Test: Class 8 General Science NCERT Based - 3 - UPSC MCQ

Statement 1 is not correct because the Pachmarhi Biosphere Reserve consists of one national park named Satpura and two wildlife sanctuaries named Bori and Pachmarhi. Satpura National Park is India’s first Reserve forest.

The best form of teak is found in this region. Bison, Indian giant squirrel and Flying squirrel are the Endemic Fauna of Pachmarhi Biosphere reserve; and Sal and wild mango are the Endemic Flora.

Sal, teak, mango, jamun, silver ferns, arjun, etc are the flora and chinkara, blue-bull, barking deer, cheetah, leopard, wild dog, wolf, etc. are examples of the fauna of the Pachmarhi Biosphere Reserve. Rock shelters are also found inside the Satpura National Park. Rock paintings are found in these shelters.

Red Data book is a book which maintains a record of all the endangered species. There are separate Red Data Books for plants, animals and other organisms.The endangered species are protected in Wildlife sanctuaries.

Large and small, all types of animals are protected in these sanctuaries, because their contribution to the ecosystem cannot be ignored. Small organisms face the danger of extinction much more than larger animals.

Sperm and ovum, both are examples of single celled bodies. The fusion of both is called fertilization, the result of which is the formation of zygote. The cells of zygote divide continuously, to form a ball of cells, after which, the cells differentiate and divide into tissues and organs. This is called an embryo.

The embryo undergoes development after being implanted on the wall of the uterus. The stage of embryo development, wherein all the body parts are distinguishable, is called foetus. Animals which give birth to offspring are called viviparous; and the ones which develop through eggs are called oviparous.

Like plants, animals too have two types of reproduction: 1. Sexual reproduction 2. Asexual reproduction The type of reproduction, wherein only one parent participates is called asexual reproduction.

Budding and binary fission are methods of reproduction. Hydra reproduces through budding, and amoeba reproduces through binary fission. The transformation of the larva into an adult through drastic changes is called metamorphosis.

An organism consisting of one cell is called unicellular. Amoeba, paramecium, hen’s egg and White Blood Cells are all examples of unicellular organisms.

Organisms made up of more than one cell are called multicellular. In unicellular organisms, the single cell itself performs all the activities that multicellular organisms do, like respiration, growth, excretion, reproduction, etc; which are performed by groups of tissues in multicellular organisms.

Various components of the cell have a boundary, which is known as plasma membrane or cell membrane. This membrane separates one cell from another and also from the surrounding medium.

It is porous and allows various substances to enter the cell. This membrane [provides structure to the plant and animal cells. Cytoplasm is a jelly like substance, which is found between the cell membrane and nucleus.

The other components of the cell (mitochondria, golgi complex, ribosomes, etc) are found in the cytoplasm itself. Nuclei are circular in shape and present in the central region of the cytoplasm.

The nuclear membrane separates the nucleus from the cytoplasm. This nuclear membrane is also porous and regulates the incoming and outgoing of materials between the cytoplasm and the nucleus.

This nuclear membrane is absent in the bacterial cells. Nucleolus and chromosomes are present within the nucleus. Chromosomes are present within the nucleus. Chromosomes carry genes and can be seen only when the cell divides. These help in inheritance or transfer of characters from the parents to the offsprings.

The cells which do not have a well organised nucleus, are called prokaryotic cells. In contrast, cells with a well organised nucleus are called eukaryotic cells. Organisms with prokaryotic cells are called prokaryotes.

Bacteria and blue green algae are examples of the same. Viruses are neither prokaryotic, nor eukaryotic. Organisms with eukaryotic cells are called eukaryotes. Onion and human cells are examples of the same.

Animal cells are devoid of cell walls. Cell wall is present in plant cells, apart from the cell membrane. It provides rigidity and shape to the plant cell. Bacterial cells also possess cell walls. Plastids are found only in plant cells.

These are mostly variously coloured. Some of these have chlorophyll, which is a green pigment. Green plastids are called chloroplast, which provide green colour to the leaves. Animal cells have many small vacuoles and plant cells have one big, central vacuole. Hence, statement 3 is correct.

Endocrine glands release hormones directly into the bloodstream, and hence are also called ductless glands. Sex hormones are also secreted through endocrine/ductless glands.

Estrogen and testosterone are sex hormones which are responsible for secondary sexual characters. Estrogen is the female hormone and testosterone is the male hormone, secreted by ovary in females and testes in males respectively.

This sex hormone is responsible for the development of facial hair, enlargement of voice box (larynx, Adam’s apple) etc in males.

Due to an enlarged voice box, boys have a deeper voice and girls have a high pitched voice. Secondary sexual characteristics like development of breasts and mammary glands in females is caused by estrogen.

The secretion of these sex hormones is regulated by a separate hormone, secreted by the pituitary. It regulates the maturation of egg/ovum in the ovary and sperms in the testes.