Table of contents

1. Introduction to Biochemistry4h 34m
2. Water3h 23m
3. Amino Acids8h 10m
4. Protein Structure10h 4m
5. Protein Techniques14h 5m
6. Enzymes and Enzyme Kinetics13h 38m
7. Enzyme Inhibition and Regulation 8h 42m
8. Protein Function 9h 41m
9. Carbohydrates7h 49m
10. Lipids5h 49m
11. Biological Membranes and Transport 6h 37m
12. Biosignaling9h 45m
Review 1: Nucleic Acids, Lipids, & Membranes2h 47m
Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway3h 12m
Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism2h 26m
Review 4: Amino Acid Oxidation, Oxidative Phosphorylation, & Photophosphorylation1h 48m

6. Enzymes and Enzyme Kinetics

Enzymes

Biochemistry

6. Enzymes and Enzyme Kinetics

Enzymes

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Multiple Choice

Which aspect of the crossbridge cycle is directly sensitive to ATP binding?

Release of calcium from the sarcoplasmic reticulum

Dissociation of myosin from actin

Hydrolysis of ADP to AMP

Phosphorylation of troponin

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Verified step by step guidance

Understand the crossbridge cycle: The crossbridge cycle is a fundamental process in muscle contraction where myosin heads interact with actin filaments. ATP plays a critical role in this cycle by binding to myosin and facilitating specific steps.

Identify the role of ATP in the cycle: ATP binding to myosin is essential for the dissociation of the myosin head from actin. Without ATP, myosin remains tightly bound to actin, leading to a state known as rigor mortis.

Clarify the incorrect options: Release of calcium from the sarcoplasmic reticulum is regulated by voltage-gated channels and not directly sensitive to ATP binding. Hydrolysis of ADP to AMP is not a primary step in the crossbridge cycle. Phosphorylation of troponin is related to calcium binding and regulation of actin-myosin interaction, but it is not directly sensitive to ATP binding.

Focus on the correct aspect: The dissociation of myosin from actin is the step in the crossbridge cycle that is directly sensitive to ATP binding. ATP binds to the myosin head, causing a conformational change that releases myosin from actin.

Summarize the connection: ATP binding is crucial for the proper functioning of the crossbridge cycle, specifically enabling the dissociation of myosin from actin, which resets the cycle for subsequent muscle contractions.