Cellular Respiration

Question 1

prep reaction

Answer 1

• pyruvate oxidized to acteyl coenzyme a and carbon dioxide is removed
• occurs twice because glycolysis produces 2 pyruvates
• produces molecule that will enter the citric acid cycle
• 2 acteyl CoA’s
• 2 NADH
• 2 carbon dioxide

Question 2

citric acid / kreb cycle

Answer 2

• c2 acteyl group from prep reaction combines with c4 molecule (oxaloacctate) to produce c6 citrate (citric acid)
• oxidation of citrate by removal of hydrogens
• produces 3 NADH and 1 FADH2
• produces 1 ATP by direct substrate phosphorylation
• CYCLE TURNS TWICE PER GLUCOSE

Question 3

glycolysis

Answer 3

• breakdown of glucose (6C) and 2 molecules of pyruvate (3C)
• oxidation by removal of hydrogen releases energy to make ATP
• makes 2 pyruvate
• 2 ATP
• 2 NADH

Question 4

citric cycle / kreb products per glucose

Answer 4

• 6 NADH
• 2 FADH2
• 4 CO2
• 2 ATP

Question 5

etc

Answer 5

• final electron acceptor is oxygen
• after receiving electrons oxygen combines with hydrogen ions to form water as an end product
• NAD &FAD recycle back to pick up more electrons from glycolysis, prep reaction, and citric acid cycle
• as the electrons move from a higher energy state to a lower one, energy is released to make ATP
• under aerobic conditions 36-38 ATP per glucose molecules can be produced

Question 6

etc products

Answer 6

• 32-34 ATP (chemiosmosis)

- H2O

Question 7

2 laws of thermodynamics

Answer 7

• energy cannot be created or destroyed -> can be changed from one fork to another
• energy cannot be changed from one for, to another without a loss of usable energy

Question 8

kinetic energy

Answer 8

• energy of motion
• mechanical energy is a form of kinetic energy
  ex) ball rolling/muscle contracting

Question 9

potential energy

Answer 9

• stored energy

- food we eat (also a form of chemical energy)

Question 10

coupled reactions

Answer 10

-energy released by an exergonic reaction is used to drive an endergonic reaction

Question 11

structure of ATP (nucleotide)

Answer 11

• adenine (nitrogen containing base)
• ribose (5 carbon sugar)
• 3 phosphate groups

Question 12

substrate concentration

Answer 12

• enzyme activity increases as substrate concentration increases because there are more collisions between substrate and enzyme
• max rate is achieved when all active sites of an enzyme are filled continuously with substrate

Question 13

temp

Answer 13

• enzyme activity as temp rises
• higher temp causes more effective collision between enzymes and substrates
• high temp may denature an enzyme

Question 14

ph

Answer 14

• has optimal ph
• enzyme structure is ph dependent
• extremes of ph may denature an enzyme by altering its structure

Question 15

enzyme activation/concentration

Answer 15

• cell regulates metabolism by regulating which enzymes are active
• genes producing enzymes can be turned on/off to regulate enzyme concentrations

Question 16

enzyme inhibition

Answer 16

• enzyme cannot bind its substrate
• activity of cell enzymes is regulated by feedback inhibitors
  ex) when product is abundant it binds to the enzymes active site and blocks further production
• when product is used up its removed from the active site
• poisons are often enzyme inhibitors
  ex) cyanide is an inhibitor of an essential enzyme (cytochrome c oxidase) which is essential in the process of ATP production -> if enzyme is inhibited cell death will occur

Question 17

enzyme cofactors

Answer 17

• molecules which help enzymes function
• may be organic non proteins (coenzymes) or inorganic ion (cofactors) helpers
• vitamins are small organic molecules that are required in our diets for the synthesis of coenzymes
  ex) niacin (vitamin) integral component of 2 important enzymes, specifically NAD vitamin B12 is important for the coenzyme FAD