Chapter 7

Question 1

Prototrophic

Answer 1

wild type

Question 2

Auxotrophic

Answer 2

mutant type

Question 3

Minimum Medium

Answer 3

Only required by prototrophic bacteria

Question 4

Complete Medium

Answer 4

Contain all substances required by all bacteria, including auxotrophic bacteria

Question 5

Bacterial Genome

Answer 5

mostly single, circular DNA

Question 6

Plasmid

Answer 6

extra chromosome, small circular DNA

Question 7

F+

Answer 7

present as separate circular DNA; donor

Question 8

F-

Answer 8

Absent; recipient

Question 9

Hfr

Answer 9

Present, integrated into bacterial chromosome

Question 10

F’

Answer 10

present as separate circular DNA, carrying extra bacterial genes

Question 11

Conjugation

Answer 11

direct transfer via one-way traffic from donor cells to recipient cells

Question 12

Merozygotes

Answer 12

partial diploid bacterial cells with two copies of some genes, one on the bacterial chromosome and one on the newly introduced F plasmid

Question 13

Pili

Answer 13

extension of the cell membrane of some bacteria that allows conjugation to take place

Question 14

F+ x F-

Answer 14

Two F+ cells; F- cell becomes F+

Question 15

Hfr x F-

Answer 15

One Hfr cell and one F- cell; no change

Question 16

F’ x F-

Answer 16

Two F’ cells; F- cell becomes F’

Question 17

Transformation

Answer 17

mechanism by which DNA found in the environment is taken up by the cell

Question 18

Transduction

Answer 18

when a virus carries genes from one bacterium to another

Question 19

Compentence

Answer 19

the ability to take up DNA from the environment

Question 20

Transformant

Answer 20

cell that has received genetic material through transformation

Question 21

Laboratory Use of Transformation

Answer 21

competent cells are produced by heat shock and exposure to calcium chloride; allows cells to more readily take up foreign DNA because it alters cell wall

Question 22

Transformation Efficiency

Answer 22

probability cells take up extracellular DNA and express genes encoded by it

Question 23

Factors affecting Transformation Efficiency

Answer 23

plasmid size, DNA type, cell genotype, transformation method, cell growth rate

Question 24

Cotransformed

Answer 24

process in which two or more genes are taken up together during cell transformation

Question 25

Horizontal Gene Transfer

Answer 25

transfer of genes from one organism to another by a mechanism other than reproduction

Question 26

Restriction Modification System

Answer 26

a type of bacterial defense that uses restriction enzymes to cleave foreign DNA

Question 27

CRISPR Array

Answer 27

a series of repeated DNA sequences called clustered regularly interspaced short palindromic repeats located in the bacterial or archaeal chromosome

Question 28

Two Major Components of CRISPR-Cas System

Answer 28

CRISPR Array and set of genes encoding Cas proteins

Question 29

Cas Protein

Answer 29

protein that functions in CRISPR-Cas system; combine with crRNA to form an effector complex that cleaves DNA at specific base sequences

Question 30

Three Steps in CRISPR-Cas Immunity

Answer 30

Adaptation, Expression, Interference

Question 31

Protospace-Adjacent Motif

Answer 31

adjacent DNA sequence required for binding by a CRISPR-Cas effector complex; the complex associates with the PAM and unwinds the DNA nearby

Question 32

Virus

Answer 32

noncellular replicating structure consisting of nucleic acid surrounded by a protein coat; can only replicate within a host cell

Question 33

Virulent Phage

Answer 33

bacteriophage that reproduces strictly through the lytic cycle and always kills its host cell

Question 34

Temperate Phage

Answer 34

bacteriophage that can undergo the lysogenic cycle, in which the phage DNA integrates into the bacterial chromosome and remains in an inactive state

Question 35

Prophage

Answer 35

phage genome that is integrated into bacterial chromosome

Question 36

Generalized Transduction

Answer 36

any gene may be transferred between bacteria by viruses

Question 37

Specialized Transduction

Answer 37

genes near special sites on the bacterial chromosome are transferred from one bacterium to another; requires lysogenic bacteriophages

Question 38

Transducing Phage

Answer 38

phage that contains a piece of the chromosome of its bacterial host inside the phage coat

Question 39

Transductants

Answer 39

bacterial cell that has received genes from another bacterium through transduction

Question 40

Cotransduced

Answer 40

process in which two or more genes are transferred together from one bacterial cell to another by a virus; only genes located close together on a bacterial chromosome will be cotransduced

Question 41

Retrovirus

Answer 41

virus that injects its RNA genome into a host cell, where reverse transcription produces a complementary, double-stranded DNA molecule from the RNA template

Question 42

Reverse Transcriptase

Answer 42

enzyme that can synthesize complementary DNA from either an RNA or DNA template

Question 43

Provirus

Answer 43

a viral genome incorporated into a host chromosome

Question 44

Integrase

Answer 44

enzyme that inserts prophase, or proviral, DNA into a host chromosome

Question 45

Oncogenes

Answer 45

dominant-acting gene that stimulates cell division, leading to the formation of tumors and contributing to cancer, arises from a mutated copy or a normal cellular gene

Question 46

Gag

Answer 46

encodes proteins that make viral protein

Question 47

Pol

Answer 47

encodes reverse transcriptase and enzyme integrase

Question 48

Env

Answer 48

encodes glycoproteins found on viral surface

Question 49

Antigenic Drift

Answer 49

the appearance of new strains of a rapidly evolving virus because of mutations

Question 50

Antigenic Shift

Answer 50

major change in a viral genome through the reassortment of genetic material from two different strains of the virus