How are general growth and sexual maturation different from each other?
Growth is a positive change in the size, often over a period of time which includes physical growth in height,... View Article
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Reproduction is linked to stability of population of a species. Justify the statement.
Reproduction is directly linked to the stability of the population of species because it helps in replacing the ageing population... View Article
Where is the zygote located in the flower after fertilization?
After fertilization, zygote is located in the ovary of the flower. Explanation Fertilization can be defined as the fusion of... View Article
Is the chromosome number of the zygote, embryonal cells and adult of a particular organism always constant? How is the constancy maintained in these three stages?
The chromosome number of the zygote, embryonal cell and adult of a particular organism is always constant. Meiosis is the... View Article
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... 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 Explanation Chromosomes are the genetic... 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... 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... 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... 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. Explanation Yeasts are eukaryotic microorganisms, classified in the kingdom... 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... 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... 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. Explanation When stamens of a bisexual flower are removed. Cross pollination can take... View Article
Which among the following diseases is not sexually transmitted? (a) Syphillis (b) Hepatitis (c) HIV – AIDS (d) Gonorrhoea
(b) Hepatitis Explanation Syphillis caused by Teponema pallidum and Gonorrhoea caused by Neisseria gonorrhoeae are sexually transmitted bacterial diseases. AIDS... 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 Explanation The sperms are produced in the Testis, stored in the epididymis and transported to the... 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) Explanation A pair of oval-shaped organs masked in a pouch called the scrotum. They are responsible... 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 Explanation Testes produce sperms. Sperms contain a haploid set of chromosomes of the father Testes produce... 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 Explanation Human female reproductive development sequence: Thelarche (Breast development), Pubarche (pubic hair development) and Menarche (menstruation). After menstruation... 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 Explanation During adolescence growth spurt occurs in both males and females, so growth velocity increases both... View Article
