Question

Help I'm very confused about this.

Hemoglobin a protein found in red blood cells, carries oxygen. Abnormal hemoglobin cannot carry as much oxygen as normal hemoglobin. The sequences below show sections of the DNA sequence that produce both the normal and abnormal types of hemoglobin.

Normal DNA sequence: GGA CTC CTC

Abnormal DNA sequence: GGA CAC CTC

Write the messenger RNA sequences that would be produced from the normal and abnormal DNA sequences shown above.
Using the codon table, write the aminoacid sequences produced from the DNA for normal and abnormal hemoglobin
Beginning with DNA, describe the process that forms proteins such as hemoglobin.

Answer 1

Answer/ Explanation:

1. Messenger RNAs are produced as a result of transcription of a DNA sequence. messenger RNAs are generated from a DNA template through complementary base pairing. That means, that A (adenine) always pairs with T (thymine), and C (cytosine) always pairs with G (guanine). However, RNA do not use, T, instead they use U (uracil) in its place.

Normal DNA sequence: GGA CTC CTC

Normal RNA sequence: CCU GAG GAG

Abnormal DNA sequence: GGA CAC CTC

Abnormal RNA sequence: CCU GUG GAG

2. The mRNA sequence is then used to assemble a sequence of amino acids through the process of translation. This also occurs through complementary base pairing by specialized molecules called tRNAs, which each hold a particular amino acid to add to the chain. This is done by matching up codons to the corresponding amino acid

Normal RNA sequence: CCU GAG GAG

Normal amino acid sequence: Proline - Glutamic acid - Glutamic acid

Abnormal RNA sequence: CCU GUG GAG

Abnormal amino acid sequence: Proline - Valine - Glutamic acid

As you can see, the abnormal DNA sequence has lead to the production of an amino acid sequence with one different amino acid.

3. DNA is copied into an RNA message (mRNA or messenger RNA) through the process of transcription. This is done through complementary base pairing using one DNA strand as a template. Transcription occurs in the nucleus. After completion and processing, the mRNA then leaves the nucleus and enters the cytoplasm. At specialized organelles called the ribosomes found in the cytoplasm, the mRNA is then translated into an amino acid sequence.

The mRNA sequence can be divided up into codons, which are complementary to anticodons found on special RNAs called tRNAs. These tRNAs are bound to a particular amino acid, so when an mRNA codon is bound by a tRNA possessing the complementary anticodon, the amino acid is added in a chain. The sequence of this chain is determined by the sequence of amino acids, which are linked together via peptide bonds.

After the amino acid chain (also called a polypeptide chain) has been made, it adopts its final structure through progressive folding and potential incorporation of functional groups (such as iron in hemoglobin).