In striated muscle the loss of tropomyosin... A. would increase influx of calciu

Question

In striated muscle the loss of tropomyosin...

A. would increase influx of calcium into sarcomere

B. Allow crossbridges to form in absence of Calcium

C. Decrease the tension-length curve

D. Prevent calcium-activation of muscle

E. would prevent actin-myosin corssbrdige formation

Which property of muscle is modified to change muscle properties to match physiological need?

a. The length of the muscle

b. The expression of a family or different mysoin gene

c. The ineraction of myosin with actin in the crossbridge

d. Power output by maximizing crossbridge formation

e. All the above

3. Main osmoregulatory organ in teleost fish is:

a.skin

b. GI tract

c. salt gland

d. rectal gland filled with aquaporin channels

e. None of above

Seawater...

a. lower osmolarity than vertebrate blood

b. is 50% of the water found on earth

c. if ingested would have little or no effect on blood osmolarity of a teleost

d. has a higher osmolarity along the coast than in deep ocean

e. is not any of these

4. The ability of a vertebrate kidney to form urine would be lost by:

a. standing on ones head

b. complete loss of the renal interstitial osmolarity gradient

c. a 15% increase in blood pressure

d. secretion of ADH into the blood

e. 25% increase in plasma osmolarity

What is a significant difference in sarcomere length among striated muscles in vertebrates and invertebrates?

a. there really is no significants, bc regardless of length, striated muscle produces same power

b. longer sarcomeres consume prower at 10 times the rate than shorter ones

c. invertebrate sarcomere length is 10-20 times as long as that of vertebrates, dramatically increasing the power of small muslces

d. sarcomere length changes legnth over which cross-bridges can form

e. mysoin heavy chains are longer in invertebrates than vertebrates

Explanation / Answer

1. The correct option is (B), because tropomyosin hides the actin binding sites on myosin. When tropomyosin is absent in muscle, and then these sites are exposed without the need of calcium. This leads to the formation of cross bridge.

2. The correct option is (e) all the above.

3. The correct option is (a) skin.

d. has a higher osmolarity along the coast than in Deep Ocean.

4. b. complete loss of the renal interstitial osmolarity gradient

c. invertebrate sarcomere length is 10-20 times as long as that of vertebrates, dramatically increasing the power of small muscles

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