Biology MCQs

Notes:
Females have single uterus. Also known as womb, it is a major female hormone-responsive reproductive sex organ of humans and most other mammals. It is within the uterus that the fetus develops during gestation.

Notes:
A cross between a homozygous plant with recessive traits and a heterozygous plant is known as a test cross. A test cross is a valuable tool in predicting the genotype of the organism in question. In its simplest form, a test cross is an experimental cross of an individual organism of dominant phenotype but unknown genotype and an organism with a homozygous recessive genotype (and phenotype). Test cross is done to determine the genotype of an F2 generation plant, showing dominant characteristics. In the test cross, an F2 plant that shows the dominant trait is crossed with the homozygous recessive.

Notes:
Calyptrogen is a layer of rapidly dividing cells at the tip of a plant root, from which the root cap is formed. It occurs in grasses and many other plants. The root cap is formed by several layers of cells that envelop the root tip externally. This covering of cells, of which the outermost ones are dead, envelops and protects the growing tip of root.

Notes:
Monocost and dicots differ in the location of stomata and shape of guard cells. In monocots stomata are Dumb-bell shaped in dicots they are bean-shaped.

Notes:
Colour blindness is a sex-linked recessive disorder that causes failure in a person to differentiate and distinguish different colours such as red and green. Colour vision deficiency, commonly called colour blindness, results from a malfunction or absence of cone cells in the retina. Cone cells are one of three types of photoreceptor cells in the retina of the human eye that are responsible for colour vision and function best in relatively bright light. Colour blindness can occur when one or more of the colour cone cells are absent, nonfunctioning, or detect a different colour than normal.

Notes:
Insects and birds have the simplest surface waxes that serve to water proof feathers. The interlocking feather barbs and a special waxy coating create a shield that water runs off of. Besides, while a few components present in surface lipids can prevent growth of pathogens, the total surface with waxed layer certainly functions to prevent microbial entry into the organism.

Notes:
Ossification is the process of laying down new bone material by cells called osteoblasts. It is synonymous with bone tissue formation. As per scientific evidence, by the age of 25 years nearly all bones are completely ossified in humans. Ossification test is a guess work based on the fusion of joints in the human body b/w birth and age 25. If all joints are fused the person must be of 25yrs of age or older.

Notes:
Vitamin A deficiency results in night blindness, the inability or reduced ability to see in dim light or darkness. Also known as nyctalopia, night blindness is due to a disorder of the cells in the retina that are responsible for vision in dim light which is caused by Vitamin A deficiency.

Notes:
Pulses are example of dicots since they have two cotyledons (dicot is short for ‘dicotyledon’, and ‘di’ means two). They contain two seeds inside the seed coat. Legumes (a family of plants that includes pluses, beans, peas and lentils) are all examples of dicot seeds.

Notes:
Animals adapted to life in air are called volant. Arboreal means living in or connected with trees. These animals such as monkeys, squirrel can live both on land and in trees. However, for protection purposes, they prefer to live in trees than on land.