Download Gene and Chromosome Mutation Worksheet and more Exercises Bioinformatics in PDF only on Docsity!
(reference pgs. 239-240 in Modern Biology textbook)
Name________________________________________ Date_________________ Per________
Look at the diagrams, then answer the questions.
Gene Mutations affect a single gene by changing its base sequence, resulting in an incorrect, or nonfunctional, protein being made.
(a) A SUBSTITUTION mutation, occurs where one nucleotide base is replaced by another. These are often called “ point mutations” , because a single base is changed, at one point in the gene.
SOMETIMES, these base (A,T,C,G) substitutions lead to “ Missense ” or “ Nonsense ” mutations:
(b) Other types of mutations ( insertions or deletions of nucleotide bases) cause FRAMESHIFTS :
…and sometimes, because there is more than one codon for each amino acid, these mutations can be SILENT :
(reference pgs. 239-240 in Modern Biology textbook)
- There are several types of gene mutations. (a) List two. (b) What do they have in common? (c) How are they different?
- A geneticist found that a particular DNA mutation had no effect on the protein coded by a gene. What kind of mutation was this? Why?
- (a) Name one amino acid that has more than one codon. (b) Name an amino acid that has only one codon
- Look at the following sequence: THE FAT CAT ATE THE RAT. (a) Delete the first H and regroup the letters in groups of three (write out the new groups of three). (b) Does the sentence still make sense? (c) What type of mutation is this?
- You have a DNA sequence that codes for a protein and is 105 nucleotides long. A frameshift mutation occurs at the 85th^ base in the nucleotide sequence. How many amino acids will be still be correct in this protein?
- Given the following three mRNA sequences, TWO code for the same protein. Which two?
#1. AGU UUA GCA ACG AGA UCA
#2 UCG CUA GCG ACC AGU UCA
#3 AGC CUC GCC ACU CGU AGU
- (a) What kind of gene mutation is more likely to result in a nonfunctional protein, a frameshift (resulting from an insertion or deletion) or a substitution point mutation? (b) Why?
(reference pgs. 239-240 in Modern Biology textbook)
- Match the chromosome mutation with its description.
____1. Translocation
____2. Inversion
____3. Deletion
____4. Duplication
A). A portion of the chromosome is missing or deleted. Known disorders in humans include Wolf-Hirschhorn syndrome, which is caused by partial deletion of the short arm of chromosome 4; Cri du chat syndrome is due to a partial deletion of the short arm of chromosome number 5.
B). A portion of the chromosome is duplicated, resulting in extra genetic material. Known human disorders include Charcot-Marie-Tooth disease type 1A which may be caused by duplication of the gene encoding peripheral myelin protein 22 (PMP22) on chromosome 17.
C). When a portion of one chromosome is transferred to another chromosome. Sometimes, parts of different chromosomes switch places (reciprocal exchange).
D). A portion of the chromosome has broken off, turned upside down and reattached, therefore the genetic material is backward.
- Why are chromosome mutations potentially more serious than gene mutations?
mRNA Codon decoder grid:
