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Why cannot fertilisation take place in flowers if pollination does not occur?

The transfer of pollen grains from the anther of a flower to the stigma of the same or another flower is known as pollination. It is done by... View Article

In the tobacco plant, the male gametes have twenty-four chromosomes. What is the number of chromosomes in the female gamete? What is the number of chromosomes in the zygote?

Number of chromosomes in female gamete is 24, number of chromosomes in zygote is 48 Chromosomes are the genetic material present in all the... View Article

From the internet, gather information about the chromosome numbers of five animals and five plants. Correlate the number with the size of the organism and answer the following questions. (a) Do larger organisms have more number of chromosomes/cells? (b) Can organism with fewer chromosomes reproduce more easily than organisms with more number of chromosomes? (c) More the number of chromosomes/cells greater is the DNA content. Justify.

(a) No, there is no relationship between size of organism and its chromosome number. (b) No, process of reproduction follows a common pattern and... View Article

Would a Planaria cut vertically into two halves regenerate into two individuals? Complete Figure, D and E by indicating the regenerated regions.

Yes Planaria cut vertically into two halves can regenerate into two individuals.Planaria are free-living flatworms that live in quiet ponds or... View Article

Give two reasons for the appearance of variations among the progeny formed by sexual reproduction.

The two major reasons for the appearance of variation among the progeny formed by sexual reproduction are Crossing over is the process in which... View Article

Colonies of yeast fail to multiply in water, but multiply in sugar solution. Give one reason for this.

a) Sugar provides energy for sustaining all life activities in yeasts. Yeasts are eukaryotic microorganisms, classified in the kingdom Fungi.... View Article

Explain how, offspring and parents of organisms reproducing sexually have the same number of chromosomes?

Chromosomes are thread-like cell organelles, present within the nucleus of the cell. It functions by carrying genetic information from one... View Article

What is a clone? Why do offsprings formed by asexual reproduction exhibit remarkable similarity?

Clone refers to offspring of an organism formed by asexual method of reproduction. Since they possess exact copies of the DNA of their parent,... View Article

Can you consider cell division as a type of reproduction in unicellular organism? Give one reason.

Yes, we can because in unicellular animals there is only one cell, when it will divide to form a new cell and hence new organisms. All... View Article

In a bisexual flower in spite of the young stamens being removed artificially, the flower produces fruit. Provide a suitable explanation for the above situation.

a) Stamens removed, but pistil is intact. When stamens of a bisexual flower are removed. Cross pollination can take place which results in... View Article

Which among the following diseases is not sexually transmitted? (a) Syphillis (b) Hepatitis (c) HIV – AIDS (d) Gonorrhoea

(b) Hepatitis Syphillis caused by Teponema pallidum and Gonorrhoea caused by Neisseria gonorrhoeae are sexually transmitted bacterial diseases.... View Article

The correct sequence of organs in the male reproductive system for transport of sperms is (a) testis → vasdeferens → urethra (b) testis → ureter → urethra (c) testis → urethra → ureter (d) testis → vasdeferens → ureter

testis → ;vasdeferens → urethra The sperms are produced in the Testis, stored in the epididymis and transported to the urethra... View Article

Which among the following is not the function of testes at puberty? (i) formation of germ cells (ii) secretion of testosterone (iii) development of placenta (iv) secretion of estrogen (a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (d) (i) and (iv)

C) (iii) and (iv) A pair of oval-shaped organs masked in a pouch called the scrotum. They are responsible for the production of sperms and the... View Article

In human males, the testes lie in the scrotum, because it helps in the (a) process of mating (b) formation of sperm (c) easy transfer of gametes (d) all the above

(b) formation of sperm Testes produce sperms. Sperms contain a haploid set of chromosomes of the father Testes produce a hormone known as... View Article

In human females, an event that reflects the onset of the reproductive phase is (a) growth of body (b) changes in hair pattern (c) change in voice (d) menstruation

d) Menstruation Human female reproductive development sequence: Thelarche (Breast development), Pubarche (pubic hair development) and Menarche... View Article

During adolescence, several changes occur in the human body. Mark one change associated with sexual maturation in boys (a) loss of milk teeth (b) increase in height (c) cracking of voice (d) weight gain

c) Cracking of voice During adolescence growth spurt occurs in both males and females, so growth velocity increases both in girls and boys.... View Article

Reproduction is essential for living organisms in order to (a) keep the individual organism alive (b) fulfil their energy requirement (c) maintain growth (d) continue the species generation after generation

d) Continue the species generation after generation Reproduction maintains a balance between the birth rate and death rate. The new... View Article

Offspring formed as a result of sexual reproduction exhibit more variations because (a) sexual reproduction is a lengthy process (b) genetic material comes from two parents of the same species (c) genetic material comes from two parents of different species (d) genetic material comes from many parents

b) Genetic material comes from two parents of the same species. Sexual reproduction is a natural way of reproduction in humans, animals and the... View Article

In Figure, the parts A, B and C are sequentially (a) cotyledon, plumule and radicle (b) plumule, radicle and cotyledon (c) plumule, cotyledon and radicle (d) radicle, cotyledon and plumule

Answer is c) Plumule, cotyledon and radicle Plumule is shoot, radicle is root and cotyledon are seed leaf.In germination process cotyledons... View Article

Which among the following statements are true for sexual reproduction in flowering plants? (i) It requires two types of gametes (ii) Fertilisation is a compulsory event (iii) It always results in the formation of zygote (iv) Offspring formed are clones (a) (i) and (iv) (b) (i), (ii) and (iv) (c) (i), (ii) and (iii) (d) (i), (ii) and (iv)

C) (i), (ii) and (iii) The main primary function of the flower is the reproduction of the individual and the species. They are the... View Article

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