(M) Lec 2: Carbohydrates Flashcards by Kchianna Lauren Coronel

The primary source of energy for the brain, erythrocytes, and retinol cells

Carbohydrates

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The major food source and energy supply of the body as the cells depend on this

Carbohydrates

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The general empirical formula “Cn(H2O)m” corresponds to what type of carbohydrate?

Monosaccharides

Note: Has the same proportion of H and O with that of water

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Carbohydrates have been described as the “what” of carbon?

Hydrates

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Depending on the location of the carbonyl functional group, carbohydrates are hydrates of the derivatives of what 2 functional groups?

Aldehydes and Ketones

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Carbohydrates are indicated by what shorthand designation?

“CHO”

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What 2 functional groups are carbohydrates made out of?

Carbonyl (C=O)
Hydroxyl (OH)

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This is known as the simplest carbohydrate

Glycoaldehyde

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Structures of carbohydrates can be depicted in 2 ways which are?

Long-chain structure (Fischer projection)
Ring structure (Haworth projection)

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What are the 4 functions of carbohydrates?

Energy
Storage
Structure
Molecular Recognition

Acronym: M-E-S-S

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Classification of Carbohydrates based on the Number of Sugar Units

Has one sugar unit (simple sugar unit)
e.g. Glucose, Fructose, and Galactose

Monosaccharides

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Classification of Carbohydrates based on the Number of Sugar Units

Has 2 sugar units or 2 monosaccharides
Requires being split up by intestinal enzymes so they can be absorbed
e.g. Sucrose, Lactose, and Maltose

Disaccharides

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Classification of Carbohydrates based on the Number of Sugar Units

Is made up of 2-10 sugar units

Oligosaccharides

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Classification of Carbohydrates based on the Number of Sugar Units

Made up of more than 10 sugar units

Polysaccharides

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What is the DISACCHARIDE?

Galactose + Glucose

Lactose

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What is the DISACCHARIDE?

Glucose + Glucose

Maltose

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What is the DISACCHARIDE?

Glucose + Fructose

Sucrose

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Classification of Carbohydrates based on the Size of the Base Carbon

5 carbons

Pentose

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Classification of Carbohydrates based on the Size of the Base Carbon

3 carbons

Triose

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Classification of Carbohydrates based on the Size of the Base Carbon

6 carbons

Hexose

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Classification of Carbohydrates based on the Carbonyl Location

Located on the TERMINAL end

Aldose

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Classification of Carbohydrates based on the Carbonyl Location

Located on the middle (usually lands on C2)

Ketose

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Reducing or Non-reducing Sugar?

A double bond is present
Can donate a free aldehyde or the ketone can be oxidized
e.g. Glucose, Maltose, Fructose, Lactose, and Galactose

Reducing Sugar

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Reducing or Non-reducing Sugar?

There is no active ketone or aldehyde to be oxidized
e.g. Sucrose

Non-Reducing Sugar

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The sugar present in fruits

Fructose

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The sugar present in milk or in mammals

Lactose

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Aside from lactose, this sugar is also present in milk

Galactose

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The sugar known as “table sugar”

Sucrose

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This is the only carbohydrate that is directly used as energy/converted to glycogen for storage

Glucose

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What happens to glycogen when the body needs energy?

Converts back to glucose

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Digestion of Carbohydrates

Carbohydrates are ingested as what 2 commonly ingested polysaccharides?

Starch and Glycogen

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Digestion of Carbohydrates

This enzyme hydrolyzes starch to convert it into disaccharides in the duodenum

Amylase

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Digestion of Carbohydrates

This type of amylase is present in the oral cavity

Salivary amylase

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Digestion of Carbohydrates

This type of amylase is present in the pancreas

Pancreatic amylase

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Digestion of Carbohydrates

After amylase hydrolyzes starch, it will be converted into what 2 products?

Dextrin and Disaccharide

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Digestion of Carbohydrates

The acidic pH of the stomach deactivates what enzyme?

Salivary amylase

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Digestion of Carbohydrates

When passing through the pancreas, this enzyme will act on the disaccharides to produce another set of disaccharides

Pancreatic amylase

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Digestion of Carbohydrates

Where are disaccharides further digested into monosaccharides through the enzymes: maltase, sucrase, or lactase?

Intestines

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Digestion of Carbohydrates

Identify the enzyme that breaks these substances apart:

Maltose to 2 glucose units

Maltase

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Digestion of Carbohydrates

Identify the enzyme that breaks these substances apart:

Sucrose to glucose and fructose

Sucrase

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Digestion of Carbohydrates

Identify the enzyme that breaks these substances apart:

Lactose to glucose and galactose

Lactase

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Digestion of Carbohydrates

What form of carbohydrates can be absorbed by the GIT before going to the liver where it will be circulated to the body?

Monosaccharides

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These 3 pathways: PPP/HMP, EMP, and TCA, convert glucose into what?

Water and Carbon Dioxide

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Aside from water and CO2, these 3 pathways: PPP/HMP, EMP, and TCA, convert glucose into what?

ADP and ATP

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Glucose Metabolism

First step for all three pathways: Glucose, with the help of ATP, is coverted into what?

Glucose-6-phosphate (G6P)

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Glucose Metabolism

These 2 pathways generate ATP from glucose

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Glucose Metabolism

This pathway allows for the storage of glucose in the form of glycogen which usually occurs in the liver or muscles specialized in storing glycogen

Glycogenesis Pathway

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Glucose Metabolism

In case the body needs glucose, what will the liver synthesize in order to convert glycogen into glucose?

Glucose-6-phosphatase (enzyme for G6P)

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Glucose Metabolism

Only the liver is capable of synthesizing glucose-6-phosphatase in order to convert glycogen into glucose, what is its equivalent for the muscle if it cannot release the enzyme?

It directly releases glucose via muscle catabolism

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Embden-Meyerhoff Pathway

Step 1: Glucose through the action of glucokinase is converted into what?

Glucose-6-phoshate (G6P)

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Embden-Meyerhoff Pathway

Step 2: Glucose-6-phoshate (G6P) is converted into what?

pathway to glycogenesis

Glucose-1-phosphate (G1P)

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Embden-Meyerhoff Pathway

Step 3: Glucose-1-phosphate (G1P) through the action of glycogen synthase is converted into?

Glycogen

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Embden-Meyerhoff Pathway

Optional step: If glycogen is acted upon by glycogen phosphorylase, it will be converted back to what?

Glucose-1-phosphate (G1P)

This becomes glucose again later on

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Embden-Meyerhoff Pathway

Step 4: Glucose-6-phosphate may also be converted to become what?

EMP

Clue: Another form of sugar

Fructose-6-phosphate

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Embden-Meyerhoff Pathway

Step 5: Fructose-6-phosphate will be converted into what?

Phosphoenol pyruvate (PEP)

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Embden-Meterhoff Pathway

Step 6: Phosphoenol pyruvate (PEP) through the action of pyruvate kinase will be converted to?

Pyruvate

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Embden-Meyerhoff Pathway

Step 7: Pyruvate will be converted into what before entering the Tricarboxylic Acid Cycle (TCA)?

Acetyl CoA

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Other Pathways involving Carbs

Conversion of glucose to pyruvate or lactate

Glycolysis

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Other Pathways involving Carbs

Formation of glucose from non-carb sources (e.g. lipids and amino acids)

Gluconeogenesis

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Other Pathways involving Carbs

From glycogen to glucose

Glycogenolysis

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Other Pathways involving Carbs

From glucose to glycogen

Glycogenesis

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Other Pathways involving Carbs

From carbs to fats

Lipogenesis

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Other Pathways involving Carbs

The decomposition of fats

Lipolysis

This cycle enables the production of glucose from amino acids, glycogen, glycerol, lactic acid/lactate, or ketone bodies

Tricarboxylic Acid/Citric Acid/ Krebs Cycle

For cases of brief fasting, what organ is the source of glucose?

Liver

For cases of longer fasting times that last for more than a day, the body relies on what process?

Gluconeogenesis

What 3 organs regulate carbohydrates?

Liver
Pancreas
Endocrine Glands

What are the 2 major hormones that control blood glucose?

Insulin and Glucagon

This is both an endocrine and exocrine gland

Pancreas

These glands are able to produce hormones

Endocrine glands

These glands are able to produce enzymes

Exocrine glands

What is the exocrine (enzyme) secretion of the pancreas?

Amylase

What are the endocrine (hormones) secretions of the pancreas?

Clue: Remember the Islets of Langerhans

Insulin
Glucagon
Somatostatin

Islets of Langerhans

Alpha cells secrete what?

Glucagon

Islets of Langerhans

Beta cells secrete what?

Insulin

Islets of Langerhans

Delta cells secrete what?

Somatostatin

Islets of Langerhans

Acinar and Duct cells (exocrine glands) produce what?

Amylase

Islets of Langerhans

F cells secrete what?

Pancreatic polypeptides

The most important hormone in the blood glucose concentration; the main hypoglycemic agent

Insulin

The only hormone responsible for the entry of glucose into the cell

Insulin

TOF: Insulin decreases the process of glycogenesis, lipogenesis, and glycolysis BUT increases glycogenolysis hence why it is a hypoglycemic agent

False (reverse the decrease and increase portions)

Insulin is released when blood glucose levels are what?

High

Stimulates the entrance of glucose into tissue (decreases blood sugar)

This is released during stressed and fasting stages; the main hyperglycemic agent

Glucagon

This hormone increases the processes of glycogenolysis and gluconeogenesis

Glucagon

Once insulin is released, the glucose in the blood goes to where?

Body cells (or muscles)

TOF: Insulin production rates increase when glucose is absorbed by the muscles

False (because glucose is now in your body cells, not your blood, so there is nothing for insulin to counter)

Insulin can stimulate what organ to take up glucose and store it as glycogen?

Liver

Once glucagon is released in the blood, it stimulates the liver to break down what to become glucose?

Glycogen

This is produced by the medulla of the adrenal glands (specifically chromaffin cells); it inhibits insulin making it a hyperglycemic agent as it increases the processes of glycogenolysis and lipolysis

Catecholamines

TOF: Catecholamines are released with stress

True

This is produced by the adrenal cortex (zona fasciculata and zona reticularis); it decreases glucose entry into the cell which increases the processes of gluconeogenesis, lipolysis, and glycogenolysis

Glucocorticoids

This is the main promoter of gluconeogenesis in glucocorticoids

Cortisol (hyperglycemic hormone)

Glucocorticoids are made up of what 2 substances?

Cortisol and Corticosteroids

Hyperglycemic Hormones

Aka “somatotropic hormone” which causes decreased entry of glucose to cells

Growth hormone

Hyperglycemic Hormones

Increases blood glucose by stimulating the release of cortisol from the adrenal glands

ACTH

Hyperglycemic Hormones

A thyroid hormone that promotes glycogenolysis and gluconeogenesis (+ intestinal absorption of glucose)

Thyroxine

Hyperglycemic Hormones

A hormone-inhibiting hormone

Somatostatin

Clinical Conditions of Carbohydrate Metabolism

An increase in blood or plasma glucose levels

Hyperglycemia

Clinical Conditions of Carbohydrate Metabolism

TOF: Insulin deficiency directly results to hyperglycemia

True

Clinical Conditions of Carbohydrate Metabolism

A lack of this receptor prevents the passing of insulin through the cells which prevents the glucose from entering the cells, contributing to hyperglycemia

Insulin receptor

Clinical Conditions of Carbohydrate Metabolism

With hyperglycemia, all adults older than how many years old should have their FBS checked every 3 years unless diabetic?

45 years old

Clinical Conditions of Carbohydrate Metabolism

TOF: Ketones are decreased in the serum and urine when a patient is hyperglycemic

False (increased)

Clinical Conditions of Carbohydrate Metabolism

Why is blood and urine pH decreased when the patient is experiencing hyperglycemia? What urinary tract event is experienced when blood glucose levels are high?

Polyuria = decreases urine pH

Clinical Conditions of Carbohydrate Metabolism

A decrease in blood or plasma glucose levels which is usually a warning sign for CNS-related disorders

Hypoglycemia

Clinical Conditions of Carbohydrate Metabolism

What is the characteristic sign and symptom of hypoglycemia?

Whipple’s Triad

Hypoglycemic symptoms
Low blood glucose concentration
Immediate relief after glucose administration

Clinical Conditions of Carbohydrate Metabolism

TOF: The Whipple’s Triad is used to diagnose patients that have diabetes

False (no diabetes)

Hypoglycemia

Clinical Conditions of Carbohydrate Metabolism

What glucose level indicates that glucagon and other hyperglycemic hormones are being released by the endocrine gland?

65 to 70 mg/dL

Clinical Conditions of Carbohydrate Metabolism

Hypoglycemia symptoms are observable at what glucose level?

50-55 mg/dL

Clinical Conditions of Carbohydrate Metabolism

What is the diagnostic glucose level for hypoglycemia?

Less than 50 mg/dL

Classifications of Hypoglycemia can be Based on:

“Whether administered with insulin, alcohol, or salicylates”

A. Drug Administration
B. Critical Illnesses
C. Hormonal Deficiency
D. Endogenous Hyperinsulinism
E. Autoimmune Hypoglycemia
F. Non-Beta Cell Tumors
G. Hypoglycemia of Infancy and Childhood
H. Alimentary Hypoglycemia
I. Idiopathic Postprandial Hypoglycemia

A. Drug Administration

Classifications of Hypoglycemia can be Based on:

“Those with hepatic failure, renal failure, or sepsis”

B. Critical Illnesses

Classifications of Hypoglycemia can be Based on:

“Deficiency of GH or cortisol deficiency”

C. Hormonal Deficiency

Classifications of Hypoglycemia can be Based on:

“Wherein there is a pancreatic beta cell disorder”

D. Endogenous Hyperinsulinism

Classifications of Hypoglycemia can be Based on:

“There is a production of insulin autoantibodies”

E. Autoimmune Hypoglycemia

Classifications of Hypoglycemia can be Based on:

“Such as leukemia or hepatoma”

F. Non-Beta Cell Tumors

Classifications of Hypoglycemia can be Based on:

“Cases of post-gastric surgery”

H. Alimentary Hypoglycemia

Classifications of Hypoglycemia can be Based on:

“Cause is unknown”

I. Idiopathic Postprandial Hypoglycemia

A group of metabolic disorders characterized by hyperglycemia

Diabetes Mellitus

This condition is caused by defects in insulin secretion, insulin receptors, or both

Diabetes Mellitus

This is exhibited when the plasma glucose level exceeds 180 mg/dL with a normal renal function

Glucosuria

This condition is also exhibited in Diabetes Mellitus but may be reversed by insulin administration

Ketosis

TOF: Ketone bodies are frequently found in patients with severe uncontrolled diabetes

True

Endocrine disorders such as Cushing’s Syndrome, Acromegaly, or Pheochromocytoma have an increased release of hormones that (increase/decrease) blood glucose levels

Increase

Types of DM:

Aka insulin dependent DM, juvenile onset DM, brittle diabetes, or ketosis-prone diabetes

Type 1

Types of DM:

Caused by the cellular mediated autoimmune destruction of B cells in the pancreas

Type 1

Types of DM:

Manifested by insulinopenia wherein there is absolute insulin deficiency due to the loss of pancreatic B cells which resuts to the dependency in insulin to sustain life and prevent ketosis

Type 1

Types of DM:

There is a genetic association with HLA DR3 and DR4 located on Chromosome 6

Type 1

Types of DM:

There is a presence of multiple autoantibodies (glutamic acid decarboxylase and insulin autoantibodies)

Type 1

Types of DM:

This type is rare, has no known etiology, strongly inherited, no B-cell autoantibodies, episodic insulin requirements, and is prone to developing ketosis

Idiopathic Type 1 DM

Types of DM:

What are the 3 signs and symptoms of type 1 DM?

Clue: 3Ps

Polyuria
Polydipsia
Polyphagia

Types of DM:

Aka non-insulin dependent DM, adult type/maturity onset DM, stable diabetes, ketosis-resistant DM, or receptor-deficient DM

Type 2

Types of DM:

This is a relative-type of insulin deficiency as opposed to the other type with absolute deficiency

Type 2

Types of DM:

This is caused by a resistance to insulin due to a deficiency in insulin receptors

Type 2

Types of DM:

This is a geneticist’s worst nightmare because of its genetic predisposition

Type 2

Types of DM:

Results to non-ketotic hyperosmolar coma (overpopulation of glucose) plus a notable increase in BUN and creatinine

Type 2

Types of DM:

This type has no presence of ketoacidosis

Type 2

Types of DM:

In this type, insulin is present but there is no receptor that is why the C-peptide is linked to be present (C-peptide is produced with insulin)

Type 2

Types of DM:

What are the 3 signs and symptoms of Type 2 DM?

Clue: 3Ps

Polyuria
Polydipsia
Polyphagia

This is characterized by a deficiency in ADH or vasopressin with normoglycemia, severe polyuria, and polydipsia (decreased SG but increased urine volume)

Diabetes Insipidus