CELL STRUCTURE

• Function of Nucleus: contains DNA which controls cell activity and controls production of protein
• NUCLEOLUS FUNCTION-synthesis of ribosomes and RNA
• RER FUNCTION - fold and process proteins
• SER FUNCTION- synthesis and packaging of lipids
• NUCLEOLUS : produces ribosomes
• MITOCHONDRIA FUNCTION- site of aerobic respiration and where ATP is made
• GOLGI APPARATUS FUNCTION- modifies, sorts and packages proteins and lipids
• LYSOSOME FUNCTION- digestion of macromolecules eg. old cells or invading cells, within the cell
• PLASMA MEMBRANE FUNCTION- controls movement into/out of cell
• CELL WALL FUNCTION- provides support to plant cells
• CYTOPLASMIC MATRIX FUNCTION- contains enzymes that catalyse reactions
• CYTOPLASM FUNCTION- contains organelles and is where reactions take place
• NUCLEAR ENVELOPE FUNCTION- protects DNA from damage AND stops genetic information mixing with cytoplasm
• what is in a plant cell that’s not in a animal cell?

  • cell wall
  • chloroplasts
  • vacuole
  • centrosome and lysosome only in animal cells
• Function of plasmids/loop of DNA

  Carry genetic information
• Things bacteria cell has that human doesn't

  • Flagellum
  • Cell wall
  • Capsule/slime layer
  • Different size ribosomes
  • Circular DNA/plasmids
• Why may 2 of the same organelle differ in shape?

  sections cut in different places/planes
• Why use a cold, isotonic buffer solution?

  COLD= reduce enzyme action

  ISOTONIC= Stop osmotic effects (which would cause cell to swell and burst)

  BUFFER= Maintain pH to stop damage to enzymes/proteins
• How is mitochondria structured?


  Double membrane folds to form Cristae and matrix
• How is structure of lysosomes help its function

  Contains digestive enzyme lysozyme
• RIBOSOME FUNCTION= Site of protein synthesis - (TRANSLATION) and also catalyses the joining of amino acids
• Structure of ribosomes?


  Made up of protein and RNA
• Structure of RER


  Surface is covered in ribosomes
• What makes up the nucleus?

  1. Nucleolus
  2. Nuclear envelope
  3. Chromatin
  4. Nuclear pores
• NUCLEAR PORES= Allow substances to pass in/out
• NUCLEUS FUNCTION= Controls cells activities eg transcription, and contains all of the genetic material in the form of chromatin
• Why are viruses classed as acellular and non living?

  ACELLULAR = Have no cell surface membrane and not made of cells (no membrane bound organelles)

  NON LIVING= can't carry out own metabolic reactions or reproduce/replicate independently
• CELL MEMBRANE= Controls movement of substances, also has receptors on it which allow response to chemicals
• GOLGI VESICLE= Stores and transports lipids and proteins out of cell
• What is a tissue?

  Group of specialised cells working together to carry out a function
• How can you homogenise cells?

  1. Blend cells
  2. Vibrate cells
• Order of fragments- heaviest go to bottom and come out first

  1. Nuclei (first to come out)
  2. Mitrochondria
  3. lysosomes
  4. ER
  5. Ribosomes
• STAGES OF MITOSIS

  1. PROPHASE= Chromosomes condense and centrioles move to opposite poles and form spindle fibres
  2. METAPHASE= Chromosomes line up in the middle of cell. They attach to spindle fibres via their centromere
  3. ANAPHASE= Centromere splits, pulling chromatids to opposite ends
  4. TELOPHASE/CYTOKINESIS= Chromosomes decondense (now long&thin) and nuclear envelope reforms. Cytoplasm splits (cytokinesis) snd 2 genetically identical daughter cells are made
• Describe interphase

  Cell grows and replicates its DNA to prepare for division
• How are epithelial cells adapted to function?

  Lots of villi/microvilli to inc SA

  Lots of mitochondria to provide ATP for transport of undigested food
• What are fungi cell walls made of?

  chitin
• What are bacteria walls made up of?

  Peptidoglycan
• What are plant walls made of?

  Cellulose
• Desc structure of virus

  • Nucleic acid eg. RNA and enzymes eg. reverse transcriptase surrounded by a Capsid
  • The above is enclosed in a nuclear envelope with attachment proteins sticking out
• CYTOSKELETON

  • Made up of microtubules
  • provides mechanical support for cells`
  • Allows movement of organelles
  • Enables movement of cytoplasm