Paper 1: Cells

• A animal and plant cells are eukaryotic cells as they have a nucleus
• Bacterial cells are prokaryotic cells, meaning they do not have a nucleus.
• Organelles- structures in a cell with different functions: cell membrane, mitochondria
• Nucleus

  • contains dna
• Cytoplasm

  • liquid substance in which chemical reactions occur
  • contains enzymes: biological catalysts
  • organelles are found in it
• Cell Membrane

  • controls what enters and leaves the cell
• Mitochondria

  • where aerobic respiration occurs providing energy for the cell
• Ribosomes

  • where protein synthesis occurs
• Only in Plant cells

  Chloroplasts

  • where photosynthesis takes place
  • contains green pigment called chlorophyll which absorbs light needed for photosynthesis
• Only in plant cells

  Permanent Vacuole

  • contains cell sap
  • found within the cytoplasm
  • improves cells rigidity
• Only in plant cells

  Cell wall

  • made from cellulose
  • provides strength to the cell
• Sperm cells are specialised cells

  Function -used to carry male's DNA to the egg cell for fertilisation

  • Many mitochondria which supply lots of energy to allow cell to move
  • The acrosome (top of the head) has digestive enzymes which break down outer layers of eggs membrane
• Nerve cells are specialised cells

  Function: transmit electrical signals quickly from one place in the body to another

  • axon is long so impulses can be carried over a longer distance
  • nerve endings have many mitochondria which supply energy to transmitters
• Muscle cells are specialised cells

  muscle cells contract quickly in aerobic respiration

  • lots of mitochondria which provides energy from respiration for contraction
  • can store glycogen which can be used in respiration by mitochondria