General Science Questions (MCQs) for Competitive Examinations

Notes:
Starfish carry out movements with the help of tube feet that are part of the water vascular system. Apart from their function in locomotion, the tube feet act as accessory gills. The water vascular system serves to transport oxygen from, and carbon dioxide to, the tube feet and also nutrients from the gut to the muscles involved in locomotion.

Notes:
PM-10 is a particulate matter having an aerodynamic diameter of less than 10 ?m. Particles larger than 10 microns tend to be filtered out in the nose and therefore do not enter the respiratory tract.

Notes:
Fertilization is the process of fusion of the male and the female gametes. This can occur either inside (internal fertilization) or outside (external fertilization) the body of the female. Humans provide an example of the former whereas seahorse reproduction is an example of the latter.

Notes:
According to the K+ ion theory the guard cells absorb K+ ions from the cells around them as they produce ATP (due to photosynthesis) and become hypertonic. This leads to absorption of water from nearby cells by endosmosis due to which the guard cells become turgid and the stomata opens. Decreasing light intensity and photosynthesis causes Stomatal closing.

Notes:
The International Commission on Zoological Nomenclature (ICZN) was founded in 1895. It provides and regulates a uniform system of zoological nomenclature ensuring that every animal has a unique and universally accepted scientific name.

Notes:
The cerebellum is known as little brain. It is a region of the brain that plays an important role in motor control. i.e. in maintaining and coordinating body posture at different times of the day/night.

Notes:
Cell theory was first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann. They stated that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all living organisms, and that all cells come from pre-existing cells.

Notes:
DNA profiling (genetic finger printing) is a technique employed by forensic scientists to assist in the identification of individuals by their respective DNA profiles. DNA profiles are encrypted sets of numbers that reflect a person’s DNA makeup, which can also be used as the person’s identifier. Each individual has unique VNTR numbers and pattern except maternal twins.

Notes:
A vein is an elastic blood vessel that transports blood from various regions of the body to the heart. Veins are components of the cardiovascular system, which circulates blood to provide nutrients to the cells of the body. Veins can be categorized into four main types: pulmonary, systemic, superficial, and deep veins.

Notes:
An antacid is a substance which neutralizes stomach acidity and is used to relieve heartburn, indigestion or an upset stomach. When excessive amounts of acids are produced in the stomach the natural mucous barrier that protects the lining of the stomach can damage the esophagus in people with acid reflux. Antacids contain alkaline ions that chemically neutralize stomach gastric acid, reducing damage and relieving pain.