why do scientists call a substitution a point mutation

Protein synthesis is the process used by the body to make proteins. The first step of protein synthesis is called Transcription. It occurs in the nucleus. During transcription, mRNA transcribes (copies) DNA. DNA is unzipped and the mRNA strand copies a strand of DNA. Once it does this, mRNA leaves the nucleus and goes into the cytoplasm. mRNA will then attach itself to a ribosome. The strand of mRNA is then read in order to make protein. They are read 3 bases at a time. These bases are called codons. tRNA is the fetching puppy. It brings the amino acids to the ribosome to help make the protein.
1 Describe how the DNA code is translated into messenger RNA. DNA is translated into messenger RNA through transcription and translation. DNA is split through transcription and then it is translated to match into RNA. 2 How is the RNA molecule a БscriptБ for the protein production process? RNA is a script for the protein production process because they set the RNA up to translate into a protein. 3 What is the function of hemoglobin in the body?


Hemoglobin functions in the body by giving oxygen to the blood. Conclusion 3. 2. 2 4 Describe (in words) the effect of the mutation. If only one base is affected, it is called a point mutation. This results from substitution. When segments are added or deleted, this is called a frame shift mutation. 5 Was the mutational effect greater in a substitution or a deletion? Explain your answer clearly. A mutational effect is greater in deletion because it affects the strand as a whole. However, with substitution, only one codon is affected. 6 Why do you think scientists call a substitution a Бpoint mutationБ? Why do you think scientists call a deletion (or an insertion) a Бframeshift mutationБ? A point mutation comes from substitution because it is only changed one codon.


However, when codons are deleted or inserted, it changes the bases as a whole, called a frame shift mutation. 7 Note the two transcribed and translated DNA strips below. The two strips are identical except for a point mutation, where the 15th base was changed from a G to a T. Fill in the corresponding mRNA, tRNA, and letter in the blanks below for the mutated DNA strip. In the space below, explain how this point mutation changes the protein. Point mutation changes a protein because the codon will be changed, resulting in a different amino acid. 8 What is the difference between normal and sickle hemoglobin at the DNA, RNA, and protein (amino acid) level? Normal and sickle hemoglobin are different at the DNA, RNA, and amino acid levels because with sickle cell, there is a change in the codon, causing different bases as well as different amino acids.


This would result in an altered hemoglobin production. 9 What type of mutation is the sickle hemoglobin mutation? Explain. A sickle hemoglobin mutation is a substitution because it is simply an altered form of hemoglobin S. If it was deletion, the body would not make hemoglobin at all. 10 Glutamic acid (Glu) and valine (Val) are two amino acids with different molecular structures. (Glutamic acid is a strongly hydrophilic molecule, and valine is a strongly hydrophobic molecule. This is something you will learn more about in the next activity). Why do you think switching the hemoglobin geneБs sixth amino acid from glutamic acid to valine would affect the hemoglobin protein? Hemoglobin would be affected by swapping these amino acids because the protein would end up being hydrophobic, meaning that it rejects water. From this, we can conclude that regular hemoglobin needs to be hydrophilic.

  • Views: 21

why does a single dna sequence encode
why does dna synthesis require an rna primer
why do we say the codon chart is universal
why do we have d n a
why is thymine replaced by uracil in rna
why is the sequence of bases in dna important
why is accurate initiation of protein synthesis important