energy and ATP

Question 1

what are the three parts of ATP?

Answer 1

adenine
ribose
phosphates

Question 2

what is adenine?

Answer 2

a nitrogen- containing organic base

Question 3

what is ribose?

Answer 3

a sugar molecule with a 5 carbon ring structure (pentose sugar) that acts as the backbone to which other parts are attached

Question 4

what are the phosphates in ATP?

Answer 4

a chain of THREE phosphate groups

Question 5

what is ATP?

Answer 5

a nucleotide that has three phosphate groups

Question 6

what is the strength of the bonds between phosphates in ATP and what does this mean?

Answer 6

unstable/ weak bonds and so they have a low activation energy- easily broken

Question 7

when is ATP synthesised or hydrolysed?

Answer 7

synthesised during reactions that release energy and hydrolysed to provide energy for reactions that require it

Question 8

write a hydrolysis reaction for turning ATP into ADP?

Answer 8

ATP + H20 —–> ADP + Pi + E

Question 9

write a hydrolysis reaction which turns adenosine triphosphate into adenosine diphosphate?

Answer 9

adenosine triphosphate + water ——> adenosine diphosphate + inorganic phosphate + energy

Question 10

what enzyme is used to hydrolyse ATP into ADP?

Answer 10

ATP hydrolase (or ATPase)

Question 11

what kind of reaction is the conversion between ATP and ADP?

Answer 11

reversible reaction!

Question 12

write a symbol equation for the condensation reaction to form ATP from ADP?

Answer 12

ADP+ Pi + E ——> ATP + H20

Question 13

what is the enzyme used in the condensation reaction to form ATP from ADP?

Answer 13

ATP synthase

Question 14

in what three ways does the synthesis of ATP from ADP occur?

Answer 14

1. in chlorophyll-containing plant cells during photosynthesis (photophosphorylation)
2. in plant and animal cells during respiration (oxidative phosphorylation)
3. in plant and animal cells when phosphate groups are transferred from donor molecules to ADP (substrate-level phosphorylation)

Question 15

why is ATP a good energy donor but not a good long-term energy store?

Answer 15

the instability of its phosphate bonds

Question 16

why is ATP a better immediate energy source than glucose?

Answer 16

• each ATP molecule releases less energy than each glucose molecule. The energy released for reactions is therefore released in smaller, more manageable quantities
  -the hydrolysis of ATP to ADP is a single reaction that releases immediate energy compared with the breakdown of glucose which is a long series of reactions

Question 17

what 5 uses of ATP in energy-requiring processes do we need to know about?

Answer 17

1. metabolic processes
2. movement
3. active transport
4. secretion
5. activation of molecules

Question 18

how is ATP used in metabolic processes?

Answer 18

ATP provides the energy needed to build up macromolecules from their basic units e.g. making starch from glucose or making polypeptides from amino acids

Question 19

how is ATP used for movement?

Answer 19

provides energy for muscle contraction
-provides energy for the filaments of muscle to slide past one another and therefore shorten the overall length of a muscle fibre

Question 20

how is ATP used in active transport?

Answer 20

provides the energy to change the shape of carrier proteins in plasma membranes- allows molecules or ions to move against the concentration gradient

Question 21

how is ATP used for secretion?

Answer 21

ATP needed to form lysosomes necessary for the secretion of cell products

Question 22

how is ATP needed for activation of molecules?

Answer 22

inorganic phosphate released during the hydrolysis of ATP can be used to phosphorylate other compounds to make them more reactive, thus lowering the activation energy in enzyme-catalysed reactions