3.11 ATP

Question 1

What are the three main types of activity that cells require energy for?

Answer 1

• synthesis for example large molecules such as proteins
• transport for example pumping molecules or ions across cell membranes by active transport
• movement for example protein fibers in muscle cells that cause muscle contraction

Question 2

What are the examples of some of the biological processes that require energy?

Answer 2

• muscle contraction, cell division, the transmition of nerve impulses and even memory formation

Question 3

What has to be ensured when energy is supplied?

Answer 3

• its has to be supplied in the right form and quantity to the processes that require it

Question 4

What chemical is inside cells is used to supply energy to the cell?

Answer 4

• Adenosine triphosphate (ATP)
• able to supply the cell in such a way that it can be used

Question 5

What is the structure of an ATP molecule?

Answer 5

• nitrogenous base, three phosphate groups and a pentose sugar

Question 6

How is ATP molecule different to an DNA nucleotide?

Answer 6

• in ATP the base is always adenine
• there are three phosphate groups instead of one
• the sugar in ATP is ribose, as in RNA nucleotides

Question 7

When is a large amount of energy released in the process of ATP?

Answer 7

• when the liberated phosphate undergoes other reactions bond formation

Question 8

When is a small amount of energy released in the process of ATP?

Answer 8

• needed to break the relatively weak bond holding the last phosphate group in ATP

Question 9

What is the hydrolysis reaction involved in the release of energy by ATP?

Answer 9

• as water is involved in the removal of the phosphate group

Question 10

How does hydrolysis of ATP happen?

Answer 10

• it does not happen in isolation but in association with energy-requiring reactions
• the reactions are said to happen simultaneously and are ‘coupled’

Question 11

What is ATP hydrolysed into?

Answer 11

• adenosine diphosphate (ADP) and a phosphate ion, releasing energy

Question 12

What does the instability of the phosphate bonds in ATP cause and what materials are much better at this?

Answer 12

• this means that it is not a good long-term energy store
• fats and carbohydrates

Question 13

What is cellular respiration?

Answer 13

• the energy released in the breakdown of these molecules is used to create ATP

Question 14

How does cellular respiration occur and what is this process called?

Answer 14

• by reattaching a phosphate group to an ADP molecule
• phosphorylation

Question 15

Water is removed in cellular respiration, so what is this reaction called?

Answer 15

• a condensation reaction

Question 16

What are the five properties of ATP?

Answer 16

small - moves easily into and out of and within cells
water soluble - energy-requiring processes happen in aqueous environments
contains bonds between phosphates with intermediate energy - large enough to be useful for cellular reactions but not so large that energy is wasted as heat
releases energy in small quantities - quantities are suitable to most cellular needs, so that energy is not wasted as heat
easily regenerated - can be recharged with energy

Question 17

What does the structure and property of ATP mean?

Answer 17

• it is ideally suited to carry out its function in energy transfer

Question 18

What happens due to the instability of ATP?

Answer 18

• cells do not store large amounts of it
• however, ATP is rapidly reformed by the phosphorylation of ADP

Question 19

What makes ATP a good immediate energy source?

Answer 19

• the interconversion of ATP and ADP is happening constantly in all living cells
• meaning cells do not need a large store of ATP