Macromolecules are large molecules within your body that serve essential physiological functions<span>. Encompassing </span>carbohydrates<span>, </span>proteins, lipids and nucleic acids<span>, macromolecules exhibit a number of similarities.
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The answer is; A
When an impulse from the motor neuron reached the neuromuscular junction, the voltage-dependent calcium channels are activated and the neurotransmitter released from the presynaptic cleft. When the neurotransmitter binds to their receptors on the sarcolemma, the muscle fibers become depolarised; the calcium is released from their vesicles. The Ca2+ ions are important in the power stroke because they bind to troponin. Upon binding calcium, troponin moves tropomyosin away from the myosin-binding sites on actin. Powered by the energy from ATP molecule, the myosin is able to bind on the actin and slides over the actin filament.
Answer: The human body is an exquisite machine, partly because it maintains functionality in a variety of environments. Humans can thrive in conditions ranging from the arctic to the equator, and with a variety of diets and lifestyles. Part of the reason for this adaptability is the body’s ability to maintain homeostasis.
