NEW! Hexokinase Physiology, Biochemistry, and Mechanism

The video tutorial explores glycolysis, focusing on the role and mechanism of hexokinase. Glycolysis occurs in the cytosol, and hexokinase is crucial for glucose metabolism, acting as a committed step in pathways like glycogen synthesis and the pentose phosphate pathway. The enzyme's mechanism involves ATP binding and phosphorylation of glucose, facilitated by electrostatic interactions. Hexokinase's closed conformation prevents ATP hydrolysis, ensuring efficient catalysis. The enzyme's function is vital for retaining glucose in cells, preventing its re-entry into the bloodstream, and committing it to metabolic pathways.

What is the primary location where glycolysis occurs?

• Cytosol

• Mitochondria

• Endoplasmic Reticulum

• Nucleus

Which enzyme is responsible for the phosphorylation of glucose as it enters the cell?

• Hexokinase

• Glucokinase

• Phosphofructokinase

• Pyruvate Kinase

What is the role of ATP in the phosphorylation of glucose?

• It inhibits the reaction

• It acts as a substrate

• It donates a phosphate group

• It acts as a catalyst

Which residue in the active site of hexokinase is critical for deprotonating the C6 hydroxyl group of glucose?

• Aspartate

• Serine

• Lysine

• Arginine

What is the significance of the closed conformation of hexokinase?

• It prevents ATP hydrolysis

• It changes the enzyme's substrate

• It allows water to enter the active site

• It increases the enzyme's size

What happens to ATP when xylos is used instead of glucose in the hexokinase reaction?

• It forms a new compound

• It is converted to ADP and phosphate

• It remains unchanged

• It is completely degraded

Why is it important to keep glucose within the cell after it enters?

• To allow it to be excreted as waste

• To prevent it from being used by other cells

• To convert it into proteins

• To ensure it is metabolized into energy or storage forms

What is the role of glucose 6 phosphate in cellular metabolism?

• It is an inhibitor of glycolysis

• It is a branch point for multiple pathways

• It is a transporter molecule

• It is a waste product

Which pathway is NOT directly associated with glucose 6 phosphate?

• Glycogen synthesis

• Pentose phosphate pathway

• Fatty acid synthesis

• Glycolysis

What is the consequence of having high glucose levels in the blood?

• Improved vision

• Cellular damage

• Increased energy

• Enhanced protein synthesis