AS/A2 Eukaryotic cell structure

contains genetic information and controls cells activities

• nuclear envelope: double membrane surrounding the nucleus. controls entry and exit 
• nuclear pores: allow passage of large molecules (RNA) out of the nucleus. around 300 pores in each nucleus.
• nucleoplasm: granular, jelly-like material that makes the bulk of the nucleus 
• chromosomes: consist of protein-bound, linear DNA
• nucleolus: a spherical region in the nucleoplasm. manufactures ribosomal RNA and assembles ribosomes.
• chromatin: chromosomes extend throughout the nucleus as chromatin to give grainy appearance.

Functions

• the control centre of the cell through production of mRNA and tRNA
• contains genetic info in form of DNA
• manufacture ribosomal RNA+ribosomes 

oxidises glucose to release energy and synthesise ATP

• double membrane: controls entry and exit of substances. inner and outer
• cristae: extensions of the inner membrane. provides large SA for attachment of enzymes and other proteins involved in respiration
• matrix: makes the remainder of the mitochondrion. contains proteins, lipids, ribosomes, DNA etc. many enzymes involved in respiration are found here.

Functions

• sites of aerobic respiration (krebs and oxidative phosphorylation)
• produce ATP from glucose
• very active cells requires lots of energy so have large quantities of mitochondria

Carry out photosynthesis

• chloroplast envelope: double plasma membrane that surrounds organelle. very selective in what it allows in and out 
• grana: stacks of up to 100 disk like structures called thylakoids
• thylakoid: contain chlorophyll(photosynthetic pigment)
• stroma: fluid-filled matrix where synthesis of sugars takes place. contains water, enzymes and other substances. 

Functions

• the granal membrane provides large SA for attachment of chlorophyll, electron carriers and enzymes for Light Dep reaction
• fluid filled stroma possesses all enzymes require to make sugars for Light Indep stage
• chloroplasts contain DNA and ribosomes so can manufacture proteins needed for photosynthesis.

a network of membrane-bound channels or lumen. link with nuclear envelope sometimes.

Rough endoplasmic reticulum- studded with ribosomes

functions 

• provide large SA for the synthesis of proteins and glycolipids
• provide a pathway for transport of molecules esp proteins throughout the cell.
• folds and processes proteins that have been made of ribosomes

Smooth endoplasmic reticulum- lacks ribosomes, more tubular in appearance

functions

• synthesise, store and transport lipids
• synthesise, store and transport carbohydrates

group of flattened membrane-bound cavities.

• very compact
• consists of stacks of membranes that make up cristae(flattened sacs)
• appearance constantly changing as material is entering/exiting.

functions

• adds carbohydrates to protein to form glycoproteins
• produce secretory enzymes like the pancreas
• secrete carbohydrates like those used in making cell wall in plants
• transport, modify and store lipids
• form lysosomes
• stores lipids and proteins made by Golgi and transport them out of the cell via cell surface membrane 

vesicles produced by Golgi that contains digestive enzymes (lipases, lysosomes)

• enzymes that hydrolyse cell walls of certain bacteria
• 50+ different types of enzymes in 1 lysosome
• no clear internal structure
• type of Golgi vesicle

Functions

• hydrolyse material ingested by phagocytic cells (WBC/ Bacteria)
• release enzymes to the outside of the cell (exocytosis) in order to destroy material around it/ digest invading cells
• digest worn out organelles so their chemicals can be reused 
• completely break down cells after they die (autolysis)

• free floating or attached to RER
• made of proteins and RNA
• 2 subunits, each contains ribosomal RNA and protein
• make up to 25% of dry mass of cell
• 80s/22nm are eukaryotic 
• 70s/18nm are prokaryotic

functions

• site of protein synthesis

• consist of microfibrils of cellulose embedded in the matrix 
• microfibrils have a considerable strength (overall strength)
• a rigid structure that surrounds the cells in plants, algae and fungi 
• plants have cellulose 
• fungi have chitin
• thin layer called middle lamella which marks boundary btw adjacent cell and cements adjacent cells together 

functions

• provide mechanical strength in order to prevent cell bursting under pressure from osmotic entry
• give mechanical strength to plant as a whole 
• allow water to pass along so it can contribute to the movement of water through the plant

• fluid filled sac bounded by a single membrane
• single membrane around it is called  tonoplast
• plant vacuole has mineral salts, amino acids, wastes etc

functions

• support plant- make them turgid
• sugars and amino acids act as temporary food stores