Cell structure

1.2 Substance movement into & out of cells

Cell structure

  1. Animal cells

    1. The nucleus controls the activities of the cell
    2. The cytoplasm is where most of the chemical reactions occur
    3. The cell membrane controls the passage of substances into and out of the cell
    4. The mitochondria is where most energy is released during respiration
    5. The ribosomes are where protein synthesis occurs
    6. Most human cells are like most other animal cells

  2. Plant cells

    1. The chloroplasts absorb light energy to produce glucose
    2. A permanent vacuole is filled with cell sap
    3. The cell wall is made of cellulose and strengthens the cell

  3. Other cells

    1. Bacterial cell

      1. It consists of cytoplasm and a membrane surrounded by a cell wall
      2. The genes are not in a distinct nucleus
      3. Plasmids are circular structures in which some of the genes are located

    2. Yeast

      1. Yeast is a single-celled organism
      2. It consists of a nucleus, cytoplasm and a membrane surrounded by a cell wall

  4. Specialisation

    1. Cells may be specialised for a particular function, and this affects their structure
    2. Cells with many mitochondria need a lot of energy, such as muscle cells
    3. Cells with many ribosomes must make a lot of proteins, such as gland cells, which make enzymes
    4. Sperm cells have many mitochondria and a tail, since they require a lot of energy and swim
    5. Receptor cells have special structures that enable them to detect stimuli, such as cone cells, in the eye, which are light sensitive and specialised to connect to the optic nerve
    6. Mesophyll cells of a leaf have many chloroplasts for photosynthesis
    7. Root hair cells increase the surface area of a root so that it can absorb water and mineral ions efficiently