Biology MCQs

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Restriction enzymes were discovered by Smith and Nathans. Proteins produced by bacteria that cleave DNA at specific sites along the molecule are called restriction enzymes.

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A plasmid is used as a tool to insert genes into bacteria to stimulate the production of therapeutic proteins such as human insulin.

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Skeletal muscle is a form of striated muscle which is under the voluntary control of the somatic nervous system. Most skeletal muscles are attached to bones by bundles of collagen fibres known as tendons. It is one of three major muscle types, the others being cardiac muscle and smooth muscle.

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Haemoglobin is the iron-containing oxygen transporting metalloprotein in the red blood cells of all vertebrates. Similarly, Cytochromes are, in general, membrane-bound haemo-proteins containing heme groups and are primarily responsible for the generation of ATP via electron transport.

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The leaves arise in the regions of the plant known as the plant nodes and are therefore the point of attachment of the leaves. The region of the plant between two nodes is known as the internode. The angle between the upper surface of the leaf and the stem from which it arises is known as the axil.

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The skin is the soft outer covering of vertebrates that guards the underlying muscles, bones, ligaments, and internal organs. The cutaneous membrane is the technical term for our skin. The skin’s primary role is to help protect the rest of the body’s tissues and organs from physical damage such as abrasions, chemical damage such as detergents, and biological damage from micro organisms. Our skin is made of three general layers. In order from most superficial to deepest they are the epidermis, dermis, and subcutaneous tissue.

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The vascular tissue system consists of the complex tissues, xylem and phloem, which constitute discrete conducting strands called vascular bundles. Gymnosperms are the vascular plants where seeds are not enclosed within an ovary (opposite to an angiosperm or flowering plants where seeds are enclosed by mature ovaries or fruits). Collateral vascular bundle is the most common type of vascular bundle in the stems and leaves of angiosperms and gymnosperms. Here xylem and phloem remain side by side arranged on the same radius.

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Sponges are sedantric, diploblastic, asymmetrical animals, once considered plants. They are characterized by the water canal system with pores called the ostia and osculum. They are also known to posses the multipurpose cells called chanocytes.

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It is generally considered that the Panda belongs to the bear family, though differences persist. Some DNA studies have shown that the giant panda is closer to the bear family while the red panda is indeed closer to the raccoon family.

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Tropism is a growth movement whose direction is determined by the direction from which the stimulus strikes the plant. Most stems are positively phototropic, while most roots are said to be negatively phototropic and positively geotropic.