ch 3- cellular energy Flashcards

1
Q

where do chylomicrons go

A

leave enterocytes and enter leacteals (lymphatic vessels that take fats to the rest of the body)

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2
Q

how are fats released into circulation

A

adipocytes have hormone sensitive lipase enzymes that release triglycerides back into circulation as lipoproteins or free fatty acids bound by albumin (protein)

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3
Q

proteins as energy source

A

least desirable energy source (4
kcal/gram) because the processes to get them into cellular respiration take considerable energy and proteins are needed for many essential functions in the body.

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4
Q

fats as energy source

A

Fats are harder to catabolize than carbohydrates as they must undergo beta-oxidation and transport away from fat cells. However, per carbon molecule, fats are the most efficient source of energy containing about ~9 kcal/gram.

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5
Q

what happens when fats undergo beta oxidation

A

convert to acetyl co-A

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6
Q

where does beta oxidation occur

A

in the mitochondrial matrix of eukaryotic cells
- requires initial investment of ATP
-then FA chain cleaved into 2 carbon acetyl coA moleucules

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7
Q

what happens to the 2 carbon acetyl coa molecules made from beta oxidation

A

can be used in the krebs cycle for ATP generation and in the process, we make FADH2 and NADH

electron carriers in Electron transport chain (NADH and FADH2- produces more ATP

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8
Q

lipases

A

digest fats into Free fatty acids and alcohols during lypolysis

diested peices then are absorbed into enterocytes in small intestine to reform triglycerides

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9
Q

glycogenesis

A

conversion of glucose into glycogen to be stored in the liver and muscle cells when energy and fuel is sufficient.

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10
Q

preferred energy source

A

Carbohydrates are the preferred energy source since they are easily catabolized and are high yield (4 kcal/gram).

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11
Q

glycogenolysis

A

release of glucose-6-phosphate from glycogen,h

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12
Q

how do dissacharides enter glycolysis

A

Disaccharides can undergo hydrolysis to release two carbohydrate monomers, which can enter glycolysis.

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13
Q

obligate aerobes

A

only perform aerobic respiration
need oxygen to survive

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14
Q

obligate anaerobes

A

only undergo anaerobic respiration or fermentation

o2 is poisonous to them

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15
Q

facultative anaerobes

A

anaerobes: Can do aerobic respiration, anaerobic respiration, or fermentation

PREFER AEROBIC RESPIRATION BC IT GIVES THEM MORE ENERGY

found all throughout the tube but most conc in the top

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16
Q

microaerophiles

A

Only perform aerobic respiration, but high amounts of oxygen are harmful to them.

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17
Q

aerotolerant organisms

A

Only undergo anaerobic respiration or fermentation, but oxygen is not poisonous to them.

found interspersed throughout the tube

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18
Q

alcohol fermentation

A

uses

-2 NADH from glycolysis

to convert 2 pyruvate to 2 ethanol

producing NAD+ allowing glycolysis to continue

1 GLUCOSE uses 2NAD+ and 2 ADP to form 2 pyruvate (3 carbons each)

each pyruvate loses CO2 producing 2 acetaldehydes

each is reduced by NADH reforming NAD+ to produce 2 two carbon ETHANOLs

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19
Q

which type of fermentation has an extra step

A

alcohol fermentation

involves decarboxylation of pyruvate into acetaldehyde which is then reduced by NADH into ethanol

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20
Q

lactic acid fermentation

A

one glucose- 2 NAD+ and 2 ADP turns it into 2 pyruvate

2 NADH reduce the two pyruvates into two 2 carbon lactates

NAD+ reformed to go back to glycolysis

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21
Q

cori cycle

A

convert lactate back into glucose once oxygen is available again.

transports the lactate to liver cells, where it can be oxidized back into pyruvate. Pyruvate can then be used to form glucose

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22
Q

where does lactic acid fermentation occur

A

in muscles when Oxygen is low

and ALWAYS in red blood cells that lack mitochondria needed for aerobic respiration

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23
Q

where does fermentation occur

A

in the cytosol

24
Q

what does fermentation rely on

A

glycolysis by converting the
produced pyruvate into different molecules in order to
oxidize NADH back to NAD+

Regenerating NAD+
means glycolysis can continue to make ATP.

25
what is ATP synthase
channel protein allows protons to move DOWN electochemical gradient
26
where do protons more from in ATP synthase
FROM intermembrane space TO mitochondrial matrix generates energy that is used to concert ADP and P into ATP (endergonic condensation reaction that is non spontaneous)
27
what is formed in glycolysis
2 ATP 2NADH
28
what is formed in pyruvate decarboxylation
2NADH
29
krebs cycle
2 ATP 6 NADH 2 FADH2
30
what is a trait of the mitochondrial intermembrane space
highly acidic so it can have an electrochemical gradient
31
chemiosmosis
use the proton electrochemical gradient- PMF to synthesize ATP
32
what is oxidative phosphorylation
when the ETC and chemiosmosis work together to produce ATP oxygen is the final electron acceptor and gets reduced to form water
33
ETC goal
to regenerate electron carriers and create and electrochemical gradient to power ATP production
34
location of ETC
eukaryotes- mitochondrial inner membrane prokaryotes- cell membrane protein complexes I-IV move electrons through a series of redox reactions that each pump protons from matrix to intermembrane space
35
NADH VS FADH2
NADH is more effective, drops electrons directly at complex I, regenerating NAD+ FADH2 drops electrons off at protein complex II regenerating FAD-- fewer protons are pumped bc complex I is bypassed
36
aerobic respiration- endergonic or exergonic?
exergonic- delta G is -686. kacl/mol glucose
37
how much ATP does NADH produce
3ATP but less from glycolysis bc varying amounts of ATP must be used to shuttle NADH from cytosol to mitochondrial matrix but prokaryotes dont need to shuttle 2NADH in glycolysis euk- 4-6 ATP prok- 6 ATP
38
how many ATP does FADH2 produce
2ATP
39
what is the reactant and product of pyruvate oxidation
2 pyruvate -> 2 acetyl coA + 2CO2+ 2NADH using pyruvate dehydrogenase
40
what are the steps of pyruvate oxidation
decarboxylation- 3 c pyruvates move from cytosol into mitochondrial matrix- are decarboxylated producing CO2 and 2 carbon molecule oxidation- 2 carbon mol is converted to acetyl group- reducing NAD+ to NADH coenzyme A- CoA binds to acetyl making acetyl coA
41
krebs cycle- reactants and products
acetyl coA( 2C) and oxaloacetate (4C) make citrate (6C) this produces 4CO2 6NADH 2FADH2 2ATP
42
krebs cycle steps
1. Acetyl-CoA joins oxaloacetate (four-carbon) to form citrate (six-carbon). 2. Citrate undergoes rearrangements that produce 2 CO2 and 2 NADH. 3. After the loss of two CO2, the resulting four-carbon molecule produces 1 ATP through substrate-level phosphorylation. 4. The molecule will now transfer electrons to 1 FAD, which is reduced into 1 FADH2 5. Lastly, the molecule is converted back into oxaloacetate and also gives electrons to produce 1 NADH. 6. Two acetyl-CoA molecules produce 4 CO2 6NADH 2 FADH2 2 ATP.`
43
what are the two laws of thermodynamics
1. Energy cannot be created nor destroyed, but can be transformed from one form to another. 2. The entropy (disorder) of the universe is always increasing. The combined change in entropy (system and surroundings) must be positive. 3. The entropy of a substance at absolute zero is 0.
44
what is more stable, ATP or ADP
ATP is less stable bc of the addiional negatively charged phosphate group
45
what are the processed involved in aerobic respiration
four catabolic processes - glycolysis -pyruvate oxidation -krebs cycle -oxidative phosphorylation
46
where does glycolysis occur
in the cytosol
47
when does glycolysis occur
in both oxygenic and non oxygenic enviroments therefore, it can be used during aerobic respiration and fermentation
48
substrate level phoshorylation
process used to generate ATP in glycolysis by transferring a phosphate group directly to ADP from a phosphorylated compound
49
glycolysis phases
energy investment phase and payoff phase
50
hexokinase
uses ATP to phosphorylate glucose to G6P G6P cant leave the cell
51
isomerase
turns G6P to Fructose 6 phosphate
52
phosphofructokinase
uses second ATP to phosphorylate F6P into F6 bisphosphate - key regulatory step in glycolysis
53
what happens after we make fructose 6 bisphosphate
it is broken down into DHAP and G3P (in eqm with each other) G3P can go onto the energy payoff phase- DHAP converts to more G3P so they stay in eqm G3P undergoes a series of redox reactions to produce 4 ATP through substrate level phosphorylation, 2 pyruvate, and 2 NADH but since we used 2 ATP initally, our final ATP payoff is only 2
54
names for krebs cycle
TCA - tricarboxylic acid cycle CITRIC ACID CYCLE
55