Bacterial Metabolism and Genetics Flashcards Preview

Micro Exam #2 > Bacterial Metabolism and Genetics > Flashcards

Flashcards in Bacterial Metabolism and Genetics Deck (54)
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1
Q
Nutrients required by bacteria
A
CHONPS and trace metal salts
2
Q
What versions of C and N are most important?
A
Reduced Form
3
Q
Describe the shape of a bacterial growth curve based on temperature.
A
The curve leans with the highest point/optimum at higher temperatures
4
Q
What is the significance of the bacterial growth curve?
A
Increase in temperature by as little as 2 degrees causes a large drop in population -- FEVER
5
Q
Three types of bacteria based on pH? Who is most common in the stomach? The body?
A
Acidophile, Neutralophile, Alkalophile
Acidophile
Neutralophile
6
Q
Circumstances in which an aerobe will grow?
A
O2
Needs an electron acceptor -- O,N,S
7
Q
Circumstances in which an anaerobe will grow?
A
Grows in No O2
O2 forms radicals
8
Q
Circumstances in which facultative anaerobes grow?
A
Grows in O2, less well without O2
Have TCA and can ferm.
9
Q
Circumstances in which aerotolerant will grow?
A
Will grow with or without O2
Doesn't use O2 anyway
10
Q
Circumstances in which microaerophile will grow?
A
Grows in O2 below 0.2 ATM
Needs O2, but too much makes radicals
11
Q
Oxygen sensitivity of more tissue?
A
Anerobic
12
Q
Oxygen sensitivity of lungs?
A
Aerobic
13
Q
Oxygen sensitivity of tonsils/back of throat?
A
Microaerophile
14
Q
Four phases of bacterial growth cycle?
A
Lag, Exponential, Stationary, Decline
15
Q
What stage are bacteria typically in the lab? In the body?
A
Exponential Phase.
Stationary Phase.
16
Q
What occurs during the lag phase?
A
Adaption to new nutrients
New enzyme synthesis/up-regulation
17
Q
What occurs in the exponential phase?
A
Growth and binary division
18
Q
What occurs in the stationary phase?
A
Crowding, Starvation or Toxic Conditions
Stress Genes Upregulated
19
Q
What occurs in the decline phase?
A
Cells begin to lyse.
20
Q
What occurs in bacterial latency?
A
No division, allows for hiding from immune response
"Persister cell"
21
Q
How do persister cells come about?
A
Turn off metabolism
Turn on dormancy pathways
No growing/dividing
22
Q
Role of persister cells in treatment?
A
Treating against persister cells leads to more rapid cure
23
Q
Describe the bacterial chromosome.
A
Circular
Stable w/out telomeres
Haploid (typically)
Associated with proteins (structural and regulatory)
24
Q
What are merodiploids?
A
Genes in multicopy in the bacterial chromosome
25
Q
Describe a plasmid?
A
Circular, smaller than chromosome
Can exist in hundreds of copies per cell
26
Q
What controls plasmid replication?
A
Cop proteins
27
Q
In a broad sense, how does bacterial transcriptional regulation occur?
A
Negative Regulation -- Protein Repressors
Positive Regulation -- Protein Activators
28
Q
Where do repressors bind?
A
Between promoter and gene
29
Q
Where do activators bind?
A
Upstream of promoters
30
Q
How do environmental signals modify gene regulation?
A
Small molecules alter the shape/bind to regulatory proteins
31
Q
Two types of environmental signals?
A
Induction and Repression
32
Q
What are two ways in which repression may work?
A
Trigger Active Repressors
Inactivate Inducer
33
Q
How does the lactose influence the lac operon?
A
Lactose present inhibits the lac repressor protein
34
Q
How does high glucose influence the lac operon?
A
High glucose will lead to low cAMP
With low cAMP, minimal binding of Lac Inducer
Transcription at low rate
35
Q
How does low glucose influence the lac operon?
A
Low glucose leads to higher cAMP levels
cAMP+CAP activator binds, induces great amount of lactase transcription
36
Q
What happens in bacterial transformation?
A
Uptake of unpackaged DNA
37
Q
What triggers bacterial transformation?
A
Competence pharomones/Quoromones are secreted as nutrients run out
Quorum Sensing
38
Q
How might DNA transformation be induced?
A
High temperature opens membrane pores
CaCl2 shields DNA- charges and lets new DNA in
39
Q
How might one make bacteria transformation occur in a laboratory setting?
A
Gene gun, electroporation
40
Q
What is conjugation?
A
Natural Plasmid Transfer
41
Q
How does conjugation occur?
A
Cells with F+ plasmid generate sex pili that binds to receptors on F- pili
42
Q
What are Hfr cells?
A
Cells that in conjugation can transfer chromosomal genes
43
Q
How are chromosomal genes transferred with plasmids?
A
Following integration of F plasmid, adjacent chromosomes be come with the F plasmid with abnormal excision
P' Plasmid
44
Q
Significance to chromosomal gene transfer in plasmids?
A
Can generate R-plasmids
Resistance genes pulled along with the plasmid
45
Q
What is transduction?
A
gene transfer mediated by imprecise excision or packaging of phage
46
Q
Difference between generalized and specialized transduction?
A
Generalized -- lytic phage -- could be any gene
Specialized -- lysogenic phage -- only genes near integration site
47
Q
What happens in bacterial gene replacement?
A
transferring genes integrate into host chromosome replacing native genes
48
Q
Homologous recombination is catalyzed by ____. What unique thing may happen to the DNA?
A
RecA
Inversions
49
Q
Where do inversions happen? Where do deletions occur?
A
Inversions -- Between Inverted Repeats
Deletions -- Between Direct Repeats
50
Q
How does recombination at dissimilar sequences occur?
A
transposons acting via transposases
51
Q
Difference between composite and non-composite transposons?
A
Non -- inverted repeats at end and transposase
Comp -- Complete IS elements at ends, genes in middle
52
Q
Two pieces of medical significance of plasmids
A
Antiobiotic resistance transfer
Interruption of genes resulting in mutation
53
Q
What are outer membrane vesicles?
A
Small vesicles that bud from outer membrane containing genetic elements and signalling molecules
54
Q
Why do we care about outer membrane vesicles?
A
Blebbing and budding with genes/proteins/virulence factors provides extra routes of transmission