 'gene regulation'?
The process of deleting genes from a genome
The control of when and how much a gene is expressed
The replication of DNA during cell division
The synthesis of proteins from RNA
Explanation - Gene regulation involves mechanisms that adjust transcription levels in response to signals.
Correct answer is: The control of when and how much a gene is expressed
Q.100 Which of the following is a key step in DNA sequencing?
Amplification of DNA fragments
Translation of RNA into protein
Degradation of DNA
Attachment of proteins to DNA
Explanation - PCR amplifies DNA fragments to generate enough material for sequencing.
Correct answer is: Amplification of DNA fragments
Q.101 Which of these describes a 'gene cluster'?
A single gene duplicated many times
A set of adjacent genes that are co‑expressed or functionally related
A group of genes located on different chromosomes
A gene that encodes multiple proteins
Explanation - Gene clusters often encode components of the same pathway or complex.
Correct answer is: A set of adjacent genes that are co‑expressed or functionally related
Q.102 What is the purpose of a 'control gene' in gene expression experiments?
To regulate the expression of the gene of interest
To provide a baseline for comparison and correct for experimental variations
To act as a toxin
To sequence DNA fragments
Explanation - Control genes (often housekeeping genes) are assumed to have stable expression across conditions.
Correct answer is: To provide a baseline for comparison and correct for experimental variations
Q.103 Which of the following best illustrates a 'gene network'?
A group of proteins that physically interact
A set of genes connected by regulatory relationships
The sequence of nucleotides in DNA
A cluster of cells in a tissue
Explanation - Gene networks depict how genes influence each other's expression.
Correct answer is: A set of genes connected by regulatory relationships
Q.104 Which of the following describes a 'feedback inhibition' mechanism?
A product enhances the activity of an enzyme in its own pathway
A product inhibits an earlier enzyme in the same pathway to prevent over‑production
A product has no effect on its own pathway
A product is secreted to the environment
Explanation - Feedback inhibition prevents wasteful production by limiting enzyme activity when the end‑product accumulates.
Correct answer is: A product inhibits an earlier enzyme in the same pathway to prevent over‑production
Q.105 What is a 'Boolean gene network' used for?
Modeling gene regulation with binary on/off states
Sequencing the entire genome
Measuring protein concentrations
Analyzing metabolic fluxes
Explanation - Boolean networks simplify gene states to 0 (off) or 1 (on) for computational tractability.
Correct answer is: Modeling gene regulation with binary on/off states
Q.106 Which of the following best describes an 'enzyme kinetic parameter' K_m?
The maximum velocity of an enzyme-catalyzed reaction
The substrate concentration at which the reaction rate is half of V_max
The activation energy of the reaction
The enzyme's size in kilodaltons
Explanation - K_m reflects enzyme affinity for its substrate.
Correct answer is: The substrate concentration at which the reaction rate is half of V_max
Q.107 What is a 'synthetic gene circuit'?
A naturally occurring genetic network
A designed set of genes that interact to produce a predictable behavior
A random sequence of DNA
An unmodified promoter region
Explanation - Synthetic gene circuits are engineered to perform functions like toggles or oscillators.
Correct answer is: A designed set of genes that interact to produce a predictable behavior
Q.108 Which of the following best illustrates a 'feedback control system' in a biological context?
A cell producing a metabolite that inhibits its own synthesis pathway
A pathway that runs without regulation
A pathway that only operates during embryogenesis
A gene that is expressed only once per cell cycle
Explanation - The metabolite acts as a negative regulator, adjusting pathway activity.
Correct answer is: A cell producing a metabolite that inhibits its own synthesis pathway
Q.109 Which of the following best describes 'metabolic flux'?
The concentration of a metabolite in a cell
The rate at which metabolites are produced and consumed in a pathway
The size of an enzyme
The sequence of a metabolic gene
Explanation - Flux indicates how quickly metabolites move through a network.
Correct answer is: The rate at which metabolites are produced and consumed in a pathway
Q.110 Which of the following is a key component of the 'central dogma'?
Protein synthesis from RNA
RNA synthesis from DNA
Both A and B
Protein synthesis from DNA directly
Explanation - The central dogma includes transcription (DNA→RNA) and translation (RNA→protein).
Correct answer is: Both A and B
Q.111 What does 'gene expression analysis' typically involve?
Measuring DNA mutation rates
Quantifying RNA levels across conditions
Sequencing proteins
Identifying chromatin modifications
Explanation - Gene expression analysis assesses RNA abundance to infer functional activity.
Correct answer is: Quantifying RNA levels across conditions
Q.112 Which of the following best describes a 'promoter'?
A protein that degrades RNA
A DNA sequence where RNA polymerase binds to initiate transcription
An enzyme that synthesizes DNA
A lipid that anchors proteins to membranes
Explanation - Promoters are essential for starting gene transcription.
Correct answer is: A DNA sequence where RNA polymerase binds to initiate transcription
Q.113 What is a 'ribosome'?
An organelle that synthesizes proteins
A DNA segment that codes for enzymes
A type of cell wall
A lipid molecule
Explanation - Ribosomes translate mRNA into proteins.
Correct answer is: An organelle that synthesizes proteins
Q.114 Which of the following describes 'gene duplication'?
The creation of identical copies of a gene within a genome
The deletion of a gene
The mutation of a gene’s sequence
The regulation of gene expression by a repressor
Explanation - Gene duplication can lead to new gene functions through divergence.
Correct answer is: The creation of identical copies of a gene within a genome
Q.115 What is 'chromatin remodeling'?
Changing the sequence of DNA bases
Altering the structure of chromatin to regulate gene accessibility
Breaking down proteins
Transporting RNA across membranes
Explanation - Chromatin remodeling controls access to DNA for transcription and repair.
Correct answer is: Altering the structure of chromatin to regulate gene accessibility
Q.116 What does 'signal transduction' refer to?
The process of DNA replication
The conversion of a chemical or physical signal into a cellular response
The synthesis of proteins
The packaging of DNA into chromosomes
Explanation - Signal transduction cascades transduce extracellular cues into intracellular actions.
Correct answer is: The conversion of a chemical or physical signal into a cellular response
Q.117 Which of the following best describes a 'feedback inhibition' loop?
A product activates an upstream enzyme
A product inhibits an upstream enzyme to reduce its own synthesis
A product has no effect on its pathway
A product is secreted outside the cell
Explanation - Negative feedback ensures that production of the product is self‑regulated.
Correct answer is: A product inhibits an upstream enzyme to reduce its own synthesis
Q.118 Which of the following best illustrates a 'control system' in biology?
An enzyme that works independently of other molecules
A network where the output influences its own input to maintain homeostasis
A one‑way signal cascade
A pathway that only functions during development
Explanation - Control systems enable cells to adjust processes in response to internal and external cues.
Correct answer is: A network where the output influences its own input to maintain homeostasis
Q.119 Which of the following is an example of a 'synthetic biological circuit'?
A natural operon in bacteria
A designed set of genes that switch on a reporter only in the presence of a toxin
A ribosome that translates mRNA
A DNA polymerase that replicates DNA
Explanation - Synthetic circuits can be engineered to respond to specific stimuli with a desired output.
Correct answer is: A designed set of genes that switch on a reporter only in the presence of a toxin