Is the chromosome number of zygote, embryonal cells and adult of a particular organism always constant? How is the constancy maintained in these three stages?
Why cannot fertilisation take place in flowers if pollination does not occur?
In 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?
From the internet, gather information about the chromosome numbers of five animals and five plants. Correlate the number with the size of 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.
Would a Planaria cut vertically into two halves regenerate into two individuals? Complete Figure D and E by indicating the
regenerated regions.
Give two reasons for the appearance of variations among the progeny formed by sexual reproduction
Why does bread mould grow profusely on a moist slice of bread rather than on a dry slice of bread?
Colonies of yeast fail to multiply in water, but multiply in sugar solution. Give one reason for this.
Explain how, offspring and parents of organisms reproducing sexually have the same number of chromosomes?