Consider statements about human diseases: 1. Ascariasis is caused by a roundworm. 2. Ringworm is caused by a fungus. 3. Amoebiasis is caused by a bacterium. Which are correct? MCQ with Answer and Explanation

Explanation:
Vitamin A is essential for the synthesis of rhodopsin, a visual pigment; its deficiency leads to night blindness, the inability to see in low light conditions. Vitamin B1 (thiamine) is crucial for carbohydrate metabolism; its deficiency causes beriberi, characterized by nerve and heart dysfunction, and muscle weakness. Vitamin C (ascorbic acid) is essential for collagen synthesis; its deficiency causes scurvy, characterized by bleeding gums, loose teeth, and poor wound healing. All three statements are correct.

Explanation:
RNA polymerase recognizes and binds to the promoter region of DNA, which is located upstream of the coding sequence. This initiates transcription. The terminator signals the end of transcription. Start codon (AUG) is on mRNA where translation begins. Enhancers are regulatory DNA sequences that increase transcription but are not the primary binding site for polymerase.

Explanation:
ATP synthase (Complex V) uses the proton gradient generated by the electron transport chain to phosphorylate ADP to ATP. Cytochrome oxidase is Complex IV, succinate dehydrogenase is part of the Krebs cycle and Complex II, citrate synthase is in the Krebs cycle.