a. How do alterations during replication cause mutations?
Alterations in DNA cause a difference in the nucleotide chain which can cause a difference in the sequence of nucleotides in mRNA. Therefore, these changes can cause different amino acids to be brought to the ribosome which can create different proteins in the cell.
b. How do insertions cause mutations?
Insertions cause too many nucleotides in a sequence to be read because there's an incorrect amount of nucleotides. Because the nucleotides are incorrectly grouped, a frameshift mutation occurs and the incorrect instructions for the assembly of a protein are created.
c. How do deletions cause mutaions?
Deletions cause too little nucleotides in a sequence to be read because there's an incorrect amount of nucleotides. Because the nucleotides are incorrectly grouped, a frameshift mutation occurs and the incorrect instructions for the assembly of a protein are created.
d. How do substitutions cause mutations?
During a substitution a nucleotide is swapped with another nucleotide causing a change in the sequence of the nucleotide chain. These changes can code for the wrong amino acid which can cause a change in the proteins. For example, in sickle-cell anemia thymine is swapped with adenine causing valine to be created instead of glutamic acid. This change causes the shape of red blood cells to be distorted, causing anemia and circulatory problems.
e. How do mutagenic factors that can alter DNA cause mutations?
Many types of rays can ionize molecules causing a change in the structure of some the nucleotides nitrogen containing bases with their different kinds of energy charged particles. This will lead to a misread of genetic informatoin during transcription which can effect the outcome of a protein. Also, other agents such as chemicals can react directly with DNA changing its structure.
f. How does high energy radiation (x-rays and ultraviolet) cause mutations?
High energy radiation comes in the form of ionizing radiation. This means that energetic particles or waves have the potential to alter a molecule through radioctive interactions. The energy contained in the photons of such is mutagenic to the point if it is absorbed in large doses, becuase of the amount of energy being recieved.
g. How do chemicals cause mutations?
Some chemicals act as base analogs and get inserted into the DNA strand during replication in place of the substrates causing a great change in a nucleotide sequence. Also, some chemicals work indirectly by causing the cells to synthesize chemicals that have the direct mutagenic effect on the DNA of an organism. When this occurs the chemicals react with DNA to change the structure of a molecule when it is being replicated.
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