Bio Test 3 (Part 1)
(139).webp "Bio Test 3 (Part 1) - Quiz")
Bio test part 1 of 5.55 question test.
- 1.
The significance of Fred Griffith's experiment in which he used two strains of Streptococcus pneumoniae is that
- A.
Harmless and pathogenic bacteria function differently in mice than in other organisms.
- B.
It demonstrated that harmless bacteria can become transformed into disease-causing bacteria by some association with pathogenic bacteria.
- C.
It established that pure DNA extracted from disease-causing bacteria transformed harmless strains into killer strains.
- D.
Dead cells lose their genetic information.
- E.
The genetic material is DNA, not protein.
Correct Answer
B. It demonstrated that harmless bacteria can become transformed into disease-causing bacteria by some association with pathogenic bacteria.Explanation
Fred Griffith's experiment using two strains of Streptococcus pneumoniae demonstrated that harmless bacteria can become transformed into disease-causing bacteria by some association with pathogenic bacteria. This was a significant finding because it provided evidence for the concept of bacterial transformation, where genetic material can be transferred between bacteria and alter their characteristics. This experiment laid the foundation for understanding the role of DNA in genetic transformation and paved the way for further research in the field of molecular biology.Rate this question:
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- 2.
The significance of the Hershey and Chase experiments in which 32P and 35S were used is that
- A.
DNA labeled with 35S and proteins labeled with 32P can be traced in the course of an experiment
- B.
They demonstrated that DNA labeled with 32P is transferred from the bacteriophage to the virus.
- C.
They established that proteins labeled with 35S become deactivated and unable to be transferred.
- D.
They demonstrated that bacteriophages transfer their DNA, not their protein coats, into their hosts.
- E.
DNA may be the hereditary material; although bacteriophages transfer both DNA and proteins into their hosts.
Correct Answer
D. They demonstrated that bacteriophages transfer their DNA, not their protein coats, into their hosts.Explanation
In the Hershey and Chase experiments, 32P and 35S were used to label DNA and proteins respectively. The significance of these experiments is that they demonstrated that bacteriophages transfer their DNA, not their protein coats, into their hosts. This finding supported the idea that DNA may be the hereditary material, as opposed to proteins. By using radioactive isotopes to track the location of the labeled molecules, the researchers were able to show that the DNA from the bacteriophage was transferred to the host bacteria, while the protein coats remained outside. This provided strong evidence for the role of DNA in inheritance.Rate this question:
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- 3.
DNA polymerase assembles new strands
- A.
In a 5' to 3' direction only.
- B.
In a 5' to 3' direction building one strand and a 3' to 5' direction building the second half of a strand.
- C.
In a 5' to 3' direction building the first half of a strand and a 3' to 5' direction building the second half of a strand.
- D.
In a 3' to 5' direction building the first half of a strand and a 5' to 3' direction building the second half of a strand.
- E.
In a 3' to 5' direction on the "old" 3' to 5' strand.
Correct Answer
A. In a 5' to 3' direction only.Explanation
DNA polymerase is responsible for synthesizing new DNA strands during DNA replication. It adds nucleotides to the growing DNA strand in a specific direction. The 5' to 3' direction refers to the orientation of the DNA molecule, where the 5' end has a phosphate group and the 3' end has a hydroxyl group. DNA polymerase can only add nucleotides to the 3' end of the growing DNA strand, resulting in synthesis occurring in the 5' to 3' direction. Therefore, the correct answer is that DNA polymerase assembles new strands in a 5' to 3' direction only.Rate this question:
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- 4.
A linear stretch of DNA that specifies the sequence of amino acids in a polypeptide is called a(n)
- A.
Codon.
- B.
Intron.
- C.
Messenger.
- D.
Gene.
- E.
Enzyme.
Correct Answer
D. Gene.Explanation
A linear stretch of DNA that specifies the sequence of amino acids in a polypeptide is called a gene. Genes contain the instructions for building proteins, and they are made up of codons, which are sequences of three nucleotides that code for specific amino acids. Introns are non-coding regions within genes, messengers are molecules involved in gene expression, and enzymes are proteins that catalyze biochemical reactions. Therefore, gene is the correct answer as it accurately describes the DNA segment responsible for protein synthesis.Rate this question:
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- 5.
Before leaving the nucleus, the RNA molecule
- A.
Acquires a poly-A tail.
- B.
Is released from the STOP signal on the template.
- C.
Becomes capped.
- D.
Is stripped of its introns.
- E.
All of these.
Correct Answer
E. All of these.Explanation
The correct answer is all of these. Before leaving the nucleus, the RNA molecule undergoes several modifications. It acquires a poly-A tail, which consists of a long string of adenine nucleotides added to its 3' end. It is also released from the STOP signal on the template, allowing it to detach from the DNA strand. Additionally, the RNA molecule becomes capped, meaning a modified guanine nucleotide is added to its 5' end. Lastly, the process of splicing removes the introns, non-coding regions of the RNA molecule, leaving only the exons, which are the coding regions.Rate this question:
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- 6.
The genetic code
- A.
Is nearly universal for all organisms.
- B.
Is based upon 64 codons made of sequences of three nucleotides.
- C.
Also comes equipped with "punctuation marks."
- D.
Is redundant, that is, many amino acids have more than one codon.
- E.
All of these.
Correct Answer
E. All of these.Explanation
The genetic code is nearly universal for all organisms, meaning that the same codons code for the same amino acids across different species. It is based on 64 codons, each made up of three nucleotides. Additionally, the genetic code includes "punctuation marks" such as start and stop codons that indicate the beginning and end of protein synthesis. The code is also redundant, as multiple codons can code for the same amino acid. Therefore, all of the given statements are correct.Rate this question:
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- 7.
Each "word" in the mRNA language consists of how many letters?
- A.
3
- B.
4
- C.
5
- D.
More than 5
- E.
None of these
Correct Answer
A. 3Explanation
In the mRNA language, each "word" consists of three letters. This means that the genetic code in mRNA is made up of sequences of three nucleotides called codons. Each codon codes for a specific amino acid, which is then used to build a protein during the process of protein synthesis. Therefore, the correct answer is 3.Rate this question:
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- 8.
Refer to Figure 14-1. AUGCGUCCAThe sequence of amino acids specified by this mRNA is
- A.
Serine -- histidine -- lysine.
- B.
Methionine -- arginine -- proline.
- C.
Methionine -- alanine -- serine.
- D.
Valine -- arginine -- leucine.
- E.
None of these.
Correct Answer
B. Methionine -- arginine -- proline. -
- 9.
Sickle-cell anemia has been traced to what type of mutation?
- A.
Frameshift
- B.
Transposable element
- C.
Mutagenic
- D.
Base-pair substitution
- E.
Viral
Correct Answer
D. Base-pair substitutionExplanation
Sickle-cell anemia is a genetic disorder caused by a mutation in the gene that codes for hemoglobin, the protein responsible for carrying oxygen in red blood cells. This mutation involves a base-pair substitution, where one nucleotide is replaced by another in the DNA sequence. This change leads to the production of abnormal hemoglobin, causing the red blood cells to become sickle-shaped and leading to various health problems. Therefore, the correct answer is base-pair substitution.Rate this question:
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- 10.
In a mutation,
- A.
The new codon may specify a different amino acid but may not change the function of the new protein produced.
- B.
The new codon may specify the same amino acid as the old codon.
- C.
The new codon and resulting amino acid may destroy the function of the protein specified.
- D.
The new codon may specify no amino acid.
- E.
All of these may be true.
Correct Answer
E. All of these may be true.Explanation
In a mutation, any of the given statements may be true. A mutation can result in a new codon that specifies a different amino acid, which can change the function of the new protein produced. However, it is also possible for the new codon to specify the same amino acid as the old codon, maintaining the function of the protein. Additionally, the new codon and resulting amino acid may disrupt the function of the protein specified. Finally, a mutation can lead to a new codon that does not specify any amino acid, resulting in a non-functional protein. Therefore, all of these statements may be true in the context of a mutation.Rate this question:
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- 11.
The color distribution in the fur of calico cats results from
- A.
Hybridization.
- B.
A specific nutritional deficiency.
- C.
A genetic defect.
- D.
X chromosome inactivation.
- E.
Selective breeding.
Correct Answer
D. X chromosome inactivation.Explanation
Calico cats have a unique fur color distribution due to X chromosome inactivation. In female cats, one of the X chromosomes is randomly inactivated in each cell during early development. This results in patches of different colored fur, as the genes responsible for fur color are located on the X chromosome. This phenomenon is not caused by hybridization, nutritional deficiency, genetic defect, or selective breeding.Rate this question:
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Feb 14, 2024Quiz Edited by
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Dec 12, 2009Quiz Created by
Ohchimonkey
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