Bioenergetics and Regulation

Question 1

Internal energy change of a closed system

Answer 1

ΔU = Q - W

work constant in most living systems

Question 2

change in free energy physiological conditions

Answer 2

ΔG = ΔG° + RTln(Q)

Question 3

least stable to most table energetic compound

Answer 3

cAMP
creatine phosphate
ATP
ADP
G6P
AMP

Question 4

pmf of ETC

Answer 4

electrons passed down ETC, give up free energy for form the pmf across inner mitochondrial membrane

Question 5

flavoproteins

Answer 5

• contain modified B2 riboflavin
• presence in mitochondria and chloroplasts as e- carriers
• coenzymes for FA oxidation, decarboxylation of pyruvate, and reduction of glutathione
• modification of other B vit

Question 6

insulin effects

Answer 6

• glycogen synthesis in liver and muscle (promote glucokinase and inhibit G6Pase)
• liver convert XS gluc to FA and triacylglycerols
• triacylglycerol synthesis in adipose tissue
• gluc and triacylglycerol uptake by fat cells
• lipoprotein lipase activity clearing VLDL abs chylomicrons from blood
• protein synthesis in muscle

dec lipolysis in adipose tissue and ketone formation by liver

Question 7

after a meal how are energy needs of liver met?

Answer 7

oxidation of XS aa

Question 8

in well-fed and normal fasting states, how does nervous tissue sustain itself

Answer 8

oxidizing gluc to CO2 and water

Question 9

how do RBCs sustain themselves

Answer 9

• use gluc anaerobically

Question 10

hormones that oppose insulin actions

Answer 10

glucagon, cortisol, epi, NE, and GH

Question 11

effects of glucagon and epi

Answer 11

• glycogen degradation in liver
• gluc release into blood
• hepatic gluconeogenesis
• epi causes aa and FA release from skeletal and adipose for gluconeogenesis

Question 12

once elevated FA and ketone levels are reached…

Answer 12

muscle used FA as major fuel source and brain uses ketones to spare aa for proteins

Question 13

tissues in which glucose uptake not affected by insulin…

Answer 13

nervous
kidney tubules
intestinal mucosa
RBCs
β-cells of the pancreas

Question 14

tissues in which insulin is effective for gluc uptake

Answer 14

resting skeletal tissue and adipose tissue

Question 15

glucagon activates __________ and inactivates ___________

Answer 15

glycogen phosphorylase
glycogen synthase

Question 16

in terms of ketones and fats, glucagon…

Answer 16

inc liver ketogenesis and dec lipogenesis

in lipolysis by activating lipase

Question 17

glucagon converts pyruvate to _________ by _________ in liver to promote __________. It also ____.

Answer 17

PEP
PEPCK
gluconeogenesis

inc conversion of F1,6-BP to F6P by F-1,6-BPase

Question 18

cortisol

Answer 18

glucocorticoid
adrenal cortex
sympathetic response
steroid hormone
promotes mobilization of energy stores

inc aa delivery, lipolysis, and blood glucose levels

XS will promote insulin release

Question 19

catecholamines

Answer 19

secreted by adrenal medulla
epi, NE
inc activity of liver and muscle glycogen phosphorylase promoting glycogenolysis
inc lipolysis

Question 20

adrenaline rush

Answer 20

inc BMR through sympathetic NS

Question 21

Thyroid hormone functions

Answer 21

inc BMR
accelerate cholesterol clearance from plasma and inc gluc absorption in small intestine
Epi dependent on thyroid hormones
T3 faster than T4

Question 22

BMI

Answer 22

BMI = mass/(height^2)

above 30 obese
25-30 overweight
18.5-25 normal

Question 23

ghrelin

Answer 23

secreted by stomach in response to impending meal

inc appetite and signals for orexin release

Question 24

orexin

Answer 24

inc appetite
alertness
triggered by hypoglycemia

Question 25

leptin

Answer 25

secreted by fat cells dec appetite suppress orexin production mutation implicated in obesity

Question 26

respirometry/respiratory quotient

Answer 26

RQ = CO2 consumed/O2 consumed 1.0 for carbs 0.7 for lipids 0.8 in humans at rest

Question 27

calorimeter measure…

Answer 27

BMR

Question 28

liver role

Answer 28

- maintain blood gluc - syn ketones when XS FA oxidized - replenish glycogen stores - XS gluc used to make acetyl CoA for FA synthesis - process and release FA as VLDL - most energy comes from aa oxidation - glycogen degradation and gluconeogenesis - provide carbon skeletons for glucose synthesis

Question 29

adipose tissue role

Answer 29

- elevated insulin levels gluc uptake - release FA from VLDL and chylomicrons - lipoprotein lipase induced by insulin - for triacylglycerols for storage - insulin suppresses FA release - dec insulin and inc epi activate hormone sensitive lipase for FA to be released into circulation

Question 30

resting muscle energy consumption

Answer 30

- major fuels gluc and FA - in fasting state, FA derived from bloodstream - ketone bodies used for energy if fasting is prolonged

Question 31

active muscle energy consumption

Answer 31

- short lived, creatine phosphate which transfers a P to ADP to form ATP - short high intensity exercise, anaerobic glycolysis and draw on stored glycogen - moderate high intensity continuous oxidation of gluc and FA - lengthy high intensity exercise, glycogen depleted and FA oxidation takes over

Question 32

cardiac muscle energy consumption

Answer 32

- prefer FA - ketones during prolonged fasting - in a failing heart, gluc oxidation inc and B-ox falls

Question 33

brain energy consumption

Answer 33

- glucose primary fuel - ketones during prolonged fasting - between meals, glycogenolysis and gluconeogenesis - hypothalamic center signal for epi and glucagon release in hypoglycemic conditions