GATE BM flashcards

33 cards. Read the term and the definition here. The deck at the top of this page is optional.

Michaelis constant Km

The substrate concentration at which an enzyme-catalyzed reaction proceeds at half its maximum velocity (Vmax/2). It indicates enzyme affinity: lower Km means higher affinity for substrate.

Competitive inhibition

An inhibitor binds reversibly to the enzyme active site, competing with substrate. It increases apparent Km but leaves Vmax unchanged; can be overcome by raising substrate concentration.

Polymerase chain reaction

In vitro DNA amplification using thermal cycling: denaturation, primer annealing, and extension by a thermostable DNA polymerase. Product doubles each cycle, giving exponential amplification.

Hybridoma technology

Fusion of an antibody-producing B cell with an immortal myeloma cell to create a hybridoma that secretes monoclonal antibodies indefinitely. Selection is done in HAT medium.

CRISPR-Cas9 mechanism

A guide RNA base-pairs with target DNA and directs the Cas9 nuclease to create a double-strand break. Repair by NHEJ causes knockouts; HDR with a template enables knock-ins.

Restriction enzyme Type II

Recognizes a specific palindromic DNA sequence and cleaves within or near it, producing sticky or blunt ends. Widely used in cloning because cleavage is sequence-specific and predictable.

BOD and ultimate BOD

Biochemical oxygen demand measures oxygen consumed by microbes decomposing organic matter. BOD_t = L0(1 − e^(−kt)), where L0 is ultimate BOD and k is the deoxygenation constant.

Effective stress principle

Total stress σ equals effective stress σ' plus pore water pressure u: σ' = σ − u. Effective stress controls soil strength, compressibility, and volume change in saturated soils.

Proctor compaction test

Laboratory test relating dry unit weight to moisture content for a given compactive effort. Yields maximum dry unit weight and optimum moisture content; higher effort raises maximum dry density.

Rational method runoff

Peak runoff Q = C i A, where C is runoff coefficient, i is rainfall intensity, and A is catchment area. Used for small urban catchments; assumes uniform rainfall and linear response.

Unit hydrograph

Direct runoff hydrograph resulting from one unit of effective rainfall uniformly distributed over a catchment in a specified duration. Assumes linearity and time invariance for superposition.

Master theorem

Solves recurrences T(n)=aT(n/b)+f(n) by comparing f(n) with n^(log_b a). If f(n)=Θ(n^(log_b a) log^k n), then T(n)=Θ(n^(log_b a) log^(k+1) n).

NP-complete problem

A decision problem in NP to which every NP problem reduces in polynomial time. If any NP-complete problem has a polynomial algorithm, then P = NP. SAT is the canonical example.

TCP three-way handshake

Connection setup: client sends SYN, server replies SYN-ACK, client sends ACK. Establishes sequence numbers and confirms both sides are ready before data transfer begins.

Deadlock conditions

Four necessary conditions: mutual exclusion, hold and wait, no preemption, and circular wait. Deadlock prevention breaks at least one; avoidance uses the Banker's algorithm.

Belady's anomaly

In FIFO page replacement, increasing the number of page frames can increase the number of page faults. LRU and optimal replacement do not exhibit this anomaly.

IEEE 754 single precision

32-bit floating-point format: 1 sign bit, 8 exponent bits with bias 127, and 23 fraction bits. Represents normalized numbers, denormals, infinity, and NaN with special exponent patterns.

Thevenin's theorem

Any linear two-terminal network can be replaced by an equivalent voltage source V_th in series with resistance R_th. V_th is open-circuit voltage; R_th is equivalent resistance with sources dead.

Induction motor slip

Slip s = (N_s − N_r)/N_s, where N_s is synchronous speed and N_r is rotor speed. Rotor frequency equals s times supply frequency; slip increases with load.

Symmetrical components

Unbalanced three-phase quantities decomposed into positive, negative, and zero sequence sets. Used for fault analysis; zero-sequence currents require a return path such as neutral or ground.

Per-unit system

Normalizes electrical quantities by base values: per-unit = actual/base. Base impedance Z_base = V_base^2/S_base. Simplifies transformer and power system calculations across voltage levels.

Second-order overshoot

Percent overshoot = 100 e^(−ζπ/√(1−ζ^2)), where ζ is damping ratio. Settling time for a 2% band is approximately 4/(ζω_n).

Carnot efficiency

Maximum theoretical efficiency of a heat engine operating between hot and cold reservoirs: η = 1 − T_L/T_H, with absolute temperatures. No real engine exceeds this limit.

Euler buckling load

Critical axial load for an ideal slender column: P_cr = π^2 EI/(KL)^2, where K depends on end conditions. Buckling occurs before yielding for long columns.

Taylor's tool life equation

V T^n = C, where V is cutting speed, T is tool life, n is a tool-material exponent, and C is a constant. Higher cutting speed shortens tool life.

Chvorinov's rule

Solidification time t = B (V/A)^2, where V is volume, A is surface area, and B is a mold constant. Riser design uses the modulus M = V/A to ensure feeding.

Rankine cycle pump work

For a liquid pump, specific work ≈ v_f (p_2 − p_1), where v_f is saturated liquid specific volume. Small compared with turbine work in a steam power plant.

Break-even point

Sales volume at which total revenue equals total cost: Fixed cost / (Selling price − Variable cost per unit). Contribution margin per unit drives the calculation.

WACC formula

Weighted average cost of capital = (E/V) R_e + (D/V) R_d (1 − T), where E is equity, D is debt, V = E + D, and T is tax rate. Interest tax shield lowers debt cost.

NPV decision rule

Net present value = Σ CF_t/(1+r)^t − initial outlay. Accept independent projects with NPV > 0; for mutually exclusive projects, choose the highest positive NPV.

Accounting equation

Assets = Liabilities + Equity. Every transaction preserves this balance through double-entry bookkeeping, with equal debits and credits recorded.

Price elasticity of demand

Percentage change in quantity demanded divided by percentage change in price. Demand is elastic if absolute value exceeds 1, inelastic if below 1, and unit elastic if equal to 1.

Modus tollens

A valid argument form: if P implies Q, and Q is false, then P is false. Denying the consequent is valid, unlike affirming the consequent, which is a fallacy.