energy Flashcards
(14 cards)
where does all energy come from?
all energy comes from the sun
what do plants and animals do with this energy?
plants use this energy to combine water and carbon dioxide to make complex organic molecules such as carbohydrates. plants and animals can then oxidise these molecules during respiration to form ATP which is the main energy source used in cell.
where does energy always come from when cells carry out any process that requires energy?
when cells carry out any process that requires energy, the energy always comes from ATP, never directly from any nutrient. ATP is the cell’s form of energy.
ATP is continuously …
ATP is continuously hydrolysed and then re-synthesised
how is ATP synthesised?
ATP is synthesised by the phosphorylation of ADP via a condensation reaction using the enzyme ATP synthase. the energy released from the breakdown of glucose during respiration is used to join a phosphate molecule to adenosine diphosphate to produce adenosine triphosphate.
what does phosphorylation of ADP require?
energy : from respiration
in what three ways is ATP synthesised?
- photophosphorylation in chloroplast of plant cells during photosynthesis
- oxidative phosphorylation during respiration in animal and plant cells
- substrate level phosphorylation when phosphates from donor molecules are used during respiration in animal and plant cells
cells use ATP as …
cells use ATP as the immediate energy source for biological processes
how is ATP hydrolysed?
ATP is easily hydrolysed as the phosphoanhydride bonds between the phosphate groups have a low activation energy. ATP is hydrolysed using the enzyme ATP hydrolase to release energy when the bond between phosphates is broken.
what is ATP known as and why?
ATP is known as the universal energy carrier, because it is used by all biological organisms
why is ATP an ideal energy carrying molecule?
- when ATP is hydrolysed energy is released in small, manageable amounts
- energy is released immediately in a single step reaction
- it is soluble in water
- it cannot be stored
the inorganic phosphate that is removed during the hydrolysis of ATP can be used to …
the inorganic phosphate that is removed during the hydrolysis of ATP can be used to make other molecules more reactive (for example, in respiration the phosphate is added to the stable glucose molecule to make phosphorylated glucose. this is unstable and can be broken down to release energy)
what are examples of energy requiring processes in living cells that energy released from ATP used for?
- active transport
- synthesis reactions eg protein / DNA synthesis
- muscle contraction
- cell division
- light independent reactions of photosynthesis
- first stage of glycolysis
describe the turnover and storage of ATP
ATP is not stored in cells or in organisms. instead, ATP is continuously hydrolysed and then phopshorylated. each molecule is ‘recycled’ hundreds of times per day.
