Organelles

Nucleus

Function: Controls cell activities; stores genetic material (DNA)
Description: Large organelle with a double membrane (nuclear envelope) and nuclear pores; contains chromatin (DNA)

Rough Endoplasmic Reticulum (RER)

Function: Protein synthesis and transport
Description: Flattened membrane sacs (cisternae) covered in ribosomes, giving a rough appearance

Ribosomes

Function: Site of protein synthesis
Description: Small, round structures found free in cytoplasm or attached to RER; not membrane-bound

Golgi Apparatus

Function: Modifies, sorts, and packages proteins and lipids into vesicles
Description: Stack of flattened cisternae with associated vesicles

Lysosome

Function: Digests waste, old organelles, and pathogens using enzymes
Description: Small membrane-bound vesicles containing digestive enzymes

Mitochondrion

Function: Site of aerobic respiration; produces ATP (energy)
Description: Double membrane; inner membrane folded into cristae; contains matrix

Vesicles (transport/secretory vesicles)

Function: Transport and storage of substances within the cell
Description: Small membrane-bound sacs that move materials around the cell

Chloroplast

Function: Site of photosynthesis (converts light energy → glucose)
Description: Double membrane; contains thylakoids (stacked into grana), stroma, and often starch grains

Vacuole

Function: Storage of water, nutrients, and waste; maintains turgor pressure in plant cells
Description: Large membrane-bound sac (especially large in plant cells); contains cell sap

Centriole

Function: Involved in cell division; helps organise spindle fibres
Description: Made of triplets of microtubules arranged in a cylindrical structure

Cytoskeleton

Function: Provides structural support; maintains cell shape; enables movement within the cell
Description: Network of protein filaments (microtubules, microfilaments)

Cilium (or Flagellum depending on context, but this image is cilium)

Function: Movement of the cell or movement of substances across the cell surface
Description: Hair-like projection with a 9+2 arrangement of microtubules (doublets)