Chapter 13, Problem 1P

Choose the phrase from the right column that best fits the term in the left column.

a. transformations	1. requires supplements in medium for growth
b. conjugation	2. a method for mutagenizing genes in bacterial genomes
c. transduction	3. small circular DNA molecule that can integrate into the chromosome
d. lytic cycle	4. the core genes that define a bacterial species plus all of the genes unique to individual strains
e.lysogeny	5. transfer of DNA requiring direct physical contact
f. episome	6. integration of phage DNA into the chromosome
g. auxotroph	7. infection by phages in which lysis of cells releases new virus particles
h. pangenome	8. transfer of naked DNA
i. gene targeting	9. transfer of DNA between bacteria via virus particles

Summary Introduction

a.

To determine:

The phrase that describes “transformation.”

Answer to Problem 1P

Correct answer:

Transformation: transfer of naked DNA.

Explanation of Solution

Transformation is the process by which the bacterium transforms into another by receiving the naked DNA molecule. This process does not require physical contact like conjugation or virus particles like transduction.

Summary Introduction

b.

To determine:

The phrase that describes “conjugation.”

Answer to Problem 1P

Correct answer:

Conjugation: transfer of DNA requiring direct physical contact.

Explanation of Solution

Conjugation is the process by which the donor bacterium forms a conjugation tube and then transfers the DNA through this tube into the recipient bacterium. A conjugation is a form of sexual reproduction that takes place in the higher eukaryotes.

Summary Introduction

c.

To determine:

The phrase that describes “transduction.”

Answer to Problem 1P

Correct answer:

Transduction: transfer of DNA between bacteria via virus particles.

Explanation of Solution

Transduction is the process the transfer of the bacterial DNA takes place through virus particles also known as a bacteriophage, which attacks the bacteria and carries it’s DNA and then integrates this DNA into another bacterium while causing infection.

Summary Introduction

d.

To determine:

The phrase that describes “lytic cycle”.

Answer to Problem 1P

Correct answer:

Lytic cycle: infection by phages in which lysis of cells releases new particles.

Explanation of Solution

The bacteriophage is the virus that attacks bacteria, hence named bacteriophage. The term phage implies ‘to eat,’ thus bacteriophage means ‘eating bacteria.’ The bacteriophage performs two types of life cycle inside the host. The latent or lysogenic cycle and the virulent lytic cycle.

Summary Introduction

e.

To determine:

The phrase that describes “lysogeny.”

Answer to Problem 1P

Correct answer:

Lysogeny: integration of phage DNA into the chromosome.

Explanation of Solution

Lysogeny is another form of the viral life cycle in which it does not kill the host buts integrates its DNA inside the host’s DNA and then replicates, causing latent infection. The lysogenic bacteria can be converted into lytic bacteria through some external agents.

Summary Introduction

f.

To determine:

The phrase that describes “episome.”

Answer to Problem 1P

Correct answer:

Episome: small circular DNA molecule that can integrate into the chromosome.

Explanation of Solution

Episomes are the small circular DNA fragments like plasmid that can replicate on their own and can also integrate into the chromosomes and then replaced along with the chromosomes.

Summary Introduction

g.

To determine:

The phrase that describes “auxotroph”.

Answer to Problem 1P

Correct answer:

Auxotroph: requires supplements in medium for growth.

Explanation of Solution

Auxotrophs are the special type of organisms that require a certain type of nutrients in the medium from an external source as they cannot synthesize the substrate or enzyme and require it for their proper growth and multiplication. These microbes are used to test the importance of specific substrates in growth and reproduction.

Summary Introduction

h.

To determine:

The phrase that describes “pangenome.”

Answer to Problem 1P

Correct answer:

Pangenome: the core genes that define a bacterial species plus all of the genes unique to individual strains.

Explanation of Solution

The pangenome is the entire genetic material of an organism. It consists of diploid content of the genome and all the genes that are unique to that specific organism. Hence, it represents the genetic composition of the entire species of an organism.

Summary Introduction

i.

To determine:

The phrase that describes “gene targeting.”

Answer to Problem 1P

Correct answer:

Gene targeting: a method for mutagenizing genes in bacterial genomes.

Explanation of Solution

Gene targeting is the method of bringing about changes in the gene of the desired organism. This technique belongs to the field of DNA recombinant technology and is used to remove the defective genes or incorporate desired genes inside the DNA and then improve the variety of existing species.