1.
If transcription is like copying out a recipe, translation is like...
Correct Answer
A. Actually baking a cake
Explanation
Transcription involves copying out a recipe, which is a written text. Similarly, translation involves actually baking a cake, which is the process of transforming the written text of a recipe into a tangible and edible cake. Both transcription and translation require taking the original text and producing a new form based on its content and instructions. Therefore, the analogy between transcription and copying out a recipe, and translation and actually baking a cake, is appropriate.
2.
If a sequence of DNA codes AAA TCG GGC GTA CCT
What will be the sequence of the corresponding mRNA?
Type your answer with a space between each codon.
Correct Answer
UUU AGC CCG CAU GGA, uuu agc ccg cau gga, UUUAGCCCGCAUGGA
Explanation
The sequence of DNA codes AAA TCG GGC GTA CCT will be transcribed into the sequence of mRNA UUU AGC CCG CAU GGA. The DNA codes are converted to mRNA by replacing each DNA base with its complementary RNA base (A with U, T with A, G with C, and C with G). Therefore, the sequence UUU AGC CCG CAU GGA is the correct mRNA sequence corresponding to the given DNA sequence.
3.
The normal DNA sequence for a portion of the gene for the hormone insulin is:
TGT TTA TTC AAG GCC CGG ATA
What is the normal amino acid sequence of this portion of the insulin polypeptide?
*Use three-letter abbreviations for amino acid names, separated by a space
Correct Answer
Thr Asn Lys Phe Arg Ala Tyr, thr asn lys phe arg ala tyr, thrasnlyspheargalatyr,ThrAsnLysPheArgAlaTyr
Explanation
The normal amino acid sequence for the given DNA sequence is Thr Asn Lys Phe Arg Ala Tyr. This is determined by using the genetic code, which translates the DNA sequence into specific amino acids. Each set of three DNA bases, called a codon, corresponds to a specific amino acid. By matching each codon in the DNA sequence to its corresponding amino acid, we can determine the amino acid sequence of the insulin polypeptide.
4.
Which of these is a mutagen? Check all choices that apply.
Correct Answer(s)
A. UV Radiation
C. Lead, Mercury and other metals
D. X Rays
Explanation
Mutagens are agents that can cause changes in the DNA sequence, leading to mutations. UV radiation is a known mutagen as it can cause damage to the DNA structure. Lead, mercury, and other metals can also act as mutagens by interfering with DNA replication or causing DNA damage. X-rays, which are a form of ionizing radiation, can cause mutations by directly damaging the DNA. Fiberglass dust and vitamin C are not known to be mutagens.
5.
If an mRNA has the following sequence:
ACA AUU CGG UAU GAG UUU AGC
What is the sequence of amino acids in the resulting polypeptide?
Correct Answer
B. Thr Ile Arg Tyr Glu pHe Ser
Explanation
The given mRNA sequence "ACA AUU CGG UAU GAG UUU AGC" corresponds to the codons "ACA-AUU-CGG-UAU-GAG-UUU-AGC". Each codon codes for a specific amino acid. Therefore, the sequence of amino acids in the resulting polypeptide is "Thr-Ile-Arg-Tyr-Glu-Phe-Ser".
6.
For the same sequence as in the previous question, imagine that a mutation occurs so that the codon UAU mutates to UAA. What type of mutation occurs?
ACA AUU CGG UAU GAG UUU AGC
Correct Answer
C. Chain Termination
Explanation
A mutation occurs when the codon UAU mutates to UAA. This type of mutation is known as a chain termination mutation. In this case, the mutation causes the codon to change from encoding an amino acid to a stop signal, leading to premature termination of the protein synthesis.
7.
When an aneuploidy occurs, there must have been an error during _______________.
Correct Answer
mitosis, meiosis, mitosis or meiosis, Mitosis, Meiosis, cell division, Cell Division
Explanation
Aneuploidy is a condition where there is an abnormal number of chromosomes in a cell. This can occur due to errors during either mitosis or meiosis, both of which are types of cell division. During mitosis, a cell divides into two identical daughter cells, while during meiosis, a cell divides into four non-identical daughter cells. Therefore, an error during either mitosis or meiosis can lead to aneuploidy. The answer options provided, including mitosis, meiosis, mitosis or meiosis, Mitosis, Meiosis, cell division, and Cell Division, all correctly identify the possible sources of error for aneuploidy.
8.
Occasionally, after fertilization, an embryo acquires an extra copy of a single chromosome. This happens, for example, in Down Syndrome (chromosome 21). What do we call this type of situation?
Correct Answer
B. Trisomy
Explanation
Trisomy is the correct answer because it refers to the situation where an embryo acquires an extra copy of a single chromosome. This condition is commonly observed in Down Syndrome, where there is an extra copy of chromosome 21. Trisomy is characterized by the presence of three copies of a particular chromosome instead of the usual two.
9.
In the DNA sequence shown, the final order of amino acids after a normal transcription and translation is shown in red above the DNA: Glu Pro Gln Leu
What would need to happen in order for the sequence shown beneath the DNA to be the result?
Correct Answer
B. Deletion of a Guanine-Cytosine base pair
Explanation
A deletion of a Guanine-Cytosine base pair would cause a frameshift mutation in the DNA sequence. This means that the reading frame of the sequence would be shifted, leading to a different amino acid sequence being produced during transcription and translation. In this case, the deletion would cause the Glu codon to be lost, resulting in a different amino acid being inserted in its place. This change would ultimately lead to a different final order of amino acids, matching the sequence shown beneath the DNA.
10.
Because most amino acids have more than one codon, we say that the genetic code is ________
Correct Answer
redundant, Redundant, redundancy
Explanation
The genetic code is considered redundant because most amino acids can be coded for by more than one codon. This redundancy ensures that even if there is a change or mutation in the DNA sequence, it is less likely to result in a change in the amino acid sequence. This redundancy provides a level of error correction and allows for greater flexibility in the genetic code.
11.
If the end of a gene has the DNA sequence: CCT GTG ACC AAA ACT
and the last codon, ACT, mutates to ACC, what type of mutation will result?
Correct Answer
C. Nonsense Mutation
Explanation
A nonsense mutation occurs when a point mutation in the DNA sequence leads to the formation of a premature stop codon. In this case, the last codon "ACT" mutates to "ACC", which codes for the amino acid threonine. Since this mutation does not result in a premature stop codon, it does not cause a nonsense mutation. Therefore, the correct answer is not Nonsense Mutation.
12.
For the same sequence of DNA, CCT GTG ACC AAA ACT
what type of mutation would occur if a Thymine was inserted between Adenine and Cytosine in the triplet ACC?
Correct Answer
B. Chain Termination mutation
Explanation
If a Thymine is inserted between Adenine and Cytosine in the triplet ACC, it would result in a chain termination mutation. This type of mutation causes the premature termination of protein synthesis during translation, leading to the production of a truncated protein or no protein at all. This occurs because the insertion of an extra base disrupts the reading frame of the DNA sequence, causing a shift in the codons and ultimately leading to the premature stop codon.
13.
For the same DNA sequence, CCT GTG ACC AAA ACT
What type of mutation would result if the second Guanine in the triplet GTG was mutated to an Adenine?
Correct Answer
A. Silent mutation
Explanation
A silent mutation is a type of mutation that does not result in any change in the amino acid sequence of a protein. In this case, if the second Guanine in the triplet GTG is mutated to an Adenine, it would still code for the same amino acid (Valine), and therefore, no change in the protein sequence would occur. This is why it is classified as a silent mutation.
14.
Which of the following will happen to an mRNA primary transcript before it is translated?
Correct Answer(s)
B. Excision of introns
D. Ligation of exons
Explanation
Before an mRNA primary transcript is translated, it undergoes a process called RNA splicing. During this process, the introns (non-coding regions) are removed from the transcript, while the exons (coding regions) are joined together. This excision of introns and ligation of exons is essential for generating a mature mRNA molecule that can be translated into a protein.
15.
For the sentence "Two men sat and had hot tea", the error that best represents a Silent mutation is
Correct Answer
A. A
Explanation
Silent mutations are genetic mutations that do not result in any change to the amino acid sequence of a protein. In the given sentence, the error that best represents a silent mutation is option A, which states "Two men sit and had hot tea". This error changes the verb "sat" to "sit", but since both words have the same meaning and the sentence still makes sense, it does not affect the overall meaning or structure of the sentence. Therefore, this error can be considered a silent mutation.
16.
For the sentence, "Two men sat and had hot tea", the error that best represents a Deletion Frameshift mutation is...
Correct Answer
E. E
Explanation
The error that best represents a Deletion Frameshift mutation is option E. In this sentence, the word "and" is missing between "sat" and "had". This deletion of the word "and" causes a frameshift in the sentence structure, altering its meaning. A frameshift mutation occurs when a nucleotide is added or deleted, shifting the reading frame of the genetic code. Similarly, the deletion of the word "and" in the sentence causes a shift in the sentence structure, resulting in a frameshift mutation.
17.
For the sentence, "Two men sat and had hot tea", the error that best represents a Chain Termination mutation is...
Correct Answer
C. C
Explanation
The error that best represents a Chain Termination mutation in the given sentence is option C. A Chain Termination mutation occurs when a sentence is abruptly ended without completing the intended thought. In this case, the sentence "Two men sat and had hot tea" is a complete sentence, and there is no indication of any abrupt termination or incomplete thought. Therefore, option C is the correct answer.
18.
For the sentence, "Two men sat and had hot tea", the error that best represents a Missense mutation is...
Correct Answer
B. B
19.
For the sentence, "Two men sat and had hot tea", the error that best represents a Insertion Frameshift mutation is...
Correct Answer
D. D