Science GCSE Revision: Cell Biology, Chemistry, and Physics

Comprehensive practice flashcards based on the Summer Revision List for GCSE-style Science, covering Cell Biology, Enzymes, Atomic Structure, and Physics concepts.

Mitochondrion

The sub-cellular structure that serves as the main site of aerobic respiration.

Electron microscope

A microscope with higher resolution and magnification than a light microscope, though it cannot view living cells easily.

Magnification formula

$$Magnification = \frac{\text{Image size}}{\text{Real size}}$$

Acrosome

A structure in a sperm cell containing enzymes used to penetrate an egg.

Ciliated epithelial cells

Specialized cells in the airways that move mucus and trapped dust away from the lungs.

Lock and key model

A model of enzyme action where the substrate fits perfectly into the enzyme's specific active site.

Denatured

The state of an enzyme when a temperature far past its optimum causes the active site to change shape.

Protease

The specific enzyme that breaks down proteins into amino acids.

Synthesis (Enzyme-controlled)

The biochemical process of building up small molecules into larger, complex molecules.

Cell wall

A plant cell structure made of cellulose that provides support.

Filtration

A separation method suitable for removing an insoluble solid from a liquid.

Fractional distillation

A technique used to separate substances with different boiling points.

Stationary phase

The component in paper chromatography that does not move, specifically the chromatography paper.

Rf value calculation

$$\text{Rf value} = \frac{\text{Distance moved by spot}}{\text{Distance moved by solvent}}$$

Chromatography start line

A line drawn in pencil because pencil lead is insoluble and will not run or interfere with the results.

Mixture

Two or more elements or compounds that are not chemically combined together.

Condensing stage

The phase of simple distillation where a gas cools down and turns back into a liquid.

Pure substance (Chromatography)

A substance that produces only one spot on a chromatogram.

Fractionating column

A column that provides a temperature gradient in fractional distillation so different vapors condense at different levels.

Atomic particle charges

Proton: $+1$, Neutron: $0$, Electron: $-1$

Nucleus

The central part of an atom where almost all of its mass is concentrated.

Atomic number

The number of protons found in the nucleus of an element.

Isotopes

Atoms of the same element with the same number of protons but different numbers of neutrons.

Relative atomic mass ($Ar$) of Chlorine

$35.5$ (calculated from $75\%$ $^{35}Cl$ and $25\%$ $^{37}Cl$).

Mendeleev's Periodic Table

A table organized by increasing atomic weight, leaving gaps for undiscovered elements.

Group

A column in the periodic table containing elements with the same number of electrons in their outer shell.

Alkali metals (Group 1) reactivity

The reactivity increases as you go down the group.

Plum pudding model

A model of the atom proposed by J.J. Thomson.

Alpha particle scattering experiment

An experiment proving that the atom is mostly empty space with a dense, positively charged nucleus.

First electron shell

The innermost shell of an atom which can fit a maximum of $2$ electrons.

Sodium electron configuration

$2, 8, 1$ (for atomic number $11$).

Metal ion formation

The process where a metal atom forms a positive ion by losing electrons from its outer shell.

Oxide ion

$$O^{2-}$$

Halogen ion charge

$$-1$$

Noble gases (Group 0)

Elements that rarely react because they have a full, stable outer shell of electrons.

Ionic bonding

The type of bonding that occurs when electrons are transferred from a metal atom to a non-metal atom.

Stable chloride ion ($Cl^-$)

In this state, the element has an electron configuration of $2, 8, 8$.

Ionic lattice

A structure held together by strong electrostatic forces of attraction between oppositely charged ions.

Mass

The amount of matter in an object.

Weight

The force acting on an object due to gravity.

Weight formula

$$W = m \times g$$

Balanced force

Forces that are equal in size and opposite in direction, resulting in a zero resultant force.

Scalar quantity

A quantity, such as speed, that has magnitude only.

Displacement

The straight-line distance and direction from an object's starting point to its ending point.

Newtonmeter

An instrument (spring balance) used to measure the weight of an object.

Friction

A force that opposes motion between two surfaces sliding past each other.

Velocity

A vector quantity that consists of both magnitude and direction.

Gradient (Distance-time graph)

The slope used to calculate the speed of an object.

Velocity-time graph (Horizontal line)

Indicates that the object is moving at a steady, constant speed.

Uniform acceleration formula

$$Acceleration = \frac{\text{Change in velocity}}{\text{Time taken}}$$

Newton's Second Law (Equation)

$$F = m \times a$$

Acceleration unit

$$m/s^2$$

Deceleration

An acceleration characterized by a negative value.