General Science Questions (MCQs) for Competitive Examinations

Notes:
Credit for developing cell theory is usually given to three scientists: Theodor Schwann, Matthias Jakob Schleiden, and Rudolf Virchow. In 1839, Schwann and Schleiden suggested that cells were the basic unit of life. In 1858, Rudolf Virchow concluded that all cells come from pre-existing cells, thus completing the classical cell theory.

Notes:
One way of analyzing carrying capacity of the earth is to calculate its net primary productivity (NPP). This is the total amount of solar energy converted into biochemical energy through plant photosynthesis, minus the energy needed by those plants for their own life processes. It represents the total food resource on earth. In the food chain, meat products stay at the top. Even at the current levels where deforestation and other forms of destruction of vegetation has been rampant, plant products can sustain an extended population base.

Notes:
The thin layer of living cells just inside the bark is called the cambium. It is found in the area between xylem and phloem. It forms parallel rows of cells, which result in secondary tissues. It is the part of the tree that makes new cells, allowing the trees to grow wider each year.

Notes:
The cerebrum is the largest part of the human brain, making up about two-thirds of the brain’s mass. It has two hemispheres, each of which has four lobes: frontal, parietal, temporal and occipital. It is involved in several functions of the body including: determining intelligence; determining personality; thinking, perceiving, interpretation of sensory functions, etc.

Notes:
The cell theory states that all living things are made of cells, cells are the basic units of structure and function of living things, and that all cells arise from pre-existing cells. Since viruses are not made of cells, and do not use cells in any of their processes, they are not related to the cell theory.

Notes:
Conglobate gland is a leaf like, median, unbranched gland of male cockroach. It lies below the ejaculatory duct and open into the genital pouch close to the male genital aperture.

Notes:
Leishmaniasis (Kala azar) is a disease spread by the bite of the female sandfly. The disease is the second-largest parasitic killer in the world (after malaria). The parasite migrates to the internal organs such as liver, spleen (hence ‘visceral’), and bone marrow, and, if left untreated, will almost always result in the death of the host.

Notes:
Resin in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. It is distinct from other liquid compounds found inside plants or exuded by plants, such as sap, latex, or mucilage.

Notes:
Brailing is the practice of preventing a bird from flying by tying the wing so that it is impossible for the bird to open wings fully and fly. The brail is a clear plastic strap, fastened by rivets, which will be used to restrain his wing. Brailing the birds helps prevent injuries during shipment.

Notes:
The word ‘comose’ means ‘hairy’ in Latin. It refers to certain seeds (such as cotton) having a tuft or tufts of hair. The seeds of plants like Calotropis, Gossypium, etc, possess a large number of hair which enable them to float in air. Such seeds with hair are described as comose.