Cells

• The cell membrane is the outermost layer that surrounds all cells.
• The nucleus is the control center of the cell, containing the genetic material and regulating cell activities.
• Cholesterol helps maintain fluidity and stability of the membrane.
• Cytoplasm is the gel-like substance inside the cell where most chemical reactions take place.
• Ribosomes are responsible for protein synthesis within the cell.
• Vacuole stores water, nutrients, and wastes in plant cells.
• Cell wall provides structural support and protection to plant cells.
• Plasma membrane regulates what enters and exits the cell.
• Chloroplasts are found only in plants and algae and are involved in photosynthesis.
• Vacoula protects the cell and makes it quite rigid
• Cell wall


  Found on the outside of a plant cell and it surrounds the cell membrane
• Cell wall


  • Small holes to allow substances to pass through the cell wall and then also through the cell membrane
• Cell wall

  Made of cellulose, which is a very tough material
• Plant cells


  • More regular shape than animal cells
• Lymphocyte


  Has a massive wobbly nucleus for storing instructions to make antibodies
• Phagocyte


  Has a big 'blobby' nucleus that can change shape easily
• White blood cells

  • Protect the body from infections
  • Irregular in shape with flowing cytoplasm causing shape changes
  • Have a nucleus unlike red blood cells
• Haemoglobin molecules give a 'piggyback ride' to oxygen and carbon dioxide in and out of the body
• Phagocytes


  Protect the body from infection by 'eating' harmful microorganisms
• Lymphocytes


  Produce antibodies that attack harmful microorganisms in the blood, such as bacteria and viruses
• Red blood cells lack a nucleus, allowing more space for haemoglobin to carry oxygen throughout the body
• Haemoglobin

  • Responsible for the delivery of oxygen from the lungs to all over the body
  • Forms oxyhaemoglobin when in contact with oxygen, facilitating oxygen transport to different tissues
  • Bonds with carbon dioxide at tissues and transports it back to the lungs via the blood stream for exhalation
• Nerve cells

  Nerve cells or neurons are highly specialised

  and adapted cells, and they look very strange

  tool The purpose of nerve cells is to transmit

  electric signals, called nerve impulses. They

  connect sense receptors in the body, such as in

  skin and muscles, to the spinal chord and then

  to the brain.
• Epithelial cells


  Type of cells that cover surfaces of the body and line organ cavities
• Our skin is made of epithelial cells tightly packed together, forming a protective barrier
• Ciliated epithelial cells


  • Have cilia on their free surface
  • Line up the cavities and pipes of the respiratory system
  • Help move foreign particles trapped in mucous out of the body
• Cilia move back and forth

  Help move foreign particles trapped in mucous out of the body
• Ciliated epithelial cells line the trachea, bronchi, lungs, and parts of the nose cavity
• Cilia


  Hair-like extensions of the cell membrane of some cells
• Dendrites


  Branch out from the head (cell body) of a neuron and receive signals
• Axon


  Nerve fibre that transmits electrical impulses
• Signal transmission in neurons

  1. Dendrites receive signals

  2. Transmits as an electrical impulse through the cell body

  3. Down the axon

  4. To the axon terminals

  5. Pass on the signal to a neighbouring neuron's dendrites
• Neurons


  • Dendrites receive signals
  • Axons send signals
• Root hair cells


  • Adapted for taking up water and minerals
  • Long hair-like projection increases surface area
  • Large vacuole stores more water and minerals
  • Contains lots of mitochondria for energy release
• Plants absorb water from the soil through their roots
• Function of root hair cells

  Absorb more water and minerals from the soil
• Role of large vacuole in root hair cells

  Stores more water and minerals
• Root hair cells do not need chloroplasts since roots are underground and cannot photosynthesise
• Palisade cells


  • Found on the upper part of a leaf
  • Absorb sunlight for photosynthesis
  • Tall and thin to fit closely together
  • Packed with chloroplasts
• Purpose of palisade cells


  To absorb sunlight for photosynthesis