5
Mendel took garden pea plants with different characteristics, such as height to study the inheritance pattern of factors (genes). He crossed tall pea plant with short pea plant and obtained all the tall plants in the $\text{F}_1$ generation.
Answer the following questions :
(a) Why only tall pea plants were observed in $\text{F}_1$ progeny ?
(b) By which method did Mendel obtain $\text{F}_2$ progeny ?
Answer the following questions :
(a) Why only tall pea plants were observed in $\text{F}_1$ progeny ?
(b) By which method did Mendel obtain $\text{F}_2$ progeny ?
Show SolutionHide Solution↓
(a) In F1 progeny, pea plants have ‘Tt' where ‘T' is dominant over ‘t'
so all the plants of F1 progeny were tall. / Tall height is dominant
trait over short height. (1)
(b) Self-pollination (1)
(c) (i)
Dominant trait
i) Expresses itself over recessive trait.
ii) Expresses in both conditions-TT and Tt. (2)
Recessive trait
i) Unable to express itself in presence of a dominant trait.
ii) Expresses itself only when it is 'tt' or in pure condition. (2)
(any one, any other suitable difference)
OR
(c) (ii) Mendel's observations:
• All plants of F1 progeny were tall.
• No medium/ no short height plants observed in F1 progeny.
• F1 progeny resembled one parent only. (1+1)
(any two observations)
so all the plants of F1 progeny were tall. / Tall height is dominant
trait over short height. (1)
(b) Self-pollination (1)
(c) (i)
Dominant trait
i) Expresses itself over recessive trait.
ii) Expresses in both conditions-TT and Tt. (2)
Recessive trait
i) Unable to express itself in presence of a dominant trait.
ii) Expresses itself only when it is 'tt' or in pure condition. (2)
(any one, any other suitable difference)
OR
(c) (ii) Mendel's observations:
• All plants of F1 progeny were tall.
• No medium/ no short height plants observed in F1 progeny.
• F1 progeny resembled one parent only. (1+1)
(any two observations)