Biology MCQs

Notes:
Anabaena is the nitrogen-fixing symbiotic organism present in Azolla. Anabaena is a genus of filamentous cyanobacteria that exist as plankton.

Notes:
Glycolysis, part of cellular respiration, is a series of reactions that constitute the first phase of most carbohydrate catabolism, catabolism meaning the breaking down of larger molecules into smaller ones. Glycolysis breaks down glucose and forms pyruvate with the production of two molecules of ATP. The entire process from conversion of glucose to pyruvate is anaerobic that is it does not take place in presence of oxygen.

Notes:
Most cases of filariasis are caused by the parasite known as Wuchereria bancrofti. A wide range of mosquitoes can transmit this parasite, depending on the geographic area. In Africa, the most common vector is Anopheles while in the Americas, it is Culex quinquefasciatus. Aedes and Mansonia transmits transmit the infection in the Pacific and in Asia. Thus, Culex, Aedes and Anopheles mosquitoes serve as vector for W. bancrofti in transmission of the disease. Aedes mosquito causes dengue fever. Anopheles mosquito causes malaria. Culex mosquito causes filaria. A wide range of mosquitoes can transmit the parasite, depending on the geographic area. In Africa, the most common vector is Anopheles and in the Americas, it is Culex quinquefasciatus. [This question was wrongly framed in exam as “filaria is caused by__:”. GKtoday has edited it to make it correct.]

Notes:
The average adult has a blood volume of roughly 4-5 to 5 litres, which is composed of plasma and several kinds of cells. By volume, the red blood cells constitute about 45% of whole blood, the plasma about 54.3%, and white cells about 0.7%.

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:
Night blindness, also called nyctalopia, is failure of the eye to adapt promptly from light to darkness that is characterized by a reduced ability to see in dim light or at night. It occurs as a symptom of numerous congenital and inherited retinal diseases or as a result of vitamin A deficiency.

Notes:
There are some plants with weak stems that cannot stand upright and spread on the ground. These are called creepers, while those that take support on neighbouring structures and climb up are called climbers. Money plant, gourd plant, etc are examples of climbers.

Notes:
The sugar present in DNA is 2-deoxyribose, which is a pentose sugar. Deoxyribose is one of the three components of nucleotides, the building blocks of DNA. Each nucleotide consists of a phosphate group, a nitrogenous base—adenine (A), thymine (T), cytosine (C), or guanine (G)—and deoxyribose.

Notes:
Parenchyma cells containing ergastic substances are called idioblasts. Tannin cells, cells filled with raphides, etc. constitute idioblast. An idioblast is an isolated plant cell that differs from neighboring tissues. It carries out storage of reserves in form of fats or oils wastes.

Notes:
Taxonomy is the academic discipline of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. Each group (taxon) is given a rank and groups of a given rank can be aggregated to form a super group of higher rank and thus create a hierarchical classification. Carlous Linneaus is considered as father of taxonomy.