Biology MCQs

Notes:
For reasons of safe transportation of fruits, mangoes, bananas etc are picked before they ripen fully. Slightly green harvested mangoes are subjected to small containers of calcium carbide (CaC2) with a plastic covering. CaC2 reacts with the moisture in the air to release acetylene (or ethyne) gas as follows:
CaC2 + 2 H2O – C2H2 + Ca(OH)2
This option may give you slightest confusion if you don’t know the difference between Ethylene and Ethyne (Acetylene). Both are chemical substances produced by fruits to accelerate the normal process of fruit maturation — is a ripening hormone. Ethylene is C2H4 and has a carbon-carbon double bond. Acetylene is C2H2 and has a carbon-carbon triple bind. Acetylene contains more energy and burns hotter than ethylene. Ethylene is a gaseous compound , Acetylene is the chemical compound , which is the simplest alkyne and is also a hydrocarbon while Ethylene is the simplest alkene and classified as an unsaturated hydrocarbon. I hope you will never forget it now.

Notes:
In some plants such as Cactuses, the stem is flattened and green and carries out the function of the leaf. Such a stem, adapted for the manufacture of food is called phylloclade. The leaves here are reduced or modified into spines to lessen the transpiring surface. Phylloclades are adapted for life in dry and arid regions.

Notes:
R.H. Whittaker proposed an elaborated five kingdom classification. He was the first to propose the five-kingdom of organisms taxonomic classification of the world’s biota into the Animalia, Plantae, Fungi, Protista, and Monera in 1969. He also proposed the Whittaker Biome Classification, which categorized biome-types upon two abiotic factors: temperature and precipitation.

Notes:
Birds evolved from theropod dinosaurs during the Jurassic around 165–150 million years ago. Birds aren’t just closely related to dinosaurs, they really are dinosaurs! This is what most people mean when they say that birds are reptiles, although technically according to the phylogenetic system mammals are also reptiles.

Notes:
Guttation takes place due to the development of root pressure. Guttation is the exudation of drops of xylem sap on the tips or edges of leaves of some vascular plants, such as grasses and a number of fungi.

Notes:
The stapedius muscle is the smallest skeletal muscle in the entire body that is located in the middle ear. Specifically, the stapedius muscle originates from a cone-shaped structure in the tympanic cavity of each ear and then extends to the stapes bone.

Notes:
Chlorophyll is a green photosynthetic pigment found in plants, algae, and cyanobacteria. Chlorophyll absorbs mostly in the blue and to a lesser extent red portions of the electromagnetic spectrum, hence its intense green color.

Notes:
Inbreeding results in homozygosity, which can increase the chances of offspring being affected by deleterious or recessive traits. This usually leads to at least temporarily decreased biological fitness of a population which is its ability to survive and reproduce. So for inbreeding they should not carry any detrimental genes and it is effective only if the herd is large.

Notes:
Blue green algae is used as a biofertilizer in rice crop. Blue green algae has the nitrogen fixing ability which enhances the production of rice. Blue–green algae are not algae at all, but types of bacteria called cyanobacteria that are normally present in many lakes.

Notes:
Ornithophily refers to the pollination assisted by the birds. Ornithology is a branch of science which studies about birds. Dr. Salim Ali is a famous Indian ornithologist.