The enzyme that catalyzes the synthesis of ATP in mitochondria is: MCQ with Answer and Explanation

Explanation:
Uracil replaces thymine in RNA. In DNA, thymine pairs with adenine; in RNA, uracil pairs with adenine. Adenine, guanine, and cytosine are present in both. The presence of uracil and the sugar ribose (vs. deoxyribose) are key structural differences between RNA and DNA.

Explanation:
Chlorophyll a is the primary photosynthetic pigment found in all algae and is essential for the light reactions of photosynthesis. Different groups of algae also contain other accessory pigments like chlorophyll b, c, phycobilins (phycocyanin, phycoerythrin), and carotenoids (fucoxanthin), which give them their characteristic colors (green, red, brown) and help in capturing light energy.

Explanation:
Veins, especially in limbs, have one-way valves that prevent the backflow of blood as it returns to the heart against gravity. Arteries have thick walls to withstand pressure and lack valves. Capillaries have no valves.