Predict the potential effect of a particular point mutation on the structure and function of a protein.
Name the three types of base substitution mutations and list the consequence of each type?
Both nonsense mutations and frameshift mutations can cause mutant proteins to be shorter than normal. Explain how the same general type of effect on protein structure is caused by these two different types of mutations.
What type of mutation would be caused if two bases are deleted from the original DNA strand? What would happen to the protein?
Define "mutation" and describe its potential consequences.
What is a missense mutation?A. a mutation whose effect is not yet known.B. a mutation that changes a codon that specifies an amino acid to one that terminates translation.C. a mutation that changes a codon to a synonymous codon.D. a mutation that alters the reading frame of the gene.E. a mutation that results in a different amino acid in a protein.
Define the following: a. Proband b. Penetrance c. Non-sense mutationd. Trisomy e. Homologous chromosomes
For the given sequence 5' - GGAGCUCGUUGUAUU - 3'A. Is this sequence RNA or DNA? How can you tell?B. Which amino acids are encoded, if the reading frame is as shown, starting from the correct end?C. What would be the effect on the amino acid sequence if the sequence were changed to 5' GGAGACUCGUUGUAUU -3'? Explain why the amino acid sequence changes.
When a chromosome has either a duplication or a deletion, the chance that the mutation will be harmful are a function of:A. its location, if it occurs in a germ-line cell, it will be more harmful than if it occurs in a somatic cell.B. its size, the larger the duplication or deletion, the greater the chance of harm.C. its position on the chromosome, if it occurs at the tip of a long arm, it is likely to be less harmful than if it occurs at the tip of a short arm.D. None of the other answer options is correct.E. its size, the smaller the duplication or deletion, the greater the chance of harm.
What type of mutation would be caused if three bases were deleted from the original DNA strand? Would this cause an amino acid to be lost?
Explain why deletion of a single nucleotide in a gene generally results in more severe defects in the polypeptide than a point mutation that changes a single nucleotide.
If a G position becomes depurinated, during the next DNA replication, that position will probably be filled with _____, if the damage is not repaired.A. AB. TC. CD. Nothing and cause a deletion
Explain how errors in DNA replication can cause mutations.
Which type of mutation usually has the largest effect on protein structure? Explain why.A. missenseB. silentC. frameshift
Compare the consequences of germline mutations to somatic mutations.
A protein-coding gene is diagrammed below, with 4 exons (blue boxes) and 3 introns. A researcher has isolated four different mutant alleles of this gene, designated A, B, C, and D. Each of the alleles has a different four-basepair insertion; their locations within the gene are shown by the red triangles in the figure. Which insertion - A, B, C, or D - is likely to have the biggest effect on protein function? Explain.
The sequence below is for a wild type gene whose mutation leads to a condition of defective iron transport called hemochromatosis. In hemochromatosis, the highlighted cysteine (Cys, C) residue is mutated to a tyrosine (Tyr, Y) residue. The coding strand of DNA is shown in the sequence as well as the protein sequence in single letter symbols. Which of the following is the most likely mutation at the DNA level?DNA : gataaccttggctgtaccccccggggaagagcagagatatacgtgccaggtggagcaccc+2fr: - I - - T - - L - - A - - V - - P - - P - - G - - E - - E - - Q - - R - - Y - - T - - C - - Q - - V - - E - - H - - P -A. UGU to UCUB. UGC to UUAC. UGC to UACD. TGC to TACE. TAC to TGC
Below is the active site of chymotrypsin. Which mutation would have a greater effect on protein function: replacing Asp102 with glutamine or glutamic acid? Why?
How might a mutation cause a change in protein function? Are there any instances when a mutation can result in no change to an organism?
Describe how a mutation can lead to large scale changers in the structure of an organism.
Mutations that inactivate metabolic pathways are called _____ mutations.A. morphologicalB. biochemicalC. lethalD. conditional
How do splice-site mutations differ from nonsense mutations?
Which of the following is the best example of a missense mutation?A. Ala-Gln-Cys-Asp-Leu → Ala-GlnB. Ala-Gln-Cys-Asp-Leu → Ala-Gln-Cys-His-LeuC. Ala-Gln-Cys-Asp-Leu → Ala-Gln-Cys-His-LysD. Ala-Gln-Cys-Asp-Leu → Ala-Gln-Cys-Asp-Leu
Which of the following mutations, resulting in an error in the mRNA shortly after the start codon is likely to have the most serious effects on the polypeptide product?A. Deletion of a single codonB. Deletion of a single nucleotideC. Insertion of three nucleotidesD. Substitution of a single nucleotide
_____ radiation excites atoms to a higher energy state within molecules such as DNA, which leads to the formation of pyrimidine dimers.A. ParticleB. IonizingC. UltravioletD. InfraredE. Gamma
Describe four types of point mutations:transitions, transversions, deletions, and additions.
Explain why a point mutation in a gene may or may not cause a change in the primary sequence of a protein.
Why are point mutations in the third nucleotide of a codon less likely to cause the production of a non-functional protein? Is this also true for frameshift mutations? Why or why not?
In the strand below, a mutation occurs at the 8th nucleotide. The nucleotide is deleted. Transcribe then translate the strand to see what happens to the protein.original : 3' - TAG CTG AAT TGC AGT GCC ATC GATG - 5'mutated : 3' - TAG CTG ATT GCA TTG CCA TTG ATG - 5'
Since the two strands of the DNA molecule are complementary, for any given gene:A. The RNA polymerase can bind to either strand.B. Only one strand actually carries the genetic code for a particular gene.C. Each gene possesses an exact replica that can be used should a mutation occur.D. A gene transcribed in the 5' to 3' direction on one strand can be transcribed in the 3' to 5' direction on the other strand.
A random mutation event has lead to the deletion of a nucleotide within the translated region of a particular gene. How would the resulting protein be different from the unmutated for of the gene? Explain your answers in 2-3 sentences.
A single base substitution is LEAST likely to be deleterious (dangerous) when the change results in _____.A. the replacement of a codon specifying a hydrophilic amino acid with a codon that specifies a hydrophobic amino acid.B. the replacement of a codon specifying an amino acid with a stop codon.C. the substitution of an amino acid in the active site of the protein.D. the replacement of a codon specifying an amino acid with a different codon that specifies the same amino acid.
List four genes whose mutations are associated with cancer. For each gene briefly describe: 1) Their normal functions, including the related signaling pathways and cell behaviors; 2) Their oncogenic roles: the effects of their mutants to cell behaviors in cancers. (Tow genes whose coding proteins are closely associated with each other will only be counted as One.)
Mutations due to small insertions and deletions can arise spontaneously during DNA replication because:A. a purine in the template DNA strand mispairs with an incoming purine.B. guanine is depurinated.C. a purine in the template DNA strand mispairs with an incoming pyrimidine.D. strand slippage occursE. a tautomeric shift takes place so that cytosine in the new DNA strand is able to pair with an adenine in the template strand.
Which of the following statements are true about mutations at the 7q11.23?A. Some individuals with autism have extra copies of this genetic region.B. This genetic region has a big impact on social ability.C. Individuals who have a deletion at this genetic region have Williams-Beuren syndrome, a disease that makes people especially social and outgoing.D. This genetic region has been identified in all the autism children studied.
Deamination of 5-methylcytosine _____.A. converts that base to a uracilB. converts that base to a thymineC. happens mostly in RNAD. is an epigenetic mark
The mRNA sequence belowcodes for part of a protein. The reading frame for the translation of this mRNA starts with the first three nucleotides as shown.AUG-CGA-UCG-GAA-CCA-CGU-GAU-AAG-CAU Met Arg Ser Glu Pro Arg Asp Lys HisA. What would be the consequence of the insertion of an A after the third nucleotide of the sequence?B. What would be the consequence of the deletion of the C at the beginning of this sequence?
A ______ mutation is one that leads to premature insertion of a stop codon within an ORF.
UV radiation is a useful tool in producing mutants of microbial culturesA. TrueB. False
UV light damages DNA. What bases in the DNA specifically does it damage? What chemical changes that occur, or how does the physical structure of the DNA change? How do these changes kill cells?