Bio1334 Genetics - Molecular Genetics - DNA And Chromosomes (Lecture One)
Quiz on content from Lecture One of Genetics module.
Questions and Answers
- 1.
Name the Scientist that isolated nuclein (now nucleic acid) from human pus.
- A.
Friedrich Miescher
- B.
Rosalind Franklin
- C.
Alfred Hershey
- D.
Francis Crick
Correct Answer
A. Friedrich MiescherExplanation
Friedrich Miescher was the Scientist that isolated nucleic acid from human pus.
At a time when scientists were still debating the concept of "cell," Hoppe-Seyler and his lab were isolating the molecules that made up cells. Miescher was given the task of researching the composition of lymphoid cells — white blood cells.
These cells were difficult to extract from the lymph glands, but they were found in great quantities in the pus from infections. Miescher collected bandages from a nearby clinic and washed off the pus. He experimented and isolated a new molecule - nuclein - from the cell nucleus. He determined that nuclein was made up of hydrogen, oxygen, nitrogen and phosphorus and there was an unique ratio of phosphorus to nitrogen. He was able to isolate nuclein from other cells and later used salmon sperm (as opposed to pus) as a source.Rate this question:
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- 2.
Which of the following did Rosalind Franklin conclude about the structure of DNA?(Select more than one answer)
- A.
The structure is double-helical
- B.
Phosphate groups lie on the outside of the molecule
- C.
The helix is 20 nanometers in diameter
- D.
DNA has directionality (5' and 3' ends)
- E.
DNA has four nitrogenous bases
Correct Answer(s)
A. The structure is double-helical
B. Phosphate groups lie on the outside of the molecule
C. The helix is 20 nanometers in diameterExplanation
Rosalind Franklin concluded about the structure of DNA:
- The structure was double helical
- Phosphate groups laid on the outside of the molecule
- The helix was 20 nanometers in diameterRate this question:
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- 3.
Name the sugar in DNA.
Correct Answer(s)
DeoxyriboseExplanation
Deoxyribose is the five-carbon sugar component of DNA, where it alternates with phosphate groups to form the “backbone” of the DNA polymer and binds to nitrogenous bases. The presence of deoxyribose instead of ribose is one difference between DNA and RNA (ribonucleic acid). Deoxyribose was synthesized in 1935, but it was not isolated from DNA until 1954.Rate this question:
- 4.
Sugar + base + phosphate(s) = ?
Correct Answer(s)
Nucleotide
Nucleotides
A nucleotideExplanation
Nucleotide - any member of a class of organic compounds in which the molecular structure comprises a nitrogen-containing unit (base) linked to a sugar and a phosphate group. The nucleotides are of great importance to living organisms, as they are the building blocks of nucleic acids, the substances that control all hereditary characteristics.Rate this question:
- 5.
Sugar + base = ?
Correct Answer(s)
Nucleoside
Nucleosides
A nucleosideExplanation
The correct answer is "Nucleoside, Nucleosides, A nucleoside." When sugar combines with a base, it forms a nucleoside. Nucleosides are organic compounds composed of a sugar molecule bonded to a nitrogenous base. They are important building blocks for nucleic acids, such as DNA and RNA. The combination of a sugar and a base in a nucleoside is crucial for the structure and function of these genetic materials.Rate this question:
- 6.
Deoxyribose + adenine = ?
Correct Answer(s)
DeoxyadenosineExplanation
Deoxyribose is a sugar molecule that is a component of DNA. Adenine is one of the four nitrogenous bases that make up DNA. When deoxyribose and adenine combine, they form deoxyadenosine, which is a nucleoside. Nucleosides are important building blocks of DNA and RNA. Deoxyadenosine consists of deoxyribose bonded to adenine, and it plays a crucial role in the structure and function of DNA.Rate this question:
- 7.
Deoxyribose + guanine = ?
Correct Answer(s)
GuanosineExplanation
When deoxyribose, a sugar molecule, combines with guanine, a nitrogenous base, they form a nucleoside called guanosine. Nucleosides are composed of a sugar molecule bonded to a nitrogenous base, and in this case, deoxyribose is bonded to guanine to create guanosine. This reaction is a key step in the synthesis of DNA molecules, as nucleosides are the building blocks of DNA. Therefore, when deoxyribose and guanine combine, they produce guanosine.Rate this question:
- 8.
Deoxyribose + cytosine = ?
Correct Answer(s)
CytidineExplanation
Deoxyribose is a sugar molecule that is a component of DNA, while cytosine is one of the four nitrogenous bases found in DNA and RNA. When deoxyribose and cytosine combine, they form a nucleoside called cytidine. Cytidine consists of a deoxyribose sugar molecule bonded to a cytosine base. Nucleosides are important building blocks of nucleotides, which are the monomers of DNA and RNA.Rate this question:
- 9.
Deoxyribose + thymine = ?
Correct Answer(s)
ThymidineExplanation
Deoxyribose is a sugar molecule found in DNA, and thymine is one of the four nitrogenous bases present in DNA. When deoxyribose combines with thymine, it forms a nucleoside called thymidine. Thymidine is an essential component of DNA as it pairs with adenine during DNA replication and transcription, contributing to the accurate transmission of genetic information.Rate this question:
- 10.
5' and 3' ends give DNA molecules directionality.True or False: DNA is synthesised in the 3'-to-5' direction.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Nucleic acids can only be synthesized in vivo in the 5′-to-3′ direction.Rate this question:
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- 11.
True or false: In a DNA double-helix, the 5' end of one strand is opposite the 3' end of another strand.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
In a DNA double-helix, the 5' end of one strand is indeed opposite to the 3' end of another strand. This is due to the antiparallel nature of DNA strands, where one strand runs in the 5' to 3' direction and the other runs in the opposite direction. The 5' end of a DNA strand has a phosphate group attached to the 5' carbon of the sugar molecule, while the 3' end has a hydroxyl group attached to the 3' carbon. This arrangement allows for complementary base pairing between the strands, enabling DNA replication and protein synthesis.Rate this question:
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- 12.
Which of the following statements is true?
- A.
Two hydrogen bonds form between adenine and thymine, whereas three form between cytosine and guanine. Bonding is therefore stronger between C and G.
- B.
Two hydrogen bonds form between cytosine and guanine, whereas three form between adenine and thymine. Bonding is therefore stronger between A and T.
- C.
Two hydrogen bonds form between both adenine and thymine, and cytosine and guanine. Bonds between the two bases are equally as strong.
- D.
Three hydrogen bonds form between both adenine and thymine, and cytosine and guanine. Bonds between the two bases are equally as strong.
Correct Answer
A. Two hydrogen bonds form between adenine and thymine, whereas three form between cytosine and guanine. Bonding is therefore stronger between C and G. -
- 13.
Which of the following statements is correct?
- A.
Adenine and thymine are purines. Cytosine and guanine are pyrimidines.
- B.
Adenine and guanine are purines. Cytosine and thymine are pyrimidines.
- C.
Guanine and cytosine are purines. Adenine and thymine are pyrimidines.
- D.
Cytosine and thymine are purines. Adenine and guanine are pyrimidines.
Correct Answer
B. Adenine and guanine are purines. Cytosine and thymine are pyrimidines.Explanation
The correct answer is that Adenine and guanine are purines, while cytosine and thymine are pyrimidines. This statement is correct because purines and pyrimidines are two types of nitrogenous bases found in DNA and RNA. Adenine and guanine are purines because they have a double-ring structure, while cytosine and thymine are pyrimidines because they have a single-ring structure. This is a fundamental concept in molecular biology and genetics, and understanding the structure and composition of DNA and RNA is crucial in understanding their functions and roles in genetic information storage and transmission.Rate this question:
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- 14.
Which of the following images shows a right-handed double helix?
- A.
This one!
- B.
This one!
- C.
Option 3
- D.
Option 4
Correct Answer
A. This one!Explanation
The answer "This one!" is correct because it implies that the image being referred to shows a right-handed double helix. The other options do not provide any specific information or context, so they cannot be determined as correct.Rate this question:
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- 15.
True or false: DNA is a right-handed double helix.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
DNA is a right-handed double helix because its two strands twist around each other in a clockwise direction. This is supported by extensive scientific research and evidence. The right-handedness of DNA is due to the specific arrangement of its sugar-phosphate backbone and the pairing of nucleotide bases. This structural characteristic is fundamental to the stability and functionality of DNA as it allows for efficient replication and transcription processes.Rate this question:
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- 16.
Fill in the blank:DNA is a _______ code, because it has four possible bases.
Correct Answer
QuaternaryExplanation
DNA is a quaternary code because it has four possible bases. The term "quaternary" refers to a system or code that is based on four elements or components. In the case of DNA, the four bases are adenine (A), thymine (T), cytosine (C), and guanine (G). These bases form the building blocks of DNA and are combined in different sequences to encode genetic information. Therefore, DNA can be described as a quaternary code due to its reliance on four possible bases.Rate this question:
- 17.
Match the following to its complementary strand: 5′-TGGTCGGAATT-3′
- A.
5′-AATTCCGACCA-3′
- B.
5′-ACCAGCCTTAA-3′
- C.
5′-TGGTCGGAATT-3′
- D.
5′-TTAAGGCTGGT-3′
Correct Answer
A. 5′-AATTCCGACCA-3′Explanation
The complementary strand of a DNA sequence is formed by pairing each base with its complementary base. In this case, the given sequence is 5'-TGGTCGGAATT-3'. To find its complementary strand, we need to pair each base with its complementary base. A pairs with T, T pairs with A, G pairs with C, and C pairs with G. Therefore, the complementary strand of 5'-TGGTCGGAATT-3' is 5'-AATTCCGACCA-3'.Rate this question:
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- 18.
Fill in the blank:A ______ is the complete set of genes for an organism.
Correct Answer
GenomeExplanation
A genome refers to the complete set of genes present in an organism. It includes all the genetic material, including both coding and non-coding regions, that determines the characteristics and traits of an individual. The genome contains all the information necessary for the development, functioning, and reproduction of the organism. It is unique to each species and plays a crucial role in understanding the genetic basis of various biological processes and diseases.Rate this question:
- 19.
How many base pairs can be found in every human cell?
- A.
6 x 10^9 base pairs
- B.
6 x 10^6 base pairs
- C.
6 x 10^12 base pairs
- D.
6 x 10^3 base pairs
Correct Answer
A. 6 x 10^9 base pairsExplanation
Every human cell contains 6 x 10^9 base pairs. This is because the human genome consists of approximately 3 billion base pairs, and each cell in the body contains a complete set of DNA, which includes the entire genome. Therefore, the correct answer is 6 x 10^9 base pairs.Rate this question:
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- 20.
Which of the following statements is correct?
- A.
DNA wraps twice around 8 histone proteins to form nucleosomes.
- B.
DNA wraps once around 8 histone proteins to form nucleosomes.
- C.
DNA wraps twice around 8 histone proteins to form nucleotides.
- D.
DNA wraps once around 8 histone proteins to form nucleotides.
Correct Answer
A. DNA wraps twice around 8 histone proteins to form nucleosomes. -
- 21.
What is the name given to the protein that DNA wraps around in order to 'package' the DNA?
Correct Answer
Histone
Histones
A histone
Histone proteins
Histone protein
A histone proteinExplanation
The correct answer for this question is "Histone, Histones, A histone, Histone proteins, Histone protein, A histone protein". Histones are proteins that DNA wraps around in order to package the DNA. They play a crucial role in organizing and compacting DNA into a structure called chromatin, which allows for efficient storage and regulation of genetic information.Rate this question:
- 22.
When DNA wraps around the histone protein, what is the name of the structure formed?
Correct Answer
A nucleosome
Nucleosome
Nucleosomes
The nucleosomeExplanation
When DNA wraps around the histone protein, the structure formed is called a nucleosome. The histone proteins act as spools around which the DNA is wound, forming a compact structure. This helps in packaging the DNA tightly and organizing it within the nucleus of the cell. The nucleosome is the basic unit of DNA packaging in eukaryotic cells and plays a crucial role in regulating gene expression and chromosome structure.Rate this question:
- 23.
There are 5 histone proteins - 4 of these histone proteins are core histone proteins (the DNA wraps around them in order to package the DNA).True or False:The names of the four core histone proteins are: H1, H2, H3 and H4.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
FALSE.
The names of the four core histone proteins are H2A, H2B, H3 and H4.Rate this question:
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- 24.
Fill in the blank:Histone protein H1 is known as a ______ protein.
Correct Answer
LinkerExplanation
Histone protein H1 is known as a linker protein. Histones are proteins that help organize and package DNA into a structure called chromatin. H1 is a specific type of histone protein that binds to the DNA between nucleosomes, which are the basic units of chromatin. This binding helps to stabilize the structure of chromatin and regulate gene expression. Therefore, H1 acts as a linker between nucleosomes, earning its name as a linker protein.Rate this question:
- 25.
Fill in the blank:Histone H1 brings the nucleosomes together to form a _________________.
Correct Answer
Chromatin fibre
ChromatinExplanation
Histone H1 is a protein that plays a crucial role in organizing DNA into a higher-order structure known as chromatin. It binds to the linker DNA between nucleosomes and helps to compact the nucleosomes together, forming a chromatin fiber. This chromatin fiber further condenses and folds to create a higher level of organization in the genome. Therefore, the correct answer is "Chromatin fiber." "Chromatin" alone refers to the DNA-protein complex, but it does not specifically describe the compaction and organization brought about by histone H1.Rate this question:
- 26.
Fill in the blank:After chromatin fibre is formed by the Histone H1 protein, chromatin is further condensed by ______________.
Correct Answer
Scaffold proteinsExplanation
After chromatin fiber is formed by the Histone H1 protein, chromatin is further condensed by scaffold proteins. These proteins play a crucial role in organizing and compacting the chromatin structure. They provide a structural framework for the chromatin, allowing it to be tightly packaged and organized into higher-order structures. This condensation helps to regulate gene expression and ensure the stability of the genome.Rate this question:
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