Ch. 50 - Sensory & Motor Mechanisms: Vertebrate Muscle Contraction

Question 1

what are muscle fibers?

Answer 1

one cell formed from the fusion of many cells

Question 2

what are the two filaments found in muscle and what proteins compose them?

Answer 2

thick filaments = mysoin proteins
thin filaments = actin proteins

Question 3

what are sarcomeres?

Answer 3

repeating units of thick and thin filaments

Question 4

what is the role of the sarcoplasmic reticulum?

Answer 4

to store calcium for use during muscle contraction

Question 5

what is the role of tropomyosin?

Answer 5

to cover the binding sites for myosin until contraction is ready to occur

Question 6

what is the role of troponin?

Answer 6

to move tropomyosin from the myosin binding sites

Question 7

what is the role of calcium in muscle excitation?

Answer 7

calcium binds to troponin, which moves tropomyosin away from binding sites which allows myosin to bind and cause contraction

Question 8

what action causes a muscle to shorten?

Answer 8

myosin heads binding to myosin-binding sites, pushing the thin muscle filaments closer together

Question 9

what is the purpose of ATP hydrolysis in muscle contraction?

Answer 9

to “cock” myosin heads into their high energy form so they can pull on muscle filaments. ATP is also needed to remove myosin after the motion is done

Question 10

what are oxidative / aerobic muscle fibers?

Answer 10

small, weak, long endurance muscle fibers with lots of mitochondria that get energy from cellular respiration. found predominantly in runners

Question 11

what are glycolytic / anaerobic muscle fibers?

Answer 11

large and strong muscle fibers that fatigue quickly and get ATP via fermentation. good for quick explosive power

Question 12

what types of energy are used in muscle contraction?

Answer 12

ATP - it provides potential energy for myosin heads when bound to their active sites as well as unbinds myosin once a contraction is finished