22 Questions
What is the primary characteristic that distinguishes D and L configurations of a monosaccharide?
The spatial configuration at the highest numbered asymmetric carbon
Which type of carbohydrate is composed of many monosaccharide units and yields more than 10 monosaccharides on hydrolysis?
Polysaccharide
What is the function of cellulose in the human body?
None of the above
What is the primary function of glycogen in the human body?
Energy storage
What is the characteristic of the glycosidic bonds in amylopectin?
a-1,4 linkages with occasional a-1,6 linkages
How many primary functions of carbohydrates are there in the human body?
Five
What is the primary reactant in the formation of glycated hemoglobin?
Glucose
Which of the following inborn errors of metabolism is associated with hypoxic conditions?
Type A Lactic Acidosis
What is the primary function of the insulin receptor in glucose metabolism?
Signaling cascade for glucose metabolism
What is the primary consequence of peripheral neuropathy in diabetes?
Foot ulcers and amputations
Which of the following tests is used to detect inborn errors of carbohydrate metabolism in infants and children?
Both glucose oxidase and copper reduction tests
What is the primary consequence of autonomic neuropathy in diabetes?
Cardiovascular symptoms and sexual dysfunction
What is the primary function of gluconeogenesis in glucose metabolism?
Forming glucose-6 phosphate from non-carbohydrate sources
Which hormone stimulates the release of cortisol, leading to an increase in plasma glucose levels?
Adrenocorticotropic hormone (ACTH)
What is the name of the process by which glucose is converted to glycogen for storage?
Glycogenesis
Which of the following hormones inhibits insulin secretion and promotes lipolysis?
Epinephrine
What is the term for the formation of glucose from non-carbohydrate sources, such as amino acids, lactate, and glycerol?
Gluconeogenesis
Which of the following is a type of diabetes that results from defects in insulin secretion, insulin action, or both?
Type 2 diabetes
What is the primary function of glycogenolysis in glucose metabolism?
Breaking down glycogen to glucose for energy production
Which hormone increases plasma glucose levels by stimulating glycogenolysis and gluconeogenesis?
Cortisol
What is the name of the process by which glucose is converted to pyruvate or lactate for energy production?
Glycolysis
Which of the following hormones regulates the rate of glucose entry into cells and promotes glucose storage?
Insulin
Study Notes
Classification of Carbohydrates
- Carbohydrates can be classified based on the number of sugar units in the chain:
- Monosaccharides: simple sugars that consist of a single polyhydroxy aldehyde or ketone
- Disaccharides: 2 monosaccharides joined by a glycosidic linkage
- Oligosaccharides: formed by the linkage of many monosaccharide units, yielding more than 10 monosaccharides on hydrolysis
- Polysaccharides: formed by the linkage of many monosaccharide units, yielding more than 10 monosaccharides on hydrolysis
- Examples of carbohydrates:
- Monosaccharides: glucose, fructose, galactose
- Disaccharides: maltose, lactose, sucrose
- Polysaccharides: starch, glycogen, cellulose
Stereochemistry of the Compound
- Stereoisomers are compounds that are identical in composition but differ only in spatial configuration
- A monosaccharide is assigned to the D or L configuration based on the configuration at the highest numbered asymmetric carbon
Functions of Carbohydrates
- Five primary functions of carbohydrates in the human body:
- Energy production
- Energy storage
- Building macromolecules
- Sparing protein
- Assisting in lipid metabolism
Fate of Carbohydrates
- Carbohydrates can be broken down into glucose, which is then used for energy production
- Glucose can be stored as glycogen in the liver and muscles
- Glucose can be converted into fat for storage
- Carbohydrates can be used to build macromolecules such as glycoproteins and glycolipids
Regulation of Carbohydrate Metabolism
- Hormones that regulate carbohydrate metabolism:
- Insulin: decreases plasma glucose levels
- Glucagon: increases plasma glucose levels
- Cortisol: increases plasma glucose levels
- Thyroid hormones: increase plasma glucose levels
- Somatostatin: decreases plasma glucose levels
- Other hormones that tend to increase glucose concentration:
- Adrenocorticotropic hormone (ACTH)
- Catecholamines
- Growth hormones
Clinical Conditions of Carbohydrate Metabolism
- Hypoglycemia: a condition where the blood glucose level falls below 70 mg/dL
- Symptoms: neurogenic and neuroglycopenic
- Causes: imbalance between glucose utilization and production, genetic defects, insulin deficiency, or abnormal insulin receptor
- Hyperglycemia: a condition where the blood glucose level rises above 126 mg/dL
- Symptoms: none or mild
- Causes: imbalance between glucose utilization and production, genetic defects, insulin deficiency, or abnormal insulin receptor
- Diabetes mellitus: a disease characterized by high blood glucose levels due to defects in insulin secretion, insulin action, or both
- Types: Type 1 DM, Type 2 DM, MODY, transient neonatal diabetes, and permanent neonatal diabetes
Test your understanding of carbohydrate metabolism, including glucose pathways, glycolysis, glycogenesis, and glycogenolysis. Learn about the different forms of carbohydrates, such as aldose and ketose, and their role in energy production and storage. Explore the fate of carbohydrates in the body and how they are broken down and synthesized.
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