The link reaction

Question 1

What is the Link reaction?

Answer 1

• first step in aeorbic respiration
• also called oxidative decarboxylation
• links anaerobic glycolisis in cytoplasm, to the aeorbic steps of respiration, occuring in the mitochnondria

Question 2

Where does pyruvate enter in eukaryotic cells? How does it do thsi?

Answer 2

• enters the mitochondrial matrix
• large molc
  
  • needs to be actively transported via specific carrier proteins

Question 3

What is oxidative decarboxylation?

Answer 3

• removal of carbon dioxide from pyruve (decarboxylation)
• along with hydrogen (oxidation)

Question 4

What happens the hydrogen atom removed?

Answer 4

• accepted by NAD
• NAD reduced to form reduced NAD (NADH)

Question 5

What happens to the remain two carbon molecule?

Answer 5

• the remaining two-carbon acetyl groups (… - COCH3) bounds by coenzyme A forming acetylcoenzyme A (acetyl CoA)

Question 6

What is the IUPAC name for acetyl group?

Answer 6

• ethanoyl (…COCH₃)
• although traditional name retained

Question 7

What is the function of acetyl CoA?

Answer 7

• delivers the acetyl group to the next stage of aeorobic respiration known as the Krebs cycle

Question 8

What is the reduced NAD used for?

Answer 8

oxidative phosphorylation to synthesis ATP

discussed later

Question 9

What happens to the carbon dioxide?

Answer 9

• diffuse away as metabolic waste
• or may beused a raw material for photosynthesis in autotrophic organisms