Energy Cycles

Question 1

Are C-H bond weaker or stronger than inorganic bonds

Answer 1

Weaker

Question 2

How is ATP made in respiration

Answer 2

Large organic molecules are broken down to form small inorganic ones, total energy needed to break less than energy released so excess energy used to make ATP

Question 3

Structure of ATP

Answer 3

Nucleotide with organic base adenine with covalent bond to ribose sugar and phosphodiester bond to chain of three phosphate groups

Question 4

How is energy released by ATP

Answer 4

Hydrolysis via enzyme ATPase releases ADP and Pi and energy

Question 5

How is ATP restored

Answer 5

Energy from food via phosphorylation by ATP synthase bonds ADP and Pi to form ATP

Question 6

Three ways phosphorylation can be done

Answer 6

-oxidative phosphorylation (occurs in membrane of mitochondria in aerobic respiration)
-photophosphorylation (occurs in thylakoid membranes in chloroplasts in plants only)
-substrate-level phosphorylation (when phosphate groups are transferred from donor molecules to ADP to make ATP eg in glycosis)

Question 7

Why is ATP universal energy currency

Answer 7

-only one enzyme needed to release energy
-releases energy in small amounts when and where needed unlike glucose
-can release a lot of energy

Question 8

How are chloroplasts adapted for their role

Answer 8

-thylakoids are flattened sacs to increase SA and maximise absorption of light
-stacked in grana to increase SA
-chlorophyll pigment to absorb light
-stroma contains enzymes for LIR and DNA to produce proteins for photosynthesis

Question 9

Why can’t protons pass through membrane by itself

Answer 9

They are charged