Podcast
Questions and Answers
The Hershey-Chase experiment confirmed that DNA, not ______ or protein, is the genetic material.
The Hershey-Chase experiment confirmed that DNA, not ______ or protein, is the genetic material.
RNA
Bacteriophages are composed of ______ and protein.
Bacteriophages are composed of ______ and protein.
DNA
In the Hershey-Chase experiment, DNA was labeled with ______.
In the Hershey-Chase experiment, DNA was labeled with ______.
32P
The transforming principle was first described by ______ in 1928.
The transforming principle was first described by ______ in 1928.
In the DNA structure, the sugar component for DNA is ______.
In the DNA structure, the sugar component for DNA is ______.
James D. Watson and Francis H. Crick proposed the ______ Model of DNA in 1953.
James D. Watson and Francis H. Crick proposed the ______ Model of DNA in 1953.
Avery's work in 1944 concluded that ______ is the transforming substance.
Avery's work in 1944 concluded that ______ is the transforming substance.
The nitrogenous bases in DNA include adenine, guanine, cytosine, and ______.
The nitrogenous bases in DNA include adenine, guanine, cytosine, and ______.
Frederick Griffith conducted transformation experiments using two strains of Streptococcus pneumoniae, namely type ______ and type R.
Frederick Griffith conducted transformation experiments using two strains of Streptococcus pneumoniae, namely type ______ and type R.
______ proposed the double-helix model of DNA in 1953.
______ proposed the double-helix model of DNA in 1953.
In 1928, Griffith’s experiments led to the conclusion that something from the dead type S transformed type ______ into type S.
In 1928, Griffith’s experiments led to the conclusion that something from the dead type S transformed type ______ into type S.
Erwin Chargaff's studies indicated that double-stranded DNA consists of ~50% ______ and ~50% pyrimidines.
Erwin Chargaff's studies indicated that double-stranded DNA consists of ~50% ______ and ~50% pyrimidines.
The unknown substance that Griffith called the ______ was later understood to be DNA.
The unknown substance that Griffith called the ______ was later understood to be DNA.
According to Chargaff’s rules, the amount of ______ is equal to the amount of thymine.
According to Chargaff’s rules, the amount of ______ is equal to the amount of thymine.
Oswald Avery performed experiments in ______ to determine the chemical identity of the transforming principle.
Oswald Avery performed experiments in ______ to determine the chemical identity of the transforming principle.
In the search for genetic material, it is essential for it to be a stable source of ______.
In the search for genetic material, it is essential for it to be a stable source of ______.
X-ray diffraction studies by Rosalind Franklin and Maurice Wilkins concluded that DNA is a ______ structure.
X-ray diffraction studies by Rosalind Franklin and Maurice Wilkins concluded that DNA is a ______ structure.
Hershey and Chase conducted their famous experiment in ______ to confirm DNA as the genetic material.
Hershey and Chase conducted their famous experiment in ______ to confirm DNA as the genetic material.
The Nobel Prize ceremony in 1962 recognized ______, Watson, and others for their contributions to the discovery of DNA.
The Nobel Prize ceremony in 1962 recognized ______, Watson, and others for their contributions to the discovery of DNA.
The double helix model of DNA was built based on ______ rules.
The double helix model of DNA was built based on ______ rules.
According to Erwin Schrodinger, genes must be ______ because they can change over time but are also stable.
According to Erwin Schrodinger, genes must be ______ because they can change over time but are also stable.
Homo sapiens have a G and C content of approximately ______%.
Homo sapiens have a G and C content of approximately ______%.
The discovery of the DNA structure exemplifies the importance of ______ research.
The discovery of the DNA structure exemplifies the importance of ______ research.
Memories may be passed down through generations in ______, which can influence phobias.
Memories may be passed down through generations in ______, which can influence phobias.
Double-stranded DNA consists of ~50% purines (A, G) and ~50% ______ (T, C).
Double-stranded DNA consists of ~50% purines (A, G) and ~50% ______ (T, C).
According to Chargaff's rules, the amount of A is equal to the amount of ______.
According to Chargaff's rules, the amount of A is equal to the amount of ______.
Rosalind Franklin and Maurice Wilkins conducted X-ray diffraction studies that concluded DNA is a ______ structure.
Rosalind Franklin and Maurice Wilkins conducted X-ray diffraction studies that concluded DNA is a ______ structure.
The discovery of the DNA structure was made possible by knowledge from chemists, biologists, physicists, and ______.
The discovery of the DNA structure was made possible by knowledge from chemists, biologists, physicists, and ______.
The percentage of GC content varies from organism to ______.
The percentage of GC content varies from organism to ______.
In the DNA structure, the two strands are held together by ______ bonds between the nitrogenous bases.
In the DNA structure, the two strands are held together by ______ bonds between the nitrogenous bases.
The model building for DNA suggested that base pairing is in agreement with ______ rules.
The model building for DNA suggested that base pairing is in agreement with ______ rules.
The significant debate around the DNA discovery in 2023 raises questions about how ______ should we be with our data.
The significant debate around the DNA discovery in 2023 raises questions about how ______ should we be with our data.
The process of transforming type R bacteria into type S was termed ______.
The process of transforming type R bacteria into type S was termed ______.
Frederick Griffith worked with two strains of ______ pneumoniae in his transformation experiments.
Frederick Griffith worked with two strains of ______ pneumoniae in his transformation experiments.
In 1944, Oswald Avery identified the ______ as the substance responsible for transformation.
In 1944, Oswald Avery identified the ______ as the substance responsible for transformation.
Erwin Schrödinger suggested that genes must be ______ because they can be stable yet change over time.
Erwin Schrödinger suggested that genes must be ______ because they can be stable yet change over time.
The 1953 proposal of the double-helix model of DNA was made by ______ and Crick.
The 1953 proposal of the double-helix model of DNA was made by ______ and Crick.
In the context of DNA, the stable source of information must have the ability to ______ accurately.
In the context of DNA, the stable source of information must have the ability to ______ accurately.
The hereditary information in chromosomes was shown to be composed of ______ and nucleic acids.
The hereditary information in chromosomes was shown to be composed of ______ and nucleic acids.
The first demonstration of RNA as viral genetic material occurred in ______.
The first demonstration of RNA as viral genetic material occurred in ______.
The Hershey-Chase experiment used the T2 bacteriophage to confirm that ______ is the genetic material.
The Hershey-Chase experiment used the T2 bacteriophage to confirm that ______ is the genetic material.
Bacteriophage T2 was labeled with ______ to track the DNA.
Bacteriophage T2 was labeled with ______ to track the DNA.
In the structure of DNA, the sugar component is known as ______.
In the structure of DNA, the sugar component is known as ______.
The nitrogenous base thymine is present in ______ but is replaced by uracil in RNA.
The nitrogenous base thymine is present in ______ but is replaced by uracil in RNA.
The two types of nitrogenous bases are ______ and pyrimidines.
The two types of nitrogenous bases are ______ and pyrimidines.
James Watson and Francis Crick proposed the ______ Model of DNA structure.
James Watson and Francis Crick proposed the ______ Model of DNA structure.
Avery’s experiments in 1944 demonstrated that ______ serves as the transforming substance.
Avery’s experiments in 1944 demonstrated that ______ serves as the transforming substance.
Frederick Griffith’s transformation experiments involved type R and type ______ strains of Streptococcus pneumoniae.
Frederick Griffith’s transformation experiments involved type R and type ______ strains of Streptococcus pneumoniae.
What percentage of GC content is found in Zea mays?
What percentage of GC content is found in Zea mays?
Which of the following statements aligns with Chargaff's rules?
Which of the following statements aligns with Chargaff's rules?
What type of research is highlighted as being crucial in the discovery of DNA structure?
What type of research is highlighted as being crucial in the discovery of DNA structure?
What was the key finding from the X-ray diffraction studies conducted by Rosalind Franklin and Maurice Wilkins?
What was the key finding from the X-ray diffraction studies conducted by Rosalind Franklin and Maurice Wilkins?
What percentage of thymine is present in Homo sapiens?
What percentage of thymine is present in Homo sapiens?
In the context of DNA, what significance does the 0.34 nm regularity represent?
In the context of DNA, what significance does the 0.34 nm regularity represent?
What is the approximate percentage of GC content in Drosophila?
What is the approximate percentage of GC content in Drosophila?
What aspect of scientific research does the debate surrounding the discovery of DNA structure in 2023 emphasize?
What aspect of scientific research does the debate surrounding the discovery of DNA structure in 2023 emphasize?
What was the main conclusion of the Hershey-Chase experiment?
What was the main conclusion of the Hershey-Chase experiment?
Which type of labeling was used in the Hershey-Chase experiment for DNA and protein respectively?
Which type of labeling was used in the Hershey-Chase experiment for DNA and protein respectively?
Which of the following components is found in RNA but not in DNA?
Which of the following components is found in RNA but not in DNA?
What did Avery demonstrate in 1944 regarding genetic material?
What did Avery demonstrate in 1944 regarding genetic material?
What type of virus is a bacteriophage characterized as?
What type of virus is a bacteriophage characterized as?
Which of the following best describes the structure of DNA?
Which of the following best describes the structure of DNA?
What did Gierer & Schramm, and Fraenkel-Conrat & Singer conclude about RNA?
What did Gierer & Schramm, and Fraenkel-Conrat & Singer conclude about RNA?
Which statement about the components of a nucleotide is correct?
Which statement about the components of a nucleotide is correct?
What was the key conclusion from Frederick Griffith's experiments with Streptococcus pneumoniae?
What was the key conclusion from Frederick Griffith's experiments with Streptococcus pneumoniae?
Which experiment was pivotal in establishing DNA as the genetic material in 1944?
Which experiment was pivotal in establishing DNA as the genetic material in 1944?
What characteristic is essential for a stable genetic material?
What characteristic is essential for a stable genetic material?
Erwin Schrödinger's perspective on genes emphasized that they must be what?
Erwin Schrödinger's perspective on genes emphasized that they must be what?
What was a common misconception about the genetic material before the discovery of DNA's role?
What was a common misconception about the genetic material before the discovery of DNA's role?
What major advance did Watson and Crick make in 1953 regarding DNA?
What major advance did Watson and Crick make in 1953 regarding DNA?
In the context of DNA, what does the term 'transformation' specifically refer to?
In the context of DNA, what does the term 'transformation' specifically refer to?
What is NOT a criterion for identifying a stable source of genetic information?
What is NOT a criterion for identifying a stable source of genetic information?
What conclusion did Griffith reach about the relationship between type S and type R strains of Streptococcus pneumoniae?
What conclusion did Griffith reach about the relationship between type S and type R strains of Streptococcus pneumoniae?
Which characteristic was NOT identified as a requirement for genetic material in the content?
Which characteristic was NOT identified as a requirement for genetic material in the content?
What did Oswald Avery use to treat cell extracts in his transformation experiments?
What did Oswald Avery use to treat cell extracts in his transformation experiments?
According to Schrodinger, what is a fundamental property of genes?
According to Schrodinger, what is a fundamental property of genes?
What was a primary reason scientists initially believed proteins were the genetic material instead of DNA?
What was a primary reason scientists initially believed proteins were the genetic material instead of DNA?
In what year did Watson and Crick propose the double-helix model of DNA?
In what year did Watson and Crick propose the double-helix model of DNA?
What aspect of DNA structure contributed to the initial skepticism regarding its role as genetic material?
What aspect of DNA structure contributed to the initial skepticism regarding its role as genetic material?
Which of the following was shown in 1900 concerning chromosomes?
Which of the following was shown in 1900 concerning chromosomes?
What was the main conclusion derived from the Hershey-Chase Experiment?
What was the main conclusion derived from the Hershey-Chase Experiment?
Which component of the T2 bacteriophage was labeled with phosphorus in the Hershey-Chase experiment?
Which component of the T2 bacteriophage was labeled with phosphorus in the Hershey-Chase experiment?
How did Hershey and Chase confirm that DNA is the genetic material?
How did Hershey and Chase confirm that DNA is the genetic material?
Which of the following is a common misconception about phage composition in the context of the Hershey-Chase experiment?
Which of the following is a common misconception about phage composition in the context of the Hershey-Chase experiment?
In terms of genetic material, what did Gierer & Schramm establish in relation to certain viruses?
In terms of genetic material, what did Gierer & Schramm establish in relation to certain viruses?
Which of the following correctly identifies a key component of the structure of DNA?
Which of the following correctly identifies a key component of the structure of DNA?
What significant role does the phosphate group play in the structure of DNA?
What significant role does the phosphate group play in the structure of DNA?
Which experiment was pivotal in establishing DNA as the transforming substance prior to the Hershey-Chase experiment?
Which experiment was pivotal in establishing DNA as the transforming substance prior to the Hershey-Chase experiment?
Which organism has the highest percentage of GC content?
Which organism has the highest percentage of GC content?
What is the significance of Chargaff's rules in the study of DNA?
What is the significance of Chargaff's rules in the study of DNA?
What is one of the major contributions of Rosalind Franklin and Maurice Wilkins to DNA research?
What is one of the major contributions of Rosalind Franklin and Maurice Wilkins to DNA research?
What aspect of DNA's structure is highlighted by the distinct regularities observed in X-ray diffraction studies?
What aspect of DNA's structure is highlighted by the distinct regularities observed in X-ray diffraction studies?
What do the findings about the percentage of A and T, as well as G and C, imply for double-stranded DNA?
What do the findings about the percentage of A and T, as well as G and C, imply for double-stranded DNA?
In the context of current scientific debates regarding DNA research, what aspect is emphasized?
In the context of current scientific debates regarding DNA research, what aspect is emphasized?
Which statement best characterizes the shared nature of DNA across different species?
Which statement best characterizes the shared nature of DNA across different species?
According to the findings presented, what can explain variations in the percentage of AT and GC content among different species?
According to the findings presented, what can explain variations in the percentage of AT and GC content among different species?
What is the primary conclusion from the Hershey-Chase experiment?
What is the primary conclusion from the Hershey-Chase experiment?
Which component was used to label the DNA during the Hershey-Chase experiment?
Which component was used to label the DNA during the Hershey-Chase experiment?
In the context of the structure of nucleotides, which nitrogenous base is exclusive to RNA?
In the context of the structure of nucleotides, which nitrogenous base is exclusive to RNA?
Which two types of components make up the structure of DNA?
Which two types of components make up the structure of DNA?
What did Avery's 1944 experiments reveal about DNA?
What did Avery's 1944 experiments reveal about DNA?
Why did Hershey and Chase label the protein with 35S in their experiment?
Why did Hershey and Chase label the protein with 35S in their experiment?
What is the significance of the pentose sugar component in DNA?
What is the significance of the pentose sugar component in DNA?
Who are the scientists credited with proposing the double helix model of DNA?
Who are the scientists credited with proposing the double helix model of DNA?
What was the main conclusion of Frederick Griffith's transformation experiments?
What was the main conclusion of Frederick Griffith's transformation experiments?
Which of the following was NOT a criterion for identifying DNA as genetic material?
Which of the following was NOT a criterion for identifying DNA as genetic material?
In Oswald Avery's Transformation Experiment, which enzyme was used to treat the cell extract from type S cells?
In Oswald Avery's Transformation Experiment, which enzyme was used to treat the cell extract from type S cells?
Which scientist first suggested that genes must be molecules in his 1944 publication?
Which scientist first suggested that genes must be molecules in his 1944 publication?
Which of the following statements about the strains of Streptococcus pneumoniae is accurate?
Which of the following statements about the strains of Streptococcus pneumoniae is accurate?
What was revealed by Griffith's Transformation Experiment regarding the existence of a genetic material?
What was revealed by Griffith's Transformation Experiment regarding the existence of a genetic material?
What did scientists initially believe to be the genetic material before DNA was recognized?
What did scientists initially believe to be the genetic material before DNA was recognized?
Which base pairing rule is established by Chargaff's findings?
Which base pairing rule is established by Chargaff's findings?
What conclusion was drawn from X-ray diffraction studies about the structure of DNA?
What conclusion was drawn from X-ray diffraction studies about the structure of DNA?
Which organism has the highest percentage of GC content according to the examples provided?
Which organism has the highest percentage of GC content according to the examples provided?
What important aspect of research does the discovery of DNA structure highlight?
What important aspect of research does the discovery of DNA structure highlight?
What percentage of adenine is found in Homo sapiens according to the provided information?
What percentage of adenine is found in Homo sapiens according to the provided information?
What does Chargaff’s rule state about the relationship between purines and pyrimidines in double-stranded DNA?
What does Chargaff’s rule state about the relationship between purines and pyrimidines in double-stranded DNA?
Which nitrogenous base pairs with guanine in DNA?
Which nitrogenous base pairs with guanine in DNA?
Flashcards
Transformation
Transformation
The ability of a substance to change the genetic makeup of another substance.
Streptococcus pneumoniae S strain
Streptococcus pneumoniae S strain
A type of bacteria possessing a smooth capsule that makes it virulent.
Streptococcus pneumoniae R strain
Streptococcus pneumoniae R strain
A type of bacteria lacking a capsule and therefore avirulent.
Griffith's Transformation Experiment
Griffith's Transformation Experiment
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Transforming Principle
Transforming Principle
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Avery's Transformation Experiment
Avery's Transformation Experiment
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Bacteriophage
Bacteriophage
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Hershey-Chase Experiment
Hershey-Chase Experiment
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Genetic material
Genetic material
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Nucleotide
Nucleotide
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Deoxyribose
Deoxyribose
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Chargaff's Rules
Chargaff's Rules
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Variable % AT and GC content
Variable % AT and GC content
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Rosalind Franklin's X-ray Diffraction of DNA
Rosalind Franklin's X-ray Diffraction of DNA
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The DNA Double Helix
The DNA Double Helix
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Significance of the DNA Double Helix Discovery
Significance of the DNA Double Helix Discovery
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The DNA Discovery: A Collaborative Effort
The DNA Discovery: A Collaborative Effort
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Hereditary Role of DNA in Memories
Hereditary Role of DNA in Memories
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Shared DNA with Other Organisms
Shared DNA with Other Organisms
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Study Notes
Learning Objectives
- Students will understand the experiments that led to the discovery of DNA's role as genetic material
- Students will know the experiments (Griffith's, Avery's, Hershey-Chase) leading to DNA's discovery.
- Students will grasp the chemical composition and structure of DNA.
Who Discovered DNA?
- The discovery of DNA was a collaborative effort spanning many scientists' work over a long time. Several landmark experiments highlighted the pivotal nature of DNA as the genetic material
- Key experimenters' names are associated with particular milestones
Timeline of Events
- 1890: Weismann proposed that a substance in cell nuclei controls development.
- 1900: Chromosomes were identified as containing hereditary material, composed of protein and nucleic acids.
- 1928: Griffith's transformation experiment
- 1944: Avery's transformation experiment
- 1953: Hershey-Chase bacteriophage experiment
- 1953: Watson and Crick proposed the double-helix model of DNA
- 1956: RNA was demonstrated to be the genetic material in some viruses.
Search for the Genetic Material
- Key criteria for the genetic material:
- Stable source of information
- Ability to accurately replicate
- Ability to change (produce variation)
- Transformation
Griffith's Transformation Experiment (1928)
- Two strains of Streptococcus pneumoniae:
- S (smooth): secretes a polysaccharide capsule, produces smooth colonies on solid media, virulent.
- R (rough): unable to secrete a capsule, colonies with a rough appearance, avirulent.
- Griffith injected mice with different combinations of S and R strains:
- Living S strain killed the mice
- Living R strain did not kill the mice
- Heat-killed S strain did not kill the mice
- Mixture of heat-killed S and living R strains killed the mice
- Living R bacteria were transformed into S bacteria by transferring some material from the dead S cells.
Avery's Transformation Experiment (1944)
- Refined Griffith's experiment, trying to identify the transforming principle.
- Removed lipids and sugars from heat-killed S cells.
- Utilized specific enzymes to selectively degrade proteins, ribonucleic acid (RNA), and deoxyribonucleic acid (DNA) in the heat-killed S strain extract, aiming to identify which macromolecule was responsible for the transformation.
- Only treating the sample with deoxyribonuclease (DNAse) successfully prevented the transformation from occurring, indicating that the DNA from the heat-killed S strain was the critical component responsible for converting the living R strain into the virulent S strain.
- Concluded that DNA was the transforming principle.
Hershey-Chase Bacteriophage Experiment (1953)
- Used bacteriophage T2.
- Labeled bacteriophage DNA with radioactive phosphorus (32P) and bacteriophage protein with radioactive sulfur (35S).
- Bacteriophages infected bacteria.
- After infection, bacteria were separated from the bacteriophages, and radioactivity within the bacteria was measured.
- DNA, labeled with 32P, was found inside the bacteria
- Protein, labeled with 35S, remained outside the bacteria.
- Confirmed DNA as the genetic material.
DNA Structure
- 1953: James Watson and Francis Crick proposed the double-helix model.
- Key idea: Watson and Crick found that the chemical structure of DNA suggested a specific arrangement of base pairs along the DNA strands -Crucial for DNA's role in replication.
DNA Structure (Continued)
- Key components:
- Pentose sugar (deoxyribose in DNA, ribose in RNA)
- Nitrogenous bases (adenine, guanine, cytosine, thymine in DNA; uracil in RNA)
- Phosphate group.
- Base pairing (Chargaff's rules):
- Adenine (A) pairs with thymine (T)
- Guanine (G) pairs with cytosine (C)
- Double helix structure and its dimensions -X-ray diffraction data of Rosalind Franklin and Maurice Wilkins played a critical role
- The double helix form confirmed that DNA contained information
Significance of Early Experiments and the 1953 work.
- The conclusions were groundbreaking and showed that the structure of DNA was important to its function
- The findings clarified the physical basis for inheritance and laid the foundation for furthering discoveries in molecular biology.
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Description
This quiz explores the crucial experiments that led to the understanding of DNA as the genetic material, including Griffith's, Avery's, and Hershey-Chase's pivotal studies. Students will also learn about the chemical composition and structure of DNA through its historical context and timeline of discoveries. Test your knowledge on the key figures and experiments in the history of genetics.
