Respiration

• What processes require ATP

  Cellular movement

  Contraction of muscles

  Homeostasis
• Glucose equation


  C6H1206 + 6 O2 → 6 CO2 + 6 H20 + energy (kJ)
• Key example that requires active transport

  Sodium-potassium pump
• How does the structure of mitochondria allow it to carry out its function properly

  You need to explain that an increased surface area of the inner membrane means there aremore electron transport chain carriersandATP synthaseenzymes which results inmore ATPbeing produced
• Four stages of aerobic respiration

  1. Glycolysis

  2. Link reaction

  3. Krebs cycle

  4. Oxidative phosphorylation

  
  

  (Look at A4 sheet)
• Define coenzyme


  An enzyme carry out its function but is not used in the reaction itself
• What does a coenzyme consist of?

  nucleoside (ribose and adenine) and a vitamin
• NAD + FAD


  Electronsfrom reduced NAD (NADH) and reduced FAD (FADH2) are given to the electron transport chain

  Hydrogen ionsfrom reduced NAD (NADH) and reduced FAD (FADH2) are released when the electrons are lost

  
• Oxygen's key role in respiration

  Oxygen is thefinal acceptor of electronsfrom the electron transport chain

  (without this):

  The electron transport chain stops functioning

  No more ATP is produced via oxidative phosphorylation

  Reduced NAD and FAD aren’t oxidised by an electron carrier

  No oxidised NAD and FAD are available for dehydrogenation in the Krebs cycle

  The Krebs cycle stops
• Anaerobic respiration


  Yeast and microorganisms useethanol fermentation

  Other microorganisms and mammalian muscle cells uselactate fermentation

  (Note that ethanol fermentation is a two-step process (lactate fermentation is a one-step process)
• Ethanol fermentation


  In this pathway reduced NAD transfers its hydrogens to ethanal to form ethanol

  In the first step of the pathwaypyruvate is decarboxylatedto ethanal (producingCO2)

  Thenethanal is reducedto ethanol by the enzyme alcohol dehydrogenase

  Ethanal is the hydrogen acceptor

  Ethanol cannot be further metabolised; it is a waste product
• Lactate fermentation


  In this pathway reduced NAD transfers its hydrogens to pyruvate to form lactate

  Pyruvate is reducedto lactate by enzyme lactate dehydrogenase

  Pyruvate is the hydrogen acceptor

  The final product lactate can be further metabolised
• Explain why carbohydrates, lipids and proteins have different relative energy values as substrates in respiration in aerobic conditions. (6 marks) (notes)

  1. Different substrates have different numbers of hydrogens

  
  

  2. lipids have more H than carbohydrates or proteins

  
  

  3. Oxidation of substrate provides H atoms for reduction of NAD/FAD

  
  

  4. NAD / FAD provides H to ETC, which dissociates into protons and electrons and creates a proton gradient

  
  

  5. Therefore chemiosomosis and oxidative phosphorylation

  
  

  6. More ATP, hence higher relative energy value

  
  

  Define the term respiratory quotient (RQ) and describe how you would carry out an investigation to determine the RQ of germinating barley seeds.[9]
• RQ equation


  CO2 produced/O2 consumed

  (no units)

  
  

  Make sure to balance equation (only look at coefficient)
• What does the matrix contain?

  Enzymes for the Krebs cycle and Link Reaction, mitochondrial DNA
• How many ATP produced from 1 glucose molecule?

  If… NADH - results in the synthesis of 3 ATPAnd… FADH2- results in the synthesis of 2 ATP
• How many ATP can be produced from 1 glucose molecule?

  38 ATP
• Enzymes used in aerobic respiration

  Dehydrogenases (involved in removal and delivery of H atoms to coenzymes).

  
  

  Decarboxylases (involved in removal of carbon dioxide (link and krebs)
• Coenzymes used in aerobic respiration

  Glycolysis =NAD coenzymes(accept removed hydrogens and electrons to form NADH)

  Link reaction =NAD coenzymesandCoenzyme A(binds acetyl group to form acetyl CoA and breaks down to form acetate at the beginning of krebs)

  Krebs cycle =NADandFAD coenzymes(accept hydrogens and electrons to become reduced)
• Conezymes aerobic respiration


  Aerobic respiration - pyruvate is decarboxylated by pyruvate dehydrogenase complex to form Acetyl-CoA

  
  

  decarboxylase - krebs and oxidative phosphorylation
• Coenzymes in anaerobic respiration


  NAD+
• NADH role


  NADH - is involved in glycolysis and the kreb cycle, acting as anelectron carrier.

  NADHacceptselectrons from glucose molecules during glycolysis andtransfersthem to other molecules in the citric acid cycle.

  This process allows for the production of ATP (ATP synthesise)Then used for; cellular movement ...
• ATP


  Part of atp synthesise

  Production of energy; cellular movement, muscle contraction