3.11 ATP Flashcards
Biological processes that require energy
A
muscle contraction
cell division
transmission of nerve impulses
memory formation
Forms of energy
heat
light
energy in chemical bonds
cells require energy for three main types of activity
synthesis
transport
movement
synthesis
for example of large molecules such as proteins
transport
pumping molecules or ions across cell membranes by active transport
movement
fro example protein fibres in muscle cells that cause muscle contraction
What supplies energy
ATP
Adenosine triphosphate
Inside cells, molecules of ATP are able to supply this energy in such a way that it can be used.
ADP And ATP stand for
Adenosine triphosphate
Adenosine diphosphate
ATP is composed of:
nirogenous base
pentose sugar
three phosphate groups
base = adenine
sugar = ribose
ATP is a type of nucleotide.
Whys ATP known as universal energy currency
ATP is used for energy transfer in all cells of all living things.
Hence known as universal energy currency
How ATP releases energy
energy is needed to break bonds
energy is released when bonds are formed.
a small amount of energy is needed to break the relatively week bond holding the last phosphate group in ATP.
however a large amount of energy is released when the liberated phosphate undergoes other reactions such as bond formation.
overalla lot more energy is released then used,
approx 30.6kJ/mol
hydrolysis in ATP
water used
phosphate group released
energy released
ATP + H2O –> ADP + P1 + energy
the hydrolosis of ATP does not happen in isolation, but with energy requiring reactions.
known as coupled as they happen simulataneously.
Condensation reaction
water is released
energy released on the breakdown of molecules (Cellular respiration)
is used to create ATP
Reattaching phosphate group to ADP.
process is called phosphorylation.
instability of phosphate bonds in ATP
means they are not good long term energy stores.
Fats and carbs are much better for this.
ATP as a good immediate energy store
ATP is instable
cells do not store a large amount of it.
However, ATP is rapidly reformed by the phospharylation of ADP.
this interconversion of ATP and ADP is happening constantly withinc cells.
meaning cells do not need a large store of ATP.
ATP is therefore a good immediate energy store.
Properties of ATP
small - moves easily into and out of and within cells
water soluble - energy requiring processes happen in aqueous environments
releases energy is small quantities - quantities are suitable to most cellular needs, so that energy is not wasted as heat.
easily regenerated - can be recharged with energy
contains bonds between phospahtes with intermediate enegry: large enough to be useful for cellular reactions but not so large that energy is wasted as heat.
