Muscles
Of the events that lead to myofilaments sliding over each other, which of the following happens first?
The myosin head engages with the binding site on actin.
Troponin changes shape and pulls on tropomyosin.
Calcium ions enter the cell cytoplasm.
ATP is hydrolysed to ADP and inorganic phosphate.
Calcium ions enter the cell cytoplasm.
Ca must first enter the cytoplasm in order to bind with troponin. Once the binding site is exposed, the myosin head may engage the site. Prior to engagement, ATP must be hydrolysed to ADP.
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Which of the following is the smallest unit in a muscle?A. Muscle fibre
B. Myosin
C. Fasciculus
D. Myofibril
What structures attach a muscle to a bone?
A. A tendon
B. A fasciculus
C. A sarcomere
D. An internal intercostal
Which muscle is located on the posterior part of the forearm?
A. Flexor digitorum superficialis
B. Flexor digitorum profundus
C. Extensor digitorum
D. Triceps brachii
Which of the following muscles is NOT named after its location in the body?
A. Deltoid
B. Extensor carpi ulnaris
C. Rectus abdominis
D. Biceps femoris
Which of the following muscles IS named after its location in the body?
A. Sartorius
B. Triceps brachii
C. Soleus
D. Trapezius
Which is the correct equation for anaerobic respiration in humans?
A. Glucose + lactic acid โ carbon dioxide + water
B. Glucose โ lactic acid + carbon dioxide
C. Glucose โ lactic acid + (little energy)
D. Glucoseโ lactic acid
The part of a skeletal muscle cell that is able to contract is called
A. Sarcoplasm
B. Sarcolemma
C. Sarcomere
D. Sarcoplasmic reticulum
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