Grade 12 biology - Cell structure and Function

Organelle

An internal functional structure that is located within the cytosol of a cell

Plasma membrane

A dynamic barrier that surrounds the cytosol of the cell

nuclear envelope

A two layer membrane that encloses the nucleus of a eukaryotic cell

Endomembrane system

A group of interacting organelles between the nucleus and the plasma membrane

Endoplasmic reticulum (ER)

A membrane-bound organelle that is folded into flattened sacs and tubes, and is often an outgrowth of the nuclear envelope in a eukaryotic cell

Rough ER

Areas of endoplasmic reticulum with ribosomes attached to the surface

Smooth ER

Areas of the endoplasmic reticulum without attached ribosomes

Vesicle

A small, membrane-bound organelle that may transport, store, or digest substances within a cell

Vacuole

A liquid-filled organelle that stores waste and aids in cellular metabolism and water balance

Lysosome

A small, membrane-bound organelle that contains digestive enzymes that aid in waste disposal (they fuse with vacuoles that carry particles or molecules for disposal, such as worn-out cell components. Lysosomal enzymes empty into those vacuoles and digest their contents.

Golgi body

An organelle with folded membranes where the final packaging of protein occurs

Mitochondrion

An idea skis with two membranes; the site of most ATP synthesis during aerobic cellular respiration

Plastid

A membrane-bound organelle that is involved in photosynthesis and storage in plants and algae

Chloroplast

A double-membrane-bound organelle that contains enzymes and pigments that are used to perform photosynthesis in eukaryotic cells

Cytoskeleton

a dynamic system of filaments that provides cell structure, helps with cell division, and enables the cell and inner organelles to move around

Microfilament

A fibre structure made from actin that is part of the cytoskeleton and is located in the cytosol of cells

Flagellum

A whiplike tail that is used in propulsion of both prokaryotic and eukaryotic cells

Cilia

Tiny hairlike structures that move water and mucus in eukaryotes; used for movement of prokaryotic cells

Cell wall

The outer barrier of a plant cell; the cell wall surrounds the plasma membrane and gives structure to the plant

Primary wall

A cellulose coating that surrounds a plant cell

Secondary wall

A coating that is added to a plant cell wall; it is more rigid and often thicker than the primary cell wall

Extra cellular matrix (ECM)

A molecular system that supports and protects a cell; a cell’s environment

Cell junction

A structure that allows cells to interact with each other and the surrounding environment

Glycolipid

Any membrane lipid that is bond to a carbohydrate

Glycoprotein

A membrane component that contains a sugar, or carbohydrate, bound to an amino acid

Sterol

A type of steroid with an OH group at one end and a non-polar hydrocarbon chain at the other

Integral membrane protein

A protein that is embedded in the lipid bilayer

Peripheral membrane protein

A protein on the surface of the membrane

Passive Transport

The movement of a substance across a membrane without expending energy

Dynamic equilibrium

The state in which continuous action results in balanced conditions

Simple diffusion

The ability of small and non polar substances to move across a membrane unassisted

Facilitated diffusion

The facilitated transport of ions and polar molecules through a membrane via protein complexes

Transport Protein

An integral membrane protein that provides a pathway for molecules to cross a membrane

Channel protein

A hydrophilic pathway I’m a membrane that enables water and ions to pass through

Carrier protein

A protein that binds to a molecule and transports it across the lipid bilayer

Osmosis

The passive diffusion of water across a membrane

Hypotonic

The property of a solution that has a lower solute concentration than another solution

Hypertonic

The property of a solution that has a higher solute concentration than another solution

Isotonic

The property of a solution that has the same solute concentration as another solution

Active transport

The movement of substances across membranes against their concentration gradient using pumps

Electrochemical gradient

The combined effects of a difference in electrical potential energy and a difference in the concentration gradients of ions