Biology notes

Movement (MRS GREN)

Movement is a change in position or place.

Respiration

The chemical process that releases energy from food.

Sensitivity

The ability to detect and respond to changes in the environment.

Growth

A permanent increase in size and dry mass.

Reproduction

The process by which organisms produce new organisms of the same species.

Excretion

The removal of waste products made by the body (metabolic waste).

Nutrition

The taking in of substances needed for energy, growth and repair.

Cell

The basic structural and functional unit of a living organism.

Unicellular organism

A organism made up of one cell.

Multicellular organism

An organism made up of many cells.

Unspecialised cell

A cell that has not yet developed a specific structure or function and can develop into specialised cells.

Specialised cell

A cell with a particular structure adapted to perform a specific function.

Organelle

A specialised structure inside a cell that performs a particular function.

Cell membrane

Thin outer boundary of the cell that controls what enters and leaves the cell.

Cytoplasm

Jelly-like substance inside the cell where many chemical reactions occur.

Nucleus

Structure that contains the cell's genetic material (DNA) and controls cell activities.

Mitochondria

Site of aerobic respiration that releases energy for the cell.

Ribosomes

Site of protein synthesis where proteins are made.

Cell wall

Structure made mainly of cellulose that gives the plant cell strength and support.

Chloroplast

Organelle containing chlorophyll that absorbs light energy for photosynthesis.

Permanent vacuole

Large structure in plant cells containing cell sap that helps keep the cell firm.

Red blood cell

Red blood cell adapted to carry oxygen; biconcave shape, contains haemoglobin, no nucleus when mature.

Nerve cell

Nerve cell with a long axon that carries electrical impulses over long distances.

Sperm cell

Sperm cell with a flagellum and many mitochondria that delivers male genetic material to the egg.

Muscle cell

Specialised cell that contracts and relaxes to produce movement and contains many mitochondria.

Root hair cell

Plant cell with a long hair-like extension that absorbs water and mineral ions from the soil.

Palisade cell

Plant cell near the upper surface of leaves containing many chloroplasts that performs photosynthesis.

Guard cells

Cells that surround stomata and control their opening and closing.

Xylem cell

Dead plant cells with thick, strengthened walls that transport water and mineral ions from roots.

Phloem cell

Plant cells that transport dissolved sugars and organic substances around the plant.

Tissue

A group of similar cells working together to perform a particular function.

Organ

A structure made from different tissues working together.

Organ system

A group of organs working together to perform major functions.

Diffusion

Net movement of particles from an area of high concentration to an area of low concentration; passive.

Osmosis

Net movement of water molecules from a region of higher water concentration to lower water concentration through a partially permeable membrane; passive.

Active transport

Movement of substances from low concentration to high concentration using energy from respiration and membrane proteins.

Selectively permeable membrane

A membrane that allows some substances to pass through more easily than others.

Plasmolysis

When a plant cell loses a large amount of water and the cell membrane pulls away from the cell wall.

Egestion

Removal of undigested food from the digestive system.