biology paper 1

• Organisms can be Prokaryotes or Eukaryotes
• All living things are made of cells
• Prokaryotic cells


  Single-celled organisms
• Eukaryotic cells


  Cells that have a nucleus and membrane-bound organelles
• Eukaryotic cells are found in animals and plants
• Prokaryotic cells are simple and single-celled
• Subcellular structures in most cells

  • Nucleus
  • Cytoplasm
  • Cell membrane
  • Mitochondria
  • Ribosomes
• Nucleus


  • Contains genetic material that controls the activities of the cell
• Cytoplasm


  • Gel-like substance where most chemical reactions happen
  • Contains organelles that control these chemical reactions
• Cell membrane


  • Holds the cell together and controls what goes in and out
• Mitochondria


  • Where most reactions for cellular respiration take place
  • Respiration transfers energy the cell needs to work
• Ribosomes


  • Where proteins are made in the cell
• Additional structures in plant cells

  • Rigid cell wall
  • Permanent vacuole
  • Chloroplasts
• Rigid cell wall


  • Made of cellulose, supports and strengthens the cell
• Permanent vacuole


  • Contains cell sap, a weak solution of sugar and salts
• Chloroplasts


  • Where photosynthesis occurs, contain chlorophyll to absorb light
• Bacterial cells are much smaller than plant and animal cells
• Bacterial cells


  • Don't have a true nucleus, instead have a single circular strand of DNA floating in the cytoplasm
  • May also contain small rings of DNA called plasmids
  • Don't have membrane-bound organelles like mitochondria or chloroplasts