IGCSE Biology Paper-4: Specimen Questions with Answers 223 - 224 of 279

Passage

Flowers from three red-flowered plants, A, B and C, of the same species were self-pollinated.

Question 223 (3 of 5 Based on Passage)

Write in Short

Short Answer▾

Seeds were collected from plants A, B and C.

The seeds were germinated separately and could grow and produce flowers. The color of these flowers is shown in the table.

The Seeds Were Germinated Separately and Could Grow and Produce Flowers. The Color of These Flowers is Shown in the Table
seeds from plant

color of flowers grown from the seeds

A

all red

B

some red and some white

C

some red and some white

State the recessive allele for flower color.

Explanation

Rr Alleles for White Color

Recessive factor or allele: The factor of an allelic or allelomorphic pair which is unable to express its effect in the presence of its contrasting factor in heterozygous state is called recessive factor or allele. A recessive allele is represented by small letter. e. g. r in Rr. The effect of recessive factor becomes known only when it is present in the pure or homozygous state, e. g. rr in white color plant.

Question 224 (4 of 5 Based on Passage)

Write in Short

Short Answer▾

Complete the genetic diagram to explain how two red-flowered plants identical to plant B could produce both red-flowered and white flowered plants. Use the symbols R to represent the dominant allele and r to represent the recessive allele.

Parent 1 and 2

Explanation

Parent 1 and 2