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Microbiology > Unit 2 videos 6-7 > Flashcards

Unit 2 videos 6-7 Flashcards

1
Q

What is Microbial growth?

A

Increase in the number of cells.

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2
Q

What are the chemical and energy requirements for growth?

A

Carbon, energy, and electrons

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3
Q

Organisms classified into two groups based on the source of carbon?

A
  • Autotrophs (inorganic) ex carbon dioxide
  • Heterotrophs (organic) ex Lipids, carbs, proteins
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4
Q

Organisms are classified into two groups based on the source of energy.

A
  • Chemotrophs (chemical)
  • Phototrophs (light)
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5
Q

What is an autotroph?

A

Make their organic carbon molecules from inorganic start materials using a process called Carbon fixation.

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6
Q

What is a heterotroph?

A

They cannot fix carbon; They require an external source of organic carbon to live and grow.

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7
Q

What are phototrophs?

A

Harvest energy from light to make ATP.

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8
Q

What are chemotrophs?

A

Harvest energy from chemical bonds of their nutrients to make ATP.

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9
Q

What are humans’ energy sources?

A

Chemohetrotrophs

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10
Q

What are pathogens’ energy sources?

A

Chemohetrotrophs

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11
Q

An organism that utilizes an inorganic source of carbon as its sole source is called?

A

Autotroph

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12
Q

What is the classification And type of cellular respiration if the final electron acceptor is oxygen?

A

Classification - obligate aerobes

Type of cellular respiration - aerobic respiration.

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13
Q

What is the classification And type of cellular respiration if the final electron acceptor is Nitrate, carbonate, or sulfate?

A

Classification - Obligate anaerobes

Type of cellular respiration - Anaerobic respiration

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14
Q

What is the classification And type of cellular respiration if the final electron acceptor is an organic compound?

A

Classification- Facultative Anaerobes

Type of cellular respiration - aerobic respiration and fermentation.

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15
Q

Oxygen is essential for?

A

Obligate aerobes

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16
Q

Oxygen is deadly for?

A

Obligate anaerobes

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17
Q

What are the four forms of toxic oxygen?

A
  • Singlet oxygen
  • Superoxide radicals
  • peroxide anion
  • Hydroxyl radical
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18
Q

What three enzymes detoxify oxygen?

A
  • Superoxide dismutase
  • catalase
  • peroxidase
    (only in obligate aerobe and facultative aerobe)
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19
Q

What is the goal of detoxifying enzymes?

A

Turn into water.

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20
Q

Physical requirements for growth?

A
  • Temperature
  • PH
  • Physical effect of water
  • Association and biofilms
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21
Q

Low temperature.

A

Decreases enzymatic reaction.

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22
Q

Increased temperature.

A
  • Speeds up enzymatic reactions.
  • Can increase the growth rate
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23
Q

High temperatures.

A

Denature proteins (kills cells)

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24
Q

Three temperature growth.

A

Maximum temperature - Highest temperature That supports growth

Minimum temp. - the lowest temperature that supports

Optimal temperature - temperature where cell growth is highest

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25
Psychrophiles temperature range.
Thrive between -20 C to 10 C
26
Psychrotrophs temperature range.
Grow at 0 - 30 C associated with food born illness
27
Mesophiles temperature range.
Grow at 10 - 50 C Humans and pathogens
28
Thermophiles Temperature range.
Grow around 40-75 C Associated with compost piles and hot springs
29
Extreme thermophiles temperature range.
Grow around 65 to 120 C
30
Neutrophiles
Grow best in a narrow range around neutral PH; make up the majority of organisms
31
Acidophiles
Grows best in acidic habitats
32
Alkalinophiles
Live in alkaline soil and water.
33
osmotic pressure
Pressure exerted on a semipermeable membrane by a solution containing salutes that cannot move free across the membrane
34
Use for osmotic pressure in life?
Preserve food
35
Halophiles
Prefer high concentrations of salt
36
Obligate Halophiles
Grow optimally in solutions of 25% NaCl ( high osmatic pressure)
37
Faculative Halophiles
They are resistant to salt, though they do not reside in high-salt environments ( S. aureus)
38
Hydrostatic pressure
Water exerts pressure in proportion to its depth.
39
Barophiles
Live under extreme pressure.
40
What is binary fission?
- Occurs in most prokaryotic cells - Involves diving a single cell into two - Asexual process
41
Steps in binary fission.
1. Replication of genetic material 2. Cell elongation 3. Cells form a new cytoplasmic membrane and wall across the midline (septum created) 4. Splitting apart of new daughter cells (identical)
42
Which step will make the two daughter cells identical to each other?
Step 1. Replication of genetic material
43
What is binary fission? A - the exchange of DNA between two cells B - a way some organisms create energy C- The fusion of two cells to create a new larger cell D - A process in which a cell grows and divides to produce to daughter cells
D - A process in which a cell grows and dividends to produce daughter cells.
44
What is generation time?
- The time that is required for one cell to divide into two cells. - Times can be from 15 min to 24 hrs - depends on species and conditions
45
Calculation for generation time
Generation time in minutes/ number of generations
46
What is the type of growth called?
Exponential growth is always doubling. (2^n)
47
Formula determines cell diving over time.
(initial number of cells) x ( 2^ number of generations)
48
Four phases of the population curve
Lag phase - intense activity preparing for population growth. But no increase in population Log phase - exponential increase in population Stationary phase - Period of equilibrium; microbial deaths balance the production of new cells Death phase - the population is decreasing at a logarithmic rate
49
What is chemostat?
Device used to maintain a continuous culture in which nutrients are supplied at a steady rate. Goal - sustain microbial growth in the log phase
50
What is the name of genes that are expressed at all times?
Constitutive genes
51
What are facultative genes?
Are made selectively, when a cell encounters a specific environmental change or has a specific job to do
52
What is pre-transcriptional gene regulation?
Allows cells to control gene expression by regulating how much mRNA is made Example - Operons
53
What is post-transcriptional gene regulation?
Allows cells to control gene expression by regulating how often mRNA is translated into protein.
54
What are operons?
A collection of genes controlled by a shared regulatory system.
55
Do operons make catabolic reactions or anabolic reactions?
Both
56
What are the four parts of an operon?
1. Promoter - the site where RNA Polymerase binds to start transcription. 2. Genes - 2 or more that encode proteins that work together toward a shared task 3. Repressor - that blocks transcription 4. Operator - part of the operon that the repressor binds to to block transcription.
57
What does the regulatory gene do?
Codify the repossessor
58
Inducible operons
- Involved in catabolic reactions - Off by default - Certain conditions activate (induce) transcription
59
Repressible operons
- involved in anabolic reactions - On by default - Actively transcribe until turned off (repressed)
60
Lactose operon with glucose present and lactose absent.
- Operon would be off (no transcription) - repressor would be active to maintain operon off
61
Lactose operon with the presence of lactose and the absence of glucose.
- inactivate repressor - operon will be on
62
Repressor operon
- usually on - anabolic operons - are transcribed continually until the repressor - For example, tryptophan operon
63
Tryptophan is an example of a Repressor operon.
When tryptophan is low/absent, the operon on the repressor is inactive. When tryptophan is high/present, the operon is off, and the repressor is active. Co-repressor; excess of end product through feedback inhibition
64
What kind of gene sequence is typically active and produces proteins but can be shut down?
A repressible operon
65
What is vertical gene transfer?
Occurs when cell pass their genetic information to the next generation as a result of sexual or asexual
66
What horizontal gene transfer?
Passes genetic information between cells by an independent process. (without cell division) - passing of genes within the same generation - Donor cell contributes part of the genome to the recipient cell
67
What is transformation?
- Recipient cell takes up all DNA in the environment - Must be competent - The donor cell is a dead cell that left behind naked DNA - naked DNA is DNA no longer enclosed in a cell
68
What is transduction?
- The donor cell is infected by bacteriophage - Goes through the lytic cycle - The donor cell will release a transducing phage that will infect the recipient cell - The bacteriophage Injects DNA in the host - recipient cell incorporates new DNA in chromosome through recombination. - Donor killed - recipient lives
69
Process of Conjunction
1. Donor cell attaches to recipient cell with sex pili 2. Pilus may draw cells together 3. One strand of F plasmid DNA transfers to the recipient 4. The recipient synthesizes a complementary strand with pilus, and the donor synthesis a complementary strand, restoring its complete plasmid Donor gives f + through sex pilus to recipient cell turning from f - to F +
70
Hfr Conjugation
1. F plasmid integrates into the chromosome by recombination 2. cells join via sex pilus 3. A portion of the plasmid partially moves into the recipient cell, trailing a strand of donor DNA. 4. conjugation ends with pieces of f plasmid and donor DNA in the recipient cell. Cells synthesize complementary DNA strands 5. Donor cells and recipient DNA recombine. Making a recombinant f - ( gains part of f plasmid and part of donor DNA)
71
just in case

Microbiology (23 decks)

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