Exam 4 Concepts Lecture 24

Front 1

What is the most common type of mutation?

Back 1

Point mutations

Front 2

What does the consequence of a mutation depend on?

Back 2

The type of mutation and the location of the mutation

Front 3

What can occur if you get a point mutation in a Coding region?

Back 3

Silent mutations, missense mutations, or frameshift mutations.

Front 4

What can happen if you get a point mutation in a non-coding region?

Back 4

No affect or possibly gene expression alteration

Front 5

What are the consequences of a change in protein sequence?

Back 5

Loss of function or gain of function

Front 6

How do consequences manifest?

Back 6

Phenotypic changes

Front 7

How are mutations subject to selective pressure?

Back 7

Organisms with different genotypes or phenotypes can be selected for or against

Front 8

How do Eukaryotes reproduce?

Back 8

Sexual reproduction

Front 9

How do Eukaryotes transfer genes?

Back 9

Vertical gene transfer

Front 10

What is genetic variation in Eukaryotes mainly due to?

Back 10

Cross over between sister chromatids during meiosis and the fusion of male and female gamets

Front 11

How do prokaryotes reproduce?

Back 11

Asexual reproduction, budding, ect.

Front 12

How do prokaryotes have the majority of genetic variation?

Back 12

Horizontal gene transfer

Front 13

How does horizontal gene transfer differ from vertical gene transfer?

Back 13

It is the transfer of genes from one independent mature organism to the other. They can be transferred to the same or different species, and as long as it’s stable transition, the recipient gains the phenotype of the donor

Front 14

How can horizontally transferred DNA become stable?

Back 14

It needs to be able to replicate or integrate the gene into the bacterial chromosome.

Front 15

How does integrating the host genome in HGT occur?

Back 15

Recombination!

Front 16

What are the two major types of recombination? What is the most common type?

Back 16

Homologous and site specific recombo. Homologous is the most common type.

Front 17

How does homologous recombination occur?

Back 17

It occurs between two similar/same long DNA sequences that break and rejoin together via a RecA protein.

Front 18

How do archaea get genetic variation for the most part?

Back 18

Horizontal gene transfer.

Front 19

What are the two types of transmissible DNA in HGT?

Back 19

Transposable elements and plasmids

Front 20

What are the three mechanism for HGT?

Back 20

Conjugation, transformation, and transduction

Front 21

What are transposable elements, and how do they work?

Back 21

They are small segments of DNA that move about the genome. They do this via transposition.

Front 22

What domains of life are transposable elements found?

Back 22

All

Front 23

What are the most simple transposable elements?

Back 23

Insertion sequences

Front 24

What are composite transposons? What are they flanked by?

Back 24

They are transposable elements containing an extra gene. They’re flanked by two insertion sequences.

Front 25

What are Unit transposons?

Back 25

Basically they’re insertion sequences with an extra gene

Front 26

What are common features of transposons?

Back 26

Inverted repeats marking the end of the IS/TN, transposase, and direct repeats

Front 27

What are the two mechanisms of action for transposable elements to take?

Back 27

Simple transposistion and replicative transposition

Front 28

What is the mechanism of action for transposable elements where a copy of the transposable element is left in whatever DNA it is leaving?

Back 28

Replicative transposition

Front 29

How does simple transposition work?

Back 29

Transposasse excites the transposable element, then binds it and gets migrated to a new insertion site. The target site is cleaved and the transposable element is litigated into the site. Then the site is replicated in process to make direct repeats

Front 30

In replicative transposition, what happens to the original transposon?

Back 30

It remains at the parental site in the DNA. It is only A COPY that ends up in a new DNA

Front 31

What are retrotransposons?

Back 31

A RNA copy of Transposable elements which are reverse transcribed into DNA. It will integrate at a new site

Front 32

What are plasmids?

Back 32

Small extrachromosomal circular DNA molecules that can exist and replicate independently of a chromosome. They contain non-essential genes that confer selective advantages to host

Front 33

Why do cells not come up with a way to keep out plasmids?

Back 33

They confer a selective advantage to the host

Front 34

What are episomes?

Back 34

Plasmids which can integrate reverseibly into the host chromosome. Also know as a F Plasmid

Front 35

When do conjugative plasmids transfer copies of themselves to other bacteria?

Back 35

Conjugation

Front 36

What is F-XF+ mating?

Back 36

A copy of the F factor is transferred to the recipient and doesn’t integrate into the host chromosome. The donor’s genes aren’t usually transferred. ROLLING CIRCLE METHOD.

Front 37

What is the rolling circle method.

Back 37

The plasmid gets nicked at the orgin and it gets replicated as it pulls.

Front 38

Where does integration occur?

Back 38

Insertion sequences

Front 39

When is a cell called F+?

Back 39

When the f factor is NOT integrated into the chromosome cell

Front 40

When is a cell called HFr?

Back 40

When F factor is integrated into chromosome cells

Front 41

When does a F’ Plasmid form?

Back 41

When the F factor incorrectly excises from the host chromosome and some of the F factor is left behind in the host chromosome.

Front 42

What occurs when a cell integrates a F’ Plasmid?

Back 42

The genes that the plasmid accidentally picked up can be transferred to a new host :D

Front 43

What does competence mean?

Back 43

It means that bacteria are good at picking up DNA around them

Front 44

When are competent cells transformed?

Back 44

When they pick up DNA

Front 45

What is it called when cells uptake extracellular DNA?

Back 45

Transformation

Front 46

What is Transduction?

Back 46

When bacterial genes are transferred via viruses

Front 47

What are the two pathways that cells can be transduced?

Back 47

Lytic and lysogenic

Front 48

What types of transduction occurs because of an error in the lysogenic cycle?

Back 48

Specialized

Front 49

What type of transduction occurs because of errors in the lytic cycle?

Back 49

Generalized

Front 50

In generalized transduction, what part of the cycle is the mistake?

Back 50

In viral assembly (the fragments of DNA end up packaged into the phage head.)

Front 51

What is in the generalized transducing particals?

Back 51

Bacterial DNA wrapped in viral proteins, but no viral DNA.

Front 52

What part of the bacterial genome can be transferred via Generalized transduction?

Back 52

Any

Front 53

In specialized transduction, when does the error occur?

Back 53

When the prophage is incorrectly excised

Front 54

What do the virions contain in a specialized transduction?

Back 54

Part of the viral genome plus host DNA surrounding the viral integration site.

Front 55

What ways can specialized transduction occur?

Back 55

IT can recombine with the genome or integrate with partial phage genome.

Front 56

What are the mechanisms of drug resistance?

Back 56

Mods of target enzymes or target organelle, inactivation of drugs, chemical modification by pathogen. Drug is pumped out of a cell (efflux), or alternative pathways or proteins are used to Mess with the antibiotics.

Front 57

How does antibiotic resistance occur?

Back 57

Mutations lead to resistance. Horizontal transfer of resistance genes.

Front 58

What is a superbug?

Back 58

A bacteria that is antibiotic resistant

Front 59

What is the origin and transmission of drug resistance?

Back 59

It is found on bacterial chromosomes, plasmids, and transposons. When it’s found on mobile genetic elements they can be freely exchanged between bacteria.