Bioenergetics and Regulation of Metabolism

Question 1

Liver:

Answer 1

The most metabolically diverse tissue. Hepatocytes are
responsible for the maintenance of blood glucose levels
by glycogenolysis and gluconeogenesis in response to
pancreatic hormone stimulation. The liver also processes
lipids and cholesterol, bile, urea, and toxins.

Question 2

Adipose Tissue

Answer 2

Stores lipids under the influence of insulin and releases
them under the influence of epinephrine

Question 3

Skeletal Muscle : also what is
Resting Muscle and Active Muscle

Answer 3

Skeletal muscle metabolism will differ depending on
current activity level and fiber type.
Resting muscle: Conserves carbohydrates in glycogen
stores and uses free fatty acids from the bloodstream.
Active muscle: May use anaerobic metabolism, oxidative
phosphorylation of glucose, direct phosphorylation from
creatine phosphate, or fatty acid oxidation, depending on
fiber type and exercise duration.

Question 4

Cardiac Muscle:

Answer 4

Uses fatty acid oxidation in both the well-fed and fasting states.

Question 5

Brain and
Nervous Tissue:

Answer 5

Consume only glucose in all metabolic states, except for
prolonged fasts, where up to 2/3 of the brain’s fuel may
come from ketone bodies.

Question 6

Calorimetry:

Answer 6

Measures metabolic rates

Question 7

Respiratory Quotient:

Answer 7

RQ. Estimates the composition of fuel that is actively consumed by the body. RQ = Co2 produced / O2 consumed

Question 8

Regulatory Hormones:

function of Ghrelin

Answer 8

increase appetite. (sight, sound, taste, smell of food)

Question 9

Regulatory Hormones:

function Orexin

Answer 9

increase appetite

Question 10

Regulatory Hormones:

function Letin

Answer 10

decrease appetite by suppressing orexin production

Question 11

Body Mass Index

Answer 11

BMI = mass/ Height^2

Question 12

Equilibrium:

Answer 12

Equilibrium is an undesirable state for most biochemical reactions because organisms need to harness free energy to survive

Question 13

Postprandial State:

Answer 13

Well-fed, absorptive. Increase ­Insulin. Anabolism prevails.

Question 14

Postabsorptive State

Answer 14

Fasting decrease .Insulin. increase ­glucagon and catecholamine. Transition to catabolism

Question 15

Prolonged Fasting:

Answer 15

Starvation increases glucagon and catecholamine. Most tissues rely on fatty acids. 2/3 of brain activity can be derived from ketone bodies.

Question 16

High Energy

Answer 16

May be soluble or membrane-bound. Includes NADH

Question 17

Electron Carriers

Answer 17

NADPH, FADH2, ubiquinone, cytochromes, and glutathione.

Question 18

Flavoproteins

Answer 18

A subclass of electron carriers that are derived from riboflavin (vitamin B2). Examples: FAD and FMN

Question 19

what is the role of ATP

Answer 19

ATP is a mid-level energy molecule. It contains high-energy phosphate bonds that are stabilized upon hydrolysis by resonance, ionization, and loss of charge repulsion

Question 20

Energy Source:

Answer 20

ATP provides energy through hydrolysis and coupling to energetically unfavorable reactions. ATP = 30 kl/mol

Question 21

Phosphoryl

Answer 21

ATP can donate a phosphate group to other molecules.

Question 22

Group Transfers:

Answer 22

For example, in Glycolysis, it donates a Phosphate group to glucose to form glucose 6-phosphate

Question 23

Open System:

Answer 23

Matter & energy can be exchanged with the environment

Question 24

Closed System:

Answer 24

Only energy can be exchanged with the environment. No work is performed because pressure and volume remain constant. ∆enthalpy = ∆internal energy = heat exchange

Question 25

Entropy

Answer 25

A measure of energy dispersion in a system

Question 26

Change in Free Energy: define Standard Free Energy

Answer 26

Standard Free Energy, DeltaG°: The energy change that occurs at 1 M concentration, 1 atm, and 25°C.

Question 27

Change in free Energy define Modified Standard State

Answer 27

Modified Standard State, DeltaG°’: Indicates physiological conditions. [H=] = 10^-7, so pH is 7.

Question 28

Define Insulin:

Answer 28

Secreted by pancreatic b-cells, regulated by glucose decrease¯blood glucose by increasing cellular uptake increase ­rate of anabolic metabolism

Question 29

Glucagon:

Answer 29

Secreted by pancreatic a-cells, stimulated by low glucose and high amino acid levels increses ­blood glucose by promoting gluconeogenesis and glycogenolysis in the liver

Question 30

Glucocorticoids:

Answer 30

Increase ­blood glucose in response to stress by mobilizing fat stores and inhibiting glucose uptake. They increase the impact of glucagon and catecholamines. Ex: cortisol

Question 31

Catecholamines:

Answer 31

Promote glycogenolysis and increase ­basal metabolic rate through sympathetic nervous system activity. “Adrenaline rush”. Ex: epinephrine and norepinephrine

Question 32

Thyroid Hormones

Answer 32

Increase ­basal metabolic rate, as evidenced by ­ Increase O2 consumption and heat production when they are secreted. T3 is more potent than T4, but has a shorter half-life and is available in lower concentrations in the blood. T4 is converted to T3 at the tissues. Thyroid hormones are tyrosine-based

Question 33

Liver definition

Answer 33

The most metabolically diverse tissue. Hepatocytes are responsible for the maintenance of blood glucose levels by glycogenolysis and gluconeogenesis in response to pancreatic hormone stimulation. The liver also processes lipids and cholesterol, bile, urea, and toxins

Question 34

Adipose Tissue:

Answer 34

Stores lipids under the influence of insulin and releases them under the influence of epinephrine

Question 35

Skeletal Muscle define Resting Muscle

Answer 35

Conserves carbohydrates in glycogen stores and uses free fatty acids from the bloodstream

Question 36

Skeletal Muscle define Active muscle

Answer 36

May use anaerobic metabolism, oxidative phosphorylation of glucose, direct phosphorylation from creatine phosphate, or fatty acid oxidation, depending on fiber type and exercise duration.

Question 37

cardiac Muscle:

Answer 37

Uses fatty acid oxidation in both the well-fed and fasting states.