General Science GK Questions with Answers – Page 112

Cones are the photoreceptor cells of the retina that respond to colour in bright light. The human retina carries two kinds of photoreceptors.

The left atrium is the chamber that receives oxygen-rich blood coming back from the lungs through the pulmonary veins. From there the blood passes the bicuspid or mitral valve into the left ventricle, which pumps it out through the aorta to the whole body.

Dendrites and the axon are the two kinds of processes that grow out of a neuron, the nerve cell that carries messages through the body.

The small intestine is the longest part of the human alimentary canal, about 6 to 7 metres in an adult, which is why it is called the longest organ of the digestive system.

Carotenoids are the yellow, orange and red pigments inside the chloroplast that absorb sunlight and hand the energy on to chlorophyll, so they are the only choice here that traps light for photosynthesis.

Inertia is the tendency of a body to stay at rest or keep moving in a straight line, and the measure of that tendency is mass.

In a suspension the particles of the solute are large enough to be seen and do not dissolve; they stay spread through the liquid only while it is stirred and settle to the bottom when it is left standing.

Johann Wolfgang Dobereiner, a German chemist, grouped elements of similar properties in sets of three that he called triads. His rule was that the atomic mass of the middle element is about the average of the other two.

Spirogyra is a green filamentous alga found in ponds, and when its filament grows long it simply breaks into two or more pieces.

A tissue is a group of cells that come from the same source, look alike and work together at one job.

Carbon occurs in nature in two ways, free and combined. In the free state the element stands alone, as in diamond, graphite and coal; diamond is pure carbon whose atoms are each joined to four others in a rigid three dimensional network, which is why it is the hardest natural…

The brain is divided into fore-brain, mid-brain and hind-brain, and the fore-brain is the main thinking part. Its largest portion is the cerebrum, whose folded outer layer holds separate areas for hearing, sight, smell and touch, for reasoning and memory, and for ordering voluntary movement.

It is a reduction division: one parent cell with the full, diploid set gives four cells with half the number of chromosomes, the haploid set.

Water behaves unlike most liquids between 0 and 4 degrees Celsius, a behaviour called the anomalous expansion of water. Almost every substance shrinks as it is cooled, but water shrinks only until it reaches 4 degrees Celsius.

Malleability is the property by which a metal can be beaten into thin sheets without breaking, which is how aluminium foil and the sheets used in car bodies are made.

Human beings are ureotelic, which means the main nitrogen waste they pass out is urea. When the body breaks down extra amino acids, ammonia is produced, and ammonia is highly poisonous even in small amounts.

Blood is filtered in the glomerulus of the nephron, and the filtrate that first enters the tubule still holds many useful substances.

A ligament is the connective tissue that joins one bone to another at a joint. It is very elastic and strong, and it holds the bones in place so that a joint can move without the bones slipping apart.

Abscisic acid is the one plant hormone in this list that slows growth instead of speeding it up, which is why it is often called the stress hormone of plants.

Testosterone is made by the Leydig cells of the testes and is the main male sex hormone.