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Chapter 27 Flashcards

1
Q

What are characteristics of prokaryotes? (3)

A

Unicellular
.5-5 micrometer
Well organized

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2
Q

What shapes are prokaryotes?

A

Sprerical, rod, or spiral

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3
Q

What are prokaryotic cell walls function? (4)

A

Protects cell
Maintains shape
Prevents from bursting in a hypotonic environment
Plasmolyzes in hypertonic environments

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4
Q

What are prokaryotic cell walls made of?

A

peptidoglycan

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5
Q

What is the prokaryotic cell wall surrounded by?

A

Surrounded by a capsule layer- a sticky layer of polysaccharide or protein

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6
Q

What does the capsule layer do? (3)

A

Used to adhere, protect against dehydration, and protect the cell

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7
Q

What are endospores? (3)

A

resistant cells developed by bacteria when lacking nutrition

The chromosome is copied within the endospore and dehydrates

Endospore rehydrates in the favorable environment and “revives”

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8
Q

What are fimbrae?

A

hairlike appendages to adhere

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9
Q

What are pili?

A

long projections allow prokaryotes to exchange DNA

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10
Q

How are prokaryotes stained?

A

Using gram stains of violet dye and iodine, which is then rinsed with alcohol

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11
Q

Why do gram-positive bacteria stain?

A

bacteria have simple walls with large amounts of peptidoglycan

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12
Q

Why do gram-negative bacteria not stain? (3)

A

have less peptidoglycan but complex cell walls

Contains lipopolysaccharide

Peptidoglycan gets shielded from the stain

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13
Q

Why do we stain bacteria?

A

To determine if an infection is gram positive or negative

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14
Q

Gram negative bacteria characteristics (2)

A

have toxic cell walls

Resists antibiotics

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15
Q

How does penicillin work?

A

Penicillin interacts with peptidoglycan, killing bacteria but not human cells

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16
Q

How do archaeal cell walls differ>

A

lack peptidoglycan, made from polysaccharides and proteins instead

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16
Q

How do prokaryotes move?

A

taxis- directed movement towards and away from a stimulant

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17
Q

What is chemotaxis? (2)

A

change of movement pattern in response to chemicals

Positive chemotaxis is moving towards nutrients, and negative chemotaxis is vice versa

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18
Q

How do prokaryotic flagellum differ from eukaryotic flagellum?

A

Lack of a plasma membrane
Shorter width

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19
Q

How did bacterial, archaeal, and eukaryotic flagellum arise?

A

independently
Analogous

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20
Q

What is the structure of bacterial flagellum? (2)

A

It consists of a motor, hook, and filament

Only half of the protein is necessary to function (Proteins in the flagella are homologous to proteins found in other parts of the bacteria)

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21
Q

What is exaptation?

A

a process in which existing structures take on new functions through descent with modification

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22
Q

What are the characteristics of prokaryotic cells? (9)

A

Simpler than eukaryotic cells

Most undergo anaerobic respiration

Do not have membranes that can perform metabolic functions

Lack complex compartmentalization

Some have membrane-enclosed organelles

Contain less DNA compared to eukaryotic cells

Circular chromosomes

Lack a nucleus

Chromosome is found in the nucleoid/ cytoplasm

Possesses plasmids, rings of DNA molecules

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23
Q

How do prokaryotes reproduce quickly? (3)

A

By reproducing in favorable environments

have short generation times

by binary fission

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24
What stops prokaryotes from reproducing too much?
due to exhausted nutrient supply, metabolic waste poisoning, and competition from other organisms
25
How do mutations arise in prokaryotes? (2)
Results from rapid reproduction, mutation, and genetic recombination Occurs commonly with species that have short generation time and large population Leads to rapid evolution
26
What is genetic recombination?
combining of DNA from two sources
27
What is horizontal gene transfer?
movement of genes from one organism to another of different species
28
What is transformation, and an example?
Genotype and phenotype are altered by the uptake of foreign DNA, forming a recombinant Ex- nonpathogenic strain taking pathogenic DNA, replacing its own allele with foreign allele
29
What is transduction? (3)
phages carry prokaryotic genes from one host cell to another Results from accidents during the replication cycle ex- A Virus carrying prokaryotic genes attaches to a recipient prokaryotic cell and injects DNA acquired from the first cell
30
What is conjugation? (2)
DNA is transferred between 2 prokaryotic cells that are temporarily joined always one way (one donates , other receives)
31
How does conjugation occur? (2)
Donor forms a pili and creates a mating bridge to pass DNA Done by the F factor
32
What is the F plasmid? (4)
F factor in its plasmid form Functions as DNA donors during conjugation Cells that lack this act as DNA recipients Can be transferred
33
What is the F factor in chromosomes?
Done when the F factor of the donor is integrated into the chromosome
34
What is the Hfr cell?
cell with F factor built into its chromosome
35
What are R plasmids?
resistance genes that cause bacteria to become antibiotic-resistant
36
How do antibiotics work? (2)
Bind to bacterial ribosomes, preventing them from growing Allows the immune system to catch up and eliminate these bacteria
37
How do bacteria acquire antibiotic resistance? (2)
Protein that is affected by an antibiotic changes structure They may gain a way to deactivate an antibiotic
38
What are phototrophs?
organisms that obtain energy from light
39
What are chemotrophs?
organisms that obtain energy from chemicals
40
What are autotrophs?
organisms that only need CO2 or related compounds
41
What type of nutritional modes are there? (4)
Photoautotrophy Chemoautotrophy Photoheterotrophy chemoheterotrophy
42
What are heterotrophs?
organisms requiring at least one organic nutrient like glucose
43
What are obligate aerobes?
use oxygen for cellular respiration and cannot grow without it
44
What are obligate anaerobes? (2)
poisoned by oxygen Some live exclusively by fermentation, while others undergo anaerobic respiration
45
What is anaerobic respiration?
The use of substances like nitrate ions or sulfate ions for the ETC
46
What are facultative anaerobes?
use oxygen if present but can also carry out fermentation or anaerobic respiration
47
What is nitrogen fixation, and what does it do for plants?
conversion of atmospheric nitrogen to ammonia Increases nitrogen available to plants
48
Example of prokaryotic cells cooperating to survive
Anabaena can photosynthesize and fix nitrogen, but not at the same time Groups so that most photosynthesize, while heterocysts fix nitrogen
49
What are biofilms? (2)
-surface-coating colonies that undergo metabolic cooperation Secretes signaling molecules to recruit and grow its colony
50
What is metagenomics?
used to obtain prokaryotic genomes from environmental samples
51
What is the prokaryotic genome like? (3)
mosaic of genes due to horizontal gene transfer between distantly related species genetically diverse more related to eukaryotes compared to bacteria
52
What is proteobacteria?
Largest clade of gram-negative bacteria
53
What are alpha proteobacteria, and an example?
Associated with eukaryotic hosts Rhizobium- converts N2 to beneficial proteins for plants
54
What is an example of a beta proteobacteria?
Nitrosomonas- converts ammonia to nitrite
55
What are examples of gamma proteobacteria?
Salmonella and E. Coli
56
What are examples of Delta Proteobacteria?
Slime-secreting myxobacteria
57
What are epsilon proteobacteria, and examples?
Pathonogenic Helicobacter pylori (stomach ulcers) and Campylobacteria (blood poisoning)
58
What is chlamydia, and an example?
Cannot make its own ATP Chlamydia trachomatis
59
What are spirochetes, and examples?
Gram-negative bacteria Treponema pallidum (syphillis) Borrelia burgdorferi (lyme disease)
60
What are cyanobacteria, what are they responsible for, and what did they evolve into?
Photoautotrophs that generate O2 Responsible for the original presence of atmospheric O2 Plant chloroplasts evolved from cyanobacteria by endosymbiosis
61
What are examples of gram-positive bacteria?
Botulism, bacillus anthracis (anthrax), staphylococcus and streptococcus
62
What are extremophiles?
prokaryotes in Archaea that live in extreme environments
63
What are extreme halophiles?
archaea that live in highly saline environments
64
What are extreme thermophiles?
archaea that live in high temperatures
65
What are methanogens, what do they use, and where are they found?
archaea that live in a moderate environment that release methane Uses CO2 to oxidize H2 Poisoned by O2 Found in gut
66
What are decomposers? (2)
organisms that break down dead organisms and waste products It helps recycle chemical elements
67
What do autotrophic prokaryotes do?
use CO2 to make organic compounds Produces oxygen, fixes nitrogen, and builds proteins and nucleic acids
68
What is symbiosis?
an ecological relationship in which two species live in close contact with each other
69
What are hosts?
larger organism in a symbiotic relationship
70
What are symbionts?
smaller organism in a symbiotic relationship
71
What is mutualism?
ecological interaction between two species where both benefit
72
What is commensalism?
one species benefits while the other is unaffected
73
What is parasitism?
a parasite eats the cell contents, tissues, or body fluid of the host, harming the host
74
What are pathogens?
mostly prokaryotic parasites causing disease
75
four roles of mutualistic bacteria
Many mutualistic bacteria live in the gut and help digest food Some synthesize carbohydrates, vitamins, and nutrients needed by humans Others activate human genes in the blood vessels to absorb nutrients Others activate antimicrobial compounds it is unaffected by but prevent harmful bacteria from the host
76
What do pathogenic bacteria cause, and what are they transmitted by?
Cause about half of all human diseases Some are transmitted by fleas or ticks, like Lyme disease
77
What are exotoxins?
proteins secreted by certain bacteria, like cholera
78
What are endotoxins, when are they released, and an example?
lipopolysaccharide of gram-negative bacteria Released when bacteria die Ex- salmonella
79
What prevents pathogenic bacteria?
improved sanitation and antibiotics
80
What can create pathogenic bacteria?
Horizontal gene transfer can spread genes to make harmless bacteria pathogenic
81
What are 6 methods of prokaryotes used in research?
Use of E. coli in gene cloning Others produce transgenic plants Some are used to combat disease-affecting crops Some are used to break down plastic Bioremediation- prokaryotes that remove pollutants Some are used to produce vitamins, antibiotics, hormones, and other products

BI158 (16 decks)

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