How many types of gametes will be produced in F2 generation of a monohybrid cross of Mendel :-
Each dihybrid plant produces 4 gamete types of equal frequency. In the offspring F2 showed 4 different phenotypes : the round and yellow traits did not stay linked to each other.
Recessive gene can express only in :-
Considering tallness and dwarfness, tallness is more wide spread among pea plants because :-
A red-flowered pea plant was crossed with white-flowered plant. In F1 generation all plants were red. It confirms that white colour is :-
A woman with straight hair mates with a man with curly hair who is known to be heterozygous for that trait. What is the chance that their first child will have curly hair :-
The main reason of Mendel's successs in discovering the principles of inheritance was :-
Mendel was lucky in the choice of the material of his experiments, among the following, which contributed, to his success ?
The year 1990 AD is highly significant for genetics due to :-
Mendel's work was not recognized since 1900. Rediscovery of Mendel's work was done by three scientists, Karl Correns of Germany, Hugo de Vries of Netherlands, and Erich Von Tschermark of Austria.
Genotype means :-
The genotype of an organism is the chemical composition of its DNA, which gives rise to the phenotype, or observable traits of an organism. A genotype consists of all the nucleic acids present in a DNA molecule that code for a particular trait
An organism with two identical alleles of a gene is a cell is called :-
Diploid organisms, for example, humans, have paired homologous chromosomes in their somatic cells, and these contain two copies of each gene.
An organism in which the two copies of the gene are identical — that is, have the same allele — is called homozygous for that gene.
When an individual is having both the alleles of contrasting characters it is said to be :-
When an individual is having both the alleles of a contrasting character, it is said to be HETEROZYGOUS .
When an allele fails to express itself in F1 generation in the presence of other allele, the former is said to be :-
If a plant is heterozygous for tallness, the F2 generation has both tall and dwarf plants. This proves the principle of :-
In F2 -3 tall : 1 dwarf This is the law of segregation. 1 Homozygous tall 1 Homozygous dwarf 2 Heterozygous tall.
Mendel crossed a pure white flowered recessive pea plant with a dominant pure red flowered plant. The first generation of hybrids from the cross should show :-
All red flowered plants; according to Mendel's law of dominance.
If a couple has three daughters, what are the chances that the fourth child will be a son ?
Almost everyone has around a 50% chance of having a boy and a 50% chance of having a girl. What we can say is that dad's sperm determines whether a baby will be a boy or a girl. About half of his sperm will make a boy and half a girl. The sex of the baby depends on which sperm gets to the egg first.
If a heterozygous tall palnt is crossed with a homozygous dwarf palnt, the proportion of dwarf progeny will:-
The crossing of a homozygous tall plant with a dwarf would yield plants in the ratio of :-
When a true breeding tall plant is crossed with a true breeding short plant and the F1 produced is self pollinated to produce F2 ratio of true breeding tall and true breeding short plant in F2 will be :-
Blue eye colour in human is recessive to brown eye colour. The expected children of a marriage between blue- eyed woman and brown-eyed male who had a blue-eyed mother are likely to be :-
According to the law of dominance, a trait is represented by two contrasting factors of a gene in a heterozygous individual; the allele/factor that can express itself in a heterozygous individual is called as a dominant trait. The other factor whose effect is masked by the presence of dominant factor is called recessive factor. Since blue eye colour is recessive to brown eye colour, the genotype of blue eyed woman will be “bb”. Since brown eyed man had blue eyed mother (bb); he must have inherited one copy of “b” allele from the mother and thus is heterozygous brown eyed (Bb). A cross between blue eyed woman (bb) and heterozygous brown eyed man (Bb) will produce blue eyed and brown eyed children in 1:1: ratio. A cross between two pure breeding organisms obtains uniform F1 generation; here father is not pure breeding. Recessive individuals never outnumber the dominant one.
Allosomes are :-
The human sex chromosomes are a typical pair of allosomes. These chromosomes determine the sex of an individual when reproducing. Allosomes are also referred to as sex chromosomes or idiosomes
Mutation is :-
A mutation is a change that occurs in our DNA sequence, either due to mistakes when the DNA is copied or as the result of environmental factors such as UV light and cigarette smoke.
The palnt that was made popular by "De Vries mutation theory" :-
"Barr body" is derived from :-
The Barr body, also sometimes called the sex chromatin, is the inactive X chromosome in female somatic cells. Human females have two X chromosomes, while males have one X and one Y. In all of the female somatic cells, which don’t take part in sexual reproduction, one of the X chromosomes is active.
The DNA is the genetic material was proved conclusively by :-
In 1952, Hershey & Chase were the ones to conclusively prove that DNA is the genetic material. They worked with bacteriophages – viruses that infect bacteria. A bacteriophage attaches and delivers its genetic material into a bacterial cell, where it generates more virus particles.
Nobel Prize for "one gene one enzyme theory" was given to :-
The proof for the fact that protein synthesis occurs through enzymes was given by George Beadle and Edward Tatum. They proposed the one gene one enzyme theory. According to this theory, one gene accounts for producing one protein. The scientists won the Nobel Prize for this concept in 1958.