Biology MCQs

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A layer of cells immediately surrounding the ovum but outside the zona pellucida is called corona radiata.

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Ovarian or germinal epithelium is the outermost layer of the ovary composed of simple cuboidal cells. It is actually a modified visceral peritoneum.

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Rabies disease is transmitted by animal bites and saliva.

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Huntington’s disease and Marfan syndrome are examples of autosomal dominant disorders. One of many ways that a trait or disorder can be passed down through families is called autosomal dominant.

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Some strains of Bacillus thuringiensis can kill certain insects such as Lepidoptera. They are an order of insects consisting of moths and butterflies.

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Keratin is a family of fibrous structural proteins involved in making up the outer layer of human skin. It is also the key structural component of hair and nails. Cells in the epidermis contain a structural matrix of keratin, which makes this outermost layer of the skin almost waterproof, and along with collagen and elastin, gives skin its strength. It also makes up fish scales and crustacean shells, bird feathers and beaks, animal horns and hooves.

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Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest. Pesticides are a special kind of products for crop protection. A pesticide is generally a chemical or biological agent (such as a virus, bacterium, antimicrobial or disinfectant) that through its effect deters, incapacitates, kills or otherwise discourages pests. Target pests can include insects, plant pathogens, weeds, molluscs, birds, mammals, fish, nematodes (roundworms), and microbes that destroy property, cause nuisance, spread disease or are vectors for disease.

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Gastric acid, gastric juice or stomach acid, is a digestive fluid, formed in the stomach. It is composed of hydrochloric acid (HCl), potassium chloride (KCl) and sodium chloride (NaCl). Gastric acid plays a key role in digestion of proteins, by activating digestive enzymes.

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Evolutionary biologists now classify wisdom teeth as vestigial organs, or body parts that have become functionless due to evolution. They believe wisdom teeth, or the third set of molars, were the evolutionary answer to our ancestor’s early diet of rough food – like leaves, roots, nuts and meats – which required more chewing power and resulted in excessive wear of the teeth. The modern diet with its softer foods has made the need for wisdom teeth nonexistent.

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Lactobacillus acidiphilous is used in milk curdling by producing lactic acid and reducing the pH of the milk. These bacteria convert the lactose into lactic acid, which imparts the sour taste to curd. It is a genus of Gram positive facultative anaerobic or microaerophilic rod-shaped bacteria.