Muscle Physiology and Motor Proteins Quiz

Internal framework of a cell, made of microtubules and microfilaments, providing structural support, enabling movement, and transporting materials.

Proteins that use energy from ATP to move along cytoskeletal filaments, like microtubules and microfilaments, carrying cargo and contributing to cellular movement.

A type of motor protein that moves cargo towards the plus end of microtubules, usually towards the cell's periphery.

A type of motor protein that moves cargo towards the minus end of microtubules, usually towards the cell's center.

A type of motor protein most commonly associated with muscle contraction, but also present in other cells. It interacts with actin filaments.

A type of muscle tissue that is responsible for voluntary movement and is characterized by a striated appearance under a microscope.

Involuntary muscle tissue found in the walls of organs, such as the stomach and intestines.

Specialized muscle tissue found only in the heart. It is responsible for pumping blood throughout the body.

The basic functional unit of a muscle fiber, responsible for muscle contraction.

A protein filament found in muscle fibers that interacts with myosin to generate muscle contraction.

The process by which muscle fibers shorten, generating force.

A tough, fibrous tissue that connects muscle to bone.

A functional unit of muscle contraction, made of repeating units of myosin and actin filaments.

A thick filament composed primarily of myosin protein that plays a crucial role in muscle contraction.

The region within a sarcomere that contains only myosin filaments, appearing dark under a microscope.

The region within a sarcomere containing only thin (actin) filaments, appearing lighter under a microscope.

A protein involved in muscle contraction that binds to actin filaments, blocking the myosin binding sites and inhibiting muscle contraction.

A protein involved in muscle contraction that binds calcium and regulates the position of tropomyosin, allowing contraction to occur.

A protein that caps the ends of actin filaments, preventing further polymerization.

The process by which a sarcomere shortens, leading to muscle contraction.

A network of interconnected tubes within muscle fibers, responsible for storing and releasing calcium ions (Ca2+), which are crucial for muscle contraction.

Tiny, tube-like structures that carry action potentials (electrical signals) deep into the muscle fiber, ensuring that the signal reaches all parts of the muscle cell.

A theory that explains how muscles contract, stating that thin filaments (actin) slide past thick filaments (myosin) due to the interaction of cross-bridges, bringing Z-lines closer together and shortening the sarcomere.

A protein complex that regulates muscle contraction. It binds to actin filaments, blocking the binding sites for myosin. When calcium ions are released, troponin binds calcium, causing a shift in tropomyosin, exposing the binding sites and allowing myosin to bind and initiate contraction.

The myosin head, attached to actin, rotates towards the center of the sarcomere, pulling the actin filament along. This process requires energy from ATP.

The myosin head remains attached to the actin filament until ATP binds to it, causing the myosin to detach.

After detaching from the actin filament, the myosin head gets reactivated when ATP splits into ADP and phosphate, storing energy for the next binding event.

The amount of muscle tension is determined by the amount of calcium ions available in the muscle fiber. Higher calcium levels lead to more force.

The process of increasing muscle tension or force.

The amount of calcium ions available in the muscle fiber determines the amount of force it can produce. This is controlled by various regulatory processes within the muscle fiber itself.

The protein that blocks the active sites on the actin filament when the muscle is at rest, preventing myosin from binding.

The protein found in muscle fibers that binds to calcium ions, triggering a conformational change that moves tropomyosin away from the active sites on actin, allowing muscle contraction to begin.

The process where calcium ions bind to troponin, causing troponin to move tropomyosin away from the active sites on actin, allowing myosin to bind and initiate muscle contraction.

The process where the myosin head group binds to an exposed active site on the actin filament, forming a cross-bridge. This binding requires the presence of ATP.

The energy source that is required for the myosin head group to detach from the actin filament after a power stroke.

The process where the myosin head group detaches from the actin filament after a power stroke. This process requires ATP.

The process where the myosin head group swings back to its original position, ready to bind to another active site on the actin filament. This process also requires ATP.

The repeated cycles of cross-bridge attachment, power stroke, and detachment, driven by ATP, which cause the actin filament to slide past the myosin filament, leading to muscle fiber shortening and contraction.