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Genetics and Gene Expression

See attached file for full problem description.

Note: Please do not use other sources for your answer (Eg: Wikipedia) and please answer in full (Not simplified sentences), I need to be able to understand what you are explaining. When you carry out the working, please use punnett squares and diagrams. Question 2 is the most important question here, please take your time and consideration with this. Thank you.

Question 1.

In the Andalusian fowl, the allele for black feathers (B) is incompletely dominant to that for white feathers (b) and the phenotype of the heterozygote is described as blue. The texture of the feathers is controlled by a second gene locus, silky feathers (f) being recessive to normal (F).

What phenotypic ratio would be expected for the offspring? Show your working clearly. Please do the punnett square for a dihybrid cross and then work out the phenotypes.

Question 2.

Please note that this is the most important question, it must be accurate and answered in full, take your time answering this.

The table below shows the effect of two genes in providing resistance to powdery mildew disease in peach trees.

Note that the observed phenotypic ratio did not agree with the expected phenotypic ratio.

a) If plants with the genotypes TThh and ttHH were crossed, what proportion of their offspring would be expected to be fairly resistant to powdery mildew disease? (Show your working clearly).

***BONUS QUESTION: If plants with the genotypes Tthh and ttHH were crossed, what proportion of their offspring would be expected to be fairly resistant to powdery mildew disease? (Show your working clearly).
***NOTE: The previous example is not in the attachment; it is only in the plain text.

b) Proportion fairly resistant to powdery mildew:

Question 3.

This is a diagrammatic representation of the biochemical process of translation.

Here is a list of some of the molecules shown in the diagram:

(i) mRNA
(ii) nascent polypeptide chain
(iii) uncharged tRNA

What is molecule (iv) in full answer? I know it is an anti-codon, but what does the "u" stand for? (Note: the answer "anti-codon" is not sufficient here).

See attached file for full problem description.

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Solution Preview

Describe the control of gene expression.

Note: Please do not use other sources for your answer (Eg: Wikipedia) and please answer in full (Not simplified sentences), I need to be able to understand what you are explaining. When you carry out the working, please use punnett squares and diagrams. Question 2 is the most important question here, please take your time and consideration with this. Thank you.
Question 1.

In the Andalusian fowl, the allele for black feathers (B) is incompletely dominant to that for white feathers (b) and the phenotype of the heterozygote is described as blue. The texture of the feathers is controlled by a second gene locus, silky feathers (f) being recessive to normal (F).

What phenotypic ratio would be expected for the offspring? Show your working clearly. Please do the punnett square for a dihybrid cross and then work out the phenotypes.

Since each parent is BbFf (it's a dihybrid cross), the possible gametes for each parent are BF, Bf, bF, and bf. Those gametes are in bold in the first row and column of the Punnett square, and the possible offspring are in the cells. In the cell, I also put the phenotype that goes along with each genotype.

BF Bf bF bf
BF BBFF
black, normal BBFf
black, normal BbFF
blue, ...

Solution Summary

This solution answers the genetic questions addressing concepts of phenotypic ratios, crosses, genotypes, and translation.

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