Chapter 1: ATP and Energy Flashcards
What is the structure of ATP?
- adenine
- ribose
- 3 phosphates
What is adenine?
it is a nitrogen containing base
What is ribose?
- a pentose sugar (five carbon ring)
- acts as the backbone of the molecule to which the other parts are attached
What type of molecule is ATP?
a nucleotide
What makes ATP a good energy donor?
phosphate bonds are unstable , so they can easily be broken, so the reaction to hydrolyse ATP has a low activation energy
when the bonds are broken, they release a lot of energy
What is the formula for the reaction of ATP being hydrolysed?
ATP + H₂O ——> ADP + Pᵢ + E
ADP= adenosine phosphate
E= energy
What is ATP hydrolysis?
when water is used to convert water to ADP, this reaction is catalysed by the enzyme ATP hydrolase
removes a phosphate group, releases energy
ATP—-> ADP
What kind of reaction is ATP hydrolysis?
a reversible reaction
What is ATP synthesis?
energy is used to add an inorganic phosphate to ADP to reform ATP
catalysed by ATP synthase, it is a condensation reaction
Why is ATP useful in biological processes? (5)
- released in small manageable amounts
- broken down easily, in a single one step reduction
- immediate energy available
- ATP is phosphorylated to make it more reactive
- easily generated
Where does ATP synthesis occur? (3)
- chlorophyll containing cells during photosynthesis (photo phosphorylation)
- plant/animal cells during respiration (oxidative phosphorylation)
- plant/animal cells when phosphate groups are transferred from donor molecule to ADP (substrate level phosphorylation)
Why is ATP a better energy release molecule than glucose?
-each ATP mol. releases less,more manageable quantities of ATP than glucose
-the hydrolysis of ATP to ADP is a single reaction so energy is released immediately
(breakdown of glucose is a long series of reactions so energy release takes longer)
more efficient to deliver energy in the form of ATP than gl.
When is ATP synthesised and hydrolysed?
ATP is synthesised during reactions that release energy because ATP synthesis requires energy
ATP hydrolysis occurs at the same time as reactions that require energy because ATP hydrolysis releases energy
Why can ATP not be stored?
due to the weak/unstable phosphate bonds, only little energy is required to break them (also energy density is low)
so it must be produced continuously
What effect does phosphorylation have on a molecule?
it makes it more reactive by reducing its activation energy
