Cell Wall

• Made of cellulose, provides strength and support.
• Prevents the cell from bursting due to osmotic pressure (also known as turgor pressure).
• Fully permeable to water and solutes.

Chloroplasts

• Site of photosynthesis.
• Contains chlorophyll, which absorbs light for photosynthesis.
• Chloroplast envelope - a double membrane made up of phospholipid bilayers.
• Thylakoids - Disc like structures that stack into grana. These discs are surrounded by the thylakoid membranes which have a large surface area. Stage one of photosynthesis - the light dependent reaction - occurs here.
• Stroma - This is the fluid filled centre of the chloroplast. It contains the chloroplasts own circular DNA, ribosomes (the smaller 70S size) and starch grains for storage of glucose. Stage two of photosynthesis - the light independent reaction - occurs here.

Large, Permanent Vacuole

• Large central vacuole surrounded by a membrane (tonoplast).
• Contains cell sap (water, enzymes, nutrients, and waste products).
• Provides turgor pressure, maintaining the cell shape.

Plasma Membrane (Cell surface membrane)

• Composed of a phospholipid bilayer with embedded proteins.
• Function: Partially permeable - controls the movement of substances in and out of the cell via diffusion, osmosis, active transport, and facilitated diffusion.

Cytoplasm

• Site of many metabolic reactions.
• Contains enzymes and nutrients.

Mitochondria

• Have a double membrane; the inner membrane is folded into cristae to increase the surface area for ATP production.
• The matrix contains enzymes for aerobic respiration.
• Mitochondria have their own circular DNA and their own 70s ribosomes.
• Function: Produces ATP (energy carrier) via aerobic respiration.

Ribosomes

• Small organelles composed of RNA and protein, found either free-floating in the cytoplasm or attached to the rough endoplasmic reticulum (RER).
• Function: Site of protein synthesis.

Rough ER:

• A 3D system of sheet-like membranes spreading through the cell.
• The membranes form a series of flattened sacs called cisternae.
• The Rough ER has ribosomes attached to its surface.
• The RER provides a large surface area to synthesise proteins.
• It also transports proteins and packages them into vesicles before they move to the golgi body.

Smooth ER

• A 3D system of sheet-like membranes spreading through the cell.
• The membranes form a series of flattened sacs called cisternae.
• Similar to the RER but with no ribosomes attached.
• The SER synthesises, stores and transports lipids and carbohydrates.

• A series of flattened sacs (similar to the endoplasmic reticulum but more compact) that modify, sort, and package proteins and lipids into vesicles for secretion.
• Function: Modifies and processes proteins and lipids.

Plasmodesmata

• Cytoplasmic channels connecting plant cells, allowing exchange of substances.