Biology MCQs

Notes:
The green color in leaves is caused by the presence of a compound called “chlorophyll,” which the plant produces to do photosynthesis for capturing solar energy. The chlorophyll is green because it absorbs red and blue wavelengths of light — and so green is not absorbed and is reflected, making the plant look green to eyes.

Notes:
The Eustachian Tube is a tube that links the nasopharynx to the middle ear. It is a part of the middle ear. It help to maintain air pressure of body with respect to atmospheric air pressure. It’s also because of this people flying by air feel pain in their ears when flying for long hours together.

Notes:
The chromosomes which determine the sex (maleness or femaleness) of an individual in sexually producing organisms are called sex chromosomes or allosomes. In humans an individual whose cells contain XX chromosomes (homo or isogametic) becomes a female, while one whose cells contains XY chromosomes (heterogametic) becomes a male.

Notes:
Phytochrome is a photoreceptor, a pigment that plants use to detect light. It is a protein with a bilin chromophore. It detects mainly red and far-red region of the visible spectrum and regulates germination of seeds in photoblastic seeds.

Notes:
Vitamin E is a fat soluble vitamin that is essential in many physiological processes. It plays an important role in the health and maintenance of proper reproductive system function. Without vitamin E the body cannot reproduce. It is also essential during pregnancy and is needed for the proper health and development of the fetus.

Notes:
A modified stem is a part of a plant with special features developed for special functions. Modified stems can be found either above or below ground. Above the ground are crowns, stolons, runners or spurs, while below the ground include; bulbs, corms, rhizomes, tubers and tendrils. Sweet potato is an example of a tuberous root not modified stem.

Notes:
Hibernation is a state of inactivity and metabolic depression in endotherms. Hibernation refers to a season of heterothermy that is characterized by low body temperature, slow breathing and heart rate, and low metabolic rate. Often associated with cold temperatures, the purpose of hibernation is to conserve energy during a period when sufficient food is scarce and outside temperature is low.

Notes:
Enzymes are sometimes called biological catalysts because they speed up reactions, and only small amounts are required. Digestive enzymes speed up the breakdown of complex food substances into simpler subunits. The breakdown of food in digestion is actually caused by water chemically splitting the complex food molecules, a process called hydrolysis.

Notes:
In plants, the process of photosynthesis takes place in the mesophyll of the leaves, inside the chloroplasts. Chloroplasts contain disc-shaped structures called thylakoids, which contain the pigment chlorophyll. Chlorophyll absorbs portions of the visible spectrum and captures energy from sunlight.

Notes:
Serotonin is a chemical that relays information from one part of the brain to another and is known to play a key role in a number of functions ranging from sleep to social behaviour. Indian scientists have discovered that serotonin boosts energy production in brain cells and helps them survive under stress.