BY4 2

Card Set Information

BY4 2
2014-02-18 07:12:53

Wjec BY4
Show Answers:

  1. Define the lag phase of a growth curve.
    When cells are preparing for growth, with intense metabolic activity.
  2. Define the log phase of a growth curve.
    Providing there is no limiting factor, cell numbers increase exponentially, population doubles per unit time. 
  3. What is the number of ATP produced from the Link reaction in aerobic respiration per glucose molecule?
    • 6
    • 6 from 2 reduced NAD.
  4. What is a Pathogen?
    A disease causing microbe.
  5. How is Resting Potential created?
    • Sodium ions are actively pumped out faster than Potassium ions in.
    • Also most K+ channels are open and sodium ion channels closed, so K+ ions diffuse out faster than Na+ ions in.
    • Therefore fewer +ive ions inside the axon, so the outside is positive compared to the inside.
  6. What is the effect of Axon diameter on conduction speed?
    • As diameter increases conduction speed increases.
    • Due to less resistance from the Axoplasm.
  7. What is the energy consuming process when a cell directs the contents of a secretory vesicle out from the cell membrane into the extra cellular space?
  8. Describe Gram-negative Bacteria.
    • More chemically complex cell walls.
    • Peptidoglycan is supplemented by Lipopolysaccharide.
    • Do no not retain Crystal violet, so appear red or pink.
    • They are unaffected by Lysozyme and are resistant to Penicillin
  9. Describe density independent factors.
    • Effect is the same regardless of population density or size.
    • Eg. Extreme weather or temperature change.
  10. How is Action Potential created ?
    • The energy of the stimulus causes Sodium channels to open.
    • This causes Na+ ions to rapidly diffuse into the axon, which depolarises the membrane. 
    • Once the action potential of +40mV is established the channels close.
  11. What is the function of the Loop of Henle?
    To create a lower water potential in the Medulla.
  12. What is the name of counts that include both living and dead cells?
    Total counts.
  13. What is the of counts that count living cells only?
    Viable counts
  14. What are the main photosynthetic pigments found in plants?
    • Chlorophyll a.
    • Chlorophyll b.
    • Carotene.
    • Xanthophyll.
  15. Describe Photolysis.
    • The splitting of water molecules by light to produce Hions and electrons.
    • 2H20 ⇌2H+ 2OH
    • The hydoxyl ions donate the electrons to photosystem II.
  16. What is the name given to Spiral Shaped Bacteria?
  17. What is the effect of Temperature on conduction speed?
    • As temperature increases speed of conduction increases.
    • Due to increase in ion diffusion rate.