respiratory substrates Flashcards
Intro to energy values of different respiratory substrates
When is majority of ATP produced
During oxidative phosphorylation when hydrogen ions / protons flow through channels associated with ATP synthase enzymes on the inner mitochondrial membranes
What happens to the hydrogen ions / protons and electrons later
Combine with oxygen to produce water
What is a respiratory substrate
An organic substance that can be used for respiration
What is the chief respiratory substrate in mm al am als and plants
Glucose
How do animals store glucose
And plants
Bith can be hydrolysis to glucose for respiration
As glycogen
As starch
What is a mol
The gram molecular mass of a substance
Energy values of different respiratory substrates
Theoretical max energy yield for glucose Is 2870 kj mol-1
It takes 30.6kj to produce 1 mol atp
Theoretically respiration of 1 mol of glucose should produce nearly 94 mol atp
Actual yield is more like 30 mol atp, 32% efficiency
Cz remaining energy I’d released as heat to maintain a suitable body temp allowing enzyme controlled reactions to proceed
Intro to protein
Excess amino acids coukd en delaminate after protein digestion
This involves removal of the amine group and it’s conversion to urea
The rest of the molecule is changed into glycogen or fat
Which can be stored and later respires to release energy
Energy values of protein
When an organism is fasting starving or in prolonged exercise protein muscle can be hydrolysed to amino acids which can be respired
Some can be converted to pyruvate or acetate and be carried into Krebs cycle
Some enter Krebs cycle directly
Number of hydrogen atoms per mole accepted by nad is higher than the number of hydrogen atoms per mole of glucose
So proteins release slightly more energy than equivalent masses of carbohydrate
Talk about triglycerides and their hydrolysis
They’re hydrolysed by lipase to fatty acids and glycerol
Glycerol can be converted to glucose and then respired but fatty acids can’t
Talk about intro to fatty acids
They’re long chain hydrocarbons with a carboxylic group
So have many carbon and hydrogen atoms in each molecule
Means the molecules are a good source of many protons for oxidative phosphorylation so they produce a lot of ATP
Lipids energy values
Each fatty acid is combined with coenzyme a
This requires energy from the hydrolysis of ATP to amp and 2 inorganic phosphate groups
The fatty acid-coenzyme a complex is transported into the mitochondrial matrix where it’s broken down into 2 carbon acetyl groups that are attached to coenzyme a
During this breakdown by the beta oxidation pathway, reduced nad and reduced fad are formed
The acetyl groups are releases from coenzyme a and enter Krebs cycle where 3 molecule of nad one molecule of fad and one molecule of ATP (by substrate level phosphorylation) are formed for each acetate
Large amounts of reduced nad is reoxidised at the electron transport chain, during oxidative phosphorylation, producing large amounts of ATP by chemiosmosis)
Can fats and proteins be respired anaerobically
No just carbs
They can’t go through glycolysis
