<u>Answers:</u>
8. <em>Option C</em> codominance.
9. <em>Option D </em>all with yellow and red stripes.
10. <em>Option B </em>An allele is a variant of a gene.
11..<em> Option A</em> A gene is a specific segment of DNA on a chromosome.
12. <em>Option A</em> The blue allele is dominant to the yellow allele.
<u>Explanation :</u>
1. When the pair of alleles of a given gene fully express themselves in a heterozygous condition and the phenotype corresponding to each of the alleles is visible in the progeny, this is known as<em> codominanc</em>e.
Since the progeny has both red and yellow stripes the given situation is a case of <em>codominance</em>.
2. According to the question, the following cross is made:
Red stripes X yellow stripes
RR X YY-----> RY RY RY RY
Since the alleles are <em>codominant</em>, all the progenies will have <em>yellow and red stripes. </em>
3. <em>Alleles</em> are defined as the<em> alternative forms</em> of a given gene which are found on the same position on the chromosome. A given gene can have two or more alleles.
Thus,<em> an allele is a variant of a gene.</em>
4. A chromosome is a thread like structure found in the nucleus of all eukaryotic cells and it is made up of deoxyribonucleic acid (<em>DNA</em>).
The functional segment of the DNA on the chromosome which codes for a functional molecule is known as the <em>gene</em>.
5.
- A <em>dominant</em> allele is the one which expresses itself and thus dictates the phenotype of the individual in both homozygous and heterozygous condition.
- A recessive allele is the one which only expresses itself in the absence of dominant allele, that is in homozygous condition.
On crossing true breeding yellow and blue flowers we get the following results :
YY X BB----> YB YB YB YB
Since,<em> in the heterozygotes YB the phenotype is blue color this means that allele for blue color is dominant over yellow color.</em>
