Cell structure

1000 mm

1000

1000

• vesicle • golgi body ]rough and smooth endoplasmic reticulum • 80s ribosomes • plasma/cell membrane • cytoplasm • nuclear envelope • nuclear pore • nucleolus • chromatin • lysosome • mitochondria • centrioles

30 micrometres

• under a light microscope only a few structures are visible within cytoplasm • electron microscope more structures called organelles visible in eukaryotic cells • electron miscrocopes have a shorter wave length, greater magnification , and a higher resolution

• specific roles within cells and surrounded by a membrane • membranes provie a large surface area for transport of molecules and attatchment of enzymes

• vesicle • tonoplast • cell wall • mitochondria • chloroplast • nuclear pore • nucleolus • nuclear envelope • smooth and rough endoplasmic reticulum • plasmodesma • 80s ribosomes • golgi body • cell membrane

• 30 micrometres

• largest organelle present in cytoplasm of a eukaryotic cell • contains DNA coding for protein synthesis • nucleoplasm contains chromatin which condenses to form chromosomes during cell division • double membrane thr outer membrane of which is continuous with endoplasmic reticulum • membrane has pores allow mRNA to leave nucleu • nucleoulus found within nucleus and responsible for the production of rRNA and ribsomes

• cylindrical typically 1-10 micrometres • site of aerobic respiration producing ATP • inner membrane folded into cristae providing large surface area for the attatchment of enzymes • fluid filled matric contains lipidas and proteins, 70s ribosomes and sall circular DNA • present in all cells • more in metabolically active cells eg mucle and liver

• outer membrane • inner membrane space • inner membrane • cristae • matric • circular DNA • ribosomes 70s

• found in photosynthetic plants • site of photosynthesis • surrounded by double membrane contains fluid filled stroma with starch grains • 70s ribosomes and circular DNA • thylakoids is a flattened membrane • stacks of thylarkoids conain photosynthetic pigments such as chlorophyll • inner membrane not folded

• double membrane • 70s ribosomes • thylakoid • granum • starch grain • DNA • thylakoid membrane • intergranal lamellae/ thylakoid

• double membrane form interconnected flattened fluid filled sacks called cristernae connected to the nuclear envelope • main roles concerned transport of materials through cells • rough ER has ribosomes attatched to the outer surace and once proteins sythnthesised at ribosomes are transported via criternae • Smooth ErR lack ribosomes incolced with synthesis and transport of lipids

• made from rRNA and protein • found within cytoplasm • surrounded by a membrane • role is assembly of proteins during trnaslaton • two ubunits large subunit two tRNA attatchent sites and small subunit is mRNA attatchment site • eukaryotic cells -80s • prokaryotic cells smaller - 70s

• more compact in shape stack of curves cristernae • cesicle contain polypeptides bud off RER and fuse with golgi body • proteins are modifies and packages into vesicles by golgi body for export • golgi incolves in transport and storage of lipids • production of glycoprotiens and lysosomes

• small single membrane bound vacuoles pinched off from golgi body containing digestive enzyme lysozyme • digest worn out organelles within cell and foreign materials been engulfed by phagocytosis eg bacterial engulged bu white blood cell

• present in animals cells and protocitsta • two rings of microtubules at right angles to each other • organise microtubules make spindle during cell division

• plants cells large central vacoule surrounded by tonoplast • support soft plant tissue and store chemicals eg glucose and amino acids in cell sap

• largely from cellulose - plant • peptidoglycan (murein) - bacteria • chitin - fungi • probiding trength resist expansion of vacuole due to osmosis thus creating turgor support for non woody plants • transport of water and dissolved molecules and ions through gaps in the cellulose fibres - apoplast pathway • communication between cells via pores in cell walll allow strands of cytoplam called plasmodesmata to pass • allows water to pass via symplast pathway

• plant cells • cell wall • chloroplasts resent • large permanent single ceentral vauole • plasmodesmata • starch grains used for energy store • animal cells • no cell wall • no chloroplasts • small temporary vacuoles • centrioles • no plasmodesmata • glycogen granules - energy store

• no true nucleus possess DNA loose within cytoplasm no membrane bound organelles • infolding of membrane called mesosomes where respiration though to occur • cell wall made of peptidoglycan and ribosomes are slightly smaller than eukaryotes - 70s • some bacteria contain plasmids (snall rings of DNA) antibiotic resistance genes

• slime coat • cell wall • cell membrane • loop of DA • 70s ribossomes • plasmids • cytoplassm • mesosome