Cells Biology Paper 1

• Organisms can be Prokaryotes or Eukaryotes
• Components of cells


  • Cell membrane
  • Cytoplasm
  • Nucleus
  • Mitochondria
  • Ribosomes
• Prokaryotic cells


  • Smaller and simpler than eukaryotic cells
  • Lack a true nucleus
  • Have a single circular strand of DNA floating in the cytoplasm
  • May contain plasmids
• Eukaryotic cells


  • More complex than prokaryotic cells
  • Have a true nucleus
  • Have membrane-bound organelles like mitochondria and chloroplasts
• Additional structures in plant cells

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


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


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


  Where photosynthesis occurs, contain chlorophyll to absorb light
• Bacterial cells are much smaller than plant and animal cells
• Bacterial cells lack chloroplasts and mitochondria
• The nucleus contains the genetic material (DNA) which controls all cell activities
• Mitochondria are responsible for producing energy through aerobic respiration.
• Ribosomes are involved in protein synthesis, making proteins from amino acids.
• Vacuoles store water and other substances such as pigments or starch
• Vacuoles store water, nutrients, and waste products within the cell.
• Lysosomes contain digestive enzymes that break down waste materials inside the cell.
• Lysosomes contain enzymes that break down waste materials inside the cell
• Mitochondria - produce energy from glucose
• Ribosomes - sites of protein synthesis
• Ribosomes make proteins from amino acids
• Nucleolus - site of ribosome production
• Ribosomes synthesize proteins using information from DNA.
• Cell membrane - controls what enters/exits the cell