Question 28
Of the step in excitation-contraction below, which occurs before the others?
Answer exposed actin sites bind with myosin cross bridges.
sodium channels open in the fiber's membrane.
calcium is released from the sarcoplasmic reticulum.
troponin binds calcium.
attachment of ATP allows for cross bridge detachment.
.
please help with these questions
1 points
Question 29
Which of the following statements concerning cones is incorrect?
Answer cones are used for day vision.
cones are very sensitive to light.
cones exhibit high acuity.
cones are concentrated in the fovea.
cones provide color vision.
.
1 points
Q59
Which is not characteristic of cross bridges?
Answer they are a component of thin filaments.
they are comprised of myosin.
they have an actin binding site.
they have an ATPase binding site.
they provide power stroking.
Q67
ATPase activity is associated with:
Answer myosin heads
F-actin
G-actin
tropomyosin
a and d
Question 77
Which of the following does not occur in a photoreceptor during exposure to light?
Answer membrane hyperpolarization.
closure of Na+ channels in the outer segment.
increased transmitter release from the synaptic terminal.
decrease in cyclic GMP in the outer segment.
closure of Ca2+ channels in the synaptic terminal.
Q120
The link between the nerve impulse the breakdown of ATP is the:
Answer magnesium ion
potassium ion
calcium ion
breakdown of glucose
none of the above
Q132
In order for muscle relaxation to occur:
Answer Calcium ions must be transported to troponin
power strokes must slow down
the active sites must be kept open
calcium ions must be actively transported back to the lateral sacs
sodium ions must be transported back to the longitudinal tubules
Q136
Specific immune responses
Answer require helper T cell activation.
are under control of the adaptive immune system.
could not occur if the thymus gland did not develop.
both a. and b. above.
All of these answer.
Q139
In which structure do sound waves first pass?
Answer cochlear duct.
scala media.
scala tympani.
scala vestibuli.
helicotrema.
any help would be greatly appreciated!!!
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