✓ Board-verified
Science · 2026 · 3 marks
CBSE 2026 · Region 4 · Set 3 · Q13
Use the following information for Pea plants : Dominant allele for tall plants - T Recessive allele for short plants - t Dominant allele for purple flowers - P Recessive allele for white flowers - p(a)Perform a cross between pure plant dominant for both the traits with another plant which is recessive for both the traits and work out the progeny upto $\displaystyle \mathrm{F}_{2}$ generation.(b)What is the probability of obtaining tall plants with white flowers in $\displaystyle \mathrm{F}_{2}$ progeny?
Use the following information for Pea plants : Dominant allele for tall plants - T Recessive allele for short plants - t Dominant allele for purple flowers - P Recessive allele for white flowers - p
(a)
Perform a cross between pure plant dominant for both the traits with another plant which is recessive for both the traits and work out the progeny upto $\displaystyle \mathrm{F}_{2}$ generation.
(b)
What is the probability of obtaining tall plants with white flowers in $\displaystyle \mathrm{F}_{2}$ progeny?
Marking-scheme solution
(a)
| Parents: | TTPP | X | ttpp |
| tall purple | short white |
Gametes: TP tp
| ↓ | ||
| \(\displaystyle \mathrm{F}_{1}\) | TtPp | |
| Selfing of \(\displaystyle \mathrm{F}_{1}\) | ||
| TtPp | × | TtPp |
\(\displaystyle \mathrm{F}_{2}\)
| gametes | TP | Tp | tP | tp |
| TP | TTPP | TTPp | TtPP | TtPp |
| Tp | TTPp | TTpp | TtPp | Ttpp |
| tP | TtPP | TtPp | ttPP | ttPp |
| tp | TtPp | Ttpp | ttPp | ttpp |
tall and purple : $\displaystyle 9$
(b)
In \(\displaystyle \mathrm{F}_{2}\) progeny probability of Tall, White = $\displaystyle 3$/$\displaystyle 16$
tall purple
Selfing of \(\displaystyle \mathrm{F}_{1}\)
More from Heredity
- In human beings, there are 23 pairs of chromosomes. Out of these 23 pairs of chromosomes (i.e. 46…2025 · asked 3×
- Two pea plants, one with round green seeds (RRyy) and another with wrinkled yellow (rrYY) seeds were crossed…2026 · asked 3×
- Assertion: Human female has a perfect pair of sex chromosome. Reason (R): Sex chromosome contributed by the…2024 · asked 3×
- Assertion: Human populations show a great deal of variations in traits. Reason (R): All variations in a…2023 · asked 3×
- Assertion: A mango seed will germinate to form a mango tree. Reason (R): Heredity determines the process by…2025 · asked 3×
- All human chromosomes are not paired. Most human chromosomes have a maternal and a paternal copy, and we have…2023 · asked 3×
- Consider the following two statements: (i) The trait that expresses itself in F 1 generation. (ii) The trait…2023 · asked 3×
- Using height (tallness / dwarfness) of a plant as an example, show that genes control the characteristics or…2022 · asked 3×
CBSE Class 10 Science past-paper question from the 2026board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.