All flashcard decks A-Level UK (AQA, Edexcel, OCR) syllabus →

31 cardsA-Level UK (AQA, Edexcel, OCR)

A-Level Biology and Chemistry Key Definitions

Key definitions, equations and mechanisms from A-Level Biology and Chemistry that are common to AQA, Edexcel and OCR.

Start studying Play Match

PDF study sheet

Free account needed to save, copy or download. We bring you back here.

1 / 31

0 known

TermClick or press Space to flip

Condensation reaction

GetMyMockTestQuestion side

Full list

Terms in this deck (31)

A-Level UK (AQA, Edexcel, OCR) mock tests →

Condensation reaction

A reaction in which two molecules join and a small molecule, usually water, is released.

Hydrolysis

A reaction in which a bond is broken by the addition of water.

Competitive inhibitor

A molecule with a shape similar to the substrate that binds to the active site and blocks it.

Water potential

The tendency of water to move; pure water at standard pressure has the maximum value of 0 kPa, and solutes make it more negative.

Semi-conservative replication

Each new DNA molecule contains one original strand and one newly made strand.

Transcription and translation

Transcription makes mRNA from a DNA template; translation uses mRNA at a ribosome to build a polypeptide.

Hardy-Weinberg equations

p + q = 1

and

p^{2} + 2 pq + q^{2} = 1

for a population in equilibrium.

Light-dependent reaction

Occurs on thylakoid membranes: photolysis of water, electron transport, and production of ATP and reduced NADP.

Calvin cycle

In the stroma, CO2 combines with RuBP (RuBisCO) to form GP, which is reduced using ATP and NADPH to triose phosphate.

Stages of aerobic respiration

Glycolysis (cytoplasm), link reaction and Krebs cycle (matrix), oxidative phosphorylation (inner mitochondrial membrane).

Negative feedback

A change from the set point is detected and the response reverses it, keeping conditions near normal.

Resting potential

About -70 mV inside a neurone, maintained by the sodium-potassium pump (3 Na+ out, 2 K+ in) and potassium leakage.

Simpson's index of diversity

D = 1 - \sum (\frac{n}{N})^{2}

; values near 1 mean high diversity.

Net primary production

N P P = GP P - R

, the energy stored in plant biomass available to the next trophic level.

Allopatric speciation

New species form after geographical isolation leads to different selection pressures and eventually reproductive isolation.

Mole calculations

n = \frac{m}{M}

n = c V

(V in dm3),

n = \frac{V}{24.0}

(gas at room temperature and pressure).

Percentage yield and atom economy

Yield

= \frac{actual}{theoretical} \times 100

; atom economy

= \frac{M _{r} of desired product}{\sum M _{r} of products} \times 100

Ideal gas equation in chemistry

p V = n R T

with p in Pa, V in m3, R

= 8.31

J K-1 mol-1.

Calorimetry equation

q = m c Δ T

; enthalpy change

Δ H = \frac{- q}{n}

Hess's law

The enthalpy change of a reaction is the same whichever route is taken, as long as the start and end conditions are the same.

Gibbs free energy

Δ G = Δ H - T Δ S

; a reaction is feasible when

Δ G < 0

Equilibrium constants

K_{c}

uses concentrations of products over reactants raised to their coefficients;

K_{p}

uses partial pressures.

Rate equation and Arrhenius

Rate

= k [A]^{m} [B]^{n}

;

ln k = ln A - \frac{E _{a}}{R T}

pH and Kw

p H = - lo g [H^{+}]

and

K_{w} = [H^{+}] [O H^{-}] = 1.00 \times 1 0^{- 14}

at 298 K.

Weak acid pH and buffer pH

[H^{+}] = K_{a} c

; buffer

p H = p K_{a} + lo g \frac{[ A ^{-} ]}{[ H A ]}

Standard electrode potential cell

E_{ce l l} = E_{p os i t i v e} - E_{n e g a t i v e}

; the more negative half-cell is oxidised.

Nucleophilic substitution: SN1 and SN2

SN1 (tertiary): carbocation intermediate, two steps; SN2 (primary): one step, backside attack.

Markovnikov's rule

In electrophilic addition of HX to an alkene, hydrogen adds to the carbon with more hydrogens, giving the more stable carbocation.

Functional group tests

Alkene: bromine water decolourises; aldehyde: Tollens' silver mirror; carboxylic acid: effervescence with carbonate; halide: AgNO3 precipitate colour.

Ligand substitution and coordination number

A ligand donates a lone pair to a metal ion; the coordination number is the number of coordinate bonds, for example 6 in [Fe(CN)6]3-.

Why transition metal complexes are coloured

Ligands split the d orbitals, and electrons absorb visible light to move between the levels; the complementary colour is seen.

A-Level Biology and Chemistry Key Definitions

Terms in this deck (31)

More A-Level UK (AQA, Edexcel, OCR) practice

Other A-Level UK (AQA, Edexcel, OCR) flashcard decks

A-Level UK (AQA, Edexcel, OCR) mock tests