IGCSE Science Vocabulary Flashcards

Flashcards covering key vocabulary from the IGCSE Science Study Guide.

Movement

An action by an organism causing a change of position or place.

Respiration

Chemical reactions in cells that break down nutrient molecules to release energy.

Aerobic Respiration

Requires oxygen and produces a large amount of energy.

Anaerobic Respiration

Occurs without oxygen and produces less energy.

Sensitivity

The ability to detect changes in the environment and make appropriate responses.

Growth

A permanent increase in the size and dry mass of an organism.

Reproduction

Processes that make more of the same kind of organism.

Sexual Reproduction

Involves two parents and produces genetically diverse offspring.

Asexual Reproduction

Involves one parent and produces genetically identical offspring.

Excretion

The removal of metabolic waste products from the body.

Nutrition

Taking in of materials for energy, growth, and development.

Autotrophic Nutrition

Organisms make their own food, usually through photosynthesis.

Heterotrophic Nutrition

Organisms obtain food by feeding on other organisms.

Cell membrane

Partially permeable boundary that controls what enters and leaves the cell.

Cytoplasm

Jelly-like substance where most chemical reactions occur.

Nucleus

Contains genetic material (DNA) and controls cell activities.

Mitochondria

Site of aerobic respiration, releases energy.

Ribosomes

Site of protein synthesis.

Cell wall

Provides structural support and protection to the cell in plants.

Chloroplasts

Site of photosynthesis, contains chlorophyll.

Large permanent vacuole

Maintains turgor pressure in plant cells, providing support.

Plasmids

Small, circular pieces of DNA in bacteria that can carry additional genes.

Diffusion

The net movement of particles from a region of higher concentration to a region of lower concentration.

Osmosis

The net movement of water molecules from a region of higher water potential to a region of lower water potential through a partially permeable membrane.

Active Transport

The movement of particles from a region of lower concentration to a region of higher concentration, requiring energy.

Photosynthesis

The process by which green plants convert light energy into chemical energy in the form of glucose.

Chlorophyll

A green pigment found in chloroplasts that absorbs light energy.

Limiting factor

A factor that restricts the rate of a process when it is in short supply.

Stomata

Small pores on the underside of leaves for gas exchange.

Guard cells

Cells that control the opening and closing of stomata.

Palisade mesophyll

Layer of elongated cells packed with chloroplasts for light absorption.

Spongy mesophyll

Contains air spaces in leaves for rapid gas diffusion.

Xylem

Transport water and mineral ions from the roots up to the leaves.

Phloem

Transports sugars from the leaves to other parts of the plant.

Transpiration

The loss of water vapour from plant leaves through the stomata.

Translocation

Sugars and amino acids transported from source to sink.

Ecology

Study of how organisms interact with each other and their environment.

Producers

Organisms that make their own organic nutrients (e.g., plants).

Consumers

Organisms that get energy by feeding on other organisms.

Primary Consumers (Herbivores)

Feed on producers (e.g., rabbits).

Secondary Consumers (Carnivores or Omnivores)

Feed on primary consumers (e.g., foxes).

Tertiary Consumers (Carnivores or Omnivores)

Feed on secondary consumers (e.g., owls).

Decomposers

Break down dead organic matter and recycle nutrients.

Saprophytes/Saprobionts

Organisms that feed on dead or decaying organic matter.

Food Chain

Shows the transfer of energy from one organism to the next.

Food Web

A network of interconnected food chains.

Combustion

The burning of fossil fuels releases CO2 into the atmosphere.

Deforestation

The clearing of forests for other land uses.

Pollution

The introduction of harmful substances into the environment.

Conservation

Preservation and protection of natural resources.

Monosaccharides

Simple sugars like glucose.

Polysaccharides

Large molecules like starch, glycogen, cellulose.

Fatty acids and glycerol

Building blocks of fats.

Amino acids

Building blocks of proteins.

Enzymes

Biological catalysts that speed up metabolic reactions.

Substrate

The molecule the enzyme acts upon.

Stomach

Organ containing hydrochloric acid and pepsin to begin protein digestion.

Small Intestine (Duodenum)

Organ where bile neutralises acidic chyme, and pancreatic juice containing amylase, trypsin/protease, lipase is secreted.

Salivary Glands

Associated organ that produces saliva (containing salivary amylase).

Liver

Associated organ that produces bile (stored in the gallbladder).

Protease (Pepsin)

Breaks down proteins → polypeptides.

Protease (Trypsin)

Breaks down polypeptides → amino acids.

Physical Change

A change in which no new substance is formed.

Chemical Change

A change in which one or more new substances are formed.

Element

A pure substance consisting of only one type of atom.

Compound

A pure substance formed when two or more different elements are chemically bonded together.

Mixture

Consists of two or more elements or compounds that are not chemically bonded together.

Homogeneous Mixture

Components are uniformly distributed.

Heterogeneous Mixture

Components are not uniformly distributed.

Filtration

Separates an insoluble solid from a liquid.

Crystallisation

Separates a soluble solid from its solution by evaporating the solvent.

Simple Distillation

Separates a liquid from a solution or two liquids with significantly different boiling points.

Fractional Distillation

Separates two or more miscible liquids with different, but close, boiling points.

Chromatography (Paper Chromatography)

Separates mixtures of soluble coloured substances based on their differential solubility.

Isotopes

Atoms of the same element with different numbers of neutrons.

Ions

Atoms that have gained or lost electrons, resulting in a net electrical charge.

Periods

Horizontal rows in the periodic table.

Groups

Vertical columns in the periodic table.

Group I (Alkali Metals)

Very reactive metals that react vigorously with water.

Group VII (Halogens)

Reactive non-metals that exist as diatomic molecules.

Group 0 (Noble Gases)

Unreactive gases with full outer electron shells.

Transition Metals

Metals with high melting points and good conductivity, often acting as catalysts.

Ionic Bonding

Strong electrostatic attraction between oppositely charged ions.

Formation of Ionic Bonding

Occurs between a metal and a non-metal.

Giant Ionic Lattice Structure

Ions are arranged in a regular, repeating 3D pattern.

Covalent Bonding

A chemical bond formed when a pair of electrons is shared between two atoms.

Simple Molecular Structures

Poor electrical conductivity due to no free moving ions or delocalised electrons to carry charge.

Giant Covalent Structures (Macromolecular Structures)

All atoms are held together by a vast network of strong covalent bonds.

Metallic Bonding

The electrostatic attraction between positive metal ions and delocalised electrons.

Alloys

A mixture of a metal with one or more other elements

Anhydrous cobalt(II) chloride paper

Changes from blue to pink in the presence of water.

Anhydrous copper(II) sulfate

Changes from white to blue in the presence of water.

Acid

Produce hydrogen ions (H+) when dissolved in water.

Base

Metal oxide or metal hydroxide that reacts with an acid to form a salt and water.

Alkali

A soluble base that produces hydroxide ions (OH−) when dissolved in water.

Indicators

Substances that change colour depending on the pH of the solution.

Neutralisation

The reaction between an acid and a base to form a salt and water.

Reactivity Series of Metals

A list of metals arranged in order of their decreasing reactivity.

Oxidation

Gain of oxygen, loss of hydrogen, loss of electrons.

Reduction

Loss of oxygen, gain of hydrogen, gain of electrons.