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Microbiology > Ch.5-6 > Flashcards

Ch.5-6 Flashcards

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Biology 101 flashcards
0
Q

What is an autotroph?

A

Bacteria that can use carbon dioxide or methane from the air as a source of carbon.

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1
Q

Name the 6 most abundant elements in microbes.

A
  1. Carbon - 50%
  2. Oxygen - 20%
  3. Nitrogen - 14%
  4. Hydrogen - 8%
  5. Phosphorous - 3%
  6. Sulfur - 1%
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2
Q

What is a heterotroph?

A

Bacteria that requires their carbon source already be in an organic form such as sugar or an amino acid.

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3
Q

What is an auxotroph?

A

A bacteria that can’t produce a certain vitamin and must get it from a host.

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4
Q

What is a bacteria that can produce their own energy from light?

A

Photoautotroph

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5
Q

What is a prokaryote that has adapted to survive in high salt conditions such as salt lake?

A

Halophiles

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6
Q

What is a bacteria that derives its energy from carbon dioxide and hydrogen to produce methane gas?

A

Methanogens

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7
Q

What are bacteria that derive their energy from minerals from the air and rocks?

A

Chemoautotrophs

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8
Q

What is a liquid media called?

A

A broth

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9
Q

What is a media called that consists of completely known chemicals?

A

“Defined” or “synthetic” media.

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10
Q

What type of media is the common “brain-heart infusion broth”?

A

Complex (non-synthetic) media

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11
Q

What type of media allows for certain bacteria to grow, but inhibits others?

A

Selective media

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12
Q

What type of medium will allow many bacteria to grow, but will make a specific bacteria change color due to ph or other factors?

A

Differential media

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13
Q

Molecules in a solution are always bouncing around and off one another. What is this called?

A

Brownian motion

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14
Q
  1. What is a bacteria that absolutely requires oxygen to grow?
  2. Bacteria that require the absence of oxygen to grow?
  3. Bacteria that can grow with or without oxygen?
  4. Bacteria that require low oxygen levels?
A
  1. Obligate aerobes
  2. Obligate anaerobes
  3. Facultative anaerobes
  4. Microaerophiles
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15
Q

What are bacteria that grow in acidic environments called?

Alkaline rich environments?

A

Acidophiles

Alkalinophiles

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16
Q

What are microorganisms that require a temperature below -12C in order to grow called?

A

Psychrophiles

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17
Q

What are microorganisms that grow optimally at 37C called?

A

Mesophiles

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18
Q

What are thermophiles?

A

Archaea (not bacteria) that grow best at high temps (above 55C)

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19
Q

What are cold-adapted Mesophiles called?

A

psychrotrophs

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20
Q

What do you call bacteria that cannot grow at high temps, but are not killed at high temps for a short time (such as pasteurization).

A

Thermoduric bacterium

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21
Q

What is the most abundant component of living bacteria?

A

Water

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22
Q

How are pure bacterial cultures obtained?

A

By streaking bacterial samples onto a Petri dish so that individual bacteria are isolated and can grow into colonies.

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23
Q

What prevents a bacterial cell from rupturing due to internal osmotic (hydrostatic) pressure?

A

The strength of the peptidoglycan layer.

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24
Q

There are 2 names given to the process of bacterial cell division or duplication. What are they?

A

Cell division

Binary fission

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25
Q

When bacteria are picked from a Petri dish and placed in a fresh broth, they don’t initially multiply. What is this phase called?

A

Lag phase

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26
Q

What are the 4 phases of bacterial growth?

A
  1. Lag - initially not multiplying when placed on the culture
  2. Log - dividing at a set rate (exponential growth)
  3. Stationary - dividing and dying at the same rate due to limited nutrients and buildup of waste products.
  4. Death -
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27
Q

What do you get when you combine glucose and fructose?

A

Disaccharide sucrose (common table sugar)

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28
Q

What is the process of breaking down glucose called?

What is the byproduct of this process?

A 
Glycolysis 
Pyruvic acid (2) and ATP (2)
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29
Q

What is the transfer of electrons to oxygen coupled to the synthesis of ATP called?

A

Oxidative phosphorylation

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30
Q

How many ATP are yielded from glycolysis of 1 glucose?

A

2 ATP

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31
Q

How many ATP are yielded from 1 glucose in the KREBS cycle?

A

30 ATP

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32
Q

Is fermentation aerobic or anaerobic?

explain briefly what happens to sugar during fermentation.

A

Anaerobic
Pyruvic acid is produced from glycolysis, then rather than going through the KREBS cycle, the pyruvic acid is converted to ethyl alcohol.

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33
Q

True or False: Fungi are photosynthetic?

A

False

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34
Q

If 1 bacterium goes through 4 generations, how many bacteria will result?

A

16

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35
Q

How long will it take 10 bacteria to exceed 100 if the doubling time is 30 minutes?

A

2 hours

36
Q

What information does a turbidimetric assay yield?

A

Number of bacterial cells (alive or dead) in a solution by use of a spectrophotometer.

37
Q

The use of energy and building blocks to make new cellular materials:

A

Anabolism

38
Q

The breakdown of complex materials:

A

Catabolism

39
Q

All the chemical processes occurring in the cell:

A

Metabolism

40
Q

Protein catalysts that cells use to convert some molecules into others:

A

Enzymes

41
Q

What is activation energy?

A

Activation energy refers to the amount of heat necessary for a chemical reaction. Enzymes can greatly reduce the activation energy.

42
Q

What are the 3 major pathways of catabolism in organisms.

A
  1. Glycolysis
  2. KREBS cycle
  3. Electron transport
43
Q

Name 2 possible final electron acceptors in anaerobic respiration.

A

Nitrate

Sulfate

44
Q

True or False: DNA has no functional activity.

A

True: DNA must be transcribed to RNA which is then translated into proteins which are then used for gene expression.

45
Q

What is the enzyme responsible for DNA transcription into mRNA?

A

RNA polymerase

46
Q

In bacteria, RNA polymerase (enzyme responsible for transcription), requires a “helper” before transcription begins and mRNA is made. What is this helper called?

A

Sigma or Cofactor

47
Q

What is an RNA polymerase binding site on DNA called?

A

Promotor

48
Q

What is a gene cluster that is transcribed from a single Promotor (RNA polymerase binding site on DNA)?

A

Operon. The genes of an opening typically encode

49
Q

An operon is a gene cluster. What are individual genes in an operon called?

A

Cistrons

50
Q

Once DNA is transcripted into mRNA, it still must be decoded or “translated” for protein synthesis. What is the name of the part of the cell that performs “protein synthesis” or “translation”

A

Ribosomes

51
Q

Prokaryotic _______________ contain 2 subunit complexes called 30s and 50s. The combined size of these equals ____________.

The Eukaryotic subunits are larger, _________ & ___________ equaling a total size of ___________.

A

Ribosomes. 70s.

40s, 60s
80s when combined

52
Q

___________ helps in the process of “translating” or “protein synthesis” by binding to its corresponding codon on the ribosome and transferring the appropriate amino acid to the end of the growing amino acid chain.

A

tRNA

53
Q

In prokaryotes, sometimes protein synthesis or “translation” may begin before the mRNA has detached from the DNA. What is this simultaneous synthesis of RNA and proteins called?

A

Coupling

54
Q

A typical bacterium has approx. 5 million base pairs of DNA. How many base pairs of DNA does a typical human cell have?

A

6 billion

55
Q

What does it refer to when said that eukaryotes are diploid and prokaryotes are haploid?

A 
Diploid = 2 copies of each chromosome
Haploid = 1 copy of each chromosome
56
Q

In the 1920’s, British microbiologist showed that genes can functionally affect the character of cells, and that genes can be transferred from 1 cell to another. He proved this through a study where mutated bacteria were able to regain the functionality of having a capsule from dead wild-type bacteria. What did he term this?

A

The transforming principle

57
Q

What is the enzymatic process of making another copy or “duplicate” of DNA?

A

Replication

58
Q

Bacteria are prokaryotic, meaning they do not have a nucleus. Prokaryotes DNA, rather than being located in the nucleus, is primarily located in a circular structure inside the cell called the __________.

A

Nucleoid

59
Q

What is the enzyme that performs DNA replication?

A

DNA polymerase

60
Q

What is the most widely used vector (delivery method) for gene therapy?

A

Viruses (viral vectors)

61
Q

American Geneticist Oswald Avery (1940’s) proved that genes were made of DNA by a study that showed the bacterial substance responsible for transformation was sensitive to ___________.

A

DNase

62
Q

Who were the 2 geneticists that proved, in 1952, that DNA is the genetic material and not protein?

A

Hershey & Chase

63
Q

Where does DNA synthesis begin?

A

The origin of replication

64
Q

What are the 2 major classes of gene expression control?

A

Inducible systems

Repressible systems

65
Q

Which type of gene expression is the following describing:
Mammals have ecoli in the intestinal tract where lactose might be found. Most of the time, ecoli has no need to turn on the “lac” operon. When milk is ingested, it introduces lactose. Some lactose molecules will bind to the “repressor” protein of the gene rendering the repressor inactive. This turns on the “lac” expression of the gene allowing the bacteria to utilize the external lactose to drive rapid cell growth.

A

Inducible gene expression as the presence of lactose induced the gene to be activated.

66
Q

What do you call enzymes that break down proteins?

A

Proteases or proteinases

67
Q

When do bacteria normally regulate gene expression?

A

During transcription

68
Q

Which type of gene expression (inducible or repressible) has more fine control over how much expression occurs?

A

Repressible

69
Q

Sometimes there are errors in DNA replication leading to incorrect nucleotides or base pairs. What are these called?

A

Mutations

70
Q

What do you call a cell that has a mutation in its DNA sequence?

What do you call the parental strain lacking these mutations?

A

Mutants

Wild type organism

71
Q

Chemicals and other factors not normally found in nature that alter DNA sequence or structure are called ____________.

A

Mutagens

72
Q

Name the two types of mutations and describe the difference.

A

Spontaneous mutations: occur by mistakes in DNA synthesis or from things such as sunlight.

Induced mutations: caused by man made mutagens

73
Q

What type of mutation converts a coding triplet into a stop codon, resulting in an incomplete protein.

A

Nonsense mutation

74
Q

What type of mutation causes the letters of the codon to be completely out of register, so that the correct triplets are lost from that point onward?

A

Frame-shift deletions

75
Q

What type of mutation removes 3 (or multiples of 3) nucleotides, but the sequence after the deletion is still correct?

A

In-frame deletions

76
Q

What is the difference between genotype and phenotype?

A

Genotype is the actual DNA sequence.

Phenotype is the physical expression of the gene.

77
Q

Some mutations occur outside of the structural genes, but can still cause phenotypical changes or mutations. What is this called?

A

Regulatory mutation

78
Q

Some mutations can cause “systems” to be always turned on and unable to be shut off. This is a type of regulatory mutation that is termed a _________ __________.

A

Constitutive system

79
Q

What are chemicals capable of causing mutations that lead to cancer?

A

Carcinogens

80
Q

Developed in the 1970’s, this doctor developed a test to identify which chemicals cause mutations. What is his name, and what is the name of the test?

A

Dr. Bruce Ames

The Ames Test

81
Q

Bacteria can transfer DNA from 1 cell to another. Bacterial gene transfer can occur by 3 methods. Name them.

A

Conjugation
Transduction
Transformation

82
Q

In reference to the “conjugation” method of gene transfer, donor bacteria contain a plasmid called the F-factor. What does the F stand for?

A

Fertility

83
Q

What are cells called that carry the “F-factor”?

Cells that don’t?

A

F+ or “male cells

F- or “female cells

84
Q

Only bacteria classified as “competent bacteria” are capable of the type of gene transfer where they can transport available DNA (from other lysed bacteria) and transport it through their plasma membrane. What is this kind of gene transfer called?

A

Transformation

85
Q

In which type of gene transfer does a sex pilus form a bridge between 2 bacteria?

A

Conjugation

86
Q

What type of gene transfer is mediated by a bacteriophage?

A

Transduction

87
Q

If a bacteria does not produce enzymes for the synthesis of product “X” because product “X” is already in ample supply, what is this process called?

A

Feedback inhibition.

Microbiology (9 decks)

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