Glycogen Metabolism and Functions

This video tutorial from MIT OpenCourseWare covers carbohydrate biosynthesis, focusing on glycogen synthesis and breakdown. It explains the structure of glycogen, the role of glycogenin, and the pathways of gluconeogenesis. The tutorial also details the conversion of glucose 1-phosphate to glycogen, highlighting key enzymes like UDP glucose pyro phosphorylase and glycogen synthase. The metabolic map of glucose 1-phosphate's role in various pathways is also discussed.

What is the primary function of gluconeogenesis?

• To synthesize fatty acids

• To store glucose as glycogen

• To convert non-carbohydrate precursors into glucose

• To break down glycogen into glucose

What is the role of glycogenin in glycogen synthesis?

• It phosphorylates glucose

• It acts as a primer for glycogen synthesis

• It converts glucose into glucose 6-phosphate

• It breaks down glycogen into glucose

What is the primary function of glycogen in the body?

• To act as a long-term energy storage

• To provide immediate energy through glucose release

• To synthesize proteins

• To convert glucose into fatty acids

Which enzyme is crucial for glycogen breakdown?

• Phosphoglucomutase

• Glycogen phosphorylase

• Hexokinase

• Glycogen synthase

How does glycogen phosphorylase contribute to glycogenolysis?

• It phosphorylates glucose

• It converts glucose into glucose 6-phosphate

• It removes glucose units from the non-reducing end of glycogen

• It adds glucose units to glycogen

What is the role of glucose 6-phosphate in metabolic pathways?

• It is only involved in glycogen synthesis

• It acts as a crossroads in various metabolic pathways

• It is only involved in glycolysis

• It is only involved in gluconeogenesis

What happens to glucose 6-phosphate if it is not needed for glycolysis?

• It is excreted from the body

• It is stored as fat

• It is converted to glucose 1-phosphate

• It is converted to pyruvate

Which enzyme catalyzes the conversion of glucose 1-phosphate to UDP glucose?

• Hexokinase

• Phosphoglucomutase

• UDP glucose pyro phosphorylase

• Glycogen synthase

Which molecule is a direct precursor to glycogen synthesis?

• Glucose 1-phosphate

• Glucose 6-phosphate

• Pyruvate

• UDP glucose

What is the significance of the oxonium ion in glycogen metabolism?

• It is an intermediate in both glycogen breakdown and synthesis

• It is only involved in glycogen breakdown

• It is a byproduct of glycolysis

• It is only involved in glycogen synthesis