Cellular Respiration Flashcards
Why do autotrophic organisms need to respire?
Cannot rely solely on photosynthesis as an energy source
What do autotrophic organisms do?
They can fix carbon as complex organic molecules, which are used as an energy source
What advantage do autotrophic organisms have over heterotrophic organisms?
Autotrophic organisms can create their own energy source to use when dark (no photosynthesis occurring)
How do heterotrophs gain their supply of energy?
By eating plants or organisms which have derived their energy from autotrophs (complex organic compounds)
What does ‘the energy currency of cells’ refer to?
ATP
Which types of organisms respire, transferring energy from carbon compounds into ATP?
Animals, plants, microorganisms
What processes require ATP?
Activation of chemicals/active transport/transport of molecules across cell membrane/movement/protein synthesis/cell division
What is the role of ATP?
Short term and immediate energy supply
How does ATP differ from carbs/fats?
Carbs and fats act as a long term energy storage
How does ATP turn into ADP?
The ATP is hydrolysed by the removal of one of its inorganic phosphates
How much energy is released through the hydrolysation of ATP to ADP?
30.5 kj of energy is released for immediate use by cells
What is crucial about the release of energy, as a result of the hydrolysation?
It is important energy is not released in large bursts otherwise there is risk of energy wastage and damage to cells
What is ATP?
A triphosphate nucleoside composed of; the base: adenine; the pentose sugar: ribose; and three phosphate groups
What is ADP?
A diphosphate nucleoside composed of; the base: adenine; the pentose sugar: ribose; and two phosphate groups
ADP + Pi and energy added =
ATP
Why are enzymes important in respiration?
Each step in respiration is an enzyme-catalysed reaction
What is the basic description of a coenzyme?
An additional molecule, to the enzyme, which assists the enzyme in carrying out its function
Why might hydrogenase enzymes require a coenzyme?
In oxidation/reduction reactions, they require another molecule to act as the acceptor or donor, of the hydrogen atoms removed by the enzyme
Oxidation?
A chemical reaction, in which, hydrogen atoms or electrons are lost; or oxygen atoms are gained
Reduction?
A chemical reaction, in which, hydrogen atoms or electrons are gained, or oxygen atoms are lost
What actually is a coenzyme?
A non-protein, organic molecule, which binds to an enzymes AS
What is NAD (nicotinamide adenine dinucleotide)?
A hydrogen carrier molecule, made in the body, it is an important molecule involved in all stages of respiration
What does the nicotinamide part of an NAD molecule do?
Accepts a pair of hydrogen atoms, becoming reduced as it does so. When it loses the hydrogen atoms it becomes reduced
What is FAD (flavin adenine dinucleotide)?
Similar molecule to NAD and also acts as a hydrogen carrier
How does FAD differ from NAD?
Contains riboflavin instead of nicotinamide; FAD is tightly bound to a dehydrogenase enzyme (embedded in the mitochondrial inner membrane), so only pumps hydrogens back into the matrix
How is coenzyme A similar to other co-enzymes?
Also an organic molecule
