Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology > Lecture 3 > Flashcards

Lecture 3 Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
0
Q

What macronutrients are often used to buffer and maintain osmolarity?

A

Magnesium and potassium

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

Macronutrients

A
  • carbon - 50% of cell
  • nitrogen - used in amino acids (proteins), nucleotides, NH3, NO3
  • phosphorus- nucleotides, phospholipids
  • sulfur- amino acids, SO42-, S2-
  • potassium (k)
  • magnesium (Mg)
  • calcium
  • sodium
  • iron
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The macronutrients for Sporulating cells

A

Calcium

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

Macronutrient needed by marine orgs

A

Sodium

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

Macronutrient needed by magnetic bacteria for magentisomes

A

Iron

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

Macronutrients trace elements

A

Metals: Cr, Co, Cu, Zn, Mn, etc.

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

Macronutrient growth factors

A

Vitamins and amino acids - organisms that can’t make their own growth factors have to get these from the environment= fastidious

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

Culture media

A 
- nutrient base to support the growth of M.O. 
Types:
1. Selective media
2. Differential media
3. Complex media
4. Defined media
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Selective media

A

selects for growth of a particular M.O.

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

Differential media

A

differentiates among organisms growing on media eg. usually colony color formation

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

Can media be selective and differential?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Complex media

A

cannot chemically define the exact composition of medium eg. digested protein - can’t tell the exact AA composition
- works to grow most fastidious orgs.

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

Defined media

A

know the exact chemical composition (including concentration) of the medium eg. has 2g/L glucose and can add specific growth factors for the growth of fastidious M.O.

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

Can you have selective or differential defined medium?

A

Selective defined medium

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

Can you have selective or differential complex medium?

A

differential complex medium

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

What is the universal growth medium and universal set of growth conditions?

A

There aren’t any

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

Growth is…

A

an increase in cell number

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

Through what mechanism is cell growth?

A

Binary fission (bacterial cell division)

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

How old is a bacterium?

A

Bacteria don’t age

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

What happens in binary fission?

A

Each parent cell split into two identical daughter cells (may not be true b/c of replication, mutation could occur)

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

How is growth of cells tracked?

A

As a population response, impossible to track individual cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

The steps to binary fission are largely unknown but are:

A
  1. slight elongation and duplication of resources (chromosomes, ribosomes, enzymes, transport proteins)
  2. septum formation and resource partitioning
  3. septum elongation
  4. separation of daughter cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the septum

A

cell membrane, cell wall, outer membrane if GN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Phases of the growth curve of a closed system

A
  1. lag phase: cells preparing to grow/divide under enviro. conditions but no division is occuring
  2. exponential: cell division occurs on regular basis; predictable growth
  3. stationary: cell division = cell death; growth slows, cell death begins to occur b/c of limited nutrients or buildup of waste; some cells better adapted to survive and ddivide; cellular cannibalism occurs
  4. Death phase: cell death > cell division; rarely drops to 0 because of cannibalism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Axes of growth curve

A 
Y = log # of cells per mL
X = Time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Growth curve of an open system

A

All over the place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Number of generations (N)

A

(LogN - Log No)/0.301 = N

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Growth rate (k)

A

K= N/t

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Generation time (g)

A

g = 1/k

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Factors influencing growth

A

to control growth:

  • temp. (refridgeration)
  • pH (pickling)
  • O2 availability
  • antimicrobial chemicals
30
Q

Disinfection is

A

the killing/inhibition/removal of M.O.s from a given system or enviro.

31
Q

Chemical used in disinfection:

A
  • disinfectants: chemicals used to disinfect inanimate objects (lab bench)
  • antiseptic: chemicals used to disinfect tissues (iodine)
  • chemotherapeutic agents: chemicals used inside the body
32
Q

Disinfecting chemicals are either _____ or ____ agents and either ____ or ____.

A

cidal agents: kill M.O.s (penicillin kills bacteria by destroying cell wall)
static agents: inhibit growth of M.O.s - once agent is removed, growth can resume
antibiotic: produced by other M.O.s (penicillin)
synthetic: artificially made or synthesized chemical (sulfadrug)

33
Q

What do antimicrobials usually target?

A

something structural in a cell eg. cell wall, cell membranes, enzymes, ribosomes, transport proteins, etc.

34
Q

Resistance mechanisms

A
  1. modification of structural target so antimicrobial no longer recognizes its target (eg. bonding change with NAM and NAG for penicillin resistance)
  2. degradation enzymes: enzymes designed to be excreted by the cell for degradation of antimicrobial (penicillinase degrades penicillin)
  3. Use of ATP dependent efflux pumps - transport proteins that use ATP to drive the removal of antimicrobial from the cell (penicillin-specific efflux pumps)
35
Q

Example of chemical control of microbial groups (viral)

A
  • protein capsid designed to protect genome
  • relies on use of nucleotide analogs
  • AZT (azidothydimine) is the antiviral for HIV (RNA genome virus)
  • RNA converted to DNA via reverse transcriptase (RNA dependent DNA polymerase) and then DNA goes to RNA via host cell transcriptional machinery
  • AZT is a chain terminator - lacks nucelotide 3’OH to allow for DNA synthesis to continue
  • reverse transcriptase shows a higher affinity for AZT over T
36
Q

Fungal control

A
  • challenging to design antifungal chemicals that can distinguish fungi from other euk. cells
  • ergosteral inhibitors - chemicals that inhibit the synthesis of ergosterols in fungi for maintaining membrane fluidity
37
Q

Protozoal control

A
  • challenge to design chemical that can distinguish protozoan from human cell
  • hydroxy chloroquine - used against Plasmodium (malaria), inhibits choline synthesis
38
Q

How many chromosomes do prok. have?

A

1 circular one

39
Q

Where does DNA replication start?

A

at the origin of replication (ORI) site

41
Q

What happens after DNA replication starts, what forms?

A

theta structure - visual cue of replication of chromosome; forms as 2 forks move half way through circular chromosome

42
Q

DNA always synthesized by adding onto the

A

3’ end

43
Q

Single-stranded binding protiens

A

protect single-stranded DNA from destruction by nucleases

44
Q

DNA synthesis is always from ___ to ___

A

5’ to 3’

45
Q

On the leading strand, DNA is synthesized ____ of the fork moving

A

in order

46
Q

On the lagging strand, DNA is synthesized ____ of fork moving

A

opposite

47
Q

DNA helicase

A

dsDNA –> ssDNA

48
Q

DNA (RNA) primase

A

put down RNA primers, RNA polymerase is specific to RNA primer production

49
Q

DNA gyrase

A

removes supercoiling

50
Q

ozaki fragment

A

short segments of DNA synthesized on lagging strand

51
Q

How many primers are needed to start DNA synthesis on the leading strand? And on the lagging strand?

A

leading: 1
lagging: multiple

52
Q

DNA polymerase I (DNA pol. I)

A
  • removes the RNA primer and fills gap with DNA on ozaki fragments but nick remains
  • has exonuclease activity for RNA
  • replaces with DNA using 3’OH from previous ozaki fragment
53
Q

DNA ligase

A

connects 3’OH and the 5’PO4 of neighboring bases to seal ozaki fragment nicks

54
Q

What two proteins are used to seal ozaki fragments?

A
  • DNA pol. I

- DNA ligase

55
Q

Mistakes made during replication

A
  • 1 error/ 10^8 - 10^11 base pairs

- DNA polymerases have ability to correct some “incorrect” bases during DNA synthesis = exonuclease activity

56
Q

Transcription is

A

DNA —> RNA (mRNA)

57
Q

How does RNA differ from DNA?

A
  • RNA is single-stranded

- Has U instead of T

58
Q

RNA polymerase

A
  • DNA dependent RNA polymerase (reads DNA but makes RNA)
  • adds nucleotides to 3’OH of growing RNA strand (5’ —> 3’)
  • synthesizes RNA denovo (doesn’t need primer)
  • needs to act on conjunction with sigma factor protein to initiate transcription
59
Q

Sigma factor

A
  • recognizes gene to be transcribed

- recognizes start site (=promoter) for transcription

60
Q

Promoter region

A
  • many types of sigma factors in cell
  • each sigma factor is specific to given variable region within the promoter region
  • each sigma factor is specific to specific gene(s)
  • -35 region (conserved), variable region, -10 region (conserved)
  • promoter region activates transcription of a given gene via binding gene’s sigma factor but also aligns transciption machinery so that mRNA synthesis begins at the start of coding region of gene
61
Q

Pribnow box

A

-35 and -10 sequences in promoter region

62
Q

How serious is it if mistakes are made during transcription?

A

not fatal, always making multiple mRNA

63
Q

What happens to the sigma factor once RNA pol. starts synthesizing RNA?

A

it is released

64
Q

Rho independent termination

A
  • stops transcription

- destabilization comes from stem loop and run of Us (run of A’s in DNA)

65
Q

Rho dependent termination

A
  • stops transcription
  • rho protein recognizes rut site in mRNA
  • rho moves along mRNA towards RNA pol.
  • rho catches up and collides with RNA pol. and destabilizes it
  • rho is a hexomer (has 6 subunits)
  • destabilization occurs via stem loop and rho protein
66
Q

The genetic code

A
  • 4 bases –> 64 possible codons
  • 1 start codon (AUG) = Met
  • 3 stop codons (UAA, UAG, UGA)
  • code is degenerate: many codons per amino acid; 1st 2 bases important, 3rd doesnt matter as much = wobble effect
67
Q

DNA pol. III

A

main DNA polymerase synthesizing leading and lagging strands

68
Q

translation

A

mRNA —> protein

69
Q

Prok. translation

A
  • AUG = N-formyl methhion (fMet) precursor to Met

- ribosome recognizes 5’ end of mRNA via shine degarno sequence (SDseq.)

70
Q

transfer RNA (tRNA)

A
  • single-stranded molecule folded in on itself
  • has anticodon that is sequence of bases complimentary to codon
  • Charged tRNA = AA attached
  • uncharged tRNA = AA not attached
71
Q

aminoacyl tRNA synthetases

A

enzymes that “charge” tRNAs with their appropriate AA

72
Q

Ribosome

A
  • comprised of RNA and protein
  • prok: 30s subunit and 50s subunit: 70s ribosome
  • euk. 40s subunit and 60s subunit = 80s subunit
73
Q

prok. 70s ribosome

A
  • 30s subunit: 16s rRNA + 21 proteins

- 50s subunit: 23s rRNA + 34 proteins

Microbiology (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions