A plant has two varieties, one with red petals and the other with white petals. When these two varieties are cross-pollinated, all the offsprings have red petals?(a) Which gene is dominant?
(b) Choose suitable letters to represent the two genes.
A plant has two varieties: Red petals (RR) & White petals (rr)
When these varieties were cross-pollinated, F1 generation: All Red petals (Rr)
Therefore,
(a) Red petal gene is dominant over white petal gene.
(b) The gene for red petal can be denoted by R and gene for white petal can be denoted by r.
Related Articles
- When the leaves of a sensitive plant are touched with a finger, they fold up and when light fades at dark, the petals of a dandelion flower close.(a) State one way in which the above two processes are similar.(b) State two ways in which the above two processes differ.
- Some plants occur in one of the two sizes: tall or dwarf. This characteristic is controlled by one pair of genes. Tallness is dominant to dwarfness. Choose suitable letters for this gene pair.
- Name two varieties of cloth materials which are commonly used.
- When the ovary turns into a fruit, the petals and sepals fall off, then is the fruit protected?
- Which of the following is a growth movement and which is not ?(a) folding up of leaves of sensitive plant on touching with hand.(b) folding up of petals of dandelion flower when light fades.
- A plant with two 'small' genes breeds with a plant with two 'tall' genes to produce:(a) small plants and tall plants in the ratio 1:3 (b) all small plants(c) all tall plants (d) tall plants and small plants in the ratio 3:1
- Correct the following statements and rewrite them in your notebook.(a) Stem absorbs water and minerals from the soil.(b) Leaves hold the plant upright.(c) Roots conduct water to the leaves.(d) The number of petals and stamens in a flower is always equal.(e) If the sepals of a flower are joined together, its petals are also joined together.(f) If the petals of a flower are joined together, then the pistil is joined to the petal.
- There are three plants A, B and C. The flowers of plant A open their petals in bright light during the day but close them when it gets dark at night. On the other hand, the flowers of plant B open their petals at night but close them during the day when there is bright light. The leaves of plant C fold up and droop when touched with fingers or any other solid object.(a) Name the phenomenon shown by the flowers of (i) plant A, and (ii) plant B.(b) Name one flower each which behaves like the flower of (i) plant A, and (ii) plant B.(c) Name the phenomenon exhibited by the leaves of plant C.(d) Name a plant whose leaves behave like those of plant C.(e) Which plant/plants exhibit the phenomenon based on growth movements?
- (a) E is the gene for brown eye colour and e is the gene for blue eye colour. Which gene is (i) recessive, and (ii) dominant?(b) Both father and mother have the genes Ee in their cells. What colour are their eyes? (c)Which combination of genes in the zygote will produce children with blue eyes? (d)Which combinations of genes in the zygote will produce children with brown eyes?
- Which of the following may be used to obtain an F2 generation?(a) allowing flowers on a parent plant to be self-pollinated(b) allowing flowers on an F1 plant to be self-pollinated(c) cross-pollinating an F1 plant with a parent plant(d) cross-pollinating two parent plants
- The size of a red blood cell is $0.000007\ m$ and the size of a plant cell $0.00001275\ m$. Compare these two, which of the following is correct?A. A red blood cell is approximately $\frac{3}{4}$ of the plant cell in size.B. A red blood cell is approximately $\frac{1}{4}$ of the plant cell in size.C. A red blood cell is approximately half of the plant cell inn size.D. A red blood cell is approximately equal to the plant cell in size.
- A black mouse mates with a brown mouse, and all the offsprings are black.(a) Why are no brown offsprings produced? (b) If two of the black offsprings mate with each other what kind of offspring would you expect and in what proportions? Give reason for your answer.
- A bag contains 7 white and 12 red balls. One ball is drawn at random from the bag. Find the probability of getting (a) a red ball (b) a white ball.
- Name two plants in which one has joined sepals and the other has separate sepals.
- The process of breeding two different varieties of crop plants each having a desired characteristics, is known asselectionhybridizationcrossingintroduction
Kickstart Your Career
Get certified by completing the course
Get Started