Signal Transduction 2 - Biological Molecules cntd.

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Signal Transduction 2 - Biological Molecules cntd.
2013-01-15 00:07:22
Biology James Jim Thomas Signal Transduction Biochemistry

Signal Transduction
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  1. What effects do Carbohydrates on cellular membranes have on hydro- interactions?
    i.e hydrophobicity/hydrophillia.
    Embedded Carbohydrate increase the hydrophillic nature of the membrane.
  2. Why do Carbohydrates cause a change in a membranes affinity with water?
    Carbohydrates contain -OH groups that will form hydrogen bonds with water. Therefore increasing hydrophillia.
  3. Glycerol is a key component of a fat molecule. It has the molecular formula, C3H8O3. Is this formula absolute?
    The molecular formula, C3H8O3 (Glycerol) is not absolute. Sometimes derivitves of glycerol are used instead. Such as a molecule with an N substituting a CH2 group.
  4. Are Steroids Proteins?
    • Steroids are not proteins. They are lipids with a variable -R group.
  5. Steroids have a backbone and an -R group. What is the basic structure of a steroid backbone?
    • A steroid backbone consists of three adjacent hexose rings, and a pentose. The -R group comes off of the pentose ring.
  6. Cholesterol is a Steroid. True or False?
    False. Cholesterol is a Sterol. A precursor to a Steroid.
  7. Cholesterol is "designed" to embed into membranes. How is this so?
    Cholesterol's large backbone and relatively small -R group mean it forms a peg-like structure that easily slips into membranes.
  8. What effect does embedded Cholesterol have on membranes?
    • Cholesterol has a stabillizing effect by increasing membrane fluidity by interfering with the fluid mosaic, preventing crystallization.
    • A lot of cholesterol however has the opposite effect, increasing crystallization.
  9. Do plants have cholesterol?
    Yes, plants do have Cholesterol.
  10. State one Similarity in behavior between Cholesterol and a Phospholipid.
    Both cholesterol and phospholipids are amphiphillic/amphoteric.
  11. How might you go about analyzing a phospholipid?
    You could use a phospholipase to cut the phospholipid at different points. By observing the fragments, conclusions can be drawn about the phospholipid.
  12. Where in the cell would you find the most proteins?
    Mitochondria and Chloroplasts have high numbers of proteins, due to their functionality.
  13. How might you identify an insulatory cell?
    Observation of it's membrane would reveal a high number lipids in it's membrane. It would also have fewer proteins than more active cells.
  14. Cells with high lipid numbers have high functionality, True or False?
    • False. Cells with high functionality have large numbers of Proteins but relatively few lipids.
  15. Name five functions of proteins.
    • Five of,
    • Structural, Storage, Transfer, Hormonal, Receptor, Contractile, Defensive and Enzymatic.
  16. Ka refers to acid dissociation in chemistry. Is this also true of cellular biology?
    Ka refers more to substrate attachment affinity of proteins to substrate, or ligands to receptors.
  17. Generally, do enzymes bind to Ligands? If not, what do they bind to?
    Enzymes do not tend to bind to Ligands. Instead they bind to other substrates, whereas Receptors are more associated with Ligand interactions.
  18. Which is more sensitive, a Receptor or an Enzyme? Be specific (Give numbers).
    • Receptors are far more sensitive than Enzymes. Receptors will begin to activate at concentrations greater than 10^-9M.
    • Enzymes only begin to show an effect at concentrations around 10^-4M.