Study Guide for Campbell Biology
Study Guide for Campbell Biology
11th Edition
ISBN: 9780134443775
Author: Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Jane B. Reece, Martha R. Taylor, Michael A. Pollock
Publisher: PEARSON
bartleby

Concept explainers

bartleby

Videos

Textbook Question
Book Icon
Chapter 16, Problem 1IQ

Hershey and Chase devised an experiment using radioactive isotopes to determine whether it was a phage’s DNA or protein that entered the bacteria and served as the genetic material of T2 phage.

  1. a. How did they label phage protein?
  2. b. How did they label phage DNA?

After infecting separate samples of E. coli with the differently labeled T2 cells, they blended and centrifuged the samples to isolate the bacterial cells from the lighter viral particles.

  1. c. Where was the radioactivity found in the samples with labeled phage protein?
  2. d. Where was the radioactivity found in the samples with labeled phage DNA?
  3. e. What did Hershey and Chase conclude from these results?

a.

Expert Solution
Check Mark
Summary Introduction

To determine: In what manner Hershey and Chase labeled phage protein.

Introduction: DNA is the organic molecule that carries information from one generation to another. Several experiments are to be conducted to prove that DNA is the genetic material. One such experiment is the Hershey–Chase experiment, which is commonly known as the blender experiment.

Explanation of Solution

In the year 1952, Alfred Hershey and Martha Chase performed a series of experiment to confirm if DNA was the genetic material inherited by the offspring from parents. DNA and protein are important macromolecules that can carry genetic information. Hershey–Chase took T2 phage in the experiment because it contained a single DNA surrounded by a protein coat. They labeled two bacteriophages with different radioactive substances. They labeled phage protein with the radioactive sulfur (S35). Radioactive sulfur tags only proteins, as protein contains sulfur.

b.

Expert Solution
Check Mark
Summary Introduction

To determine: In what manner Hershey and Chase labeled phage DNA.

Introduction: Deoxyribonucleic acid (DNA) is a macromolecule that transfers genetic information from parents to offspring. The structure of DNA is made of nucleotides, sugar, and phosphates appearing as a double-helical polymer.

Explanation of Solution

Alfred Hershey and Martha Chase labeled two bacteriophages with different radioactive substances. They labeled phage DNA with radioactive phosphorus (P32). Radioactive phosphorus tags only the DNA part, as DNA’s backbone has the phosphorus group.

c.

Expert Solution
Check Mark
Summary Introduction

To determine: Where the radioactivity was found in the samples with labeled phage protein.

Introduction: Bacteriophages are a group of viruses that infect bacteria and replicate inside the bacteria. T2 phage is called as Enterobacteria phage T2. It infects Escherichia coli.

Explanation of Solution

Alfred Hershey and Martha Chase labeled two bacteriophages with different radioactive substances. One was labeled with the radioactive sulfur, and the other with radioactive phosphorous. They allowed these two batches of radioactive-labeled bacteriophage to infect the non-radioactive bacterial cell separately in the test tube.

After centrifugation, the culture got separated into a pellet and a supernatant form. The supernatant (liquid) showed the presence of radioactive sulfur. This means that the protein part of bacteriophage was left behind, as it did not enter the bacterial cell.

d.

Expert Solution
Check Mark
Summary Introduction

To determine: Where the radioactivity was found in the samples with labeled phage DNA.

Introduction: DNA or deoxyribonucleic acid carries hereditary information from one generation to another. After several experiments, scientists have found evidence which claims that DNA is the hereditary material that passes on the genetic information from one generation to the next.

Explanation of Solution

After centrifugation, the culture got separated into a pellet and a supernatant form. The pellet showed the presence of radioactive phosphorus and the DNA of the bacteriophage was responsible for the infection of bacteria, as it entered into the bacterial cell.

e.

Expert Solution
Check Mark
Summary Introduction

To determine: What did Hershey and Chase concluded from these results.

Introduction: Bacteriophages are viruses that infect the bacteria and take up their translation machinery for their life cycle. This property was exploited to prove that DNA is a genetic material along with the help of radioactive isotopes.

Explanation of Solution

The bacterial cells that were infected by the bacteriophages consisting radioactive phosphorus showed the presence of radioactive phosphorus. This means that during infection of the bacterial cell, DNA is the part of bacteriophage that got transferred to the bacterial cell and not protein. Thus, they concluded that DNA is the genetic material which is passed on from one generation to the next generation, not the protein.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
a) Where is the F plasmid located in an Hfr cell? Where is the F plasmid located in an F+ cell? b)
(a) Why the plasmid (containing the foreign DNA), together with the competentbacterial cells are heated at 42°C? b) What would be the next stage after heat shock? Discuss the process involved.c) How would you analyze the efficiency of the competent cells used duringtransformation?
Are they true or false? a)If someone reads an absorbance of 0,25 at 260 nm, the concentration of the dsDNA is 25 ug/ml. b)If someone reads an absorbance of 0,25 at 260 nm, the concentration of the dsDNA is 25 ug/ml c)The copy number refers to the number of molecules of an individual plasmid that are normally found in a single bacterial cell. d)The amount of mRNA level can be determined via competitor RT-PCR in which two different sized products can be obtained, one of which is a known standard.
Knowledge Booster
Background pattern image
Biology
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
Text book image
Human Anatomy & Physiology (11th Edition)
Biology
ISBN:9780134580999
Author:Elaine N. Marieb, Katja N. Hoehn
Publisher:PEARSON
Text book image
Biology 2e
Biology
ISBN:9781947172517
Author:Matthew Douglas, Jung Choi, Mary Ann Clark
Publisher:OpenStax
Text book image
Anatomy & Physiology
Biology
ISBN:9781259398629
Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa Stouter
Publisher:Mcgraw Hill Education,
Text book image
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
Text book image
Laboratory Manual For Human Anatomy & Physiology
Biology
ISBN:9781260159363
Author:Martin, Terry R., Prentice-craver, Cynthia
Publisher:McGraw-Hill Publishing Co.
Text book image
Inquiry Into Life (16th Edition)
Biology
ISBN:9781260231700
Author:Sylvia S. Mader, Michael Windelspecht
Publisher:McGraw Hill Education
Molecular Techniques: Basic Concepts; Author: Dr. A's Clinical Lab Videos;https://www.youtube.com/watch?v=7HFHZy8h6z0;License: Standard Youtube License