Oxford International AQA GCSE Biology Revision - Vocabulary

Vocabulary flashcards generated from chapters B1 to B4 covering key cellular structures, transport mechanisms, organism organisation, and the circulatory system.

Eukaryotic cells

Cells that contain genetic material (DNA) forming chromosomes enclosed within a nucleus, such as animal and plant cells.

Prokaryotic cells

Single-celled organisms, such as bacteria, that are smaller than eukaryotic cells and have a single loop of DNA free in the cytoplasm with no nucleus, along with small rings of DNA called plasmids.

Cell membrane

A sub-cellular structure that controls the movement of substances in and out of a cell.

Nucleus

A sub-cellular structure that contains DNA and controls the activities of the cell.

Mitochondria

Sub-cellular structures where energy is released through respiration.

Ribosomes

Sub-cellular structures that serve as the site of protein synthesis.

Cytoplasm

A jelly-like substance inside the cell where chemical reactions happen.

Permanent vacuole

A structure in plant cells containing cell sap, which helps keep the cell rigid to support the plant.

Chloroplasts

Sub-cellular structures in plant cells containing chlorophyll to absorb light energy for photosynthesis.

Cell wall

A cell structure made of cellulose in plant cells that strengthens and supports the cell.

Plasmids

Small rings of DNA found in prokaryotic cells that contain extra genes in addition to the main loop of DNA.

Resolution

The smallest change that a measuring device can measure.

Independent variable

The variable that is changed in an investigation.

Dependent variable

The variable that changes as a result of changes to the independent variable.

Control variable

A variable that is kept constant in an investigation to ensure results are valid.

Diffusion

The spreading out of particles, resulting in a net movement from an area of higher concentration to an area of lower concentration down a concentration gradient.

Osmosis

The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.

Active transport

The movement of particles from a more dilute solution to a more concentrated solution against a concentration gradient using energy released from respiration.

Hypotonic

A condition where the solution outside a cell has a lower concentration than inside the cell, causing water to move into the cell.

Hypertonic

A condition where the solution outside a cell has a higher concentration than inside the cell, causing water to move out of the cell.

Isotonic

A condition where the concentration of the solution outside a cell is equal to the concentration inside the cell.

Tissue

A group of cells that have similar structures and functions.

Organ

A group of different tissues working together to perform a specific function.

Organ system

A group of organs working together to perform a specific function.

Muscular tissue

An animal tissue that contracts to bring about movement.

Glandular tissue

An animal tissue that produces substances such as enzymes and hormones.

Epithelial tissue

An animal tissue that covers some parts of the body.

Plasma

The liquid component of blood that transports blood cells and substances such as carbon dioxide, glucose, and urea around the body.

Platelets

Small fragments of cells in the blood that form blood clots at the site of a wound to prevent blood loss and infection.

Artery

A thick-walled, elastic blood vessel with a small lumen that carries blood away from the heart under high pressure.

Vein

A thin-walled blood vessel with a large lumen and valves that carries blood back to the heart at low pressure.

Capillary

A tiny blood vessel with a narrow lumen and walls one cell thick that connects arteries and veins to facilitate exchange of materials with tissues.

Coronary heart disease

A disease that occurs when the coronary arteries become narrowed by the build-up of layers of fatty material within them, reducing blood flow and oxygen to the heart muscle.

Stent

A device inserted into blocked coronary arteries to keep them open and allow blood to flow.

Artificial pacemaker

A small electrical device implanted into the chest that sends electrical signals to stimulate the heart to beat correctly.