Biology MCQs

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In Maize and Sugarcane, roots arise from the first few nodes of the stem and penetrate obliquely down in to the soil and give support to the plant. They are called Stilt roots.

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Each adrenal gland is located on the top of each kidney (forming a hat-like structure on the top of the kidneys). Each adrenal gland has two parts viz. outer cortical portion and inner adrenal cortex. Further, there is a central part called adrenal medulla.

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Britain is the first country to issue research licenses for human embryonic cloning to create stem cells. The cloning procedure involves the process of combining a patient’s body cell with an unfertilized egg cell from a donor.

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Alec Jeffreys scientists is known for developing techniques for DNA fingerprinting and DNA profiling which are now used all over the world in forensic science to assist police detective work.

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Coir is the nature fibre obtained from mescocarp of the coconut fruit. Coconut fruit has three layers viz. Exocarp, MesoCarp and Endocarp. Exocarp is the outer green layer, Mesocarp is the fleshy, which becomes husk on drying middle layer and endocarp is the inner woody layer.

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A pigment called luciferin is found in firefly. Luciferin is a light-emitting compound which is found in organisms that generate bioluminescence. Luciferins typically undergo an enzyme-catalyzed reaction with molecular oxygen.

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The Coral Reef ecosystem showcases the highest biodiversity among the options provided. This is due to the ideal tropical environment in which they exist, offering a wide range of habitats, shelter, and nourishment for an astonishing array of marine life. In terms of biodiversity, they are second only to tropical rainforests. Interestingly, despite covering less than 1% of the ocean floor, coral reefs support about 25% of all known marine species.

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The primary function of the Pineal gland is production of melatonin, which helps maintain circadian rhythm and regulate reproductive hormones.

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Drugs that bind to receptor sites and inhibit their natural function are called antagonists. These drugs are useful when a message needs to be blocked.
Antagonists bind to receptors but do not activate them. They compete with available agonists for receptor binding sites. Antagonists block the access or attachment of the body’s natural agonists, usually neurotransmitters, to their receptors. This prevents or reduces cell responses to natural agonists.
Antagonists still cause a response, but this is through blocking the actions of agonists.
Agonist and antagonist drugs can be used together in people with asthma. For example, albuterol can be used with ipratropium.

Notes:
The coconut water from tender coconut that we are familiar with, is nothing but free nuclear endosperm (made up of thousands of nuclei) and the surrounding white kernel is the cellular endosperm. In the most common types of endosperm development, the Primary Endosperm Nucleus (PEN) undergoes successive.