Microbial Genetics, Growth, and Metabolism (complete) Flashcards Preview

DMD 5245 > Microbial Genetics, Growth, and Metabolism (complete) > Flashcards

Flashcards in Microbial Genetics, Growth, and Metabolism (complete) Deck (88):
1

What is horizontal gene transfer

it is the passing of genetic information between two mature cells. (instead of vertical gene transfer, which is from parent to offspring)

2

Do prokaryotes have a nucleus

nope, they do have what is called a nucleoid. Which is just where the prokaryote has its genetic material, but it is not confined in a membrane

3

What are plasmids

small segments of DNA in prokaryotes that Replicate independently of the prokaryotic chromosome

4

Are plasmids essential for the life of the prokaryote

no they are not essential for normal growth, reproduction, and metabolism

5

although plasmids aren't essential, how can they be beneficial to the prokaryote

they contain factors that help it survive

6

what types of factors can be found on vectors (4)

1. Fertility Factors (genes for conjugation)
2. Resistance Factors (against antimicrobials and metals)
3. Bacteriocin Factors (toxins against similar organisms)
4. Virulence factors (virulence factors against host)

7

Can plasmids integrate themselves into the bacterial chromosomes

yep

8

What are the three ways in which bacteria can transfer genetic information

1. Transformation
2. Transduction
3. Conjugation

9

What is transformation (bacterial genetic information transfer)

when a bacterial cell picks up free DNA fragments and incorporates them into their chromosome

10

What is Transduction (bacterial genetic information transfer)

When an empty viral phage coat gets loaded with bacterial DNA, then injects it into another cell

11

What is conjugation

When a F+ (fertility plasmid) Cell uses a conjugation pilus to connect to another cell, then it transfers it DNA through the hollow conjugation pili

12

what was the finding from Griffiths experiment with rough and smooth Streptococcus Pneumoniae cells

that the new, non-virulent strain, would pick up and use the virulent DNA from the dead cells and use it to kill the mice . Proved transformation happens

13

What happens when an F+ cell successfully conjugates with an F- cell

the Fertility plasmid will be transferred to the F- cell, making it F+

14

What is an HFR cell

a cell with High Frequency of Recombination, which is a cell which has had the Fertility plasmid become integrated into its chromosome

15

What happens typically when an HFR conjugates with an F- cell

it only transfers a portion of the fertility plasmid, along with part of its chromosome. so the F- cell has more DNA, but not a complete Fertility plasmid so it is still F-, and is also F'

16

What are transposons

sequences in the prokaryotic chromosome that can break out, replicate, then reinsert themselves into different places on the chromosome.

17

can transposons jump to plasmids

yep

18

What is VRE

vancomycin resistant Enterococcus

19

what is MRSA

methicilin resistant Staphylococcus aureus

20

What is a silent mutation

a swapped out base in DNA that doesn't lead to a change in the corresponding amino acid

21

What is a missense mutation

a swapped out base in DNA that causes a change in the corresponding amino acid

22

what is a nonsense mutation

a swapped out base in DNA that leads to an early stop codon

23

What is a frameshift mutation

either an insertion or deletion of a base pair in DNA, this causes all of the following amino acids to be altered due to the way it causes the reading frame to be shifted

24

What does UV light do to DNA

causes a thymine dimer, which is the creation of bonds between two thymines on the same strand of DNA, causing a bubble of sorts between the two strands

25

How is Recombinant DNA technology done

you get your gene of interest, and cut it out of its DNA, and place it into a plasmid, put that plasmid into bacteria, and have the bacteria produce the protein of choice

26

How does PCR work

you put primers in with the DNA you are running, heat it up so the double stranded DNA separates, then cool it down so the primer attaches to a single strand of DNA, and let the transcription machinery create a copy strand. then repeat over and over again.

27

What is the end goal of all microbial metabolism

to reproduce the organism

28

what is microbial growth

an increase in a population of microbes, rather than the microbes increasing in size

29

What are the necessary elements for microbes

carbon, oxygen, nitrogen, and hydrogen

30

What is an autotroph

an organism that has the ability to get its carbon from the CO2 in the air (green plants)

31

What is a heterotroph

an organism that gets it carbon from consuming carbs, proteins, fatty acids, and amino acids.

32

What are chemotrophs

organisms that get their energy from redox reactions with organic and inorganic material

33

What are phototrophs

organisms that get their energy from light

34

What are examples of photoautotrophs

plants, algae, cyanobacteria

35

what are examples of chemoautotrophs

only prokaryotes
hydrogen, sulfur, and nitrifying bacteria

36

What are some examples of photoheterotrophs

only prokaryotes
green and purple nonsulfur bacteria

37

What are chemoheterotrophs

most animals, fungi, protozoa, many bacteria

38

What are obligate aerobes

organisms that need oxygen to survive

39

what are obligate anaerobes

organisms that are killed by oxygen

40

How does oxygen kill obligate anaerobes

O2 isn't toxic, but the Reactive Oxygen Species are, and obligate anaerobes don't have the machinery to neutralize the Reactive oxygen species

41

What are facultative aerobes

organisms that can live without oxygen, but do better with oxygen

42

What are aerotolerant aerobes

organisms that don't need oxygen, but aren't affected by it at all (not for better or for worse)

43

What are microaerophiles

organisms that require oxygen, but at lower partial pressures. can't live without it, or with too much of it

44

What would you expect to see with a strict aerobe in a thioglycollate medium

only growth in the upper oxygen rich area

45

What would you expect to see with a strict anaerobe in a thioglycollate medium

only growth in the lower oxygen depleted area

46

What would you expect to see with a facultative aerobe in a thioglycollate medium

growth throughout the medium, but more in the oxygen rich area

47

What would you expect to see with a microaerophile in a thioglycollate medium

most of the growth, somewhere in the oxygen rich area, but not at the very top

48

What would you expect to see with a aerotolerant anaerobe in a thioglycollate medium

equal growth throughout the medium

49

is nitrogen required by microbes

yes, because it is needed in proteins and nucleotides

50

are bacteria essential for life on earth when it comes to the nitrogen we need

yes, because it is bacteria that fixes the nitrogen gas to ammonia so that we get the nitrogen we can use.

51

How does temperature affect growth of microbes

there is a Minimum temperature at which membranes gel and no growing can occur, from that point activity increases with increasing temperature until it reaches an Optimum activity point. with any more temperature you begin to destroy the organism.

52

What do you call an organism that grows best in cold temperatures

psychrophile

53

what do you call an organism that grows best in moderate temperatures

mesophile

54

what do you call an organism that grows best in hot temperatures

thermophiles

55

what do you call an organism that grows in extremely hot temperatures

hyperthermophiles

56

What pH do most bacteria and protozoa prefer

neutral pH (6.5 to 7.5)
neutrophiles

57

what do you call bacteria that prefer a low pH level

acidophiles

58

what do you call bacteria that prefer a high pH level

alkalinophiles

59

do most bacteria need water

yes, most die in the absence of water (endospores and cysts are the exception)

60

What happens to cells (without walls) when placed in a hypotonic solution

water runs into them, and causes them to lyse

61

what happens to cells placed in a hypertonic solution

the cells will shrivel up

62

what are halophiles

organisms that can grow in hypertonic solutions (salty)

63

what are obligate halophiles

organisms that grow in up to 30% salt

64

what are facultative halophiles

organisms that can tolerate high salt concentrations

65

What are oganisms that live under extreme pressure called

barophiles

66

what do you call organisms that live in high CO2 concentrations

Capnophiles

67

What is an anatagonistic relationship (parasitism)

one organisms benefits, the other is harmed

68

what is a synergistic relationship (mutualism)

both organisms benefit

69

what is a symbiotic relationship

the organisms are interdependent

70

What is commensalism

one organism benefits, the other is indifferent

71

What is a biofilm

complex relationships among numerous different organisms

72

What is the CFU when creating cultures of cells

the CFU is the colony forming unit, or the progenitor (parent) of the entire colony

73

What are streak plates and pour plates used for?

isolating colonies

74

How does blood agar work as a differential medium

different specimen perform different types of hemolysis on the blood agar, which results in different looking cultures

75

what is a-hemolysis

partial RBC destruction

76

what is b-hemolysis

complete RBC destruction

77

what is y-hemolysis

no RBC destruction

78

What are the three ways to preserve cultures

Refrigeration
deep-freezing
lyophilization

79

is bacterial growth log linear

yes

80

What are the four phases of microbial growth

1. Lag phase (not much growth)
2. Log phase (exponential growth)
3. stationary phase (no growth, but at max growth level)
4. Death Phase (decline)

81

What is the equation for bacterial growth

N(t) = N(o) (2^n)
n=t/g
n= number of replications
t = time
g = generational time

82

How do bacterial multiply

binary fission

83

What are the four direct methods for measuring microbial growth

1. Viable plate counts
2. membrane filtration
3. microscopic counts
4. electronic counters

84

how is a viable plate count performed

you make plates with increasing diluted (10x less concentrated each step) samples of the culture, then once you can get to a countable number of colonies you can estimate how many colonies were in the original concentration

85

how is microscopic counting performed

you spread out colonies on a grid, then choose one specific square, magnify it and count the colonies. Then you can multiply the number of colonies in that square by the total number of squares

86

What are the three methods for indirect measuring of microbial growth

metabolic activity
dry weight
turbidity

87

What is turbidity and how does it measure microbial growth

you shoot light through a control tube without growth in it and measure the light that gets through, then you do the same to a tube with growth in it and see how much light has been reflected.

88

how does turbidity correlate with concentration

the relationship is log linear, the higher the concentration the lower the transmittance