Biology

2. During evolution why DNA was chosen over RNA as genetic material? Give reasons by first discussing the desired criteria in a molecule that can act as genetic material and in the light of biochemical differences between DNA and RNA.

Solution: The desired criteria in a molecule that can act as genetic material are 1. It should be chemically and structurally stable. 2. It should be able to duplicate in order for replication to...

read more

17. Now, the sequencing of total genomes is getting less expensive day by the day. Soon it may be affordable for a common man to get his genome sequenced. What is your opinion could be the advantage and disadvantage of this development?

Solution: Advantages 1. It would lead to improved genetic condition diagnosis, treatment, and prevention. 2. A better grasp of the DNA gene sequence might aid in the comprehension of biological...

read more

10. Recall the experiments done by Frederick Griffith, Avery, MacLeod and McCarty, where DNA was speculated to be the genetic material. If RNA, instead of DNA was the genetic material, would the heat-killed strain of Pneumococcus have transformed the R-strain into virulent strain? Explain.

Solution: The R-strain would not have been converted into the virulent strain if the Pneumococcus strain had been heat-killed. This is due to the fact that RNA is not thermostable.

read more

8. In an experiment, DNA is treated with a compound which tends to place itself amongst the stacks of nitrogenous base pairs. As a result of this, the distance between two consecutive base increases from 0.34nm to 0.44 nm calculate the length of DNA double helix (which has 2×109 bp) in the presence of saturating amount of this compound.

Solution: Distance between two consecutive base pairs: 0.44 nm or 0.44 x 10-9. Length of the DNA: 2 x 10 9 x 0.44 x 10-9 Length of DNA = 0.88m

read more

(a) The shift from grain to meat diets creates more demands for cereals. Why?
(b) A 250 kg cow produces 200 g of protein per day but 250 g of Methylophillusmethylotrophus can produce 25 tonnes of protein Name this emerging area of research. Explain its benefits.

Solution: (a) We know that an organism at a specific trophic level consumes 90% of the biomass it consumes for its own needs, leaving just 10% for the creature at the next trophic level. So, to...

read more

7. In peas, tallness is dominant over dwarfness, and red colour of flowers is dominant over the white colour. When a tall plant bearing red flowers was pollinated with a dwarf plant bearing white flowers, the different phenotypic groups were obtained in the progeny in numbers mentioned against them:

Tall, Red = 138 Tall, White = 132 Dwarf, Red = 136 Dwarf, White = 128 Mention the genotypes of the two parents and the four offspring types. Solution:

read more

9. In a monohybrid cross of plants with red and white-flowered plants, Mendel got only red-flowered plants. On self-pollinating these F1 plants got both red and white-flowered plants in 3:1 ratio. Explain the basis of using RR and rr symbols to represent the genotype of plants of the parental generation.

Solution: Mendel obtained only red-flowered plants with genotype Rr by crossing red (RR) and white (rr) flowering plants. This is the first hybrid generation's filial progeny (F1) or plants. F1...

read more

Lifestyle diseases are increasing alarmingly in India. We are also dealing with large scale malnutrition in the population. Is there any method by which we can address both of these problems together?

Solution: Adopting nutritious foods can help prevent both malnutrition and lifestyle problems. As part of an overall healthy diet, eating a diet high in various vegetables and fruits may protect...

read more

You are planning to set up a Dairy Farm. Describe the various aspects you would consider before you start the venture. Solution: Before launching the business, keep the following factors in mind:

(i) Breed Selection: The breed should be capable of producing a high milk output. It should be able to fend off a variety of ailments. (ii) Cattle shed construction: Cattle sheds should be well...

read more