Glycolysis Flashcards
What is the function of the glycolytic pathway in terms of the metabolic release of energy?
the glycolytic pathway breaks down trapped glucose into 2 pyruvate molecules and releases energy
It also produces NADH which provides electrons later in cellular respiration
Identify the key features of glycolysis
- utilises substrate level phosphorylation
- breaks down 1 molecule of glucose (6 carbon) into 2 molecules of pyruvate (3 carbon)
What factors effect how pyruvate is used/produced?
- the oxygen levels present within the body
What is the metabolic importance of regenerating NAD+?
NAD+ is required to continue glycolysis from the beginning again, without it’s production energy cannot be produced
When and why might anaerobic glycolysis be important?
- during strenuous exercise
- in red blood cells where there is no mitochondria
What is the difference between the digestion and mobilisation of sugars?
digestion refers to breaking down large molecules in food via mechanical processes such as chewing
mobilisation refers to breaking down already stored molecules such as glycogen
Why is glycogenolysis important?
This process is important when gaining glucose from other sources or when it is not available
What occurs in step 2?
conversion of glucose-6-phosphate to fructose-6-phosphate
What occurs in step 3?
phosphorylation of fructose-6-phosphate into fructose -1,6- biphosphate
What occurs in step 4?
fructose 1,6 biphosphate is cleaved
What occurs in step 5?
DHAP is converted into glyceraldehyde-3-phosphate
What occurs in step 6?
glyceraldehyde 3- phosphate is oxidised to 1,3-biphosphoglycerate
What occurs in step 7?
phosphoryl transfer from 1,3-biphosphoglycerate to 3-phosphoglycerate
ATP is formed
What occurs in step 8?
3- phosphoglycerate becomes 2-
What occurs in step 9?
2-phosphoglycerate is dehydrated
What occurs in step 10?
a phosphoryl group is transferred
ATP is formed
What happens to pyruvate under aerobic conditions?
- pyruvate is oxidised to acetyl-coA (oxidative decraboxylation)
- Five coenzymes are involved in this five step reaction
- NAD+ is reduced to NADH producing 5 ATP (2 pyruvate = 2x 2.5 )
What happens to pyruvate under anaerobic conditions?
- pyruvate is reduced to lactate in animals via lactate dehydrogenase
Which cells may always undergo anaerobic respiration
- Red blood cells
as they do not have mitochondria
How does glucose get produced from our diet?
- polymers in our food (beginning in the salivary glands) are hydrolysed into glucose
How does glycogen get broken into glucose?
- glycogen stores are our main glucose storage
- it is hydrolysed into subunits
What occurs to glycogen stored in the liver?
- glycogen is hydrolysisd to glucose by the enzyme glucose 6 phosphate which only exists in the liver
- this helps to maintain blood glucose levels
What occurs to glycogen stored in the muscle?
- Glucose 6 phosphate directly enters glycolysis
- this acts as energy for muscle contraction
