Resit unit 1 Organelles AS OCR BIO

brief overview by spec ocr

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  • Created by: Maryan
  • Created on: 03-04-12 17:19

Organelles and their functions

Nucleus: Contains cell genetic info

  • Large contains chromatin and has a nuclear envelope and nuclear pores.


  • Flattened membrane sacs called cisternae,
  • Rough ER studded with ribosomes- Transports proteins
  • Smooth ER isnt- site of lipid synthesis

Golgi Apparatus: packages and modifies proteins

  • Stack of flat membrane bound stacks
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Mitochondria: Sight of aerobic respiration

  • Sausage shaped with a inner and outer membrane. Inner membrane highly folded into cristae for larger surface area. The middle of it is called the matrix

Chloroplast: sight of photosynthesis

  • Only in plants, has two membranes- inner and outer membrane
  • Has Thylakoids and granum (plural grana)

Lysosome: Breaks down pathogens

  • Contains digestive enzymes
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Ribosome: Sight of protein synthesis

  • Consists of two subunits: Light subunit and heavy subunit
  • 80S- eukaryotes
  • 70S- Prokaryotes


  • Involved in cell division where it produces the spindles

Vacuole: Keeps the cell turgid and supports it

  • membrane bound sac containing cell sap
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  • Cytoskeleton: Supports and aids with movement e.g spindles during cell division
  • Network of protein fibers
  • Plasma cell surface membrane: Controls what goes in and out of cells
  • Cytoplasm:
  • Contains enzymes needed for metabollic reactions
  • Flagella: Tail that enables movement
  • Cillia:
  • Wafts dirt up the trachea
  • nucleolus: contains the DNA
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Protein production

  • Proteins are made at RER
  • Proteins made are either excreteed or attached to the cell surface membrane
  • proteins made by free ribsomes stay in the cytoplasm
  • the proteins are then folded and packaged into vesicles
  • they are then transported to the golgi apparatus where they are further modified
  • After this they are packaged off into ore vesicles where they are transported around the cell.
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  • Microtubules and microfilaments
  • Hold organneles in position by providing support
  • Give the cell strength and help maintain its shape
  • Helps transport materials e.g spindles pulling chromatids during cell division
  • Enables movement by the protein fibers cillia and flaggela
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Prokaryotes vs Eukaryotes

  • Prokaryotes are smaller (2um)
  • No nucleus- DNA(circular)floats free in cytoplasm
  • No mitochondria
  • Fewer organneles
  • 70S Ribosomes
  • Eukaryotes
  • Larger about 200um
  • Has a nucleus, DNA is linear
  • Many mitochondria
  • Alot of organelles
  • 80S ribosomes
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Plant VS animals


  • Cell wall with plasmodesmata
  • Vacuole
  • Chloroplast


  • Has lysosomes
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