B1

Cell

The basic unit of all living organisms

Nucleus

Contains genetic material (DNA); controls cell activities

Cytoplasm

Gel-like substance where most chemical reactions occur

Cell membrane

Controls what enters and leaves the cell

Mitochondria

Where aerobic respiration takes place to release energy

Ribosome

Where protein synthesis occurs

Cell wall

Supports and strengthens plant cells (made of cellulose)

Chloroplast

Contains chlorophyll for photosynthesis in plant cells

Vacuole

Contains cell sap; helps maintain pressure in plant cells

Prokaryotic cell

A cell without a nucleus (e.g. bacteria)

Eukaryotic cell

A cell with a nucleus (e.g. animal, plant cells)

Diffusion

The movement of particles from high to low concentration

Osmosis

The movement of water across a partially permeable membrane from high to low water concentration

Active transport

Movement of substances from low to high concentration using energy

Surface area to volume ratio

A measure that affects how quickly substances can diffuse into or out of cells; smaller cells have a higher SA:V ratio, so diffusion is more efficient

Tissue

A group of similar cells working together

Organ

A group of different tissues working together to perform a function

Organ system

A group of organs working together to carry out a task