100,000 years ago, there were three species of hominin that coexisted on Earth. They were Homo heidebergensis, <span>Homo neaderthalensis, and Homo erectus.</span>
Sickle-cell disease is common in tropical and sub-tropical regions because being a carrier, carrying a single sickle-cell mutation (sickle cell trait), affords some resistance to malaria.
Answer:A. The release of calcium ions causes myosin and actin to attach to each other.
The contraction of skeletal muscles takes place by induction of a nerve impulse, which produces a movement and the interaction of the filaments containing proteins named as actin and myosin. This interaction of filaments is regulated by proteins called tropomyosin and troponin present on the actin filaments. The motor nerve causes the depolarization of the muscle membrane sarcolemma. This triggers the sarcoplasmic reticulum to release calcium ions. This calcium binds to troponin and thus allows the tropomyosine strand on the actin filament to displace so that the part of the actin where myosine head needs to be attached remain uncovered. Binding of the actin myosine filament results in contraction.
Hence, the release of calcium ions causes myosin and actin to attach to each other causes muscle contraction.
During an enzymatic reaction, a molecule of substrate binds to the enzyme and is broken down into one or more molecules of product , which are released.
<h3>What is substrate and product ?</h3>
While products can be produced at the end of the reaction, substrates are the reaction's initial raw material. The distinction between a substrate and a product is that a substrate is the substance used to initiate a chemical reaction, whereas a product is the compound formed when the reaction is finished.
<h3>What do you mean by enzymatic reaction ?</h3>
In an enzyme reaction, the free enzyme E binds to its substrate S to form the enzyme-substrate complex (C1), which is then catalyzed into the enzyme-product complex (C2), from which the free enzyme and product P are released: S + E ↔ C1 ↔ C2 → P + E. This is known as the "lock-and-key" model in enzymatic reactions. The great majority of cellular reactions are represented by this paradigm.
Thus from the above conclusion we can say that during an enzymatic reaction, a molecule of substrate binds to the enzyme and is broken down into one or more molecules of product , which are released.
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Answer:
In the electromagnetic spectrum, the visible spectrum is the part, which is perceptible to the human eye. The electromagnetic spectrum in this array of wavelengths is known as simply light or the visible light. A general human eye will react towards the wavelengths in the range between 380 to 740 nm. A human eye sees the sky as blue that comes in the wavelength 490 nm because of the scattering of the visible light by the particles in the atmosphere. This concludes that 490 nm is the sole wavelength, which is reaching the eye.
