Unit 3 Target 4: Translation
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Which of the following mRNA sequences codes for valine (Val), glutamic acid (Glu), and serine (Ser), respectively?
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GUA-GCC-AGU
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GUA-GGG-AGC
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GUG-GAC-GGU
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GUG-GAG-AGC
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This quiz, titled 'Unit 3 Target 4: Translation', assesses understanding of mRNA sequences and their role in protein synthesis. It explores mutations, translation processes, and amino acid coding, crucial for students learning advanced biology.
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- 2.
The mRNA sequence ACU codes for the amino acid Thr. A mutation occurs, and the resulting mRNA sequence is AUU. What amino aci will replace Thr?
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Val
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Met
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Ile
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Ala
Correct Answer
A. IleExplanation
The original mRNA sequence ACU codes for the amino acid Thr. However, due to a mutation, the sequence changes to AUU. AUU codes for the amino acid Ile, which means that Ile will replace Thr in the resulting protein.Rate this question:
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- 3.
Persons A and B have similar mRNA sequences with the exception of 1 nucleotide. Person A: AUGGUUACUAAGGGCUGA Person B: AUGGUUACUGAGGGCUGAUse the genetic code chart to determine how this difference affects the sequence of amino acids in the resulting protein.
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Lys in Person A is replaced with Glu in Person B.
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Phe in Person A is replaced with Leu in Person B.
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Persons A and B have identical amino acid sequences.
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A stop codon is generated in Person B and not in Person A.
Correct Answer
A. Lys in Person A is replaced with Glu in Person B.Explanation
The difference in the mRNA sequence between Person A and Person B leads to a change in the corresponding amino acid. In Person A, the codon AUG codes for the amino acid Lysine (Lys), while in Person B, the codon AUG codes for the amino acid Glutamic acid (Glu). This substitution of Lys with Glu is caused by the change in the nucleotide sequence of the mRNA.Rate this question:
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- 4.
Refer to the illustration above. What is the portion of the protein molecule coded for by a piece of mRNA with the sequence CUCAAGUGCUUC?
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Ser—Tyr—Arg—Gly
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Val—Asp—Pro—His
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Leu—Lys—Cys—Phe
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Pro—Glu—Leu—Val
Correct Answer
A. Leu—Lys—Cys—PheExplanation
The given mRNA sequence is CUCAAGUGCUUC. Each set of three nucleotides in mRNA, called a codon, codes for a specific amino acid. By referring to the genetic code chart, we can determine the amino acids coded for by each codon. In this case, the codons are CUC, AAG, UGC, and UUC, which correspond to the amino acids Leucine (Leu), Lysine (Lys), Cysteine (Cys), and Phenylalanine (Phe) respectively. Therefore, the portion of the protein molecule coded for by this mRNA sequence is Leu—Lys—Cys—Phe.Rate this question:
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- 5.
What happens during the process of translation?
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Messenger RNA is made from DNA.
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The cell uses information from messenger RNA to produce proteins.
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Transfer RNA is made from messenger RNA.
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Copies of DNA molecules are made.
Correct Answer
A. The cell uses information from messenger RNA to produce proteins.Explanation
During the process of translation, the cell utilizes the information encoded in messenger RNA (mRNA) to synthesize proteins. mRNA is transcribed from DNA in the nucleus and then transported to the ribosomes in the cytoplasm. Ribosomes read the mRNA sequence and use it as a template to assemble amino acids in the correct order, forming a polypeptide chain. This process, known as translation, is essential for protein synthesis and is a crucial step in gene expression.Rate this question:
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- 6.
During translation, the type of amino acid that is added to the growing polypeptide depends on the
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Codon on the tRNA only.
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Anticodon on the tRNA to which the amino acid is attached only.
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Codon on the mRNA and the anticodon on the tRNA to which the amino acid is attached.
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Anticodon on the mRNA only.
Correct Answer
A. Codon on the mRNA and the anticodon on the tRNA to which the amino acid is attached.Explanation
During translation, the type of amino acid that is added to the growing polypeptide depends on both the codon on the mRNA and the anticodon on the tRNA to which the amino acid is attached. The codon on the mRNA determines the specific amino acid that needs to be added, while the anticodon on the tRNA ensures that the correct tRNA molecule carrying the corresponding amino acid is brought to the ribosome. This interaction between the codon and anticodon ensures that the correct sequence of amino acids is added to the growing polypeptide chain.Rate this question:
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- 7.
Where does translation occur?
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Nucleus
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Nucleolus
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Cytoplasm
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Ribosome
Correct Answer
A. RibosomeExplanation
Translation occurs in the ribosome. The ribosome is responsible for the synthesis of proteins by decoding the information contained in mRNA molecules. It acts as a molecular machine that reads the mRNA sequence and assembles the corresponding amino acids into a polypeptide chain. This process occurs in the cytoplasm of the cell. The nucleus contains the DNA, which serves as the template for mRNA synthesis, but translation itself occurs outside the nucleus in the ribosome. The nucleolus is involved in the production of ribosomes, but not directly in translation.Rate this question:
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- 8.
The 3 base sequence found on a tRNA molecule is called a ______.
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Codon
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Anticodon
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Amino acid
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Polypeptide
Correct Answer
A. AnticodonExplanation
The 3 base sequence found on a tRNA molecule is called an anticodon. The anticodon is complementary to the codon on the mRNA molecule during translation. It helps in the recognition and binding of the correct amino acid to the tRNA molecule, ensuring that the correct amino acid is added to the growing polypeptide chain. Therefore, the anticodon plays a crucial role in protein synthesis.Rate this question:
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- 9.
Which of the following is a STOP codon?
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UCA
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UGG
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UAA
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All of the above
Correct Answer
A. UAAExplanation
UAA is a STOP codon because it signals the end of protein synthesis during translation. When UAA is encountered by the ribosome, it does not code for any amino acid, but instead acts as a signal for the ribosome to stop translating the mRNA and release the newly synthesized protein. This termination codon is one of the three stop codons, along with UAG and UGA, that are responsible for terminating protein synthesis.Rate this question:
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- 10.
How many codons are needed to specify three amino acids?
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3
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6
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9
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12
Correct Answer
A. 3Explanation
In the genetic code, each amino acid is specified by a sequence of three nucleotides called a codon. Therefore, to specify three amino acids, three codons are needed. Each codon codes for a specific amino acid, and by combining multiple codons, the genetic code can create a sequence of amino acids to form a protein.Rate this question:
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- 11.
Why is it possible for an amino acid to be specified by more than one kind of codon?
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Some codons have the same sequence of nucleotides.
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The codon AUG codes for the amino acie methionine and serves as the "start" codon for protein synthesis.
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Some codons do not specify an amino acid.
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There are 64 different kinds of codons but only 20 amino acids.
Correct Answer
A. There are 64 different kinds of codons but only 20 amino acids.Explanation
There are more codons than there are amino acids, so it is possible for an amino acid to be specified by more than one kind of codon.Rate this question:
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.png "Refer to the illustration above. What is the portion of the protein molecule coded for by a piece of mRNA with the sequence CUCAAGUGCUUC?")
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Mar 20, 2023Quiz Edited by
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Oct 22, 2014Quiz Created by
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