In a certain plant, smooth edge leaves(S) are dominant over roughed edge leaves (s)Two plants heterozygous for smooth edges are crossed. What proportion of the offspring are expected to be heterozygous for smooth edges leaves
a)1/4
b)1/2
c)3/4
d 1
Use Punnett square to answer your question
http://carrier.pbworks.com/f/punnett.jpg
In a certain plant, smooth edge leaves(S) are dominant over roughed edge leaves (s)Two plants heterozygous for smooth edges are crossed. What proportion of the offspring are expected to be heterozygous for smooth edges leaves
To determine the proportion of offspring that are expected to be heterozygous for smooth edge leaves, you can use Punnett squares.
Let's represent the dominant smooth edge allele as 'S' and the recessive roughed edge allele as 's'. Since both plants are heterozygous (meaning they carry one dominant and one recessive allele), their genotypes can be represented as follows:
Plant 1: Ss
Plant 2: Ss
To create a Punnett square, you'll cross each allele from one parent with the alleles from the other parent. In this case, you'll cross each 'S' allele from Plant 1 with both alleles from Plant 2 (Ss), resulting in the following Punnett square:
```
| S s
-------- |--------------
S | SS sS
s | sS ss
```
From the Punnett square, you can see that there are 2 out of 4 possible genotypes that have the dominant smooth edge allele 'S'. Therefore, the proportion of offspring expected to be heterozygous for smooth edge leaves (carrying one 'S' allele and one 's' allele) is 2/4 or 1/2.
Therefore, the correct answer is b) 1/2.
To determine the proportion of offspring that are expected to be heterozygous for smooth-edged leaves, we need to use a Punnett square.
Let's represent the alleles for smooth edges as "S" (dominant) and rough edges as "s" (recessive). Since both parent plants are heterozygous for smooth edges, their genotypes will be "Ss".
To construct the Punnett square, we will take one parent's alleles (either "S" or "s") and place them along the top of the square, and the other parent's alleles along the side.
S s
________________
S | SS Ss
s | Ss ss
The four boxes in the Punnett square represent the possible combinations of alleles that the offspring can inherit. From this, we can see that 2 out of 4 boxes (Ss, Ss) have at least one "S" allele for smooth edges.
Therefore, the expected proportion of offspring that are heterozygous for smooth edges is 2/4, which simplifies to 1/2.
Hence, the correct answer is b) 1/2.