Importance Of ATP

Question 1

ATP structure

Answer 1

• nucleotide

- 3 phosphates, ribose, adenine

Question 2

ATP equation

Answer 2

ATP + water—-ADP + Pi
🔺H = -30kJmol^-1

(Forwards reaction = hydrolysis, backwards reaction = condensation)

Question 3

How is ATP formed/how does it store energy?

Answer 3

• Energy (30kJmol^-1) needed to form
• Phosphorylation (ADP + Pi combined)
• Endergonic reaction catalysed by ATP synthetase
• Respiration - energy from enzyme-controlled reactions at different stages of aerobic respiration

Question 4

What happens when ATP is broken down (releases energy)?

Answer 4

• Energy (30kJmol^-1) released
• Broken down into ADP + Pi
• Exergonic reaction catalysed by ATPase
• Energy-requiring cell processes - energy for active transport, contraction of muscle cells, transmission of nerve impulses, polypeptide synthesis

Question 5

ATP - Universal energy currency

Answer 5

-ATP supplies energy for all energy-requiring reactions in all types of cells (in all living organisms)

Question 6

ATP - Energy carrier

Answer 6

• Picks up energy from glucose in respiration, passes on to help power cell processes
• supplies energy for all energy-requiring reactions in all types of cells
• Carries energy from where it’s stored (carbohydrates & lipids)
• Respiration - glucose broken down by enzyme-catalysed reactions for energy to be carried by ATP

Question 7

ATP - Synthesis by ETC/Chemiosmosis

Answer 7

• Electrons from hydrogen atoms transferred from donor molecule to recipient
• Electrons transferred from one molecule to the next by ETC
• Each transfer = redox reaction (one molecule oxidised, next reduced)
• Oxidation reactions make energy which pumps protons from hydrogen atoms across a membrane. Membrane concentrated on one side, difference in concentration = electrochemical gradient in chemiosmosis through enzyme ATP synthetase
• Energy released converted into chemical energy in ATP

Question 8

ATP - Advantage as an energy source (over glucose)

Answer 8

• Breakdown (hydrolysis) involves just one reaction that releases energy immediately
• Energy released in usable amounts when and where it’s needed
• Only one enzyme needed to release energy from ATP

Question 9

Examples of processes ATP provides energy for

Answer 9

• Metabolic processes
• Active transport
• Movement - contraction of muscle cells
• Transmission of nerve impulses
• Secretion
• Synthesis of polypeptides

Question 10

Importance of ATP (why its suited to its role)

Answer 10

universal energy currency
is inert
can pass out of mitochondria into cytoplasm
releases energy efficiently
releases energy in useable quantities (little wasted as heat)
easily hydrolyzed to release energy
readily reformed by phosphorylation

Question 11

how do inner membranes of mitochondria and chloroplast support theory of endosymbiosmosis?

Answer 11

membranes only allow protons through in a highly controlled way, known as ‘sealed membranes’