Chapter 12- Bioenergetic and Regulation of Metabolism Flashcards Preview

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Flashcards in Chapter 12- Bioenergetic and Regulation of Metabolism Deck (59)
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1

what does the brain rely on for metabolism

only glucose

2

what type of system is a biological system?

open system, b/c they can exchange both energy and matter with the environment.

energy exchanged in form of mechanical work or heat.
matter exchanged through food consumption and elimination, as well as respiration.

3

biochemical studies

typically done on cellular or subcelluar level, which is considered a closed system b/c there is no exchange of energy with the environment.

- in a closed system change in internal energy can only come from work or heat (change U = Q - W).... so in this system only heat applies.

4

internal energy

sum of all different interactions b/w and w/i atoms in a system
ex: vibration, rotation, linear motion, and stored chemicals

5

bioenergetics

describes energy states in biological systems.
ex: changes in free energy.

6

Gibbs free energy equation

chgG = chgH -T chgS

-G = spontaneous
+G = nonspontaneous

7

modified standard state (G*')

necessary change in pH for biochemical reactions.
pH - 7 (usually concentration of 1, so pH of 0)
T - 25*C
p - 1 atm

8

most energy-rich nutrient

fats (9 kcal/g of energy), preferred for long-term energy storage.

carbs, proteins, and ketones only have about 4 kcal/g

*same physical space but more energy in it.

9

2 processes in which ATP is formed

1. substrate-level phosphorylation
2. oxidative phosphorylation

10

why is it good that ATP is a midlevel

b/c when an ATP is used it provides G*' = 30 kJ/mol of energy no matter what the reaction needs. so it may lose energy if the reaction only requires 10 kJ/mol.

if it were any larger it would waste too much.
*numbers are actually negative when releasing energy

11

highest to lowest G*' energy provided

(MOST NEGATIVE CAUSE RELEASES MOST ENERGY)
cAMP, Creatine phosphate, ATP, Glucose 6-phosphate, AMP (adenosine monophosphate)
(MOST POSITIVE CAUSE RELEASES LEAST ENERGY)

12

what is ATP typically used for

to fuel energetically unfavorable reactions or to activate or inactivate other molecules

13

ATP hydrolysis vs. ATP cleavage

hydrolysis: usually part of coupled reactions, like with Na/K pump

cleavage: transfer of phosphate group to another molecule-aka. phosphoryl group transfers-, typically (in)activates a target molecule

14

if chgG is negative and E (electromotive force) is positive then...

the oxidation-reduction reaction is spontaneous

15

high-energy electron carriers in cytoplasm

NADH, NADPH, FADH2, ubiquinone, cytochromes, and glutathione

16

flavin mononucleotide (FMN)

membrane-bound electron carriers embedded within the inner mitochondrial membrane. this one is bound to complex I of the electron transport chain and can also act as a soluble electron carrier

17

flavoproteins

contain modified vitamin B12 (riboflavin). They are nucleic acid derivatives (FAD or FMN).
they are in the mitochondria or chloroplasts as electron carriers. also used as cofactors for enzymes in oxidation of fatty acids, decarboxylation of pyruvate, and reduction of glutathione.

18

key difference between chemistry and biochemistry?

chemistry- equilibrium states are desired
biochemistry- equilibrium states are NOT desired (homeostasis is desired instead)

19

homeostasis

physiological tendency toward a relatively stable state that is maintained and adjusted, often with expenditure of energy

20

postprandial state

aka. absorptive or well-fed state. occurs shortly after eating and lasts for 3 to 4 hours after eating. greater anabolism and fuel storage. nutrients flood from the gut to the liver via the heptaic portal vein.

insulin release due to high blood glucose levels.

21

anabolism

synthesis of biomolecules

22

catabolism

breakdown of biomolecules for energy

23

3 major target tissues for insulin

promotes glucose entry into all of these.

1. liver - promotes glycogen synthesis
2. muscle- promotes glycogen synthesis and protein synthesis
3. adipose tissue- promotes triacylglycerol synthesis

24

what happens after the glycogen stores are filled?

liver converts excess glucose to fatty acids and triacylglycerols

25

tissues that are insensitive to insulin

1. nervous tissue- gets energy from oxidizing glucose to CO2 and water
2. red blood cells- can only use glucose anaerobically cause they lack mitochondria
3. intestinal mucosa
4. kidney tubules
5. B-cells of the pancreas

26

postabsorptive state and counterregulatory hormones

aka. fasting state. release of amino acids from skeletal muscle and fatty acids from adipose tissue are both stimulated by the decrease in insulin and by an increase in levels of epinephrine.

counterregulatory hormones have opposite effect of insulin:
1. glucagon
2. cortisol
3. epinephrine
4. norepinephrine
5. growth hormone

27

hepatic

relating to the liver

28

prolonged fasting

aka. starvation. levels of glucagon and epinephrine are markedly elevated. rapid degeneration of glycogen stores in the liver. both gluconeogenesis and lypolysis are occurring rapidly.

29

peptide hormones

typically water-soluble. able to rapidly adjust metabolic processes of cells via second messenger cascades. (ex: insulin)

30

amino acid-derivative hormones

typically fat-soluble. enact longer-range effects by exerting regulatory actions at the transcriptional level.