respiration Flashcards
define aerobic respiration
the controlled release of energy from food using oxygen
what is the chemical equation for aerobic respiration
C6H1206 +602 –> 6Co2 + 6H2O + energy
what is the first stage of aerobic respiration
glycolysis, it takes place in the cytosol
does glycolysis require oxygen
no
is glycolysis a high or low energy process
low energy
what are the products of glycolysis
pyruvic acid, 2ATP molecules, water
is stage 2 aerobic or anaerobic
aerobic, O2 is needed
where does stage two take place
in the mitochondria
what is formed from pyruvate in stage two
acetyl coenzyme A (acetyl coA)
how does NADH form
pyruvic acid loses two high energy electrons which combine with NAD+ and a proton to form NADH
where does NADH go at the end of stage two
it enters an electron transport system
where does acetyl coA go after being formed in stage two
it enters a series of reactions called the krebs cycle
where does the krebs cycle take place
the lumen of the mitochondria
is oxygen required for the krebs cycle
yes
what happens to the acetyl coA during the krebs cycle
it is broken down into carbon dioxide and protons
describe the main events of the krebs cycle
- acetyl coA combines with a 4 carbon molecule to form a 6 carbon molecule. 2. this 6 carbon molecule is broken down by releasing a Co2 and removing 2H which containes 2 electrons. 3. these two electrons and a proton combine with NAD+ to form NADH. 4. The five-carbon molecule releases another Co2 and 2H to form NADH. 5. one molecule of ATP + water are made from ATP + P. 6. another 2H are removed to form NADH.
what are the products of the krebs cycle
3 NADH molecules, two Co2 molecules, one ATP + water
outline the main events of the electron transport system
NADH formed in the krebs cycle enters an eectron transport chain. High energy electrons are passed from the NADH to electron acceptors. As this happens, energy is released and is used to form ATP and the rest is lost as heat . At the end of each system, the now low energy electron is removed by combining it with oxygen and hydrogen to form water.
what is oxidative phosphorylation
the production of ATP by the electron transport system, as it requires oxygen and phosphate
where does the electron transport system take place?
in the cristae of the mitochondria
what is fermentation
anaerobic respiration is called fermentation… two types: lactic acid fermentation and alcohol fermentation
what is lactic acid fermentation
occurs in some anaerobic bacteria, fungi and animal cells when there is not enough oxygen. glucose -> 2 lactic acid + small amout of energy
describe alcohol fermentation
takes place in bacteria, some fungi and plants when they are deprived of oxygen. this involves the partial breakdown of glucose. glucose -> 2 ethanol + 2 carbon dioxide + small amount of energy
how are micro-organisms used in bioprocessing
bacteria can be used to make yoghurts, antibiotics. yeast can be used to make beer + wine, fungi can produce antibiotics + citric acid
experiment: to prepare and show the production of alcohol by yeast
- dissolve 5g of glucose in 100cm^3 of water. 2. boil the solution in a conical flask for 5mins to elimiate gases + form anaerobic conditions. 3. when the solution cool, add a sachet (5G) of dried yeast. 4.cover the liquid with a thin layer of oil to prevent oxygen from entering. 5. add an airlock to the top of the conical flask with limewater. 6. Co2 produced will turn limewater cloudy/milky
Explain how you tested for ethanol production
- filter the solution to remove yeast cells. 2. add 3cm^3 of potassium iodide in a test tube. 3. add 3cm^3 of filtrate to the solution. 4. add 5cm^3 of sodium hypochlorite to the test tube. 5. warm the test tube gently in a water bath. 6. watch for pale yellow crystals being formed
