Biology

• Characteristics of a living thing

  • Require source of energy
  • Nutrition
  • Respire (require oxygen)
  • Require water
  • Excretion (produce and remove wastes)
  • Movement
  • Composed of cells
  • Reproduce
  • Grow
  • Respond to stimuli
• These molecules came together to form primitive single celled organisms
• The 92 elements that are naturally occurring on Earth


  • Water
  • Oxygen and carbon dioxide
  • Nitrogen
  • Minerals (sodium etc)
• Organic molecules

  • Carbohydrates
  • Lipids
  • Proteins
  • Nucleic acids (DNA and RNA)
• Organic molecules are the predominant compounds of organisms and are produced by them
• Organic molecules are made up of the elements carbon, hydrogen, oxygen and nitrogen
• Cell types

  • Animal cells
  • Plant cells
  • Bacteria cells
• Animal cells

  • Only small vesicles for transport etc
• Plant cells

  • Denotes organelle is present in plant but not animal cells
• Prokaryotic cells

  Cells without a nucleus
• Eukaryotic cells


  Cells with a nucleus
• Surface Area: Volume Ratio
• Cell Theory


  • All living things are composed of cells
  • All cells come from pre-existing cells
  • The cell is the smallest living organisational unit
• Animal Cells


  • Only small vesicles for transport etc
• Plant Cells


  • Denotes organelle is present in plant but not animal cells
• Nucleus


  • Enclosed by a double membrane (nuclear envelope) with pores to allow m-RNA to leave
  • Role is to protect and confine the genetic information (DNA) of the cell
  • Contains chromosomes and nucleolus
  • Nucleolus is the site of ribosome production
  • Controls activities of the cell
• prokaryotes do not have mitochondria or chloroplasts.
• both prokaryotes and eukaryotes have ribosomes.
• the nucleus contains DNA which controls all activities within the cell.
• prokaryotes lack a nucleus and organelles such as ribosomes.
• prokaryotes reproduce by binary fission.
• prokaryotes have circular DNA that floats free within the cytoplasm.
• the cell wall provides support and protection to plant cells.
• the cytoplasm contains organelles such as the endoplasmic reticulum, golgi apparatus, lysosome, vacuole, cytoskeleton and ribosomes.
• mitosis is when cells divide into identical daughter cells.
• in eukaryotes, the cytoplasm is surrounded by a nuclear envelope with pores that allow substances to move between the two compartments.
• meiosis is where one parent cell divides twice to produce four genetically different gametes.
• eukaryotes contain a nucleus that is surrounded by a nuclear envelope.
• eukaryotes reproduce through sexual reproduction (meiosis) or asexual reproduction (mitosis).
• eukaryotic cells are larger than prokaryotic cells
• Eukaryotic organisms, multicellular
• prokaryotic organisms

  unicellular
• Six kingdoms of life

  animalia, plantae, fungi protista, bacteria and archaea
• Cell theory

  applies to all living things
• Nucleus

  protects and confines the genetic information of the cell
• Ribosomes

  assemble the building blocks to make proteins
• rough endoplasmic reticulum

  flattened sacs which are coated by ribosomes. allows the R.E.R to synthesise and modify proteins
• Smooth endoplasmic reticulum

  responsible for the production of lipids in a cell
• golgi apparatus

  sacs that are the sites of protein sorting, packaging and modification for use in the cell
• Lysosome

  contains digestive enzymes. responsible for breaking down waste and toxins.