Biology MCQs

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Fungi & Bacteria are called scavengers of ecosystems. Scavengers keep the ecosystem free of the bodies of dead animals, or carrion. They break down the dead organic material and recycle it into the ecosystem as nutrients.

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Cuttle fish or cuttles are marine molluscs of the order Sepiida. Molluscs are an important phylum of invertebrate animals. It is the second-largest phylum of invertebrate animals after the Arthropoda.

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Ribulose-1,5-bisphosphate carboxylase oxygenase first enzyme of Calvin Cycle of Carbon Fixation

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When we respire, most of the carbon dioxide as bicarbonate ions is transported in the blood. The carbon dioxide dissolved in the blood reacts with water and by the help of zinc containing enzyme called carbonic anhydrase, they form carbonic acid. It immediately dissociates to give H+ and bicarbonate ions once carbonic acid is formed. The haemoglobin present in the erythrocytes (RBCs) combines with the H+ ions immediately. The bicarbonate ion goes into the blood plasma which creates an ionic imbalance between the plasma and the erythrocytes. The chloride ions then diffuse from the blood plasma into the RBCs to maintain the ionic balance. The process of chloride ion diffusing into the erythrocytes to maintain the ionic balance is described as Hamburger’s Phenomenon.

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Uric acid is not soluble in water and is excreted as a dry crystal by the animal’s digestive system. Ammonia is the most toxic nitrogenous waste and must be excreted in large volumes of water.

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Bones have blood vessels, but cartilage does not. Bones have a network of blood vessels that deliver oxygen and nutrients to the bone marrow. Cartilage is avascular, meaning it doesn’t have blood vessels. Instead, cartilage relies on diffusion to get nutrients from the surrounding environment. Because of this, cartilage heals more slowly than bone.
Cartilage is made up of chondrocyte cells that produce a matrix of collagen, proteoglycan, and elastin fibers. Cartilage is found in the joints, rib cage, ear, nose, throat, and between vertebral disks.

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Chloramphenicol is a broad spectrum antibiotic. It can be given orally in case of typhoid, dysentery, acute fever, certain form of urinary infections, meningitis and pneumonia.

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Lactogenic hormone is a gonadotropic hormone which is secreted by anterior pituitary gland. It stimulates growth of the mammary glands and lactation after childbirth.

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The full form of DNA is deoxyribonucleic acid. DNA is a molecule that carries the genetic instructions used in the development and function of all living organisms and some viruses. It is a double-stranded, helical molecule made up of nucleotide units, each of which contains a sugar, a phosphate group, and a nitrogenous base (adenine, guanine, cytosine, or thymine). The sequence of these bases determines the genetic information that is stored in DNA, and this information is passed down from one generation to the next through the process of reproduction.

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Bacillus Calmette Guérin or BCG is usually given around birth to prevent severe TB in infants. The neonatal immune system is immature. Delaying BCG vaccination from birth to 10 weeks of age would enhance the vaccine-induced immune response. The BCG vaccine is an injection given to children who have a higher risk of catching TB. The BCG vaccine helps your child’s immune system fight the germs that cause TB and helps stop them from getting serious TB disease.