Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Microbiology > Chapter 10 > Flashcards

Chapter 10 Flashcards

1
Q

What are the four reasons bacteria has been a workhorse of genetic research?

A
  1. Rapid growth
  2. Small, haploid genomes- mutations
  3. Excellent tools- plasmids etc
  4. Genetic information of all cellular organisms is encoded in the same way
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why does genetic variation matter?

A

The Central Dogma of Molecular Biology: DNA to RNA to Protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Any change in the DNA sequence is a ___

A

Mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are mutations? What do they lead to?

A

Changes in the DNA sequence. Either spontaneous or induced. They may lead to a different phenotype.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Most prokaryotes are ___

A

Haploid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Types of mutants based on phenotype are __

A

Observable change in appearance or function of a strain carrying the mutation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Spontaneous changes in DNA sequence:

A

Generally low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Mutagens change in DNA sequence:

A

Increases the rate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the four types of changes in the DNA sequence?

A

Spontaneous, mutagens, transposons, horizontal gene transfer.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do we find mutations? (3 ways)

A
  1. Direct selection, like antibiotic resistance, reversion mutants.
  2. Enrichment method.
  3. Screening method- replica plating.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Direct Selection Diagram:

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Enrichment method diagram:

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Replica plating diagram:

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are transposable elements?

A

Jumping genes.
*likely to disrupt genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How are transposable/mobile elements catalyzed?

A

By transposase encoded in the transposon.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are Terminal Inverted repeats?

A

Recognition sites for transposase.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What happens when transposable/mobile elements carry extra genes?

A

Antibiotic resistance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are transposable/mobile elements likely to do?

A

Disrupt genes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is site-directed mutagenesis for?

A

To mutate a gene of interest exactly how we want.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the steps of site-directed mutagenesis? (5)

A
  1. Start with PCR and a modified primer
  2. Introduce into microbial strain of interest
  3. Recombination
  4. Characterize
  5. Genetic complementation to confirm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the 4 methods of mutation repair?

A
  1. Direct repair- photolyases
  2. Excision repair
  3. Recombination repair
  4. SOS repair
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the four genetic differences between prokaryotes and eukaryotes?

A
  1. DNA exchange not prerequisite for reproduction in prokaryotes.
  2. If DNA exchange occurs, generally only small section of DNA exchange in prokaryotes.
  3. Several mechanisms of DNA exchange in prokaryotes- only one in eukaryotes.
  4. Prokaryotes are usually haploid and higher, eukaryotes are usually diploid.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When does vertical gene transfer occur?

A

Occurs during reproduction between generations of cells.

24
Q

What is horizontal gene transfer?

A

The transfer of genes between cells of the same generation.

25
What is transformation in DNA transfer, and what are the three types?
Transformations are DNA from the environment. Genes are transferred from one bacterium to another as "naked" DNA in solution. Few species are able to transform. Natural, artificial, and competent.
26
What is transduction in DNA transfer and what are the two types?
Bacteriophage transfers DNA. Generalized and specialized.
27
What is conjugation in DNA transfer and what are the types?
Direct cell-cell contact is required. Opposite mating sites. Donor (plasmid) and recipient. Gram-positive, gram-negative (F+, F-, Hfr)
28
What does competent mean in transformations?
Alterations in the cell wall that make it permeable to large DNA molecules.
29
Natural transformation: What do single strands come in and do?
Recombine with DNA in chromosome- stretch of hybrid DNA. (RecA proteins)
30
What DNA is released from donor in natural transformation?
Dead cells Alive: Quorum sensing/biofilms
31
Artificial transformation:
Generate "competent" cells by some treatment to permeabilize the cell membrane. Chemical competent (Ca2+ treatment, heat shock), electroporation.
32
What is artificial transformation generally restricted to and why?
Generally restricted to plasmids (self-replicating, circular DNA that contains genes) because of exonucleases in cytoplasm,
33
What are plasmids?
Self-replicating, circular DNA that contains genes. 1-5% the size of the bacterial chromosome.
34
Transducing particles:
Bacterial DNA is transferred from a donor cell to a recipient cell inside a bacteriophage.
35
Generalized transduction:
All genes contained within a bacterium are equally likely to be packed in a phage.
36
Specialized transduction:
Only certain bacterial genes are transferred. Distinct from generalized, not due to packaging errors. Due to excision errors when going from lysogenic phase to lytic phase.
37
What are the types of phage replication?
Virulent/Lytic Phages Temperate phages: lysogenic or lytic pathway, lysogeny at att sites, prophage (excised due to environmental cues).
38
What percent of progeny in a P22 lysate are generalized transducing particles?
2% Some recombined into host, most circularized.
39
Is one or two crossovers more stable in specialized transduction?
Two crossovers.
40
Conjugative plasmid:
Carries genes for sex pili and transfer of the plasmid. F factor
41
Dissimilation plasmids:
Encode enzymes for catabolism of unusual compounds.
42
R factors of plasmids:
Encode resistance to antibiotics, heavy metals, and cellular toxins.
43
What secretion system type do gram negatives use?
Type IV secretion system.
44
Common F factor in plasmids of conjugation:
* Transfer within the enterics (intestinal) * Contains 13 tra genes required for its transfer – Including encoding subunits for the sex pili * Cells with F factor (F+) * No F plasmid are F- * F+ cells attach to F- cells with the pilus, pull the two together, transfer copy of the plasmid, both cells are now F+ * Hfr (High freq of recombination): F plasmid becomes inserted into the chromosome – Now transfers chromosomal genes with itself.
45
Hfr (high freq of recombination:
F plasmid becomes inserted into the chromosome.
46
Conjugation: Mating gram positives __
Clump together.
47
Conjugation (gram-positive): Pilus mediated conjugation seemingly __
Absent.
48
CRISPR/Cas:
Prokayotix mechanism for immunity. Vaccine for microbes. Foreign DNA into the cell.
49
How is DNA processed in CRSPR?
Cas system: cleaves foreign DNA Cleaved DNA "archived" within organized clusters aka CRISPRs.
50
What is CRSPR transcribed as?
A long precursor RNA (pre crRNA) - Spacers- complementary sequences to foreign DNA. - Palindromic repeats that form hairpins.
51
CRSPR is processed by __ to __
Processed by Cas enzymes to crRNAs
52
Other uses for CRSPR: (4)
1. Silence or downregulate the expression of specific genes- target specific mRNAs 2. Cas proteins role in adaptive immunity, stress response- repair proteins and refold proteins. 3. Immunize industrial strain of bacteria 4. Genome editing and transcriptional regulation in microbes and eukaryotes- genetic engineering.
53
What is CRSPR ready to recognize and do?
Ready to recognize foreign DNA and target for degradation
54
What is CRSPR inherited by?
Progeny.
55
CRSPR is FDA approved to treat what?
Sickle cell disease.
56
What do genomes tell us about bacteria and archaea? (6)
1. DNA sequencing and genomics 2. Thousands of DNA sequences available 3. A lot of information 4. Many ORKs without known functions (putative functions) 5. Metagenomics: microbes present, genes present, metabolism 6. Phylogenetic analysis: relatedness/similarity of organism (tracking sources of epidemics/ disease epidemiology, changes in microbes over time.)

Microbiology (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions