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Actin is essentially a ball ('globular') with two key features: 1. a particular region binds and hydrolyzes adenosine triphosphate (ATP); 2. Other regions allow actin molecules to bind to one another head-to-tail. I won't discuss the ATP hydrolysis here. When actin molecules bind each other, they form a spiral-staircase-like ('alpha-helical') string called a 'filament.' Multiple actin filaments come together to form bundles or fibers. These higher-order structures are so big and so prevalent that they can be seen in living cells through a microscope.
The atomic structure of globular actin is available for free here:
http://www.ncbi.nlm.nih.gov/Structure/mmdb/mmdbsrv.cgi?uid=47984
What else can I help you with?
How many amino acids make up actin?
Actin is composed of around 375 amino acids. These amino acids form the primary structure of the actin protein, which plays a key role in cell structure and movement.
What separates one sarcomere from the next?
Z-lines separate one sarcomere from the next within a myofibril. These are structures composed of actin filaments where thin filaments from adjacent sarcomeres are anchored.
What 2 molecules are part of actin?
The two main molecules that make up actin are globular actin (G-actin) and filamentous actin (F-actin). G-actin is the monomeric form of actin, while F-actin is the polymeric form that results from the polymerization of G-actin subunits.
What shape is the protein actin?
Actin is a globular molecule
What Primarily composes myofibrils?
Myofibrils are primarily composed of proteins called actin and myosin. These proteins are arranged in repeated units called sarcomeres, which are responsible for muscle contraction. Other proteins such as troponin and tropomyosin also play important roles in regulating muscle contraction.
The thick filaments of muscle fibers are composed of what?
Myosin
Do actin filaments have membranes?
No, actin filaments do not have membranes. They are composed of actin protein subunits and are involved in providing structural support and facilitating movement within the cell, but they are not enclosed within a membrane themselves.
Which cytoskeletal element is NOT correctly associated with its characteristics?
C. Centrioles are found in the microtubule organizing centers of plants.
What are thick myofilaments of muscles called?
Actin. Myosin are the thin ones.... it's actually the reverseThe thin filaments are composed primarily by the protein Actin.The thick filaments are composed primarily of the protein Myosin.
What are Myofibrils composed primarily of?
Myofibrils are primarily composed of proteins called actin and myosin. These proteins are arranged in a repeating pattern along the length of the myofibril, forming the sarcomeres, which are the functional units responsible for muscle contraction.
What material are microtubules composed of?
Microtubules are polymers of tubulin. Microfilaments are polymers of actin.
How many amino acids make up actin?
Actin is composed of around 375 amino acids. These amino acids form the primary structure of the actin protein, which plays a key role in cell structure and movement.
Muscle cells contain contractible units called?
Myofibril, composed of actin and myosin.
Which type of myofilament is composed of thick long complexes of protein molecules and have appendages known as bridges?
actin
What are the thick protein filaments in the cell made of?
The thick protein filaments in a cell are primarily made of a protein called myosin. Myosin filaments are involved in muscle contraction and various other cellular processes such as cell motility and cytokinesis.
What do sarcomere contain?
Sarcomeres contain thin (actin) and thick (myosin) filaments. These filaments overlap to create the striated appearance of skeletal muscle fibers. Sarcomeres also contain Z-lines, which anchor the thin filaments and help define the boundaries of the sarcomere.
What separates one sarcomere from the next?
Z-lines separate one sarcomere from the next within a myofibril. These are structures composed of actin filaments where thin filaments from adjacent sarcomeres are anchored.
