Answer: The calcium ion binds to troponin, and this slides the tropomyosin rods away from the binding sites.
Explanation:
Contraction and relaxation of muscle cells brings about movements of the body. The contractile myofilament called sarcomeres are bounded at each end by a dense stripe called the Z - line, to which the myosin fibres are attached, and lying in the middle of the sarcomere are the actin filaments, overlapping with the myosin.
When action potential spreads from the nerve along the sarcolemma (muscle cell membrane), it penetrates deep into the muscle cell through the sarcoplasm (cytoplasm of muscle cell), and releases CALCIUM from the intracellular stores.CALCIUM triggers the binding of myosin to the actin filament next to it forming CROSS BRIDGES.
For this to occur, ACTIN BINDING SITE has to be made available. TROPOMYOSIN is a protein that winds around the chains of the actin filament and covers the myosin-binding sites to prevent actin from binding to myosin. The first step in the process of contraction is for calcium ions to bind to troponin so that tropomyosin can slide away from the binding sites on the actin strands.
Answer:
Option (B).
Explanation:
Liver is an important organ that regulates the metabolic pathway of the body and helps in the process of digestion. The improper functioning of liver can cause yellowish skin, edema and high blood pressure.
Mrs F medical condition clearly describes the improper functioning of liver. The liver helps in the formation of bile juice. Bile is a soapy compound that helps in the emulsification of lipids.
Thus, the correct answer is option (B).
Human reproductive cloning should not now be practiced. It is dangerous and likely to fail.
<span>One type of organisms known as sponges have collar cells that trap food and ingest it by ___ or by the enzymes of lysosomes. The word that would best complete the sentence is "phagocytosis". This is also most commonly known as the food-eating that is the process of engulfing food. </span>
<em>A circadian rhythm /sɜːrˈkeɪdiən/ is any biological process that displays an endogenous, entrainable oscillation of about 24 hours. These 24-hour rhythms are driven by a circadian clock, and they have been widely observed in plants, animals, fungi, and cyanobacteria.</em>
the correct answer is a)I only
