Cell Sub-Structures

• A distinct nucleus
• Membrane-bounded organelles

• Contains genetic material in the form of DNA + chromosomes
• Acts as control centre through production of mRNA and tRNA, hence protein synthesis
• Manufactures ribosomal RNA + ribosomes

• Nuclear envelope - double membrane. Outer membrane is continuous with ER and has ribosomes
• Nuclear pores - allow passage of large molecules eg RNA. 3000 pores
• Nucleoplasm is granular, jelly material that makes up bulk
• Chromosomes have protein-bound, linear DNA
• Nucleolus - small spherical region. Manufactures ribosomal RNA + assembles ribosomes

• Sites of aerobic respiration
• Produce ATP from substrates e.g. glucose

• Double membrane - controls exit/entry of material. Inner membrane is folded to form cristae
• Cristae - extensions of inner membrane, provide large SA for attachment of enzymes/proteins for increased rate of respiration
• Matrix - space containing protein, lipids, ribosomes, DNA, enzymes

• In cells that have a high level of metabolic activity so require lots of ATP
• e.g. muscle cells, epithelial cells -> need lots of ATP in active transport when absorbing substances from intestines

• Chloroplast envelope - double plasma membrane that controls exit/entry of materials
• Grana - stacks of thylakoids, containing chlorophyll, where light absorption for PSN takes place
• Stroma - fluid-filled matrix where synthesis of sugars for PSN takes place

Carries out PSN by absorbing sunlight

• Granal membranes - provide large SA for attachment of substances that carry out PSN
• Fluid of stroma - has enzymes needed to make sugars in 2nd stage of PSN
• Contains DNA = ribosomes - to quickly manufacture proteins needed for PSN

• 3D system of sheet-like membranes spreading through cytoplasm
• Membranes enclose network of tubules + flattened sacs called cisternae

• Has ribosomes
• Large SA for synthesis of proteins
• Provide pathway for transport of materials through cell

• Synthesise, store + transport lipids
• Synthesise, store + transport carbohydrates

• In cells that manufacture + store large quantities of carbohydrates, proteins, lipids
• e.g. liver, secretory cells (epithelial)

Stacks of membranes that make up flattened sacs called cisternae, with small rounded hollow structures called vesicles

• Modifies + sorts proteins
• They are transported in vesicles which are pinched off from ends of cisternae

• Formed when vesicles produced by Golgi contain enzymes such as proteases/lipases
• Contain enzymes that hydrolyse some cell walls

• Hydrolyse material ingested by phagocytic cells
• Release enzymes to outside of cell
• Digest worn out organelles to be reused
• Completely break don cells after they've died

• Small cytoplasmic granules
• Occur in cytoplasm or with RER
• 80S - eukaryotic
• 70S - prokaryotic (smaller)
• One large unit, one small, containing ribosomal RNA + protein

The site of protein synthesis

• Has microfibrils made of cellulose embedded in matrix
• Thin layer called middle lamella marking boundary between adjacent cell walls

• Provide strength to prevent cell bursting from osmotic gain of water
• Provide strength to whole plant
• Allow water to pass along it

Fluid-filled sac bounded by a single membrane called a tonoplast

• Support plants by making cells turgid
• Sugars + amino acids act as temporary food store
• Pigments may colour petals to attract insects

• Prokaryotic
• Cell wall - made of murein
• Capsule - (some bacteria) slime wall for protection
• Cell-surface membrane - with 70S ribsomes
• Circular DNA 
• Plasmids - extra loops of DNA

• Smaller
• No nucleus
• No nuclear envelope

• Acellular
• Non-living particles
• Smaller than bacteria
• Contain nucleic acids - DNA/RNA - within capsid, a protective protein coat
• Only multiply inside living host cells
• Lipid envelope - (some) if not then attachment proteins to allow virus to attach to host cell