Homework Help is Here – Start Your Trial Now!
Science
Biology
The Evidence 1869-1924 1869: DNA, first called "nuclein," is identified by Friedrich Miescher as a weakly acidic substance found in cell nuclei of human white blood cells. 1924: Chromosomes are shown to be composed of both DNA and protein. QUESTIONS 1. What should you conclude at this time? 2. What experimental question would you propose to investigate at this time? The Evidence: 1928-1944 1928: Frederick Griffith discovers that heat-killed bacteria can transform a non-virulent strain. This phenomenon, called transformation, provides the first evidence that genetic material is a heat- stable chemical. 1944: Oswald Avery, Maclyn McCarty, and Colin MacLeod identify Griffith's transforming agent as DNA. QUESTIONS 1. What should you conclude at this time? 2. What experimental questions would you propose to investigate at this time? 3. How would you have answered the criticism of Avery's work; that DNA was too simple to be the genetic molecule? The Evidence: 1949-1952 1949: Erwin Chargaff, a biochemist, reports that DNA composition is species-specific, that is, the amount of DNA and its nitrogenous bases varies from one species to another. In addition, Chargaff finds that the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine in DNA from every species. 1952: Alfred Hershey and Martha Chase use bacteriophages grown in a radioactive medium to show that DNA enters the cells as the transforming agent. QUESTIONS 1. What should you conclude at this time? 2. What experimental questions would you propose to investigate at this time? 3. What previous experiment did the Hershey and Chase results confirm?

The Evidence 1869-1924 1869: DNA, first called "nuclein," is identified by Friedrich Miescher as a weakly acidic substance found in cell nuclei of human white blood cells. 1924: Chromosomes are shown to be composed of both DNA and protein. QUESTIONS 1. What should you conclude at this time? 2. What experimental question would you propose to investigate at this time? The Evidence: 1928-1944 1928: Frederick Griffith discovers that heat-killed bacteria can transform a non-virulent strain. This phenomenon, called transformation, provides the first evidence that genetic material is a heat- stable chemical. 1944: Oswald Avery, Maclyn McCarty, and Colin MacLeod identify Griffith's transforming agent as DNA. QUESTIONS 1. What should you conclude at this time? 2. What experimental questions would you propose to investigate at this time? 3. How would you have answered the criticism of Avery's work; that DNA was too simple to be the genetic molecule? The Evidence: 1949-1952 1949: Erwin Chargaff, a biochemist, reports that DNA composition is species-specific, that is, the amount of DNA and its nitrogenous bases varies from one species to another. In addition, Chargaff finds that the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine in DNA from every species. 1952: Alfred Hershey and Martha Chase use bacteriophages grown in a radioactive medium to show that DNA enters the cells as the transforming agent. QUESTIONS 1. What should you conclude at this time? 2. What experimental questions would you propose to investigate at this time? 3. What previous experiment did the Hershey and Chase results confirm?

Human Anatomy & Physiology (11th Edition)
Human Anatomy & Physiology (11th Edition)
11th Edition
ISBN:9780134580999
Author:Elaine N. Marieb, Katja N. Hoehn
Publisher:Elaine N. Marieb, Katja N. Hoehn
Chapter1: The Human Body: An Orientation
Section: Chapter Questions
Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...
See similar textbooks
icon
Related questions
Question
**DNA Structure** DNA is composed of a double chain of four alternating nucleotides. Each nucleotide contains a sugar (deoxyribose), a phosphate group, and a nitrogenous base. There are only four different nitrogenous bases in DNA: adenine, thymine, guanine, and cytosine. Figures 7.1 and 7.2 show the structure of each of these bases. The nucleotides differ only in the nitrogenous base. **Figures Explanation:** - **Figure 7.1: Double-ringed purines found in DNA.** - **Adenine (A):** Displays a double-ring structure with nitrogen atoms. - **Guanine (G):** Similar double-ring structure with additional functional groups. - **Figure 7.2: Single-ring pyrimidines found in DNA.** - **Cytosine (C):** Illustrates a single-ring structure with nitrogen atoms. - **Thymine (T):** Similar single-ring structure with methyl groups. **The Evidence: 1953** - **1953:** Rosalind Franklin, working in Maurice Wilkins's lab, determines the spatial relationships of DNA and that the A form is antiparallel using X-ray crystallography. She shows the overall structure of DNA. - **1953:** James Watson and Francis Crick discover the molecular structure of DNA. **QUESTIONS** 1. What should you conclude at this time? 2. What was the contribution of Watson and Crick?
Transcribed Image Text:**DNA Structure** DNA is composed of a double chain of four alternating nucleotides. Each nucleotide contains a sugar (deoxyribose), a phosphate group, and a nitrogenous base. There are only four different nitrogenous bases in DNA: adenine, thymine, guanine, and cytosine. Figures 7.1 and 7.2 show the structure of each of these bases. The nucleotides differ only in the nitrogenous base. **Figures Explanation:** - **Figure 7.1: Double-ringed purines found in DNA.** - **Adenine (A):** Displays a double-ring structure with nitrogen atoms. - **Guanine (G):** Similar double-ring structure with additional functional groups. - **Figure 7.2: Single-ring pyrimidines found in DNA.** - **Cytosine (C):** Illustrates a single-ring structure with nitrogen atoms. - **Thymine (T):** Similar single-ring structure with methyl groups. **The Evidence: 1953** - **1953:** Rosalind Franklin, working in Maurice Wilkins's lab, determines the spatial relationships of DNA and that the A form is antiparallel using X-ray crystallography. She shows the overall structure of DNA. - **1953:** James Watson and Francis Crick discover the molecular structure of DNA. **QUESTIONS** 1. What should you conclude at this time? 2. What was the contribution of Watson and Crick?
**The Evidence: 1869–1924** - **1869:** DNA, first called “nuclein,” is identified by Friedrich Miescher as a weakly acidic substance found in cell nuclei of human white blood cells. - **1924:** Chromosomes are shown to be composed of both DNA and protein. **Questions** 1. What should you conclude at this time? 2. What experimental question would you propose to investigate at this time? --- **The Evidence: 1928–1944** - **1928:** Frederick Griffith discovers that heat-killed bacteria can transform a non-virulent strain. This phenomenon, called transformation, provides the first evidence that genetic material is a heat-stable chemical. - **1944:** Oswald Avery, Maclyn McCarty, and Colin MacLeod identify Griffith’s transforming agent as DNA. **Questions** 1. What should you conclude at this time? 2. What experimental questions would you propose to investigate at this time? 3. How would you have answered the criticism of Avery’s work; that DNA was too simple to be the genetic molecule? --- **The Evidence: 1949–1952** - **1949:** Erwin Chargaff, a biochemist, reports that DNA composition is species-specific, that is, the amount of DNA and its nitrogenous bases varies from one species to another. In addition, Chargaff finds that the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine in DNA from every species. - **1952:** Alfred Hershey and Martha Chase use bacteriophages grown in a radioactive medium to show that DNA enters the cells as the transforming agent. **Questions** 1. What should you conclude at this time? 2. What experimental questions would you propose to investigate at this time? 3. What previous experiment did the Hershey and Chase results confirm?
Transcribed Image Text:**The Evidence: 1869–1924** - **1869:** DNA, first called “nuclein,” is identified by Friedrich Miescher as a weakly acidic substance found in cell nuclei of human white blood cells. - **1924:** Chromosomes are shown to be composed of both DNA and protein. **Questions** 1. What should you conclude at this time? 2. What experimental question would you propose to investigate at this time? --- **The Evidence: 1928–1944** - **1928:** Frederick Griffith discovers that heat-killed bacteria can transform a non-virulent strain. This phenomenon, called transformation, provides the first evidence that genetic material is a heat-stable chemical. - **1944:** Oswald Avery, Maclyn McCarty, and Colin MacLeod identify Griffith’s transforming agent as DNA. **Questions** 1. What should you conclude at this time? 2. What experimental questions would you propose to investigate at this time? 3. How would you have answered the criticism of Avery’s work; that DNA was too simple to be the genetic molecule? --- **The Evidence: 1949–1952** - **1949:** Erwin Chargaff, a biochemist, reports that DNA composition is species-specific, that is, the amount of DNA and its nitrogenous bases varies from one species to another. In addition, Chargaff finds that the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine in DNA from every species. - **1952:** Alfred Hershey and Martha Chase use bacteriophages grown in a radioactive medium to show that DNA enters the cells as the transforming agent. **Questions** 1. What should you conclude at this time? 2. What experimental questions would you propose to investigate at this time? 3. What previous experiment did the Hershey and Chase results confirm?
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 3 steps

SEE SOLUTIONCheck out a sample Q&A here
Blurred answer
Knowledge Booster
Virus
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
Human Anatomy & Physiology (11th Edition)
Human Anatomy & Physiology (11th Edition)
Biology
ISBN:
9780134580999
Author:
Elaine N. Marieb, Katja N. Hoehn
Publisher:
PEARSON
Biology 2e
Biology 2e
Biology
ISBN:
9781947172517
Author:
Matthew Douglas, Jung Choi, Mary Ann Clark
Publisher:
OpenStax
Anatomy & Physiology
Anatomy & Physiology
Biology
ISBN:
9781259398629
Author:
McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa Stouter
Publisher:
Mcgraw Hill Education,
Molecular Biology of the Cell (Sixth Edition)
Molecular Biology of the Cell (Sixth Edition)
Biology
ISBN:
9780815344322
Author:
Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter Walter
Publisher:
W. W. Norton & Company
Laboratory Manual For Human Anatomy & Physiology
Laboratory Manual For Human Anatomy & Physiology
Biology
ISBN:
9781260159363
Author:
Martin, Terry R., Prentice-craver, Cynthia
Publisher:
McGraw-Hill Publishing Co.
Inquiry Into Life (16th Edition)
Inquiry Into Life (16th Edition)
Biology
ISBN:
9781260231700
Author:
Sylvia S. Mader, Michael Windelspecht
Publisher:
McGraw Hill Education
SEE MORE TEXTBOOKS