Biology (B3)

All of biology (Section B3)

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Cells and DNA

What is found in both plant and animal cells?

  • Nucleus
  • Cell Membrane
  • Cytoplasm - Gel like solution containing enzymes
  • Mitochondria

What is found only in plant cells?

  • Chloroplasts - Where photosynthesis takes place
  • Rigid cell wall of cellulose (Support)
  • Large vacuole - Contains cell sap and helps with support
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Cells and DNA

By which process to do all living organism get their energy?

  • Respiration

Where does this process take place?

  • Mitochondria

What is the word equation for this process?

Glucose + Oxygen - Water + Carbon Dioxide (+ Energy)

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Cells and DNA

Where is DNA found?

  • Nucleus

Describe the structure of DNA:

  • Two strands (Double Helix) that contain lots of nucleotides
  • Each nuceoltide contians small molecules called bases (A& T / C&G)

What happens during DNA replication?

  • DNA copies itself everytime a cell divides
  • Double Helix 'unzips' to form to single strands
  • DNA unwides and new nucleotides join where the bases fit
  • Result = Two molecules of identical DNA
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DNA fingerprinting

What is genetic fingerprinting used for?

  • Pinpointing individuals
  • DNA is unique so used to compare samples of DNA
  • Used in foresic science - Crime scenes
  • Used in paternity tests

How does it work?

  • Isolate DNA from the cells
  • Use special enzymes to cut DNA into fragments (Cut at every place they regonise the order of bases)
  • DNA seperated using a process like chormotography - Suspended in gel, electric current passed through, DNA -ve so atttacted to +ve anode
  • DNA tagged with radioactive marker
  • Placed into photographic film, where it is dark thats were radioactivity is
  • Smaller bits move further throught so position of DNA revealed 
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Protein Synthesis

Describe DNA

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