With the Cell Membrane

• What is the cell membrane & its function?

  The cell membrane is a differently permeable membrane, meaning only specific molecules can pass through it. its ability to keep the concentration of substances within the cell fairly constant and very different from the external environment depends on its structure. its phoslipid bilayer gives it the ability to flow and change.
• What are channel proteins & their functions?


  -> interspaced in the bilayer

  • channel proteins are as transport proteins, assisting in moving specific substances across the membrane.
  • acts as a passage way for substances -> example; rapid move of ions when a nerve is stimulated
• What is glycoprotein (where is it found) & its functions?

  -> Found on surface on the bilayer

  • functioning & facilitating, cell signaling, cell to cell recognition & cell adhesion.
• What are membrane proteins & their functions?

  -> various different proteins interspaced in the bilayer (ex; adhesion proteins)

  • have unique functions including;

  1. adhesion proteins; link cells
  2. receptor proteins; bind hormones & substances for cell activity
  3. recognition proteins; act as markers allowing the immune system to work.
• What is the phoslipid bilayer & its function?

  -> represented by a head & 2 tails (x2 'bi' layer)

  • a phosphate group on the head makes it hydrophilic (absorb + dissolve) & two fatty acid tails are hydrophobic (water avoidant).
• What is cholesterol & its function?

  -> interspaced among the phoslipid molecules

  • cholesterol strengthens & maintains the membrane via maintaining suitable fluidity.
• What can move through the phoslipid bilayer?

  -> oxygen

  -> carbon dioxide

  -> small amounts of water

  -> nonpolar molecules

  • fatty acids
  • vitamins
  • steroids
• What can't move through the phoslipid bilayer?

  • ions (+ & -); Na+, Ca²+,H+
  • polar molecules
  • glucose (sugar)
  • amino acids (proteins)
  • nuclei acids