Unit 2 - Efficiency and Inhibitors

Question 1

tally;
CO2 / ATP / NADH / FADH2

in
gylocolysis =
PO =
krebs =

Answer 1

glycolysis = 0,2,2,0
Pyruvate Oxidation = 2,0,2,0
Krebs cycle = 4,2,6,2
Total 6,4,10,2

Question 2

1 NADH makes….
1 FADH2 makes…
substrate level ATP…

Answer 2

3 ATP x 10 = 30
2 ATP x 2 = 4
= 4
TOTAL ATP = 38

Question 3

Grand total of ATP

Answer 3

• 34 mols of ATP formed in ETC
• 2 in Krebs
• 2 in Glycolysis
• per glucose = 38ATP
• actual yield =30ATP

Question 4

Why is the actual yield only 30 ATP?

Answer 4

-inner mitochondrial membrane may leak H+
- ATP required to prepare cell for glycolysis

Question 5

How Efficient is Cellular Respiration

Answer 5

-Hydrolysis of ATP from ADP Pi = 31kj/mol

Question 6

if the complete oxidation of glucose produces 38 ATP…

Answer 6

then the total energy stored through ATP is 1178kj/mol

but glucose contains 2870kj/mol of energy

1178/2870 x 100 = 41%

Question 7

41% efficientce

Answer 7

therefore a max of 41% in glucose is made into ATP and the rest of potenital energy is dissipated as thermal energy

Question 8

what abt the NADH formed in the cytosol

Answer 8

during glycolysis, 2 NADH r formed. these 2 electron carriers cannot access the ETC in the mitochondria. to overcome this problem, cells use one of two shuttle systems that transfer the high energy e- from NADH across the inner mitochondrial membranes and into the matrix

Question 9

2 types of shuttles

Answer 9

1) malate-aspartate shuttle
2) glycerol-2-phosphate shuttle

Question 10

Malate-aspartate shuttle

Answer 10

the NADH in the cytosol is oxidized to NAD+ and e- r transferred across the membrane and used to reduce NAD+ to NADH within the matrix

Question 11

Glycerol-3-phosphate shuttle

Answer 11

-invloves the transfer of e- across the membrane from NADH to FAD in the matrix
- forming FADH2 = less free energy
- CELLS that use this system generate the equivalent of 2 rather than 2 ATP for every NADH
- why malate shuttle is more efficient
- produce 2 fewer ATPs per glucose

Question 12

Creatine Phosphate

Answer 12

demand for energy in the cell can fluctuate dramatically. Cells may need a burst of energy during periods of high activity (muscle cells) buta low demand for energy at another time

Question 13

ATP levels high in the cell

Answer 13

the last phosphate of ATP gets transferred to creatine. when phosphorylated, creatine bc a high energy mol called creatine phospahte

Question 14

high levels of ATP reaction

Answer 14

creatine + ATP = creatine phosphate + ADP

Question 15

ATP levels r low

Answer 15

it gets transferred back to ADP to make more ATP. The cell is able to recerse the rxn abt to generate more ATP quickly.

Question 16

Low levels of ATP reaction

Answer 16

creatine phosphate = creatine + ATP

Question 17

what is the final e- acceptor in ETC

Answer 17

oxygen

Question 18

what happens if oxygen is unavailable (4)

Answer 18

1) ETC backs up
2) ATP production ceases
3) cells run out of energy
4) and u die

Question 19

Interrupting Cellular Respiration (3)

Answer 19

Poisons
1) block electron transport chain (ie. CO)
2) inhibit ATP synthase (ie. antibiotic oligomycin)
3) make membrane leaky to H+ ions (ie. dinitrophenol)

Question 20

Poisons (5)

Answer 20

1) hydrogen cyanide
2) carbon monoxide
3) rotenone
4) dinitrophenol
5)oligomycin

Question 21

Hydogen Cyanide

Answer 21

• a chemical used in poisonous gas
• inhibits cytochrome oxidase (supply of oxygen to body tissues is still plentiful but cells cannot use the oxygen efficiently)

Question 22

Carbon Monoxide

Answer 22

• binds to and inhibits cytochrome c oxidase
  (binds to hemoglobin at an oxygen binding site)
• sources of CO house fires, paint strippers, exhaust etc

Question 23

Rotenone

Answer 23

• used in pesticides of piscicide
• prevents e- passing from NADH, and dehydrogenase to UB
• poorly absorbed through the skin, but not often deadly but can cause vomiting. but purposeful ingestion can be fatal

Question 24

Dinitrophenol

Answer 24

• DNP is an uncoupler or has the ability to separate the flow of e- and pumping of H+ ions from ATP synthesis
  -energy from e- cannot be used in ATP synthesis
• used to be given as a weight loss drug

Question 25

Oligomycin

Answer 25

- antibiotic that inhibits ATP synthase by blocking its proton channel necessary for oxidative phosphorylation of ADP to ATP - stop ETC

Question 26

Brown Fats

Answer 26

-special type of tissue associated w generation of heat and more abundant in hibernating mammals and newborns

Question 27

white / brown / beige fats

Answer 27

white = found in surrounding organs brown = important for energy storage, burns fat to help make heat beige = mix of both

Question 28

Regulating Cellular Respiration

Answer 28

most metabolic pathways r regulated by supply and demand through the process of feedback inhibition

Question 29

how do we avoid making to much ATP

Answer 29

FEEDBACK INHIBITION - we dont wanna waste cell resources - so FI regulates pathway by one of the products of the pathway

Question 30

Phosphofructokinase (PFK)

Answer 30

regulated by ATP and ADP derivative called AMP, and CITRATE, as well as some other mols we won't discuss here

Question 31

Feedback Inhibition in ATP

Answer 31

-in aerobic respiration, ATP inhibits enzymes throughout the pathway

Question 32

ATP - regulator of PFK =

Answer 32

if there is already enough ATP in the cell, glycolysis does not need to make more

Question 33

ATP inhibits PFK

Answer 33

which prevents creation of fructose-1,6-bisphosphate slows or stops glycolysis

Question 34

AMP

Answer 34

Adenosine monophosphate is a + regulator of PFK. when a cell is v low on ATP, it will star squeezing more ATP out of ADP mols by converting them to ATP and AMP (ADP + ADP = ATP + AMP)

Question 35

Feedback Inhibition high levels of AMP

Answer 35

means that the cell is starved for energy, and that glycolysis must run quickly to replenish ATP

Question 36

Feedback Inhibition Citrate

Answer 36

the first product of Krebs cycle, can also inhibit PFK. if citrate builds up, this is a sign that glycolysis can slow down, bc the Krebs cycle is backed up and doesn't need more fuel

Question 37

Alternatives to Glucose

Answer 37

carbs, fats, and proteins can fuel respiration - when they r converted to mol that enter glycolysis or the Krebs cycle

Question 38

Other carbohydrates

Answer 38

glycolysis accepts a wide range of carbs fuels - single or joined sugars - broken dow into single sugars - converted to glucose or glycolysis intermediate, enters glycolysis

Question 39

Polysaccharides = other 6c sugars =

Answer 39

(Hydrolysis)= glucose ie. starch / glycogen (Modified)= glucose ie. galactose/fructose

Question 40

Proteins

Answer 40

- the chain of AA - amino acid have NH3 groups removed and converted to pyruvate, acetyl-CoA, or CA cycle intermediate to enter pyruvate oxidation or Krebs cycle

Question 41

Proteins =

Answer 41

(Hydrolysis)= aa

Question 42

three types of extracted fluids

Answer 42

= waste product excreated as ammonia, urea, or uric acid

Question 43

carbon skeleton

Answer 43

= enters glycolysis or Krebs cycle at different stages

Question 44

Fats (triglycerides)

Answer 44

Triglyceride = glycerol + 3 fatty acids - broken down into gycerol and fatty acids - glycerol converted to G3_ and enters glycolysis - fatty acids r converted to acetly-CoA and enters Krebs

Question 45

Beta-Oxidation

Answer 45

a process in which fatty acids r broken down into acetly-CoA through catabolism

Question 46

Fats =

Answer 46

(Hydrolysis) = glycerol and fatty acids

Question 47

glycerol (2C) makes=

Answer 47

G3P = glycolysis

Question 48

fatty acids =

Answer 48

2c acetyl groups = acetyl CoA = Krebs cycle

Question 49

Carbs vs. Fats

Answer 49

fat generates 2x ATP vs. carbs - more C in gram of fat - more O in gram of carbs

Question 50

energy density in carbs fats proteins

Answer 50

carbs = 17 fats = 37 proteins = 17

Question 51

Metabolism

Answer 51

coordination of diestion and synthesis - by regulating enzymes

Question 52

Digestion

Answer 52

-digestion of carbs, fats, and proteins (all catabolized through the same pathways but enter at diff points) - cell extracts energy from every source

Question 53

Synthesis

Answer 53

- enough energy? build stuff - cell uses points in glycolysis and krebs as links to pathways - run the pathways backwards (eat to much fuel; build fat)

Question 54

pyruvate = krebs cycle = acetyl CoA

Answer 54

= glucose = aa = fatty acids

Question 55

food mols provide raw materials for biosynthesis

Answer 55

cells use some food mols and intermediates from glycolysis and the krebs as raw materials ie process of biosnthesis and consumes ATP

Question 56

Fuelfor respiration ultimately comes from photosynthesis

Answer 56

all organisms - can harvest energy from organic mols plants but not animals - can also make mols from inorganic sources by the process of photosynthesis