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: Mitochondria
Explanation:
This image represents the aerobic breakdown of glucose (respiration), this occurs in the mitochondria.
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The mechanisms of reproductive isolation prevent the reproduction of two individuals from different species. The prezygotic mechanisms disrupt the stages of reproduction before the forming of the zygote or prevent the mating at the start, and the postzygotic mechanisms affect the stages of reproduction after the forming of the zygote.
So, the first and the third example (the urchins and the grasshoppers) show the prezygotic mechanism, as the two individuals are not able to mate or form a zygote.
The second and the fourth example ( zonkey and the death of a zygote) show the working of the postzygotic mechanisms, as the zygote is formed, but it seems to be inviable, and the zonkeys are sterile, preventing the individual to reproduce.
Answer:Argon is the third noble gas, in period 8, and it makes up about 1% of the Earth's atmosphere.
Explanation: because ik trust me lmk if im right and give my brainliest answer and likes plz
Answer:
After intense activity, your muscles feel sore because of _____. a) the accumulation of NAD+ b) the accumulation of lactic acid c) the accumulation of ATP d) the accumulation of carbon dioxide. B. ... ATPc "carbon planet," because carbon is the central element in organic compounds. ... After intense activity, your muscles feel sore because of a. the accumulation of NAD+. b. the accumulation of lactic acid. c. the accumulation of ATP. d. the accumulation of carbon dioxide. b. the accumulation of lactic acid.
Explanation:
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