Review 2.8: Muscle Contraction & Relaxation

What is the name of the structure that is the contractile unit of the muscle?

• Myofibril

• Sarcomere

• Muscle cell

• Z disc

The thick filament in the sarcomere is made up of which protein?

• Actin

• Myosin

• Troponin

• Collagen

How do proteins interact?

• Based on their 3D molecular structures

• Based on their color

• Based on their size

What are the locations called where proteins interact with other molecules?

• Active sites

• Binding sites

• Reaction sites

• Contact points

In cells, what molecule provides energy for proteins to work?

• DNA

• ATP

• Glucose

• Oxygen

Tags

NGSS.HS-LS1-7

Where does the initial signal for a muscle to contract come from?

• A neuron

• A muscle

• The spinal cord

• The muscle contracts without any signal

The molecule released by nerve cells to trigger muscle contraction is called ________.

• acetylcholine

• dopamine

• insulin

• serotonin

Refer to the diagram showing nerve cell, membrane of muscle cell, and acetylcholine. Which structure releases acetylcholine?

• Muscle cell

• Nerve cell

• Membrane of muscle cell

• Blood vessel

Acetylcholine triggers the release of _______ ions from the sarcoplasmic reticulum into the cytoplasm of muscle cells.

• calcium

• sodium

• potassium

• chloride

The function of the sarcoplasmic reticulum in muscle contraction is:

• to store and release calcium ions

• to generate electrical impulses

• to provide energy for contraction

• to transmit nerve signals