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

8. Protein Function

Skeletal Muscle Contraction

Biochemistry

8. Protein Function

Skeletal Muscle Contraction

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Multiple Choice

Which of the following statements correctly describes the relationship between cytosolic [Ca2+] and the corresponding sarcomere response?

Increasing [Ca²⁺] causes troponin to bind to tropomyosin.

Increasing [Ca²⁺] causes movement of tropomyosin, exposing myosin-binding-sites on actin.

Decreasing [Ca²⁺] promotes interactions between actin and myosin.

Increasing [Ca²⁺] causes troponin and tropomyosin to bind to actin.

Increasing [Ca²⁺] causes dissociation of Ca²⁺ from troponin.

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Verified step by step guidance

Understand the role of calcium ions ([Ca2+]) in muscle contraction. Calcium ions are crucial for the regulation of muscle contraction by interacting with proteins in the sarcomere.

Recognize the key proteins involved: troponin, tropomyosin, actin, and myosin. Troponin and tropomyosin are regulatory proteins that control the access of myosin to actin filaments.

Learn how increasing cytosolic [Ca2+] affects these proteins. When [Ca2+] increases, calcium binds to troponin, causing a conformational change.

Explain the effect of this conformational change. The binding of calcium to troponin leads to the movement of tropomyosin away from the myosin-binding sites on actin, allowing myosin to bind to actin and initiate contraction.

Clarify the incorrect statements: Decreasing [Ca2+] does not promote actin-myosin interaction; it reduces it. Increasing [Ca2+] does not cause troponin and tropomyosin to bind to actin; they are already associated with actin. Increasing [Ca2+] does not cause dissociation of Ca2+ from troponin; it causes binding.