2.8.4Inquiry Process
Requirements for Movement — IB Biology HL Revision Notes & Topical Questions
5 min read 4 parts Lesson 89 of 160
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Section 1 of 4Energy for Contraction
ATP use
- ATP use ATP is needed to detach myosin heads from actin, reset the heads and pump calcium ions back into the sarcoplasmic reticulum.
Stored ATP
- Stored ATP Muscle holds only a few seconds' worth of ATP, so it must be regenerated continuously.
Creatine phosphate
- Creatine phosphate This store transfers phosphate to ADP and rapidly restores ATP for the first seconds of intense activity.
Aerobic respiration
- Aerobic respiration Mitochondria produce large amounts of ATP from glucose or fatty acids, using oxygen delivered by blood and stored by myoglobin.
Anaerobic respiration
- Anaerobic respiration When oxygen is limited, glycolysis produces a small amount of ATP and lactate accumulates, causing fatigue.
| Source | Speed | Duration |
|---|---|---|
| Creatine phosphate | Very fast | A few seconds |
| Anaerobic | Fast | Short bursts |
| Aerobic | Slower | Long periods |
Section 2 of 4Supplies and Control
Supplies and Control
Blood supply
- Blood supply Capillaries bring glucose, fatty acids and oxygen and remove carbon dioxide and heat.
Myoglobin
- Myoglobin This red pigment in muscle stores oxygen and releases it when oxygen is scarce.
Nerve signals
- Nerve signals Motor neurons release acetylcholine at neuromuscular junctions to trigger contraction.
Calcium ions
- Calcium ions Ions must be released and then pumped back to allow contraction and relaxation.
Section 3 of 4Mechanical Requirements
1
Muscles can only pull, so they work in antagonistic pairs: when one contracts the other relaxes.
2
Tendons connect muscles to bones, transmitting the pull without stretching much.
3
The skeleton provides a rigid lever for the muscles to act on.
4
Joints allow bones to move relative to each other in controlled directions.
5
After vigorous exercise, extra oxygen is taken in to remove lactate and restore ATP and creatine phosphate stores.
Section 4 of 4Exam Checklist & Tips
2.8.4 – Key Points for the Exam
- Creatine phosphate A store of phosphate that can regenerate ATP rapidly.
- Myoglobin An oxygen-storing protein in muscle cells.
- Lactate The product of anaerobic respiration in animal muscle.
- Antagonistic pair Two muscles that produce opposite movements at a joint.
Common Mistakes
- Saying that muscles produce ATP from nothing; they must regenerate it from respiration.
- Stating that lactate is the cause of muscle soreness days later.
- Claiming that muscles can push as well as pull.
- Confusing myoglobin with haemoglobin; myoglobin stays in muscle.
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