All of the following are correct for Thick filaments of a sarcomere EXCEPT –
ANSWER -B
Thicker filaments, composed principally of the protein myosin, traverse the A band; they are about 10 nm (100 Å) in diameter
Which of the following is FALSE -
ANSWER -D
In the process of activation- the A band remains constant in length, whereas the I band shortens and the Z lines move toward one another.
Both the thick and the thin filaments are constant in
length during both contraction and relaxation.
The part of myosin which is the site of ATPase activity:
ANSWER -A
The globular portions of myosin form the bridges to actin and are the site of ATPase activity.
Which class of myosin commonly responsible for producing muscle contraction in muscle cells ?
ANSWER -B
Myosin II (also known as conventional myosin) is the myosin type responsible for producing muscle contraction in muscle cells in most animal cell types.
Which type of Myosin forms Stress fibers ?
ANSWER -B
Stress fibers are primarily composed of composed of actin (microfilaments) and non-muscle myosin II .
In the sarcomere Titin connects -
ANSWER -C
Titin is important in the contraction of striated muscle tissues. It connects the Z line to the M line in the sarcomere.
Which is the largest known protein?
ANSWER -C
Titin is the largest known protein. The gene for titin contains the largest number of exons (363) discovered in any single gene.
Which of the following is responsible for substantial Ca2+ release from the SR, inducing contraction?
ANSWER -D
Ca2+-induced Ca2+ release, triggers substantial Ca2+ release
from the SR, inducing contraction.
Which isoform of Ryanodine receptor is expressed in myocardium?
ANSWER -B
RyR1 is primarily expressed in skeletal muscle.
RyR2 is primarily expressed in myocardium (heart muscle)
RyR3 is expressed more widely, but especially in the brain.
Non-mammalian vertebrates typically express two RyR isoforms, referred to as RyR-alpha and RyR-beta.
Physiological process through which new blood vessels form from pre-existing vessels is called –
ANSWER -B
Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis.
Angiogenesis continues the growth of the vasculature by processes of sprouting and splitting.
