IISER IAT flashcards

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

Central dogma

Genetic information flows from DNA to RNA by transcription and from RNA to protein by translation; retroviruses reverse this with reverse transcriptase making DNA from an RNA template.

Hardy–Weinberg equation

In an ideal population, allele frequencies p and q satisfy p² + 2pq + q² = 1, where p² and q² are homozygote frequencies and 2pq is the heterozygote frequency.

Competitive inhibition

An inhibitor resembling the substrate binds the enzyme active site reversibly, raising the apparent Km while leaving Vmax unchanged; excess substrate can outcompete the inhibitor.

Calvin cycle

Light-independent reactions in the chloroplast stroma where RuBisCO fixes CO2 onto ribulose bisphosphate, and ATP and NADPH from light reactions reduce the product to sugar.

Meiosis crossing over

Homologous chromosomes exchange segments during prophase I of meiosis, producing recombinant chromatids and increasing genetic variation among the four haploid products.

Fick's law of diffusion

The diffusion rate across a membrane is proportional to surface area and concentration gradient and inversely proportional to thickness, so thin, large, well-perfused surfaces exchange gases fastest.

Operon regulation

A cluster of genes transcribed together under one promoter; the lac operon is induced by lactose and repressed by glucose, while the trp operon is repressed by excess tryptophan.

Surface tension

The energy per unit area of a liquid surface arising from unbalanced intermolecular forces; it makes drops spherical and causes capillary rise in narrow tubes.

Gibbs free energy

ΔG = ΔH − TΔS determines spontaneity: negative ΔG means the process is spontaneous at that temperature, and at equilibrium ΔG equals zero.

Le Chatelier's principle

When a system at equilibrium is disturbed by changes in concentration, pressure, or temperature, it shifts in the direction that partially counteracts the disturbance.

Buffer capacity

The amount of acid or base a buffer can absorb before pH changes appreciably; it is greatest when the buffer pH equals the pKa of the weak acid.

First-order kinetics

Reaction rate depends on the first power of one reactant concentration; the half-life t½ = 0.693/k is constant and a plot of ln[A] versus time is linear.

Aromaticity rule

A planar, cyclic, fully conjugated molecule with 4n + 2 π electrons is aromatic; 4n π electrons make it antiaromatic, and non-planar rings are generally non-aromatic.

Electrochemical cell EMF

Cell potential E°cell = E°cathode − E°anode; a positive value indicates a spontaneous reaction, and ΔG° = −nFE°cell links potential to free energy.

Chirality

A molecule is chiral if it is non-superimposable on its mirror image, usually due to a carbon bearing four different groups; enantiomers rotate plane-polarized light oppositely.

L'Hôpital's rule

For a limit giving 0/0 or ∞/∞, differentiate numerator and denominator separately and take the limit of the resulting quotient, provided that limit exists.

Mean value theorem

If f is continuous on [a, b] and differentiable on (a, b), some c in (a, b) satisfies f'(c) = [f(b) − f(a)]/(b − a).

Integration by parts

The rule ∫u dv = uv − ∫v du reverses the product rule; choose u by the LIATE order to make the remaining integral simpler.

Bayes' theorem

P(A|B) = P(B|A)P(A)/P(B), which updates a prior probability of A using evidence B and the total probability of that evidence.

Binomial coefficient

C(n,k) = n!/[k!(n−k)!] counts k-element subsets of an n-element set and gives the coefficient of x^k y^(n−k) in the binomial expansion.

Determinant and singularity

A square matrix is invertible exactly when its determinant is nonzero; for 2×2 matrices ad − bc = 0 means rows are linearly dependent.

Cross product magnitude

For vectors a and b, |a × b| = |a||b| sin θ, equal to the area of the parallelogram they span; the result is perpendicular to both.

Convergence of geometric series

The infinite geometric series Σ arⁿ converges to a/(1 − r) when |r| < 1 and diverges when |r| ≥ 1.

Projectile range

For launch speed u at angle θ on level ground, range R = u² sin 2θ / g, which is maximum at 45° and equal for complementary angles.

Banking angle

On a frictionless banked curve, the angle satisfying tan θ = v²/(rg) provides exactly the centripetal force needed at speed v with radius r.

Elastic collision

A collision conserving both momentum and kinetic energy; for equal masses in one dimension, the bodies exchange velocities, and relative speed of approach equals separation.

Simple pendulum period

For small oscillations, T = 2π√(L/g), independent of mass and amplitude; the approximation fails as amplitude grows because the restoring force is not linear.

Total internal reflection

When light travels from a denser to a rarer medium beyond the critical angle sin θc = n₂/n₁, it is entirely reflected back into the denser medium.

Lens equation

1/f = 1/v − 1/u with the sign convention in use; a convex lens has positive focal length and forms a real image when the object lies beyond f.

Photoelectric effect

Light ejects electrons only above a threshold frequency; maximum kinetic energy equals hf − φ, where φ is the work function, supporting photon quantization.

Kirchhoff's rules

The junction rule states current into a node equals current out; the loop rule states the sum of potential changes around any closed circuit loop is zero.