module 5 - 17.1 energy cycles & 17.2 ATP synthesis

Question 1

what are some examples of metabolic activities that living organisms need to do to survive?

Answer 1

• active transport - essential for uptake of nitrates by root hair cells, loading sucrose into sieve tube cells, conduction of nerve impulses
• anabolic reactions - building polymers like proteins, polysaccharides and nucleic acids essential for growth and repair
• movement due to cilia, flagella or contractile filaments in muscle cells

Question 2

what does energy have to be transferred to?

Answer 2

cellular processes in the right form and right amount

Question 3

what do plants need to do to start the photosynthetic process?

Answer 3

make ATP from ADP and Pi

Question 4

where is the vast majority of the energy required for ATP transferred from?

Answer 4

the sun as light energy

Question 5

what is the equation for photosynthesis?

Answer 5

6CO2 + 6H2O –light–> C6H12O6 + 6O2

Question 6

how does energy from the sun flow through organisms?

Answer 6

• high energy radiation from the sun is used in photosynthesis
• photosynthesis is used by producers
• some of that energy goes to consumers, and then to decomposers, other energy goes straight to decomposers
• all producers, consumers and decomposers respire and release heat as low energy radiation

Question 8

what are the 2 rules of biochemistry?

Answer 8

1. energy is required to break bonds
2. energy is released when bonds are made

Question 9

what is bond energy?

Answer 9

the amount of energy required to break a bond or released when the bond is made

Question 10

what are exothermic reactions?

Answer 10

release energy to the environments

Question 11

why is respiration exothermic?

Answer 11

• releases energy from glucose
• this energy is transferred to ADP and Pi when ATP is made

Question 12

what are endothermic reactions?

Answer 12

absorb energy from the surroundings

Question 13

why is photosynthesis endothermic?

Answer 13

energy is absorbed in the form of light

Question 14

what are small inorganic molecules?

Answer 14

• carbon dioxide and water
• covalent bonds are strong because they have high bond energies
• release lots of energy when the bonds are made but require lots of energy to break the bonds
• don’t have carbon, hydrogen AND oxygen (only 2)

Question 15

what are larger organic molecules?

Answer 15

• glucose and amino acids
• covalent bonds are weaker than in small inorganic molecules
  release energy when the bonds are made but require less energy to break the bonds
• must have all 3 carbon, hydrogen and oxygen

Question 16

what are the effects of respiration?

Answer 16

1. large organic molecules are broken down into small inorganic molecules
2. total energy require to break all the bonds in organic molecules is less than total energy released in making bonds in small organic molecules
3. respiration is exothermic and released energy is used to make ATP from ADP and Pi

Question 17

what are the effects of photosynthesis?

Answer 17

1. small organic molecules are joined together into larger organic molecules
2. total energy required to break all bonds in the small inorganic molecules is greater than total energy released in making the bonds in larger organic molecules
3. photosynthesis is endothermic, with energy from the environment coming from the suns light energy

Question 18

which bonds do organic molecules contain?

Answer 18

SOME carbon-hydrogen bonds

Question 19

which bonds to triglycerides contain?

Answer 19

MANY carbon-hydrogen bonds

Question 20

why do carbon-hydrogen bonds have low bond energy?

Answer 20

because it is non-polar (electrons are shared equally between carbon and hydrogen)

Question 21

what happens when carbon-hydrogen bonds are broken?

Answer 21

• carbon and hydrogen atoms make bonds in small inorganic molecules, carbon doixide and water
• these carbon-oxygen and hydrogen-oxygen bonds are strong and have higher bond energies so release energy when they’re made

Question 22

what is ATP synthesis?

Answer 22

• energy flow from the sun
• energy -> ATP -> large organic molecules (glucose) -> ATP -> energy requiring reactions/processes

Question 23

what is ATP synthase?

Answer 23

• an enzyme that ctatlyses the formation of ATP using ADP and Pi
• is a molecular machine
• ADP + Pi + 2H+ (out) ⇌ ATP + H2O + 2H+ (in)
• ensures the reaction goes in the right direction

Question 24

what are the energy sources needed to make sure ATP synthase can ensure the reaction goes in the right direction?

Answer 24

• an electrochemical gradient created by the difference in proton or H+ concentration across the inner mitochondrial membrane is generated
• the protons diffuse back into the matrix by diffusing through ATP synthase, which supplies energy to the reaction of ADP and Pi to make ATP

Question 25

which chemicals are both the products of respiration and the raw materials of photosynthesis?

Answer 25

carbon dioxide and water