MBBS/BDS Admission flashcards

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

Newton's second law

The net force on a body equals its mass times acceleration, F = ma. Acceleration points in the direction of the net force and is inversely proportional to mass.

Projectile range formula

For launch speed u at angle θ on level ground, horizontal range is R = u² sin 2θ / g. The range is maximum at 45 degrees.

Centripetal acceleration

A body moving in a circle of radius r at speed v has acceleration v²/r directed toward the centre. This requires a net inward force, such as tension or gravity.

Work-energy theorem

The net work done on an object equals its change in kinetic energy. Work by conservative forces can be stored as potential energy, such as ½kx² in a spring.

Conservation of momentum

In an isolated system, total momentum remains constant in all collisions. Kinetic energy is conserved only in perfectly elastic collisions, not in inelastic ones.

Pendulum period

For small swings, a simple pendulum has period T = 2π√(L/g), independent of mass and amplitude. A spring-mass system instead has T = 2π√(m/k).

Ohm's law and power

Current through a conductor equals voltage divided by resistance, I = V/R. Electrical power dissipated is P = VI, also written as I²R or V²/R.

Snell's law

At an interface, n₁ sin θ₁ = n₂ sin θ₂, where n is refractive index and θ is measured from the normal. Light bends toward the normal entering a denser medium.

Photoelectric equation

Light of frequency f ejects electrons only above a threshold frequency, where hf₀ = φ. Maximum kinetic energy of emitted electrons is hf − φ.

Mole concept

One mole contains 6.022×10²³ particles, the Avogadro constant. It equals the formula mass in grams, and one mole of gas occupies 22.4 L at STP.

Molarity

Molarity is the number of moles of solute per litre of solution. It changes with temperature because solution volume expands or contracts.

Ideal gas law

PV = nRT relates pressure, volume, moles and absolute temperature, with R the gas constant. It assumes negligible molecular volume and no intermolecular forces.

Quantum numbers

Four quantum numbers describe an electron: n (shell), l (subshell shape), m_l (orientation) and m_s (spin). A shell n holds at most 2n² electrons.

Periodic trends

Atomic radius decreases left to right across a period and increases down a group. Ionisation energy and electronegativity increase across a period and decrease down a group.

VSEPR theory

Electron pairs around a central atom repel and arrange as far apart as possible, setting molecular shape. Lone pairs repel more strongly than bonding pairs, compressing bond angles.

pH definition

pH equals the negative logarithm of hydrogen ion concentration. A pH below 7 is acidic, 7 is neutral at 25 °C, and above 7 is basic.

Le Chatelier's principle

A system at equilibrium shifts to oppose any imposed change. Raising temperature favours the endothermic direction; raising pressure favours the side with fewer gas moles.

Gibbs free energy

ΔG = ΔH − TΔS determines spontaneity. A negative ΔG means the reaction is spontaneous; at equilibrium ΔG equals zero, giving T = ΔH/ΔS.

Functional group priority

In IUPAC naming, the principal functional group takes the lowest locant and the suffix. Priority order runs carboxylic acid, then aldehyde, ketone, alcohol, amine, alkene.

Photosynthesis equation

Six carbon dioxide molecules and six water molecules yield one glucose and six oxygen molecules using light energy. Light reactions occur in thylakoids; the Calvin cycle occurs in stroma.

Glycolysis

Glycolysis splits one glucose into two pyruvate molecules in the cytoplasm, producing a net two ATP and two NADH. It requires no oxygen and occurs in nearly all cells.

Xylem versus phloem

Xylem transports water and dissolved minerals upward from roots, driven by transpiration pull. Phloem translocates sugars bidirectionally between sources and sinks by pressure flow.

Plant hormones

Auxin promotes cell elongation and phototropism. Gibberellin promotes stem elongation and seed germination, while abscisic acid closes stomata and enforces dormancy.

Monohybrid cross ratio

Crossing two heterozygotes for one gene gives a 3:1 phenotype ratio and a 1:2:1 genotype ratio. A test cross with a recessive reveals an unknown dominant genotype.

Dihybrid cross ratio

Two heterozygotes for independently assorting genes give a 9:3:3:1 phenotype ratio. Independent assortment requires genes on different chromosomes or far apart on one.

Heart chambers

The human heart has two atria and two ventricles. The left ventricle pumps oxygenated blood into the aorta; the right ventricle sends deoxygenated blood to the lungs.

SA node

The sinoatrial node in the right atrium generates the heartbeat impulse and sets heart rate. It is called the pacemaker because it depolarises spontaneously.

Resting potential

The sodium-potassium pump maintains a resting membrane potential near −70 mV, with more sodium outside and more potassium inside the neuron.

Action potential

A stimulus opens sodium channels, causing depolarisation as sodium enters. Potassium then exits, repolarising the membrane, and the impulse propagates along the axon.

Nephron function

The glomerulus filters blood by pressure, and tubules reabsorb water, glucose and ions. Remaining waste forms urine, concentrating via the loop of Henle.

Binomial nomenclature

Each species has a two-part Latin name: capitalised genus followed by lowercase species, both italicised. This system was established by Carl Linnaeus.

Ten percent rule

Only about ten percent of energy at one trophic level transfers to the next. The rest is lost as heat, movement and waste, limiting food chain length.