Cambridge Science Comprehensive Practice Flashcards

A complete set of vocabulary flashcards covering the key concepts of Biology, Chemistry, and Physics from the Cambridge Science Notes.

Movement

An action by an organism or part of an organism causing change of position or place

Respiration

The chemical reaction in cells that break down nutrient molecules and release energy for metabolism

Sensitivity

The ability to detect and respond to changes in the internal or external environment

Growth

A permanent increase in size and dry mass

Reproduction

The process that makes more of the same type of organism

Excretion

The removal of waste products of metabolism and substances in excess of requirements

Nutrition

The taking in of materials for energy, growth and development

Cell membrane

The thin layer of protein fat that surrounds the cell which is semi-permeable, allowing some substances to pass but blocking others

Nucleus

Controls many of the functions of the cell and contains the cell's genetic material (DNA)

Cytoplasm

The jellylike material outside the cell nucleus in which the organelles are located

Vacuole

Used for storage and waste disposal; plant cells have a single large one filled with cell sap, while animal cells have smaller ones

Mitochondria

Converts the energy stored in glucose (sugar) into usable energy for the cell

Ribosome

Structure used to produce proteins

Chloroplasts

Organelles containing chlorophyll which is needed for photosynthesis

Cell wall

A rigid structure that gives the cell its structure; in plants it is made of cellulose, while in bacteria it is not

Plasmids

Smaller circles of DNA found in bacterial cells

Cell

The smallest unit from which all organisms are made

Tissue

A group of similar cells that work together to perform a particular function

Organ

A structure made up of a group of tissues working together to perform specific functions

Organ system

A group of organs with related functions working together to perform body functions

Organism

A living thing

Magnification Formula

$\text{magnification} = \frac{\text{image size}}{\text{actual size}}$ ($M = \frac{I}{A}$)

Diffusion

The net movement of particles from a region of higher concentration to a region of lower concentration as a result of their random movement

Osmosis

The net movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution) through a partially permeable membrane

Active transport

The movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiration

Turgid

A description of a plant cell that is tight and firm

Turgor pressure

The pressure of the water pushing outwards on a plant cell wall

Flaccid

A description of a plant cell that has lost its turgor pressure and is soft

Plasmolysed

A description of a cell in which the cell membrane tears away from the cell wall

Enzymes

Proteins that are involved in all metabolic reactions, where they function as biological catalysts

Active site

The specific shape of an enzyme where the substrate fits

Denatured

The state of an enzyme when its protein structure changes shape due to high temperature or pH, meaning the substrate can no longer fit

Photosynthesis

The process by which plants synthesise carbohydrates from raw materials using energy from light

Photosynthesis Word Equation

$\text{carbon dioxide} + \text{water} \rightarrow \text{glucose} + \text{oxygen}$ (in the presence of light and chlorophyll)

Photosynthesis Balanced Symbol Equation

$$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$$

Ingestion

The taking of substances (e.g. food and drink) into the body

Digestion

The breakdown of food

Absorption

The movement of nutrients from the intestines into the blood

Assimilation

The uptake and use of nutrients by cells

Egestion

The removal of undigested food from the body as faeces

Peristalsis

The muscular contractions of the wall of the alimentary canal that move food along

Amylase

An enzyme that breaks down starch into simple reducing sugars

Proteases

Enzymes that break down proteins to amino acids

Lipase

An enzyme that breaks down fats and oils to fatty acids and glycerol

Boiling

A change of state from liquid to gas occurring throughout the whole substance where molecules have enough kinetic energy to vaporise

Evaporation

The conversion of a liquid to its vapor below the boiling temperature, occurring only at the surface

Kinetic Particle Theory

The theory that all matter is formed of tiny particles in constant random motion, where higher temperature increases average kinetic energy

Element

A substance made of only one type of atom that cannot be broken into anything simpler by chemical reactions

Compound

A substance made of two or more different types of atoms chemically bonded together in a consistent ratio

Mixture

Different parts that can be separated using simple physical techniques as they are not chemically bonded

Atomic number (Proton number)

The number of protons in the nucleus of an atom

Mass number (Nucleon number)

The total number of protons and neutrons in the nucleus of an atom

Isotopes

Different atoms of the same element that have the same number of protons but different numbers of neutrons

Ionic bond

A strong electrostatic attraction between oppositely charged ions (cations and anions)

Covalent bond

Formed when a pair of electrons is shared between two atoms leading to noble gas electronic configurations

Metallic bonding

The electrostatic attraction between the positive ions in a giant metallic lattice and a ‘sea’ of delocalised electrons

Molecular formula

Shows the type and exact number of each atom in one molecule

Relative atomic mass ($A_r$)

The average mass of an element's isotopes compared to $\frac{1}{12}$th of the mass of an atom of $^{12}C$

The mole ($mol$)

The unit for amount of substance; one mole contains $6.02 \times 10^{23}$ particles

Avogadro constant

The number of particles in one mole, which is $6.02 \times 10^{23}$

Molar gas volume

The volume occupied by one mole of gas, taken as $24\,dm^3$ at room temperature and pressure (r.t.p.)

Scalar quantity

A quantity that has magnitude (size) only, such as distance, speed, time, mass, energy, and temperature

Vector quantity

A quantity that has magnitude and direction, such as force, weight, velocity, acceleration, and gravitational field strength

Speed

Distance travelled per unit time; $v = \frac{s}{t}$

Velocity

Speed in a given direction

Acceleration

The change in velocity per unit time; $a = \frac{\Delta v}{\Delta t}$

Acceleration of free fall ($g$)

The acceleration of an object near the surface of the Earth, which is approximately $9.8\,m/s^2$

Mass

A measure of the quantity of matter in an object, measured in kilograms

Weight

The gravitational force on an object that has mass, calculated as $W = mg$, measured in Newtons

Gravitational field strength ($g$)

The gravitational force per unit mass; near the surface of the Earth, it is approximately $9.8\,N/kg$

Density (\rho)

Mass per unit volume; $\rho = \frac{m}{v}$

Friction

The force between two surfaces that may impede relative motion and produce heating

Inertia

The tendency of an object to remain unchanged (at rest or in motion at constant velocity)

Spring constant ($k$)

The force per unit extension; $k = \frac{F}{x}$

Limit of proportionality

The point beyond which load and extension are no longer directly proportional on a graph

Moment of a force

A measure of the turning effect of a force; $\text{moment} = \text{force} \times \text{perpendicular distance from the pivot}$

Equilibrium

A state where there is no resultant force and no resultant moment acting on an object

Centre of gravity

The point at which an object behaves as if all of its mass were concentrated