edexcel Sliding Filament Theory

SFT

• There are 4 main stages to muscle contraction

• 1. Detachment

• 2. Hydrolysis

• 3. Cross Bridge

• 4. Power Stroke

Multiple Choice

What does the sliding filament theory explain?

• How muscles contract at the molecular level

• How muscles grow in size

• How muscles generate heat

• How muscles store energy

Multiple Choice

Thick filaments within a myofibril are:

• ATPase

• Sarcoplasmic reticulum

• Actin

• Myosin

Multiple Choice

Thin filaments in a myofibril are

• Sarcomeres

• Sarcoplasm

• Actin

• Myosin

Multiple Choice

The energy needed to perform a muscle contraction comes directly from

• ATP

• Oxygen

• Glucose

• Calcium

Multiple Choice

The neurotransmitter stored in the axon terminal identified as #3

• Calcium Ion (Ca²⁺)

• Protein Channel

• Acetylcholine

• Synaptic Cleft

Multiple Choice

The gap between a neuron and a muscle cell: (#4 in the diagram)

• synaptic cleft (synapse)

• sarcolemma
• vesicle
• Ca²⁺ ion

Multiple Choice

The plasma membrane of a skeletal muscle cell is called the:

• sarcomere
• myofilament
• sarcolemma
• sarcoplasm

Multiple Choice

What state is the sarcomere in #1

• Relaxed
• Contracting
• Fully Contracted
• None of the above

Multiple Choice

What state is the sarcomere in #2

• Relaxed
• Contracting
• Fully Contracted
• None of the above

Multiple Choice

What are the repeating units called in myofibrils?

• Muscle fibers

• Sarcomeres

• Cylindrical structures

• Myofibrils

Multiple Choice

What triggers the release of calcium ions in muscle contraction?

• Action potential

• Troponin

• Tropomyosin

• Myosin-binding sites