Biology MCQs

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Hemoglobin in humans has a very high affinity for carbon monoxide, forming carboxyhemoglobin which is a very bright red in color. Carbon monoxide is thus problematic for humans because it has affinity higher than that of oxygen.

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Wind is the most common media of pollination in flowers without petals. Pollination refers to the transfer of pollen from a male part of a plant to a female part of a plant which enables fertilisation and the production of seeds, most often by an animal or by wind.

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MON 863 is a genetically engineered variety of maize produced by Monsanto. It was generated by transformation of Zea mays cell culture line AT824 with a MIuI restriction fragment from plasmid PV-ZMIR13 using particle acceleration technology.

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Vitamin C which is also called ascorbic acid can be replaced with citric acid. Vitamin C is a water-soluble vitamin which is found in many foods, particularly fruits and vegetables. It is a potent antioxidant, and has a positive effects on skin health and immune function.

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Pipe Plant is a total saprophyte i.e. thrives on dead or decayed organic matter

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• Octopus: Octopuses belong to the class Cephalopoda within Phylum Molluska. Cephalopoda is a group of highly evolved, predatory marine animals. While they share some common ancestors with mollusks, they have distinct characteristics such as a complex nervous system, a beak-like mouth, and tentacles equipped with suckers.
• Snail: Snails are indeed mollusks. They are part of the class Gastropoda within the phylum Mollusca. Snails have a coiled shell and a soft body.
• Oyster: Oysters are also mollusks. They belong to the class Bivalvia within the phylum Mollusca. Oysters are characterized by their two hinged shells and are known for their filter-feeding lifestyle.
• Starfish: Starfish, also known as sea stars, are not mollusks. They belong to the phylum Echinodermata, and they have a completely different body plan and structure compared to mollusks. Starfish have radial symmetry and a unique water vascular system that helps them move and feed.

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Thymine is the nitrogenous base that is present in DNA but not in RNA. Thymine is a pyrimidine base that pairs with adenine through hydrogen bonding in DNA. In RNA, thymine is replaced with uracil, which pairs with adenine.
The four nitrogenous bases in DNA are adenine, guanine, cytosine, and thymine. The four nitrogenous bases in RNA are adenine, cytosine, guanine, and uracil.

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Water is passively transported into the roots and then into the xylem. The forces of cohesion and adhesion cause the water molecules to form a column in the xylem. Water moves from the xylem into the mesophyll cells, evaporates from their surfaces and leaves the plant by diffusion through the stomata.

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Cattle quickly swallow grass and store it in rumen. The rumen serves as a large fermentation vat in which bacteria and other microorganisms reside. The rumen, also known as a paunch, forms the larger part of the reticulorumen

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Metaxylem is the part of the primary xylem that differentiates after the protoxylem and that is distinguished typically by broader tracheids and vessels with pitted or reticulate walls.