[12.1] glycolysis Flashcards
what are the 4 stages of respiration?
- glycolysis
- link reaction
- krebs cycle
- oxidative phosphorylation
what is the purpose of glycolysis?
a hexose sugar (usually glucose) is split into two molecules of the 3-carbon molecule, pyruvate
what are the 4 stages of glycolysis?
- phosphorylation of glucose into glucose phosphate
- splitting of the two phosphorylated glucose
- oxidation of triose phosphate
- production of ATP
what occurs during the 1st step of glycolysis?
before it can be split into two, glucose must first be made more reactive by adding 2 phosphate molecules (phosphorylation)
where do the phosphate molecules required for phosphorylation come from?
hydrolysis of 2 molecules of ATP to ADP + Pi
what does energy produced during hydrolysis of ATP in phosphorylation do?
- energy is provided to activate glucose
- lowers the activation energy for the enzyme-controlled reactions that follow
what occurs during the 2nd step of glycolysis?
glucose bisphosphate molecule (6C) is split into two 3C molecules (triose phosphate)
what occurs during the 3rd step of glycolysis?
H is removed from each of the 2 triose phosphate molecules and transferred to NAD to form reduced NAD
what occurs during the 4th step of glycolysis?
- enzyme-controlled reactions convert each triose phosphate into another 3-carbon molecule called pyruvate
- in the process two molecules of ATP are regenerated from ADP
describe the equations for the 5 reactions involved in glycolysis
- glucose + 2ATP -> phosphorylated glucose
- phosphorylated glucose -> 2 triose phosphate
- 4H + 2NAD -> 2NADH + 2H⁺
- 4Pi + 4ADP -> 4ATP
- 2 triose phosphate -> 2 pryuvate
what are the products formed from 1 molecule of glucose in glycolysis?
- 2 x ATP
- 2 x NADH
- 2 x pyruvate
