Podcast
Questions and Answers
The process by which one strain of bacterium is apparently changed into another strain is called _____.
The process by which one strain of bacterium is apparently changed into another strain is called _____.
transformation
What are bacteriophages?
What are bacteriophages?
viruses
Who used radioactive markers in experiments to show DNA was the genetic material in cells?
Who used radioactive markers in experiments to show DNA was the genetic material in cells?
Alfred Hershey and Martha Chase
Before DNA could definitively be shown to be the genetic material in cells, scientists had to show that it could _____.
Before DNA could definitively be shown to be the genetic material in cells, scientists had to show that it could _____.
What was the conclusion of Frederick Griffith's experiments?
What was the conclusion of Frederick Griffith's experiments?
What key factor allowed Hershey and Chase to show that DNA alone carried the genetic information of bacteriophage?
What key factor allowed Hershey and Chase to show that DNA alone carried the genetic information of bacteriophage?
Describe the location in which the bacterial DNA withstood conditions that killed the bacteria. What happened to the DNA during the rest of the experiment?
Describe the location in which the bacterial DNA withstood conditions that killed the bacteria. What happened to the DNA during the rest of the experiment?
How did Avery and his team control variables in their experiment to ensure that only DNA caused the effect?
How did Avery and his team control variables in their experiment to ensure that only DNA caused the effect?
What does a nucleotide contain?
What does a nucleotide contain?
According to Chargaff's rule of base pairing, A = ? and C = ?.
According to Chargaff's rule of base pairing, A = ? and C = ?.
What do the bonds that hold two strands of DNA together come from?
What do the bonds that hold two strands of DNA together come from?
Describe the components and structure of a DNA nucleotide.
Describe the components and structure of a DNA nucleotide.
Explain how Chargaff's rule of base pairing helped Watson and Crick model DNA.
Explain how Chargaff's rule of base pairing helped Watson and Crick model DNA.
What important clue from Rosalind Franklin's work helped Watson and Crick develop a model of DNA?
What important clue from Rosalind Franklin's work helped Watson and Crick develop a model of DNA?
Why is it significant that two strands of DNA are anti-parallel?
Why is it significant that two strands of DNA are anti-parallel?
How did Watson and Crick's model of DNA molecule explain base pairing?
How did Watson and Crick's model of DNA molecule explain base pairing?
How did Rosalind Franklin's x-ray pattern help Watson and Crick determine how bases are paired?
How did Rosalind Franklin's x-ray pattern help Watson and Crick determine how bases are paired?
In prokaryotes, DNA molecules are located in the _____.
In prokaryotes, DNA molecules are located in the _____.
In eukaryotes, nearly all the DNA is found in the _____.
In eukaryotes, nearly all the DNA is found in the _____.
The main enzyme involved in linking individual nucleotides into DNA molecules is _____.
The main enzyme involved in linking individual nucleotides into DNA molecules is _____.
What is meant by the term base pairing? How is base pairing involved in DNA replication?
What is meant by the term base pairing? How is base pairing involved in DNA replication?
Describe the appearance of DNA in typical prokaryotic cells.
Describe the appearance of DNA in typical prokaryotic cells.
Explain the process of replication. When a DNA molecule is replicated, how do the new molecules compare to the original molecule?
Explain the process of replication. When a DNA molecule is replicated, how do the new molecules compare to the original molecule?
Is photocopying a document similar to DNA replication? Explain.
Is photocopying a document similar to DNA replication? Explain.
Describe similarities and differences between DNA replication in prokaryotic cells and in eukaryotic cells.
Describe similarities and differences between DNA replication in prokaryotic cells and in eukaryotic cells.
Knowing that ozone is a molecule that is very effective at absorbing ultraviolet light from the sun and evidence indicates that human activities have contributed to the destruction of ozone in the atmosphere, what question could you ask about the effect of removing it from the atmosphere?
Knowing that ozone is a molecule that is very effective at absorbing ultraviolet light from the sun and evidence indicates that human activities have contributed to the destruction of ozone in the atmosphere, what question could you ask about the effect of removing it from the atmosphere?
What does a gene consist of?
What does a gene consist of?
During replication, which sequence of nucleotides would bond with the DNA sequence TATGA?
During replication, which sequence of nucleotides would bond with the DNA sequence TATGA?
Who is responsible for the discovery of bacterial transformation?
Who is responsible for the discovery of bacterial transformation?
Which of the following options does not describe the structure of DNA?
Which of the following options does not describe the structure of DNA?
What did Hershey and Chase's work show?
What did Hershey and Chase's work show?
The two 'backbones' of the DNA molecule consist of _____.
The two 'backbones' of the DNA molecule consist of _____.
In eukaryotic chromosomes, DNA is tightly coiled around proteins called _____.
In eukaryotic chromosomes, DNA is tightly coiled around proteins called _____.
When prokaryotic cells copy their DNA, replication begins at _____.
When prokaryotic cells copy their DNA, replication begins at _____.
Compared to eukaryotic cells, prokaryotic cells contain how much DNA?
Compared to eukaryotic cells, prokaryotic cells contain how much DNA?
How does a eukaryotic cell keep such large amounts of DNA in the small volume of the cell nucleus?
How does a eukaryotic cell keep such large amounts of DNA in the small volume of the cell nucleus?
Study Notes
Transformation and Genetic Material
- Transformation is the process that changes one bacterium strain into another.
- Bacteriophages are viruses that infect bacteria.
- Alfred Hershey and Martha Chase demonstrated that DNA is the genetic material in cells using radioactive markers.
- DNA must carry and replicate information to be recognized as genetic material.
Key Experiments and Findings
- Frederick Griffith's experiments led to the discovery of the "transforming principle."
- Hershey and Chase concluded that DNA alone carries genetic information in bacteriophages due to the absence of sulfur in DNA and absence of phosphorus in proteins.
- Avery and his team controlled variables using various enzymes to isolate the effect of DNA.
DNA Structure and Composition
- A nucleotide consists of a five-carbon sugar, a nitrogenous base, and a phosphate group.
- Chargaff's rule states that adenine pairs with thymine (A=T) and cytosine pairs with guanine (C=G).
- DNA strands are held together by weak hydrogen bonds between nitrogenous bases.
- DNA nucleotides are composed of four different nitrogenous bases.
Watson and Crick Model
- The anti-parallel structure of DNA allows nitrogenous bases from both strands to pair correctly in the double helix.
- Watson and Crick's model explained base pairing behavior of DNA.
- Rosalind Franklin's X-ray diffraction image showed a helical structure which guided the DNA model development.
DNA in Prokaryotes vs. Eukaryotes
- In prokaryotes, DNA exists in the cytoplasm as a circular molecule.
- In eukaryotes, most DNA is located in the nucleus and tightly coiled around histones.
- DNA replication initiation occurs at a single point in prokaryotes, whereas eukaryotes have multiple sites.
DNA Replication Process
- During DNA replication, the molecule separates into two strands, each serving as a template for new complementary strands.
- Each newly synthesized strand contains one original and one new nucleotide strand.
- Base pairing during replication ensures the production of identical complementary strands.
- DNA polymerase is the main enzyme that links nucleotides during DNA synthesis.
Additional Concepts
- Genes consist of a start codon, genetic information, and an end codon.
- Similarities exist in DNA replication processes between prokaryotic and eukaryotic cells, though differences in replication initiation sites are notable.
- The effect of ozone depletion, which absorbs ultraviolet light, poses questions regarding environmental impacts due to human activities.
- Prokaryotic cells contain approximately one-thousandth of the DNA found in eukaryotic cells.
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Description
Test your knowledge of key concepts from Biology Chapter 12 with these flashcards. This assessment covers transformation in bacteria, the role of bacteriophages, and crucial experiments by Alfred Hershey and Martha Chase. Perfect for reviewing essential topics before your exam!
