_______ is the observable set of characteristics of an organism.
Phenotype
Genes
DNA
All of these
(1)
The term “phenotype” refers to an organism’s observable physical properties, such as its appearance, development, and behaviour.
Which of the following is not controlled by genes?
Eye colour
Height
Hair colour
None of the above
(4)
Characters or traits are the characteristics that a person expresses and can be seen in their phenotype. Height, eye colour, and body colour are all controlled by genes and can be inherited.
Two pink coloured flowers on crossing resulted in 1 red, 2 pink and 1 white flower progeny. The nature of the cross will be:
Double fertilisation
Self pollination
Cross fertilisation
No fertilisation
(3)
The cross described in the question is a typical Mendelian genetic cross showing incomplete dominance, where the offspring display a 1:2:1 phenotypic ratio (1 red, 2 pink, 1 white). Among the given options, "Cross fertilisation" (This involves the fertilisation of an organism with the gametes from another organism. It typically refers to the process between two different plants, not necessarily describing the specific genetic inheritance pattern observed) is the most applicable.
Dominant alleles are expressed exclusively in a heterozygote, while recessive traits are expressed only if the organism is _______ for the recessive allele.
Homozygous
Heterozygous
Normal
None of these
(1)
Mendel’s law of dominance states that in a heterozygote, one trait will conceal the presence of another trait for the same characteristic. Rather than both alleles contributing to a phenotype, the dominant allele will be expressed exclusively. The recessive allele will remain “latent,” but will be transmitted to offspring by the same manner in which the dominant allele is transmitted. The recessive trait will only be expressed by offspring that have two copies of this allele.
A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers but almost half of them were short. This suggests that the genetic make-up of the tall parent can be depicted as:
TTWW
TTWw
TtWW
TtWw
(4)
This represents a parent that is heterozygous for both tallness and violet flower color. This genotype allows for the possibility of both tall and short offspring as well as violet and white flowers. However, since all progeny were violet, the white allele seems to have no effect in this cross, suggesting that the other parent must carry the recessive allele for white flowers.
A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because:
Tallness is the dominant trait
Shortness is the dominant trait
Tallness is the recessive trait
Height of pea plant is not governed by gene ‘T’ or ‘t’
(1)
When two traits of a character are crossed, the plants only show one of the two traits, which is known as the dominant trait. The recessive trait (dwarfness) is a trait that does not manifest itself in the generation
Which of the following is a recessive trait in pea plants?
Dwarf stem height
Violet flowers
Axial flowers
Inflated pods
(1)
Recessive traits are the ones that require both alleles to be present to result in the expression of the gene product. Of the mentioned traits, only dwarf stem height is a recessive trait.
