Biology MCQs

Notes:
Syphilis is a bacterial infection mostly spread by sexual contact. It is caused by Treponema pallidum bacteria.

Notes:
Bioethanol is produced by fermentation of residues from corn, potatoes, cereals, sugar beets, sugarcane and vegetables.

Notes:
Pond silk is the common name of Spirogyra (algae) because it is very slimy in shape. It is also known as pond silk, water silk, pond scum or mermaid’s trees because of its bright green silky appearance. Its filaments shine like silk due to the presence of mucilage and spiral shaped chloroplast.

Notes:
Female gametes are also called eggs or ova. They are created during the cellular reproduction process known as meiosis. The resulting gamete cell is a haploid cell. When the two haploid cells, the egg and sperm, fuse together during fertilization, the result is a diploid cell called a zygote.

Notes:
The respiratory bronchioles are the narrowest airways of the lungs, one fiftieth of an inch across. The bronchi divide many times before evolving into the bronchioles. The bronchioles deliver air to the exchange surfaces of the lungs.

Notes:
Muscle fatigue refers to the decline in muscle force generated over time. Several factors contribute to muscle fatigue, the most important being lactic acid accumulation. Lactic acid is formed and accumulated in the muscle under conditions of high energy demand, rapid fluctuations of the energy requirement and insufficient supply of O2.

Notes:
The human brain sends messages to other parts of the body through a network of connecting wires (neurons) called the nervous system. Neurons carry messages in the form of electrical signals called nerve impulses. The human brain contains about 100 billion neurons.

Notes:
Malaria is a life-threatening mosquito-borne blood disease caused by a Plasmodium parasite. It is transmitted to humans through the bite of the Anopheles mosquito. Tuberculosis (TB) is an infectious disease usually caused by the bacterium Mycobacterium tuberculosis. Measles is a highly contagious infection caused by the measles virus.

Notes:
It is during the pupa or cocoon stage that the silkworm yields the fibre of commercial use. As the silkworm prepares to pupate, it spins a protective cocoon. About the size and color of a cotton ball, the cocoon is constructed from one continuous strand of silk, perhaps 1.5 km long (nearly a mile). The silk cocoon serves as protection for the pupa.

Notes:
2, 4-Dichlorophenoxyacetic acid is a s a wide range selective weedicide which controls broad leaf type (DICOT) weeds in paddy fields, tea plantations, sugarcane fields, fruit orchards etc. It is one of the most widely used herbicides in the world.