Class 10 Science Chapter 7 MCQ

The disease which are spread by sexual contact with an infected person are called Sexually Transmitted Disease or STD. Example: Gonorrhea, Syphilis and AIDS. Hepatitis is a waterborne a viral disease which affects liver.

Here, only one statement is correct. Hence, your answer will be option [A].

Sperms formed in testis are delivered through the vas deferens which joins with another tube called urethra, coming from the urinary bladder.

Microscopic single celled animal, plasmodium is a protozoa which reproduces by the method of “Multiple fission”.

Formation of germ cell or sperms take place in the testes and it lies in the scrotum. In the scrotum outside the abdominal cavity, the temperature is about 3 degree Celsius lower than the temperature of the body. Testes lies in the scrotum because the sperm formation require a lower temperature than the normal body temperature.

In early e teenage girls should, breast size increased with darkening of the skin of nipples at the tip of breast. Also, girls begin to menstruate at around this time. In human females, this reflects onset of reproductive phase.

It is “not” necessary to plant the whole potato tuber in the ground to produce the new potato plants. We can even plant, to “cut pieces” of a potato tuber in the ground to obtain new plants potato plants. But all these cut pieces of potato tuber should have a bud or eye on them. Each potato plant produces more than one tuber and each tuber has more than one bud which produce more than one new plant. Due to this, the vegetative propagation method of producing potato plants by tuber is much faster than the production of potato plants from seeds.

Reproduction is not essential for the survival of an individual, but it is an important function of a living being as it helps and organisms to perpetuate it its own kind. Through this process, new individuals are produced, that grow and reproduce again, so as to continue the species generation after generation. Reproduction is a process to maintain the progeny of an organisms.

Sexual reproduction occurs between two parents of the same species, not a different species. Sexual reproduction, the offspring are not identical to the parents or to one another. This is because the offspring receive some genes from mother and some from father. Because of mixing of genes on re-establishment of number of chromosome in various different combinations the offspring show both similarities and variations with characters of parents. Thus, creates new combination of variants and each combination is novel.

Sexual reproduction creates variation in organisms. So, clones cannot be produced through it. Clones are identical copy of parent organism. Sexual reproduction needs two types of “Gametes” i.e. male and female to form zygote after fertilization.

The flowers are unisexual (papaya, watermelon) contains either stamens or carpels. Since only one reproductive organ is present in them. They depend on cross pollination to form zygote after fertilization. Both stamen and carpels are required for fertilization, so only one of them cannot produce fruits.

The replication or copying of DNA in the cells is done by certain biochemical reaction which synthesize more of genetic material. When the DNA already present in the nucleus of the parent cell is replicated or copied by making more DNA at the time of “asexual reproduction”, then slight variation come in the two copies formed. Due to this, the two DNA molecules formed by replication will be similar but may not be exactly identical to the original DNA. No biochemical reaction can produce 100% same results.

Flowers are the sexual reproductive organs of a plant. They are produced in angiosperms. Majority of flowers are bisexual. After fertilization, they give rise to fruits.

Here, all the statements are correct. Hence, your answer will be option [D].

In sexual reproduction, though the genetic material DNA from two gametes, male and female gametes, combined together to form a new cell “zygote” but the amount of DNA in zygote does not get the doubled. This can be explained as: When a male gamete combined with the female gamete during sexual reproduction, then the new cell zygote will have the normal amount of DNA or normal number of chromosomes in it. For example, the human sperm has 23 chromosomes and the human egg or ovum has also 23 chromosomes. So, when a sperm and an egg fuse together during fertilization, then the zygote formed will have 23 + 23 = 46 chromosomes, which is the normal number of chromosomes.

Under favorable condition (like damp and warm conditions, nutrients), the airborne spores land on food, germinate and produce new plants. These spores spread into air when spore case of plant containing hundreds of spore busts.

Here, all the statements are correct. Hence, your answer will be option [D].

In vegetative propagation, vegetative parts of a plant such as root, stem leaf, etc. can produce new plants. Vegetative reproduction is seen in plants like orchids, ornamental plants, grasses, banana, rose, jasmine etc.

Here, all the statements are correct. Hence, your answer will be option [D].

The number of chromosomes in parents and off-springs of a particular species remains constant due to halving of chromosome during gamete formation. The gametes are a special type of cells which contain only half of the amount of DNA as compared to normal cells of an organism. So when a male gamete combines with a female gamete during sexual reproduction, then the new cell “zygote” will have normal amount of DNA.

Multiple fission-organisms divided into many daughters cells simultaneously, example Plasmodium. Budding small bud develops on the cell wall of organism that separate and grow further, example yeast. Reduction division-meiosis is described as a process of reduction division. The number of chromosomes is reduced to half. Binary fission-organisms divided into two daughters cells, example Amoeba.

Amoeba and yeast are unicellular while spirogyra is multicellular. But all the three reproduce asexually.

Characters are transmitted from parents to offspring through genes. Genes are the hereditary units of the body in living organisms. Chromosomes in the nucleus of a cell contain information for the inheritance of features from parents in the form of DNA (Deoxyribonucleic acid). This DNA contains genes.

In a flower, the parts that produce male and female gametes are anther and ovary respectively. Stamen is the male reproductive unit of the flower. It contains a bilobed anther at the top which produces male gametes. Filament is the stalk of the stamen that supports anther. Pistil (carpel) is the female reproductive part of the flower. It consists of ovary (forms ovules-female gametes), stigma (receives pollen) and style (elongated tube).

A sexual reproduction take place without the process of gamete formation and only one parent is needed, examples include Amoeba reproduce by binary fission (division of cell into two similar cells). Yeast, reproduce by budding (small bud develops from body wall of parent that separate and grow further). Banana, reproduce by vegetative propagation (vegetative parts of a plant such as root, stem etc. can produce new plants) In dog, sexual reproduction take place (i.e. it involves two sexes-male and female whose gametes fuse constituting sexual reproduction).