Chapter 7 - Genetic Transfer and Mapping in Bacteria

Question 1

Are bacteria usually haploid or diploid?

Answer 1

Haploid

Question 2

Bacteria reproduce asexually through this method

Answer 2

Binary fission

Question 3

In this process, a segment of bacterial DNA is transferred from one bacterium to another

Answer 3

Genetic transfer (or horizontal genetic transfer)

Question 4

These are viruses that infect bacteria

Answer 4

Bacteriophages

Question 5

Do bacteriophages contain their own genetic material?

Answer 5

Yes

Question 6

Like sexual reproduction in eukaryotes, genetic transfer in bacteria enhances this

Answer 6

Genetic diversity

Question 7

What are three ways in which genetic material can transfer from one bacterium to another?

Answer 7

Conjugation, transduction, transformation

Question 8

This method of genetic transfer involves direct physical contact between bacteria

Answer 8

Conjugation

Question 9

This method of genetic transfer involves bacteriophages

Answer 9

Transduction

Question 10

This method of bacterial genetic transfer involves uptake from the environment

Answer 10

Transformation

Question 11

In conjugation, this circular segment of DNA is transferred to a recipient cell

Answer 11

Plasmid

Question 12

In transformation, is the donor cell alive or dead?

Answer 12

Dead

Question 13

Genetic transfer in bacteria was discovered in 1946 by these two scientists

Answer 13

Joshua Lederberg and Edward Tatum

Question 14

What are the two different strains of E. coli that Joshua Lederberg and Edward Tatum studied?

Answer 14

Auxotrophs and prototrophs

Question 15

This strain of E. coli cannot synthesize a particular nutrient and therefore need it in their growth medium

Answer 15

Auxotrophs

Question 16

This strain of E. coli make all their nutrients from components in their growth medium

Answer 16

Prototrophs

Question 17

This scientist showed that bacterial strains must make physical contact for transfer of genetic material to occur

Answer 17

Bernard Davis

Question 18

Bernard Davis used this apparatus to show that bacteria must make physical contact to transfer genetic material

Answer 18

U-tube

Question 19

This apparatus has a filter at the bottom with pores that are large enough to allow the passage of genetic material but small enough to prevent the passage of bacterial cells

Answer 19

U-tube

Question 20

Can all species of bacteria conjugate?

Answer 20

No

Question 21

Can only certain strains of bacteria act as donor cells in conjugation?

Answer 21

Yes

Question 22

Certain donor strains of E. coli contain this small circular piece of DNA

Answer 22

F factor (fertility factor)

Question 23

Bacteria strains containing an F factor are designated this

Answer 23

F+

Question 24

Bacteria strains lacking an F factor are designated this

Answer 24

F-

Question 25

Genes that play a role in DNA transfer are named either of these two prefixes

Answer 25

tra or trb followed by a capital letter

Question 26

What initiates conjugation between bacteria cells?

Answer 26

Contact between donor and recipient cells

Question 27

These act as attachment sites for F- minus bacteria onto F+ bacteria

Answer 27

Sex pili (or F pili)

Question 28

Once contact is made and the pili shorten, donor and recipient bacteria cells are drawn together and this forms between the two cells

Answer 28

Conjugation bridge

Question 29

During conjugation, this recognizes the origin of transfer (DNA sequence) and makes a cut in the DNA

Answer 29

Relaxosome

Question 30

This protein remains bound to the end of the T-DNA after most accessory proteins of the relaxosome are released

Answer 30

Relaxase

Question 31

This is a complex of 10 to 15 proteins encoded by the F factor that span both inner and outer membranes and pumps DNA/relaxase into the recipient cell

Answer 31

Exporter

Question 32

This is the general term used to describe extra-chromosomal DNA

Answer 32

Plasmid

Question 33

Do plasmids replicate independent of bacterial chromosomes?

Answer 33

Yes

Question 34

Plasmids can exist as a single copy or up to 100 copies per cell, depending on this

Answer 34

Strength of origin

Question 35

Are plasmids usually required for survival?

Answer 35

No

Question 36

Plasmids can provide these to bacteria

Answer 36

Growth advantages

Question 37

What are the five different categories of plasmids?

Answer 37

1. Fertility plasmids; 2. Resistance plasmids; 3. Degradative plasmids; 4. Col-plasmids; 5. Virulence plasmids

Question 38

This category of plasmids allows conjugation

Answer 38

Fertility plasmids

Question 39

This category of plasmids contain genes conferring resistance to antibiotics

Answer 39

Resistance plasmids

Question 40

This is another term for resistance plasmids

Answer 40

R factors

Question 41

This category of plasmids carries genes allowing digestion of unusual substances

Answer 41

Degradative plasmids

Question 42

This category of plasmids contain genes that kill other bacteria

Answer 42

Col-plasmids

Question 43

This category of plasmid carries genes that turn bacterium into pathogenic strains

Answer 43

Virulence plasmids

Question 44

In the 1950s, this scientist discovered a strain of E. coli that was very efficient at transferring chromosomal genes

Answer 44

Luca Cavalli-Sforza

Question 45

Luca Cavalli-Sforza discovered a strain of E. coli that was very efficient at transferring chromosomal genes and he designated it this

Answer 45

Hfr (high frequency of recombination)

Question 46

F factors that were excised imprecisely and carry genes that were found on the bacterial chromosome are called this

Answer 46

F' factors (F prime factors)

Question 47

This scientist demonstrated that conjugation between an Hfr and an F- strain involves the transfer of a portion of the Hfr bacterial chromosome

Answer 47

William Hayes

Question 48

How long does it take for the entire Hfr chromosome to be passed into the F- cell during conjugation?

Answer 48

1.5 - 2 hours

Question 49

Do most conjugations take less than the full 1.5-2 hours?

Answer 49

Yes

Question 50

Because most conjugations take less than the full 1.5-2 hours, only a portion of this chromosome gets into the F- cell

Answer 50

Hfr chromosome

Question 51

Chromosomal material from Hfr cell can recombine with this in the recipient cell

Answer 51

Homologous region on chromosome of recipient cell

Question 52

This technique to map chromosomes was developed by Elie Wollman and Francois Jacob in the 1950s

Answer 52

Interrupted conjugation technique

Question 53

These two scientists developed the interrupted conjugation technique in the 1950s

Answer 53

Elie Wollman and Francois Jacob

Question 54

What is the rationale behind the interrupted conjugation technique?

Answer 54

The time it takes genes to enter the recipient cell is directly related to their order along the bacterial chromosome

Question 55

In the interrupted conjugation technique, the order of genes along the chromosome can be deduced by determining this

Answer 55

The length of time it takes to transfer certain genes

Question 56

How long is the E. coli genetic map?

Answer 56

100 minutes

Question 57

This is a virus that specifically infects bacterial cells

Answer 57

Bacteriophage

Question 58

A bacteriophage is composed of genetic material surrounded by this

Answer 58

Protein coat

Question 59

Bacteriophages may follow one or both of these two different cycles

Answer 59

Lytic and lysogenic

Question 60

This scientist discovered bacterial transformation in 1928 while working with strains of Streptococcus pneumoniae

Answer 60

Frederick Griffith

Question 61

What are the two types of bacterial transformation?

Answer 61

Natural and artificial

Question 62

Bacterial cells that are able to take up DNA are termed this

Answer 62

Competent cells

Question 63

Competent bacterial cells carry genes that encode these proteins

Answer 63

Competence factors

Question 64

Competence factors are proteins that facilitate this

Answer 64

Binding/uptake/incorporation of DNA into bacterial chromosome

Question 65

This enzyme cuts extracellular environmental DNA into smaller fragments

Answer 65

Endonuclease

Question 66

Are both extracellular DNA strands cut by endonuclease transported into the recipient cell?

Answer 66

No (one is degraded and the other enters cell)

Question 67

This is a region of mismatch caused by sequence differences between two alleles during transformation

Answer 67

Heteroduplex

Question 68

If the transformed DNA is homologous to a region in the bacterial chromosome, it can be incorporated through this process

Answer 68

Homologous recombination

Question 69

If the transformed DNA is not homologous to any genes on the chromosome, it may be incorporated at a random site on the chromosome through this process

Answer 69

Nonhomologous recombination

Question 70

Streptococcus pneumoniae secretes this, which leads to competence only when many cells of the same species are nearby

Answer 70

Competence-stimulating peptide

Question 71

Some species use these to preferentially take up DNA

Answer 71

DNA uptake signal sequences

Question 72

How many base pairs long are DNA uptake signal sequences?

Answer 72

9 or 10 bp

Question 73

How many times are DNA uptake signal sequences repeated throughout a bacterial genome?

Answer 73

1,000 - 2,000 times

Question 74

This is a common method to artificially induce bacterial transformation

Answer 74

Treat with calcium chloride and high temperature shock to make cells permeable to small DNA molecules

Question 75

This artificial transformation method makes cells permeable with an external electrical field

Answer 75

Electroporation

Question 76

Horizontal gene transfer has dramatically contributed to this

Answer 76

Acquired antibiotic resistance

Question 77

Some strains of this bacterial species are resistant to methicillin and all penicillins

Answer 77

Staphylococcus aureus