[BIOCHEM-LEC-FINALS] OVERVIEW OF METABOLISM (2/2)

Covers: Subcellular Level

• Mitochondrion

• Cytosol

• Smooth ER

What are the three subcellular levels?

• Citric Acid Cycle

• B-oxidation

What are the processes under mitochondrion?

Acetyl-CoA

The precursor of Citric Acid Cycle.

Fatty Acids

The precursor of B-oxidation.

• Pentose Phosphate Pathway

• Fatty Acid Synthesis

• Gluconeogenesis

What are processes under cytosol?

Pentose Phosphate Pathway

The alternative pathway involving carbohydrates.

• To make reducing equivalents

• To make DNA and RNA

What are the purposes of pentose phosphate pathway?

Lipogenesis

Fatty acid synthesis is also called as?

Non-carbohydrates

What is the raw material of gluconeogenesis?

Triacylglycerol Synthesis

What is the process called that takes place in the smooth endoplasmic reticulum?

Esterification

This is the production of triacylglycerol (TAGs).

• 3 fatty acids to produce 1 TAG

• 1 glycerol

What are the raw materials of TAGs.

Gluconeogenesis

In this process, there is a formation of glucose from non-carbohydrate components.

• Lactate

• Pyruvate

• Amino Acids

• Glycerol

What are the four substrates/precursors/raw materials?

Oxaloacetate

The common intermediate product whether lactate, pyruvate, amino acids, or glycerol.

Oxaloacetate

The common intermediate product of the substrates if we intend to produce glucose through gluconeogenesis.

Glucose

Oxaloacetate would eventually become?

18

Out of 20 amino acids, how many of them can produce glucose?

13

How many of the 18 amino acids can produce only glucose?

5

How many of the 18 amino acids can produce both glucose or ketone bodies.

Glucogenic

Amino acids that yields pyruvate and 4- and 5-C intermediates of the Tricarboxylic Acid Cycle.

Ketogenic

Amino acids that give rise to Acetyl-CoA.

Fed State

In this state:

• Metabolic fuel reserves are laid down.

• More on ANABOLIC EFFECT.

Fasting State

In this state:

• Metabolic fuel reserves are mobilized.

Insulin

Secreted by the B-islet cells in response to increased blood glucose concentration (fed state).

B-pancreatic cells

B-islet is also known as?

Insulin

Controls glucose uptake into the muscle and adipose tissue.

Glucose transporter type 4 (GLUT4)

This migrates to the cell surface in response to insulin.

Insulin independent

Glucose uptake in the liver is?

Fed

The insulin will rise if we are?

Blood sugar

The insulin lowers the?

Glucogen

Excess glucose in the muscle is called?

Triacylglycerols

Excess glucose in the adipose tissue is called?

Hexokinase

This is the enzyme that catalyzes this phosphoryl group transfer.

Glucokinase

When there is an excess glucose in the liver, there could be an activation of specific hexokinase called?

Weight gain

What is an example of side effect of taking insulin?

Insulin

This stimulates the enzyme, glycogen synthase.

Glycogen Synthase

The enzyme needed for glycogenesis.

Anabolism

Is glycogenesis anabolism or catabolism?

Glucose → Glycogen

Glycogen Phosphorylase

The enzyme needed for glycogenolysis.

Glycogen Phosphorylase

The insulin inhibits this enzyme.

Glycogenolysis

This is the breaking down of glycogen into glucose.

Glycogen

In glycogenolysis, this will be retained.

Insulin

In adipose tissue, this stimulates glucose uptake. Its conversion to fatty acids and their esterification to triacylglycerol (fats).

Glucagon

A hormone secreted by the a-cells in response to the fall in blood glucose concentration.

Glycogen synthase

Glucagon inhibits ___ and activates glycogen phosphorylase.

Glucose

The inhibition of glycogenesis results to higher?

Glucose

This is important if we’re hungry (for energy).

• To keep us alive even if we have nothing to eat

• Raise the levels of glucose

What are the goals of glucagon?

Hyperglycemia

The effect of glucagon that results in high blood sugar.

Lipogenesis

In adipose tissue, increase in glucagon results to inhibition of?

Acetyl-CoA

Inhibition of fatty acids from?

No

Does the level of Acetyl-CoA lowers when lipogenesis is blocked?

Acetyl-CoA

Lipogenesis uses this to produce fatty acids, so blocking the process means this is not being consumed for making fats.

Glucagon

This keeps us alive by utilizing stored energy or molecules to catabolize, producing energy.

Epinephrine and Cortisol

Other examples of hormones that both have catabolic effects.

Insulin

Who’s the king when you’re full?

Yes

Is TAG a form of energy?

Plasma-free fatty acids

These are unesterified fatty acids and not a TAG (because TAGs are hydrolyzed).

Ketone Bodies

These are only alternative source of energy, especially if the glucose are running low.

Lower

If we’re hungry, is the level of glucose gets higher or lower?

B-oxidation

The process of cutting every 2-carbon.

Acetyl-CoA

What is the product of B-oxidation?

• Glycogen from the liver were used

• This process is called glycogenolysis

Why is glycogen low when we’re hungry?

Glucagon

What facilitates or enhances glycogenolysis?

Higher utilization of tissue substrates

Higher respiratory quotient is equals to?

1.00

Respiratory quotient of Carbohydrates.

0.81

Respiratory quotient of Proteins.

0.71

Respiratory quotient of Fats.

0.56

Respiratory quotient of Alcohol.

Carbohydrates

This is the greatest energy provider, with a respiratory quotient of 1.00—quickly enters the oxidative phosphorylation.

5.5

Plasma Concentrations of Metabolic Fuels:

During fed state, what is the plasma concentration of glucose?

0.30

Plasma Concentrations of Metabolic Fuels:

During fed state, what is the plasma concentration of non-esterified fatty acids?

Negligible

Plasma Concentrations of Metabolic Fuels:

During fed state, what is the plasma concentration of ketone bodies?

3.6

Plasma Concentrations of Metabolic Fuels:

After 40 hours of fed state, what is the plasma concentration of glucose?

1.15

Plasma Concentrations of Metabolic Fuels:

After 40 hours of fed state, what is the plasma concentration of non-esterified fatty acids?

2.9

Plasma Concentrations of Metabolic Fuels:

After 40 hours of fed state, what is the plasma concentration of ketone bodies?

3.5

Plasma Concentrations of Metabolic Fuels:

After 7 days of fed state, what is the plasma concentration of glucose?

1.19

Plasma Concentrations of Metabolic Fuels:

After 7 days of fed state, what is the plasma concentration of non-esterified fatty acids?

4.5

Plasma Concentrations of Metabolic Fuels:

After 7 days of fed state, what is the plasma concentration of ketone bodies?

Glucagon

This sustains the level of blood glucose.

Ketone Bodies

These are acidic in nature, will result to acidosis.

Ketosis

This results due to high demand for glucose by the fetus, and lactose synthesis in activation.

Type 1 Diabetes Mellitus

Due to lack or absence of insulin to stimulate glucose uptake and utilization.

Type 1 Diabetes Mellitus

Characterized by the lack of insulin due to destruction of b-cells.

Hyper or Chronic Hyperglycemia

Risk of Type 1 DM—no supply of insulin that would lower blood glucose by enhancing utilization.

Glycogen Storage Disease

A group of inherited disorders characterized by deposition of an abnormal type or quantity of glycogen in tissues, or failure to mobilize glycogen.

Type 0

Glycogen Storage Disease:

Enzyme Deficiency: Glycogen synthase

Type 1A - Von Gierke’s Disease

Glycogen Storage Disease:

Enzyme Deficiency: Glucose 6-phosphatase

Type 1B

Glycogen Storage Disease:

Enzyme Deficiency: Endoplasmic reticulum glucose 6-phosphate transporter

Type 2 - Pompe’s Disease

Glycogen Storage Disease:

Enzyme Deficiency: Lysosomal a₁ → 4 and a₁ → 6 glucosidase (acid maltase)

Acid maltase

6 glucosidase is also known as?

Type 3A - Limit Dextrinosis, Forbe’s or Cori’s Disease

Glycogen Storage Disease:

Enzyme Deficiency: Liver and muscle debranching enzyme

Type 3B - Limit Dextrinosis

Glycogen Storage Disease:

Enzyme Deficiency: Liver debranching enzyme

Type 4 - Amylopectinosis, Andersen’s Disease

Glycogen Storage Disease:

Enzyme Deficiency: Branching enzyme

Acetyl-CoA

This is also the precursor for synthesis of long-chain fatty acids and steroids  (including cholesterol) and ketone bodies.

Glucose

This provides carbon skeletons for the glycerol of triacylglycerols and non-essential amino acids.

1. Liver

2. Hepatic portal vein

Water-soluble products of digestion are transported directly to the (1)___ via the (2)____.

Liver

This organ regulates the concentrations of glucose and amino acids available to other tissues.

Cytosol

Glycolysis, glycogenesis, glycogenolysis, the pentose phosphate pathway, and lipogenesis occurs in the?