M2-C3-L06 --> Microbial Genetics Ii

Front 1

What is the control mechanism for the LAC operon? x2

Back 1

NEGATIVE control of INDUCTION

POSITIVE control of INDUCTION

Front 2

What is the control mechanism for the Trp operon? x2

Back 2

NEGATIVE control of REPRESSION

Process of ATTENUATION

Front 3

Define mutation

Back 3

Heritable changes in the nucleotide sequence

Front 4

T/F - Mutations usually give rise to phenotypic changes.

Back 4

False. They usually don't always give rise to phenotypic changes, but can lead to disease.

Front 5

Define tautomerization

Back 5

An inserted base
will change its
base pairing
PROPERTIES

Front 6

Mutagens increase the rate of what?

Back 6

Mutagenesis

Front 7

Most carcinogens are mutagenic, but......

Back 7

not all mutagens are carcinogens

Front 8

Define silent mutation.

Occurs often where?

Back 8

DNA mutation without change in amino acid

often at the 3'position of codon
(tRNA wobble)

Front 9

Define Missense mutation

Back 9

Base change or substitution alters the type of amino acid

Hint 9

MIStake amino acid

Front 10

Define Nonsense mutation

Back 10

Base change causes sequence changes, such that the chain terminates

Hint 10

NOnsense = NO more elongation

Front 11

Define Frameshift mutation

Back 11

Insertion or deletion of bases (not divisible by 3) that changes the reading frame.

Front 12

Define Null mutation

Back 12

Insertion or deletion of large chunks of DNA.

Front 13

Define Direct DNA repair.

Back 13

Direct enzymatic repair of dimers.

Front 14

Define Excision repair

Back 14

Excision of DNA segment containing damaged DNA followed up by synthesis of new strand

Front 15

Define SOS response

Back 15

Forced induction of many genes after DNA damage, bypassing the errors of DNA

Front 16

Define error-prone repair

Back 16

Last resort before death

Front 17

Transfer of DNA occurs through the form of what Components? x3

Back 17

Plasmid
Chromosome
Bacteriophage

Front 18

Plasmids:

- what are they
- how do they replicate
- can they integrate into chromosomes?

Back 18

Circular INDEPENDENT pieces of dsDNA

Replicate AUTONOMOUSLY via origin of replication

Yes

Front 19

What encodes the conjugation apparatus including the sex pili and tra genes?

Back 19

F-plasmid

Front 20

What are the two main groups of plasmids and describe?

Back 20

Large plasmids that are self transmissable
(b/c can form Conjugative Apparatus)

Small plasmids that are NON-conjugative
(can NOT form conjugative apparatus, but may follow its route)

Front 21

What codes for bacterial toxins?

Back 21

Plasmids

Front 22

What codes for Antibiotic resistance?

Back 22

R-plasmids

Front 23

What are the two parts of the R Plasmids?

Back 23

Resistant Transfer Factor (RTF)

R Determinant

Front 24

What does the RTF & R Determinant code for?

Back 24

Encodes resistance to antibiotics

Front 25

What forms when the F plasmid integrates into the bacterial chromosome?

Back 25

HFr Strain

Front 26

What happens to R plasmids when selection pressure is lessened?

Back 26

It is unstable to begin with, so it will become lost.

Front 27

T/F - Phages can replicate outside living cells.

Back 27

False, it cannot replicate outside living cells.

Front 28

What does the One Step Growth curve measure? x2

Back 28

Measures

Latency Period
&
Burst Size

of specific virus

Front 29

What two cycles are possible when a Bacteriophage infects a cell?

Back 29

Lytic cycle

Lysogenic cycle

Front 30

Define prophage

Back 30

A phage genome inserted as part of the DNA chromosome of a bacterium.

Front 31

Define lysogen

Back 31

Bacterium in the state of a lysogenic cycle

Front 32

List the mechanisms for gene transfer. x3

Back 32

Transformation

Transduction

Conjugation

Front 33

Explain transformation

Back 33

Gene transfer between bacteria by means of "naked" DNA fragments, thus transforming the receiving bacteria's DNA

Front 34

Give a basic definition of Transduction.

Back 34

Transfer of viral, bacterial, or both bacterial and viral DNA from one cell to another VIA Bacteriophage

Front 35

What are the two types of transduction?

Back 35

Generalized

Specialized

Front 36

Bacteriophage gene regulation is tightly regulated in what kind of fashion?

Back 36

In a temporal fashion.

Front 37

Generalized Transduction:

- Occurs during which cycle
- What happens

Back 37

There you go bizzzzaaattttcccchhhh!!!!

Front 38

Specialized Transduction:

- occurs during what cycle
- what happens

Back 38

My NNNNNNNNNNNNUUUUUUUTTTTTTZZZZ

Front 39

What is the most frequent form of gene transfer?

Back 39

Conjugation

Front 40

Conjugation:

- occurs between?
- requires presence of what? x2

Back 40

CAN be between differing bacterial species.

Sex pili & Cell to cell contact

Front 41

List two types of Mobile DNA elements in Bacteria

Back 41

1. Bacterial Insertion Sequences (IS)

2. Bacterial Transposons

Front 42

Bacterial Insertion Sequences (IS):

- what are they
- mechanism of movment

Back 42

50-bp inverted repeats flanking regions encoding transposase.
(+/- resolvase)

Excision/copying of DNA and its insertion at the target site.

Front 43

Bacterial Transposons:

- what are they
- mechanism of movement

Back 43

Central antibiotic resistance gene flanked by IS elements

Copying of DNA and its insertion at target site

Front 44

The Ara Operon utilizes what control mechanism?

Back 44

Positive control of induction

Front 45

Describe the Negative control of induction associated with the Lac Operon.

Back 45

With NO lactose, the operon is OFF

Repressor BOUND (thus neg. control)

With ADDED lactose, it binds to repressor, changing its conformation. Thus releasing itself.

Front 46

Describe the Positive control of induction associated with the Lac Operon.

Back 46

With ADDED lactose,

cAMP generated

cAMP binds with CAP

Binds to promoter region, thus enhancing transcription

Front 47

Describe the Negative control of Repression associated with the Trp Operon.

Back 47

No Trp means No Repressor bound

With ADDED Trp, it binds to inactive repressor

Thus activating repressor which binds operon.

Front 48

Describe the process of attenuation associated with the Trp Operon when there is no Trp available

Back 48

Polymerase stalls on sequence 1

Sequence 2 & 3 bind

Thus NO Termination

Enzymes transcribed

Front 49

Describe the process of attenuation associated with the Trp Operon when there is Trp available

Back 49

Ribosome terminates when it encounters the 2 Trp on the leader sequence.

Thus sequence 1 & 2 bind
Thus sequence 3 & 4 bind

Thus creating Rho independent Termination
(hairpin & Loop with Poly U stretch)

Front 50

T/F - Plasmids can produce different sex pili.

Back 50

True

Front 51

T/F - Plasmids can not be in the same incompatible group.

Back 51

False.

Plasmids CAN be in the Same Incompatible group

Front 52

What can be used for cloning specific DNA fragments?

Back 52

Plasmids

Front 53

Plasmids can code for what? x3

Back 53

1. Bacterial Toxins

2. Enzymes that metabolize unusual substrates

3. Antibiotic resistance (R plasmids)

Hint 53

TEA

Front 54

Hfr-strain is formed when what happens?

Back 54

F plasmid integrates into bacterial chromosome

Front 55

Which infected cells are immune from Superinfections from the SAME phage?

Back 55

Lysogenic cells
(with latent phage)

Front 56

T/F - The genetic material of a phage is always DNA.

Back 56

False

Can be DNA or RNA

Front 57

In generalized transduction, what genes are involved?

what phage is involved?

Back 57

Any bacterial gene
(is randomly taken and put into capsid)

Lytic phage

Front 58

In specialized transduction, what genes are involved?

what phage is involved?

Back 58

Restricted Phage genes
(specifically put between bacteria genes: lac & biotin)

Lysogenic phage

Front 59

Conjugation requires? x2

Back 59

1. Cell to cell contact

2. Sex pili

Front 60

F-plasmids encode for what?

Back 60

Conjugation apparatus

includes pili AND tra ("transfer") genes

Front 61

T/F - Non-conjugative plasmids exist but can not be transferred along with conjugative plasmids.

Back 61

False

Non-conjugative plasmids CAN be transferred along with conjugative plasmids.

Front 62

Transformation can occur (tho rare) but requires what criteria?

Back 62

Bacteria must be in state of COMPETENCE

Front 63

T/F - Transformation works in human cells?

Back 63

True

Front 64

What type of gene transfer requires the presence of a phage?

Back 64

Transduction

Front 65

In conjugation, what initiates the "rolling circle" replication? x2

Back 65

1. Single stranded nick @ OriT

2. Binding of protein @ 5' end

Front 66

R-plasmids can be ACQUIRED how?

R-plasmids can be TRANSFERRED how?

Back 66

Transposition

Conjugation

Front 67

What are the classes of Mutagens? x2

Back 67

CHEMICAL
- Agents that Intercalcate
- Base analogs
- Chemicals that act like agents of alkylation

PHYSICAL
- Radiation

Front 68

Give an example of a Physical Mutagen and the resulting effects.

Back 68

UV light is a Physical Mutagen

causes Thymine Dimers to form

Front 69

Define Recombination (or Post-Replication) Repair.

Back 69

Retrieval of Missing Info
by
RECOMBINATION
when
BOTH strands are damaged

Front 70

Recombination (or PostReplication) repair:

- occurs when?
- does involve what process
- does NOT involve what process
- seen in what organism?

Back 70

Both strands are damaged

Genetic Recombination

DNA Synthesis
(b/c template is damaged too)

Bacteria
(just swapping DNA around)