3.3 - Respiration Flashcards
What is acetyl coenzyme A?
A two-carbon molecule formed in the link reaction when acetate reacts with coenzyme A. It is oxidised in the Krebs cycle.
What is aerobic respiration?
A form of cellular respiration that takes place in the presence of oxygen and produces carbon dioxide, water and ATP. It involves four main stages: glycolysis, link reaction, Krebs cycle and the electron transport chain. Overall:
C6H12O6 + 6O2 > 6CO2 +6H2O
Define anaerobic respiration
A form of cellular respiration that takes place in the absence of oxygen. In animals, lactate is produced. In plants and microorganisms, ethanol and carbon dioxide are produced. Less ATP is formed than is aerobic respiration.
What is coenzyme A?
a coenzyme that binds an acetyl group to form acetyl coenzyme A during the link reaction of aerobic respiration.
What is deamimation?
The removal of the amino group from a molecule. In the liver, amino acids are deaminated to form keto acids and ammonia.
What is the final electron acceptor in the electron transport chain?
Oxygen
1/2 O2 + 2e- + 2H+ > H2O
Explain what the electron transport chain (ETC) is
A series of electron carrier proteins that transfer electrons in a chain of oxidation-reduction reactions.
What is FAD?
A coenzyme that becomes reduced when it takes up hydrogen atoms during the Krebs cycle, forming reduced FAD.
What is glycolysis?
The first stage of the aerobic and anaerobic respiration that takes place in the cytosol of the cell and breaks down glucose into two molecules of pyruvate. Two molecules of ATP and two molecules of reduced NAD are also formed.
What is the inner mitochondrial membrane?
The mitochondrial membrane that segregates the matrix from the intermembrane space. It is the site of the electron transport chain.
Define Krebs cycle
A series of oxidation-reduction reactions in the matrix of the mitochondria in which acetyl coenzyme A is oxidised generating reduced NAD, reduced FAD, ATP and carbon dioxide.
What is the link reaction?
The second stage of aerobic reaction (also known as oxidative decarboxylation) that takes place in the mitochondrial matrix and converts pyruvate into acetyl coenzyme A and carbon dioxide. Reduced NAD is also formed. Overall:
Pyruvate +NAD + CoA > acetyl CoA + reduced NAD + CO2
What is NAD?
A coenzyme that becomes reduced when it takes up hydrogen atoms during aerobic respiration, forming reduced NAD.
Define oxidation
The loss of electrons, gain of oxygen or loss of hydrogen in a substance.
What is pyruvate?
A three-carbon molecule produced in glycolysis. In aerobic respiration, pyruvate is oxidised to acetate in the link reaction. In aerobic respiration it is converted to lactate (animals) or ethanol and carbon dioxide (plants and microorganisms).
