Crash Course: Muscle Cells

Actin and myosin belong to which group of biological molecules?

• Nucleic acids

• Lipids

• Carbohydrates

• Proteins

Which of the following statements correctly describes how muscles avoid being torn apart during use?

• Rope-like muscle is so strong it doesn't need any other supports.

• Rope-like connective tissue wraps delicate muscle fibers.

• Rope-like muscle tissue is wrapped with connective tissue that holds it together.

• Muscles are easily torn during use despite their strength.

Which of the following correctly describes the difference between myofilaments and myofibrils?

• Myofibrils and myofilaments are separate types of proteins within a single sarcomere.

• Myofibrils are made of myofilaments such as actin and myosin.

• Myofilaments are made of myofibrils such as actin and myosin.

• Actin is a myofibril and myosin is a myofilament.

Which of the following statements is correct?

• Thin filaments are made of the protein actin.

• Thick filaments are made of the protein actin.

• Thin filaments are made of the protein myosin.

• Thick filaments can be made of either actin or myosin.

Which of the following correctly describes ATP?

• It is a component of carbohydrates.

• It is the major energy molecule in the cell.

• You cannot make it, only eat it.

When is a new molecule of ATP required?

• When myosin pulls on actin.

• When myosin moves back to its "loaded spring" position.

• To cause myosin to let go of actin.

When does myosin stop its bind, pull, release, bind, pull, release........ cycle?

• When the calcium gets removed from the cytoplasm.

• When the myosin gets tired.

• When new ATP is produced.

• When more calcium gets released into the cytoplasm.

What is the key to a sarcomere "unbinding" the tropomyosin once your at THE actin/myosin level

• Ca and ATP

• Ca and AcH

• Ca and Na

• Ca, Na and DNA