cells

• how is human cell adapted for producing insulin?

  insulin is protein. contain many ribosomes for protein synthesis.
• why does the sourdough rise fastest at 27 degrees?

  optimum temperature for yeast. yeast respires(fermentation)
• why is the bread more sour at 32 degrees?

  more bacteria present. lactic acid produced by bacteria
• lactase is normally produced in the stomach of mammals explain why not true

  ph of stomach is acidic. if ph lower take long to digest. lactase produced where ph of stomach above 7
• how does bile increase digestion?

  emulsifies. so enzymes work better to break down lipids
• evaluate the use of embryo screening cystic fibrosis

  advantages : child with cystic fibrosis expensive to raise. greater chance have child without cystic fibrosis. disadvantages : risk from operation. ethical issues e.g. religion
• why does the movement of chloride ions cause water to pass out of the cells into the mucus?

  higher concentration of water outside cells. osmosis. water move from dilute concentration of water to concentrated area of water
• why is the mitochondria arranged around the filament near the tail of the sperm?


  mitochondria release energy for respiration. efficient arrangement. so energy available quickly
• what controls the rate of chemical reactions in the cytoplasm?

  enzymes or nucleus