3. Importance of ATP Flashcards
What is ATP comprised of?
ATP is a nucleotide containing:
A pentose ribose sugar
An adenine purine base
Three phosphate groups
Why is ATP a “universal energy currency”?
It provides energy needed by all living organisms for all metabolic functions.
What processes does ATP provide energy for?
Active transport
Muscle contraction
Protein synthesis
What are the properties of ATP?
Inert
Soluble
Easily transported
Easily hydrolysed- only needs one enzyme
Releases energy in small, useable amounts
How is ADP formed from ATP?
ATPase hydrolyses the terminal bond between two phosphate groups, releasing 30.6KJ/mol in an exergonic reaction.
How is ATP formed from ADP?
When an inorganic phosphate is added to ADP via condensation, requiring 30.6KJ/mol in an endergonic reaction.
How much energy is released when breaking a phosphate bond?
30.6KJ/mol
What is the reversible reaction for ADP and ATP synthesis?
ATP + H2O ⇌ ADP + Pi + 30.6KJ/mol
Which enzyme synthesises ATP?
ATP synthase.
What is chemiosmosis?
The flow of protons down an electrochemical gradient, through ATP synthase, which provides the potential energy necessary to synthesise ATP by phosphorylation.
Describe the role of ATP synthase
Found in the stalked particles of the inner membranes, protons must pass through the enzyme, generating an electrochemical gradient, stimulating the phosphorylation of ADP to ATP.
What is another term for ATP synthesis?
Oxidative phosphorylation.
Where does ATP synthesis occur?
In the inner mitochondrial membrane of the mitochondria
In the thylakoid membrane of the chloroplasts
What spaces of the mitochondria are used in ATP synthesis?
Inter membrane space
Inner mitochondrial membrane
Matrix
What spaces of the chloroplast are used in ATP synthesis?
Thylakoid space
Thylakoid membrane
Stroma
Describe the steps of ATP synthesis
- Energy is released when excited electrons are passed from one carrier to another
- Energy is used to pump protons across the matrix
- An electrochemical gradient is created
- H+ ions pass through ATP synthase by chemiosmosis, creating a proton motive force
- This drives the synthesis of ATP from ADP + Pi
How do protons flow in the mitochondria?
Protons flow from the matrix, through the inner mitochondrial membrane via a proton pump, to the inter membrane space, then back into the matrix via ATP synthase.
How do protons flow in the chloroplast?
Protons flow from the stroma, through the thylakoid membrane via a proton pump, into the thylakoid space, then back into the stroma via ATP synthase.
What processes generate ATP (free energy)?
Aerobic respiration
Photosynthesis
What is an electrochemical gradient?
The flow of protons from a high to a low concentration, which is a source of potential energy.
What enzymes can also synthesise ATP?
Kinases.
