FSHN 2650 - Bioenergetics

Bioenergetics, Metabolism, Catabolism, Metabolic Pathways

Where does glycolysis take place?

Cytosol

Function of mitochondria?

Generates most of cells energy from carbs, proteins, and fats

Hormones regulate ____&____ reactions

Catabolic, anabolic

Energy is stored in ____ of molecules making up protein, carbs, and fats

Bonds

Fast, with oxygen reactions

Aerobic

Slow, without oxygen reactions

Anaerobic

Products of betaoxidation

NADH(+) + H(+) & FADH

What is the biochemical reason ketogenesis occurs during carbohydrate deficiency?

The TCA cycle has too much NADH + H(+) being produced

The build up of ___ in the ____ promotes the synthesis of fatty acids.

Citrate, TCA cycle

What cannot use ketone bodies for ATP production?

Red blood cells

What dictates the fate of pyruvate following glycolysis?

The presence of oxygen

What’s essential for fatty acid oxidation to occur?

CoA

What’s essential for the quick synthesis of ATP in a working muscle?

Creatine phosphate, ADP, glycolysis

What would classify as a catabolic process?

Beta-oxidation

What cannot be converted into glucose by the liver?

Fatty acids

What dicates whether someone is in a state of acute starvation?

Lack of glycogen

What hormone is involved in the absorptive state?

Insulin

What hormone is involved in the post-absorptive state?

Glucagon & epinephrine

Glucokinase can ___

Churn out products faster in the liver

Involved in the fasted state, low insulin, activated by glucagon

Hormone sensitive lipase

Involved in the fed state, activated by insulin

Lipoprotein lipase

What is the fuel ratio percentage of (glucose:ketone bodies) during a carb deficiency?

70:30

What compound is released when muscle protein transfers to amino acids?

NH3

Glucagon stimulates liver _____.

Glycogen

Glycogen releases ____

glucose

Where does ketogenesis take place?

liver

What 3 hormones are active during the acute starvation state?

Glucagon, epinephrine, cortisol

Carbs broken down into glucose, then a (+) ____ breaks it down to glycogen

insulin

Glucose is stored in ____ & ____

fat cells, liver

The liver prioritizes making ____.

Glycogen

How many hours does acute starvation occur?

24 hours after last meal

How many hours does the post-absorptive state occur?

4 hours

T/F: The absorptive state is when there is the MOST fuel in the blood

True

What are the products of glycolysis?

2 ATP

2 Pyruvate

2 Coenzymes

Insulin bonds to the ____ on a triglyceride when fed.

hormone-sensitive lipase

What is ATP?

Cell’s direct energy source

What is energy metabolism?

Sum of all chemical reactions

Glucose —> ____

glycogen

Amino acids —> ____

proteins

Fatty acids & glycerol —> ____

Triglycerides

In what way does a metabolic pathway relate to energy metabolism?

Metabolic pathways are chemical reactions where energy is stored or released

Cofactor:

Inorganic; tightly bound to enzyme

Coenzyme:

organic; loosely bound to the enzyme

Roles of coenzymes and cofactors:

Assist in catalyzing reactions with their non-protein components

What happens when there is EXCESS ATP present?

Acetyl CoA is turned into fatty acid and stored as fat

What happens when there is LOW ATP present?

Acetyl CoA enters the TCA cycle

The 3 main portions of the molecule ATP are: ___, ___, & ___

adenine, phosphates, & ribose

1 ___ is hydrolyzed to produce energy from ATP

phosphate

The body regenerates ATP by ___ & ___

ADP, creatine phosphate

The hormonal signal for anabolic storage of energy is ___

Insulin

The signals for the catabolism (mobilization) of energy are ___, ___, & ___

Glucagon, epinephrine, & cortisol

Fate of Pyruvate: Aerobic

Acetyl CoA

Fate of Pyruvate: Anaerobic

Lactate

Where does the Cori cycle occur?

Liver

The Cori cycle: ___ —→ blood —→ ___ —→ ___ —→ blood

Lactate, pyruvate, glucose

The TCA cycle occurs in the _____ matrix.

mitochondrial

Pyruvate must convert to ___ to enter the TCA cycle

Acetyl CoA

Where does oxidative phosphorylation (ETC) occur?

Mitochondria

What are the final products of the ETC?

H2O, ATP, NAD+, FAD

How would creatine supplementation aid in the regeneration of ATP from ADP?

CrP releases a P and that’s added to ADP to form ATP.

What is the molecular focal point in lipid metabolism?

Glycerol undergoing beta-oxidation

Where does beta oxidation occur?

Mitochondrial matrix

What are the hormonal signals for lipolysis?

Lipase

Lipid Metabolism (Stage 1): Process & Product

Lipolysis

Fatty Acids

Lipid Metabolism (Stage 2): Process & Product

Beta-Oxidation

Acetyl CoA

Lipid Metabolism (Stage 3): Process & Product

TCA cycle

CO2

Lipid Metabolism (Stage 4): Process & Product

Oxidative Phosphorylation (ETC)

ATP

Lipid Metabolism

Carnitine’s role in Beta-oxidation:

transfers long-chain fatty acids to the mitochondria for B-oxidation

Practice Problem

You slam a Monster Energy drink with 2500 mg proprietary energy blend with L-carnitine for fat burning, are you burning more fat as you sit down studying?

No

Transamination

transfer of an amino group

Deamination

complete removal of an amine group

Protein Metabolism (Stage 1): Proteolysis

Proteins —→ amino acids

Protein Metabolism (Stage 2): Transamination/Deamination

NH3 & keto acids

Protein Metabolism (Stage 3): TCA cycle

NADH & FADH2

Protein Metabolism (Stage 4): Process & Product

Oxidative phosphorylation (ETC)

ATP

How’s protein metabolism different than lipid and carbohydrate in relation to entry into the TCA cycle?

Proteins —→ amino acid —→ TCA cycle

OR —→ deaminated —→ glycolysis —→ acetyl CoA

Gluconeogenesis:

generation of glucose from non-carb C substrates

(e.g.) lactate, glycerol, and glucogenic aa

Where does gluconeogenesis occur?

liver

What hormone stimulates gluconeogenesis?

cortisol

Glycogenesis:

formation of glycogen from glucose

The hormonal signal for glycogenesis is ___

insulin

The important branch point for shuttling glucose to form glycogen is ___ & ___ cells

liver, muscle

Lipogenesis:

converting glucose to fat for storage

Lipogenesis is stimulated by increased ___ & ___

carbs, insulin

Where are new triglycerides stored?

adipose tissue

Ketogenesis:

formation of ketone bodies from excess acetyl CoA

Why is ketogenesis important?

creates ketone bodies

High levels of ketogenesis lead to ________

drop in pH and ketoacidosis

Processes that occur in the absorptive state

Lipogenesis

Glycogenesis

Protein synthesis

Processes that occur in the post-absorptive state

Glycogenolysis

Lipolysis

Processes that occur in acute starvation

Gluconeogenesis

Ketogenesis

Catabolism

release of energy

In the mitochondria, the metabolic pathways used for catabolizing fatty acids are ___ and the ___ ___ which create ___ + ___ and ___ for the creatione of ATP during oxidative phosphorylation.

B-oxidation, TCA cycle, NADH + H+ and FADH2

What is the objective of the Cori cycle?

recycle lactate

B-oxidation process:

Add a CoA to the Carbon chain producing NADH + H+ & FADH

Protein —→ Amino Acid —→ Keto Acid

Why is the N removed during: Amino Acid —→ Keto Acid?

So it can be used for energy

Glucose Catabolism: Stage 1 — Glycogenolysis

Glucose —(2 hormones)—→ G-6-P

hexokinase & glucokinase

Glucose Catabolism: Stage 1 —Glycolysis

G-6-P —(hormone)—→ F-6-P

Phospho hexose isomerase

Glucose Catabolism

F-6-P —(hormone)—→ F-1,6-P

PFK1

Glucose Catabolism

During the transition of F-6-P to F-1,6-P — F,2,6-BP is made by ___ from an increase in ___.

PFK2, insulin