Cell structure

• Ribosomes

  Responsible for protein synthesis

  Smaller 70s in prokaryotes.

  Larger 80s in eukaryotes
• Endoplasmic reticulum

  Series of flattened sacs, double membraned cisternae leading on from the nuclear envelope.
• Rough endoplasmic reticulum 


  Studded with ribosomes for protein synthesis;

  cisternae then transport the protein.
• Smooth endoplasmic reticulum -

  Synthesis and transport of lipids.
• Golgi apparatus

  • Modifies and packages proteins.
  • Produces secreting enzymes
  • secretes carbohydrates
  • produces glycoproteins
  • transports and stores lipids
  • forms lysosomes and digestive enzymes
• Vacuole

  Contains cell sap and is surrounded by the tonoplast membrane.

  Contractile vacuole in animals that pump out excess water.

  In plants, helps support cell structure and,

  storage of amino acids, sugars and cellular waste.
• Centrioles

  Only found in animal cells. Not membrane bound.

  2 cylinders of microtubules that form the spindle in cell division.
• Mitochondria

  Site of aerobic respiration.

  Site of ATP synthesis.

  Cylindrical for large surface area.

  Cristae increases surface area for ATP synthesis.

  A) Inner membrane

  B) Ribosomes

  C) Mitochondrial DNA

  D) Outer membrane

  E) Matrix

  F) Cristae

  
• Cell wall

  Cellulose in plant cells.

  Chitin in fungi cells.

  Peptidoglycan in prokaryotes.

  Antibiotics, such a penicillin, work by disturbing the peptidoglycan cell wall in bacteria. 

  It is fully permeable for the transport of substances.

  It provides strength to the plant.

  It communicates through the cell wall via plasmodesmata.
• Chloroplasts

  • The thylakoid membranes of the chloroplasts contain chlorophyll, a pigment that traps light energy for photosynthesis.
  • Chlorophyll can be found in the thylakoid membranes, which make up the granum.

  A) Granum

  B) Lumen

  C) Outer membrane

  D) Inner membrane

  E) Thylakoids

  F) & Circular DNA

  
• Lysosomes

  Breakdown old worn out organelles.

  Specialist vesicles containing hydrolytic enzymes and chemicals

  Digests engulfed particles
• Endosymbiotic theory


  The presence of 70s ribosomes and DNA in mitochondria and chloroplasts indicates they were once free living cels engulfed by ancient bacteria, therefore developing a symbiotic relationship was formed.
• Cell theory


  All new cells are formed from other existing cells and the cell is therefore a fundamental unit of structure, function and organisation in all living organisms.
• Eukaryotes


  80s Ribosomes

  DNA in nucleus

  Cellulose cell wall

  Mitochondria for aerobic respiration
• Prokaryotes


  70s ribosomes

  DNA free in cytoplasm

  Peptidoglycan cell wall

  Mesosome for aerobic respiration
• Viruses


  Not living, not a cell, contains no organelles with no cytoplasm.

  It injects its genetic material into a living cell that creates more viruses.