Answer:
Correct answer is c. It is the final electron acceptor in the aerobic respiration.
Explanation:
Oxygen is a substrate of the aerobic respiration, but it is not the only one. Glucose is also a substrate.
Oxygen is used in the cells to be the final electron acceptor, this means that receives the electrons from NADH and FADH2. That is why, when there is no oxygen available for aerobic respiration, the NADH and FADH2 cannot be oxidized and therefore remain in their reduced form. As a consequence, they cannot be re-utilized during different cellular processes that are NAD+ and FAD dependant, such as glycolysis, pyruvate oxidation and cellular respiration. This means that the ATP synthesis stops.
Oxygen itself does not transport any electrones, this are transported by the cytochrome complex in the mitochondrial membrane. But oxygen is key in receiving those electrones, therefore a very important piece of the electron transport across the mitochondria.
Answer: 1930s
The term stress as it relates to the human condition first emerged in scientific literature in the 1930s, but it did not enter the popular vernacular until the 1970s (Lyon, 2012).
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The most natural approach to get enough Vitamin D is through regular sun exposure. Aim for 10 to 30 minutes of midday sunshine many times per week to maintain appropriate blood levels. Those with darker complexion may require a little more.
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What is Vitamin D ?</h3>
According to the National Institutes of Health, two to three times per week, between five and thirty minutes of unprotected sun exposure to your face, arms, legs, or back between the hours of 10 a.m. and 3 p.m. is sufficient for your body to produce all of the D3 it requires. Vitamin D synthesis can be inhibited by sunscreen.
Your skin tone, age, dietary habits, and the environment in which you reside all have a role. In general, scientists believe that 5 to 15 minutes, or up to 30 minutes if you have dark skin, is approximately right to get the most benefit without endangering your health. If you wear sunscreen, you can spend more time outside and yet receive the same result.
In the continental United States, UV rays are typically highest between 10 a.m. and 4 p.m. (9 a.m. to 3 p.m. standard time). The UV Index predicts each day's UV ray intensity. Avoid overexposing your skin to the sun if your area's UV index is 3 or higher.
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Answer:
– Natural exposure to infectious agent stimulates your own B cells to produce antigen-specific antibodies – Artificial immunization (vaccination) with key antigens or epitopes from an infectious agent does the same thing – Active immunization results in immunologic memory (more vigorous response next time)
Explanation:
