Table of contents

1. Introduction to Genetics51m
2. Mendel's Laws of Inheritance3h 37m
3. Extensions to Mendelian Inheritance2h 41m
4. Genetic Mapping and Linkage2h 28m
5. Genetics of Bacteria and Viruses1h 21m
6. Chromosomal Variation1h 48m
7. DNA and Chromosome Structure56m
8. DNA Replication1h 10m
9. Mitosis and Meiosis1h 34m
10. Transcription1h 0m
11. Translation58m
12. Gene Regulation in Prokaryotes1h 19m
13. Gene Regulation in Eukaryotes44m
14. Genetic Control of Development44m
15. Genomes and Genomics1h 50m
16. Transposable Elements47m
17. Mutation, Repair, and Recombination1h 6m
18. Molecular Genetic Tools19m
- Genetic Cloning
  9m
- Methods for Analyzing DNA
  9m
19. Cancer Genetics29m
- Overview of Cancer
  21m
- Cancer Mutations
  7m
20. Quantitative Genetics1h 26m
21. Population Genetics50m
- Hardy Weinberg
  19m
- Allelic Frequency Changes
  31m
22. Evolutionary Genetics29m

5. Genetics of Bacteria and Viruses

Working with Microorganisms

Genetics

5. Genetics of Bacteria and Viruses

Working with Microorganisms

Previous problemNext problem

1:06 minutes

Problem 1a

Textbook Question

How do we know that genes exist in bacteria and bacteriophages?

Verified step by step guidance

Understand the historical context: Scientists first observed that bacteria and bacteriophages exhibit heritable traits, such as antibiotic resistance in bacteria or the ability of bacteriophages to infect specific bacterial strains. This suggested the presence of genetic material controlling these traits.

Review experiments demonstrating transformation: Frederick Griffith's experiments with Streptococcus pneumoniae showed that non-virulent bacteria could acquire virulence from heat-killed virulent bacteria. This transformation indicated the presence of genetic material in bacteria.

Examine experiments on conjugation: Joshua Lederberg and Edward Tatum demonstrated bacterial conjugation, where genetic material is transferred between bacterial cells through direct contact. This provided further evidence of genes in bacteria.

Consider bacteriophage experiments: The Hershey-Chase experiment used radioactive labeling to show that DNA, not protein, is the genetic material transferred by bacteriophages into bacteria during infection. This confirmed the existence of genes in bacteriophages.

Analyze genetic mapping techniques: Techniques such as interrupted mating experiments in bacteria and recombination frequency analysis in bacteriophages allowed scientists to map genes, further proving their existence and organization in these organisms.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Gene Theory

Gene theory posits that genes are the fundamental units of heredity, responsible for the transmission of traits from one generation to the next. In bacteria and bacteriophages, genes are segments of DNA that encode proteins, influencing various biological functions. The existence of genes in these organisms is supported by experimental evidence, such as mutations and phenotypic changes that correlate with specific genetic alterations.

Genetic Recombination

Genetic recombination is a process by which genetic material is exchanged between organisms, leading to new combinations of genes. In bacteria, this can occur through mechanisms like transformation, transduction, and conjugation, while bacteriophages can introduce new genetic material into bacterial genomes. This process not only demonstrates the presence of genes but also allows geneticists to map and study the genetic structure of these organisms.

Molecular Techniques

Molecular techniques, such as DNA sequencing and polymerase chain reaction (PCR), are essential tools for identifying and studying genes in bacteria and bacteriophages. These methods enable scientists to analyze genetic material directly, providing evidence for the existence of specific genes and their functions. By employing these techniques, researchers can confirm the presence of genes and explore their roles in various biological processes.

Watch next

Master Bacteria in the Laboratory with a bite sized video explanation from Kylia

Start learning

Related Videos

Related Practice

What is a plasmid?

True or False:All bacterial cells within a bacteria colony grown on a plate in a laboratory are genetically identical.

Which of the following is NOT a way scientists can phenotypically identify a bacterial mutation?

How do we know that bacteria undergo genetic recombination, allowing the transfer of genes from one organism to another?

320

views

Textbook Question

Fifteen bacterial colonies growing on a complete medium are transferred to a minimal medium. Twelve of the colonies grow on minimal medium.

The serine biosynthetic pathway is a three-step pathway in which each step is catalyzed by the enzyme product of a different gene, identified as enzymes A, B, and C in the diagram below.

Mutant 1 grows only on min + Ser. In addition to growth on min + Ser, mutant 2 also grows on min + 3-PHP and min + 3-PS. Mutant 3 grows on min + 3-PS and min + Ser. Identify the step of the serine biosynthesis pathway at which each mutant is defective.

377

views

Textbook Question

Fifteen bacterial colonies growing on a complete medium are transferred to a minimal medium. Twelve of the colonies grow on minimal medium.

The three colonies that do not grow on minimal medium are transferred to minimal medium supplemented with the amino acid serine (min + Ser), and all three colonies grow. Characterize these three colonies.

385

views

Textbook Question

Fifteen bacterial colonies growing on a complete medium are transferred to a minimal medium. Twelve of the colonies grow on minimal medium.

Using terminology, characterize the 12 colonies that grow on minimal medium and the 3 colonies that do not.

579

views

Textbook Question

In general, when recombination experiments are conducted with bacteria, participating bacteria are mixed in complete medium, then transferred to a minimal growth medium. Why isn't the protocol reversed: minimal medium first, complete medium second?

486

views

Show more practices