Animal cells

• Describe the structure of the nucleus.

  • Nuclear Envelope- double membrane
  • Nuclear Pores
  • Nucleoplasm –granular, jelly-like material
  • Chromosomes –protein bound, linear DNA
  • Nucleolus –smaller sphere in the nucleoplasm which is the site of rRNA production and ribosome synthesis.
• Describe the function of the nucleus.

  • Site of DNA replication and transcription (making mRNA)
  • Contains the genetic code for making polypeptides.
  • The nucleolus is the site of ribosome and RNA production.
• Describe the structure of the mitochondria.

  • Double membrane with inner membrane folded into cristae
  • 70S ribosomes in matrix
  • small, circular DNA
  • enzymes in matrix
• Describe the function of the mitochondria.

  Site of aerobic respiration and therefore ATP production
• Describe the structure of the golgi apparatus & the vesicles.

  • Fluid-filled, membrane-bound sacs (horseshoe shaped)
  • vesicles at edge
• Describe the function of the golgi apparatus & vesicles.

  • Modifies proteins received from RER
  • packages them into vesicles to transport to cell membrane for exocytosis
  • makes lysosomes
• Describe the structure of the lysosomes.

  A small, spherical organelle enclosed by a single membrane, containing a variety of digestive enzymes
• Describe the function of the lysosomes.

  • Hydrolyse pathogens in phagosomes.
  • Completely break down dead cells (autolysis)
  • Exocytosis– release enzymes outside of the cell to destroy material
  • Digest worn-out organelles for reuse of materials
• Describe the structure of the ribosomes.

  • Small granules, made up of two sub-units of protein and rRNA
  • 80S -large ribosome found in eukaryotic cells (25nm)
  • 70S -smaller ribosome found in prokaryotic cells, mitochondria and chloroplasts.
• Describe the function of ribosomes.

  Site of protein synthesis where polypeptide chain is made
• Describe the structure of the cell membrane.

  Phospholipid bilayer with embedded intrinsic & extrinsic proteins
• Describe the function of the cell membrane.

  • Selectively permeable barrier
  • controls passage of substances in and out the cell
  • barrier between internal and external cell environments
• Describe the function of the rough ER.

  • Site of protein synthesis
  • folds polypeptides to secondary & tertiary structures
  • packaging into vesicles to transport to Golgi
• Describe the function of the smooth ER.

  Synthesises and processes lipids
• Describe the structure of the rough ER.

  • System of membranes with bound ribosomes
  • continuous with nucleus
• Describe the structure of the smooth ER.

  System flattened, folded membranes called cisternae with no bound ribosomes