Cytoskeleton and Muscle Contraction

These flashcards cover essential terminology related to the cytoskeleton, microtubule, actin filament dynamics, and muscle contraction mechanisms.

Cytoskeleton

A network of protein filaments and motor proteins responsible for maintaining cell shape and enabling movement.

Microtubules

Hollow tubes made of tubulin proteins, about 25 nm in diameter, involved in intracellular transport and cell structure.

Actin Filaments

Protein filaments composed of actin monomers, they are thinner than microtubules and play key roles in muscle contraction and cell movement.

Nucleation

The initial process of microtubule or actin filament assembly where a small number of components come together to form a stable structure.

Motor Proteins

Proteins such as myosins, kinesins, and dyneins that move along cytoskeletal filaments and carry cellular cargo.

GTP

Guanosine triphosphate, a molecule required for microtubule growth and stability; its hydrolysis triggers depolymerization.

Myosin II

A type of motor protein involved in muscle contraction, moving along actin filaments toward the plus end.

Calcium (Ca2+)

An essential ion that, when released into muscle cells, triggers muscle contraction by allowing myosin to bind to actin.

Troponin

A protein complex that binds to calcium ions and allows muscle contraction by moving tropomyosin away from myosin binding sites on actin.

Intermediate Filaments

Fibrous proteins that provide mechanical strength to cells, found mainly in vertebrates.

ATP

Adenosine triphosphate, the main energy currency of the cell, used in muscle contraction and motor protein activity.