Zoology - Locomotion and Movement Question with Solution | TestHub
In each of the following options, there is one property and two structures. Among the two structures, whichever follows the property is marked 'Y' while the one doesn't is marked 'N'. In which of these options, it is incorrect?
| Property | Structure | ||
| i. | Higher amount sarcoplasmic reticulum: | Red muscles | N |
| White muscles | Y | ||
| ii. | Smaller size in contracted myofibril: | I band | Y |
| A band | N | ||
| iii. | An involuntary muscle with stripes: | Skeletal muscle | N |
| Cardiac muscle | Y | ||
| iv. | ATP is required: | Muscle Contraction | N |
| Muscle Relaxation | Y |
Options:
Answer:
Solution:
Myoglobin content is high in some of the muscles which give a reddish appearance. Such muscles are called red fibres. These muscles also contain plenty of mitochondria which can utilize a large amount of oxygen stored in them for ATP production. Some of the muscles possess a very less quantity of myoglobin and therefore, appear pale or whitish. These are the White fibers. The number of mitochondria are also few in them, but the amount of sarcoplasmic reticulum is high.
During muscle contraction, actin filaments slide over myosin in such a way that the 'I' bands get reduced, whereas the 'A' bands retain their length.
Cardiac muscles are involuntary and show faint striations. Skeletal muscles are voluntary and show well-developed striations.
ATP is required by the myosin to bind its head to actin during muscle contraction. ATP is also required during muscle relaxation to pump calcium ions back to the sarcoplasmic reticulum. Thus both options should have been underlined
