Essay on Biology Chromosome

849 Words4 Pages
1.
2.
3. All of Allison’s eggs will carry the X chromosome and 50% of Allison’s egg cells will carry the recessive allele (hexa).
4.a. There is a 25% chance that Allison and Tim will have a baby boy who is heterozygous for Tay-Sachs.
b. No, the baby boy will not have Tay-Sachs he will be a carrier for the disease. The boy would only have the disease if he was homozygous recessive.

| X | Y | X | XX | XY | X | XX | XY |
1:2 1:2 | T | t | T | TT | Tt | t | Tt | tt |
1x1=1
2X2=4 1:4= 25%
5. a. Yes, there is a 50% chance that the young woman will develop FFI disease.
B.
| f | f | F | Ff | Ff | f | ff | ff | This Punnett square shows that there is a 50% chance that the young woman will have
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8. An allele can produce a protein in a very specific step by step manor. The whole process starts with transcription. Transcription starts in the nucleus. Transcription is the process of how RNA is created from a DNA template with the help of RNA polymerase. mRNA is a complimentary stand to the DNA template. This is a messenger to carry the information stored in the DNA in the nucleus out into the cytoplasm and to ribosomes on the ER. mRNA has to go through processing before it is able to pass through the membrane of the nucleus. The mRNA has a methylated cap added to the 5’ end and the poly-A tail is added to the 3’ end. Then there are certain sequences in the mRNA that are useless and are spliced out, these are called introns, the sequences of information that is important are called exons they are put together. On the mRNA each three bases in a row are called a codon. Each codon is specific to a certain amino acid. Translation occurs in the cytoplasm at the ribosomes, this is the process of how information from mRNA is used to synthesize a polypeptide. The codons on the mRNA have a matching complimentary anticodon on the tRNA molecules. A tRNA molecule is small and only can bind to one specific amino acid amino acid at one end and one specific mRNA codon at the other end. Protein folding is when the alpha helices and beta sheets fold on to itself to form a 3D shape. The dominant XPA allele is present all of this normally occurs in a human. All the
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