Beriberi is due to thiamine (B₁) deficiency. It presents as two forms: wet beriberi (cardiovascular) and dry beriberi (neurological). Thiamine is a coenzyme (TPP) in decarboxylation reactions. Common in populations consuming polished rice. Riboflavin deficiency causes cheilosis, pyridoxine deficiency causes peripheral neuropathy and anemia, B₁₂ deficiency causes pernicious anemia.
Explanation:
Myoglobin is a red protein in muscle cells that stores oxygen and facilitates its diffusion during muscle contraction. It has a higher affinity for O₂ than hemoglobin, allowing oxygen transfer from blood to muscle. Hemoglobin is in RBCs, hemocyanin is in some invertebrates, cytochromes are electron carriers.
Explanation:
Chlorophyll and other photosynthetic pigments are embedded in the thylakoid membranes of chloroplasts, where they participate in light-dependent reactions. The stroma contains enzymes for the Calvin cycle. The cell wall and cytoplasm are not sites of photosynthesis.
Explanation:
Viruses are non-living outside a host cell and cannot carry out metabolism or reproduce independently. They hijack the host cell's machinery to replicate. Hence they are obligate intracellular parasites. The reason correctly explains the assertion. Even though some debate exists on whether viruses are living, the statement that they are obligate parasites and lack metabolic machinery is accurate.
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