Respiration Flashcards
What is aerobic respiration?
requires oxygen and produces carbon dioxide, water and ATP
what is anaerobic respiration?
takes place in the absence of oxygen and produces lactate or ethanol and carbon dioxide but only little ATP
what are the 4 stages of aerobic respiration?
– glycolysis
– link reaction
– krebs cycle
– oxidative phosphorylation
what are the stages of glycolysis?
– phosphorylation of glucose to glucose phosphate (add 2 phosphate molecules which come from the hydrolysis of ATP to ADP)
– splitting of the phosphorylated glucose into triose phosphate
– oxidation of triose phosphate where hydrogen is removed from each of the two triose phosphate molecules
– the production of ATP - pyruvate is formed whilst two ATP is formed from ADP
what is the overall yield from one glucose molecule undergoing glycolysis
– two x ATP
– two x reduced NAD
– two x pyruvate
what is the link reaction?
– the pyruvate is oxidised to acetate. The 3-carbon pyruvate loses a carbon dioxide molecule and two hydrogens.
– the 2-carbon acetate combines with a molecule called coenzyme A to produce acetylcoenzyme A
what is the Krebs cycle
– 2-carbon acetylcoenzyme A from the link reaction combines with a 4-carbon molecule to produce a 6-carbon molecule
– a series of reactions this 6-carbon molecule and a single molecule of ATP produced as a result of substrate-level phosphorylation
– the 4-carbon molecule can now combine with a new molecule of acetylcoenzyme A to begin the cycle again
For each molecule of pyruvate, what does the Krebs cycle produce?
– reduced NAD
– reduced FAD
– 1 x ATP
– 3 x CO2
What is the significance of the Krebs Cycle?
– it breaks down macromolecules into smaller ones
– it produces hydrogen atoms that are carried by NAD to the electron transfer chain and provide energy for oxidative phosphorylation
– it regenerates the 4-carbon molecule that combines with acetylcoenzyme A
– it is a source of intermediate compounds used by cells in the manufacture of other important substances such as fatty acids, amino acids and chlorophyll
what is oxidative phosphorylation?
some of the energy of the electrons within the hydrogen atoms is conserved in the formation of ATP
what is the process of oxidative phosphorylation using the electron transfer chain
– the hydrogen atoms produced during glycolysis and the Krebs cycle combine with the coenzyme NAD and FAD
– reduced NAD and FAD donate the electrons of the hydrogen atoms to first molecule in the ETC
– the electrons pass along a chain of electron transfer carrier molecules in a series of oxidation-reduction reactions
– the protons accumulate in the inter-membranal space before they diffuse back into the mitochondrial matrix through ATP synthase channels
– o2 is final electron acceptor
what other substances can be oxidised by cells to release energy?
– lipids
– proteins
How does respiration of lipids happen?
– lipids are first hydrolysed to glycerol and fatty acids
– glycerol is phosphorylated and converted to TP which enters the glycolysis pathway by the krebs cycle
how does respiration of protein happen?
– first hydrolysed to amino acids
– these have amino group removed before entering the respiratory pathway at different points.
In plants what is the pyruvate converted into?
ethanol and carbon dioxide
in animals what is the pyruvate converted into?
lactate
what is the equation for respiration in plants?
pyruvate+ reduced NAD
ethanol + CO2 + oxidised NAD
what is the equation for anaerobic respiration in animals
pyruvate + reduced NAD
lactate + oxidised NAD
