What is the result of the shortening of muscle fibers?

Fill in the blank: A group of myosin molecules forms a _________.

What do actin molecules consist of?

Fill in the blank: Troponin and tropomyosin are two proteins associated with the surface of the actin molecules; together, these three proteins form the ________.

What role does Tropomyosin play in the structure of Actin filaments?

According to the sliding filament model of muscle contraction, a myosin head attaches to what during muscle contraction?

What is formed when a myosin head attaches to a binding site on the actin filament?

As the sliding filament model of muscle contraction occurs repeatedly, what happens to the filaments and the sarcomere?

What happens when many sarcomeres shorten at the same time?

Energy from the conversion of ATP to ADP is provided to the cross-bridges by the enzyme _______.

What is the condition called when skeletal muscles contract partially and become rigid after death?

What is the role of ATP in muscle relaxation according to the Sliding Filament Model?

In the Sliding Filament Model, what happens when Ca²⁺ binds to troponin?

Fill in the blank: During muscle contraction, the _______ shortens as the Z lines move closer together.

What is the neurotransmitter for skeletal muscle fiber contraction at the neuromuscular junctions?

Upon receipt of the muscle impulse, the sarcoplasmic reticulum releases its stored ________ to the cytosol of the muscle fiber.

Fill in the blank: The high concentration of calcium in the sarcoplasm interacts with the _______ and tropomyosin molecules, which move aside, exposing the myosin binding sites on the actin filaments.

What enzyme rapidly decomposes acetylcholine in the motor end plate?

To initiate relaxation in a skeletal muscle, calcium is returned to the ________, using ATP as an energy source.

What is required for the beginning of the relaxation cycle in muscle contraction?

When the sarcolemma is stimulated. An impulse travels over the surface of the muscle fiber and deep into the fiber through the ________.

Fill in the blank: Calcium ions diffuse from the sarcoplasmic reticulum into the cytosol and bind to ________ molecules.

Fill in the blank: ________ molecules move and expose specific sites on actin where myosin heads can bind.

Fill in the blank: Cross-bridges form, linking ________ and thick filaments.

Fill in the blank: Troponin and tropomyosin molecules block the interaction between myosin and ________ filaments.

What is the initial source of energy for muscle contraction?

What is present to initially regenerate ATP from ADP and phosphate?

During a high-intensity workout, Ava notices that her muscles start to fatigue as creatine phosphate is rapidly used up. What process does her body rely on to generate ATP in this situation?

Fill in the blank: When cellular ATP is low, creatine phosphate donates a phosphate group to ______ to regenerate ATP.

What is the first phase of cellular respiration?

Glycolysis yields how many ATP per molecule of glucose?

Aerobic respiration occurs in the ________.

How many ATP does aerobic respiration yield per molecule of glucose?

What carries oxygen to muscle tissue in red blood cells?

The pigment ________ stores oxygen in muscle tissue for aerobic respiration.

During rest or moderate activity, there is enough oxygen available to support what type of respiration?

During a school sports day, Grace participated in a race. Oxygen deficiency may develop during how many minutes of her strenuous running?

In the case of oxygen deficiency, what acid forms and then reacts to form lactic acid?

What is another name for oxygen debt?

How long may it take to repay the oxygen debt?

During high intensity exercise, ___ acid accumulates as a waste product.

Less than half of energy released in reactions of cellular respiration is used to form ATP; what does the rest become?

When a muscle loses its ability to contract during strenuous exercise, it is referred to as what?

During a long soccer match, what may cause a player like Daniel to experience muscle fatigue?

What is a muscle cramp?

Which type of muscle fibers are associated with rapid movements and reaching maximum force quickly?

Fast muscle fibers are best for which type of activities?

Slow muscle fibers take longer to reach peak tension but are resistant to what?

What type of activities are slow muscle fibers used in?