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bi158 > Chapter 27 > Flashcards

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
Q

What stops prokaryotes from reproducing too much?

A

due to exhausted nutrient supply, metabolic waste poisoning, and competition from other organisms

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25
Q

How do mutations arise in prokaryotes? (2)

A

Results from rapid reproduction, mutation, and genetic recombination

Occurs commonly with species that have short generation time and large population
Leads to rapid evolution

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26
Q

What is genetic recombination?

A

combining of DNA from two sources

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27
Q

What is horizontal gene transfer?

A

movement of genes from one organism to another of different species

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28
Q

What is transformation, and an example?

A

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

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29
Q

What is transduction? (3)

A

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

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30
Q

What is conjugation? (2)

A

DNA is transferred between 2 prokaryotic cells that are temporarily joined

always one way (one donates , other receives)

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31
Q

How does conjugation occur? (2)

A

Donor forms a pili and creates a mating bridge to pass DNA

Done by the F factor

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32
Q

What is the F plasmid? (4)

A

F factor in its plasmid form

Functions as DNA donors during conjugation

Cells that lack this act as DNA recipients

Can be transferred

33
Q

What is the F factor in chromosomes?

A

Done when the F factor of the donor is integrated into the chromosome

34
Q

What is the Hfr cell?

A

cell with F factor built into its chromosome

35
Q

What are R plasmids?

A

resistance genes that cause bacteria to become antibiotic-resistant

36
Q

How do antibiotics work? (2)

A

Bind to bacterial ribosomes, preventing them from growing

Allows the immune system to catch up and eliminate these bacteria

37
Q

How do bacteria acquire antibiotic resistance? (2)

A

Protein that is affected by an antibiotic changes structure

They may gain a way to deactivate an antibiotic

38
Q

What are phototrophs?

A

organisms that obtain energy from light

39
Q

What are chemotrophs?

A

organisms that obtain energy from chemicals

40
Q

What are autotrophs?

A

organisms that only need CO2 or related compounds

41
Q

What type of nutritional modes are there? (4)

A

Photoautotrophy

Chemoautotrophy

Photoheterotrophy

chemoheterotrophy

42
Q

What are heterotrophs?

A

organisms requiring at least one organic nutrient like glucose

43
Q

What are obligate aerobes?

A

use oxygen for cellular respiration and cannot grow without it

44
Q

What are obligate anaerobes? (2)

A

poisoned by oxygen

Some live exclusively by fermentation, while others undergo anaerobic respiration

45
Q

What is anaerobic respiration?

A

The use of substances like nitrate ions or sulfate ions for the ETC

46
Q

What are facultative anaerobes?

A

use oxygen if present but can also carry out fermentation or anaerobic respiration

47
Q

What is nitrogen fixation, and what does it do for plants?

A

conversion of atmospheric nitrogen to ammonia

Increases nitrogen available to plants

48
Q

Example of prokaryotic cells cooperating to survive

A

Anabaena can photosynthesize and fix nitrogen, but not at the same time

Groups so that most photosynthesize, while heterocysts fix nitrogen

49
Q

What are biofilms? (2)

A

-surface-coating colonies that undergo metabolic cooperation

Secretes signaling molecules to recruit and grow its colony

50
Q

What is metagenomics?

A

used to obtain prokaryotic genomes from environmental samples

51
Q

What is the prokaryotic genome like? (3)

A

mosaic of genes due to horizontal gene transfer between distantly related species

genetically diverse

more related to eukaryotes compared to bacteria

52
Q

What is proteobacteria?

A

Largest clade of gram-negative bacteria

53
Q

What are alpha proteobacteria, and an example?

A

Associated with eukaryotic hosts

Rhizobium- converts N2 to beneficial proteins for plants

54
Q

What is an example of a beta proteobacteria?

A

Nitrosomonas- converts ammonia to nitrite

55
Q

What are examples of gamma proteobacteria?

A

Salmonella and E. Coli

56
Q

What are examples of Delta Proteobacteria?

A

Slime-secreting myxobacteria

57
Q

What are epsilon proteobacteria, and examples?

A

Pathonogenic

Helicobacter pylori (stomach ulcers) and Campylobacteria (blood poisoning)

58
Q

What is chlamydia, and an example?

A

Cannot make its own ATP

Chlamydia trachomatis

59
Q

What are spirochetes, and examples?

A

Gram-negative bacteria

Treponema pallidum (syphillis)

Borrelia burgdorferi (lyme disease)

60
Q

What are cyanobacteria, what are they responsible for, and what did they evolve into?

A

Photoautotrophs that generate O2

Responsible for the original presence of atmospheric O2

Plant chloroplasts evolved from cyanobacteria by endosymbiosis

61
Q

What are examples of gram-positive bacteria?

A

Botulism, bacillus anthracis (anthrax), staphylococcus and streptococcus

62
Q

What are extremophiles?

A

prokaryotes in Archaea that live in extreme environments

63
Q

What are extreme halophiles?

A

archaea that live in highly saline environments

64
Q

What are extreme thermophiles?

A

archaea that live in high temperatures

65
Q

What are methanogens, what do they use, and where are they found?

A

archaea that live in a moderate environment that release methane

Uses CO2 to oxidize H2

Poisoned by O2

Found in gut

66
Q

What are decomposers? (2)

A

organisms that break down dead organisms and waste products

It helps recycle chemical elements

67
Q

What do autotrophic prokaryotes do?

A

use CO2 to make organic compounds

Produces oxygen, fixes nitrogen, and builds proteins and nucleic acids

68
Q

What is symbiosis?

A

an ecological relationship in which two species live in close contact with each other

69
Q

What are hosts?

A

larger organism in a symbiotic relationship

70
Q

What are symbionts?

A

smaller organism in a symbiotic relationship

71
Q

What is mutualism?

A

ecological interaction between two species where both benefit

72
Q

What is commensalism?

A

one species benefits while the other is unaffected

73
Q

What is parasitism?

A

a parasite eats the cell contents, tissues, or body fluid of the host, harming the host

74
Q

What are pathogens?

A

mostly prokaryotic parasites causing disease

75
Q

four roles of mutualistic bacteria

A

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
Q

What do pathogenic bacteria cause, and what are they transmitted by?

A

Cause about half of all human diseases

Some are transmitted by fleas or ticks, like Lyme disease

77
Q

What are exotoxins?

A

proteins secreted by certain bacteria, like cholera

78
Q

What are endotoxins, when are they released, and an example?

A

lipopolysaccharide of gram-negative bacteria

Released when bacteria die

Ex- salmonella

79
Q

What prevents pathogenic bacteria?

A

improved sanitation and antibiotics

80
Q

What can create pathogenic bacteria?

A

Horizontal gene transfer can spread genes to make harmless bacteria pathogenic

81
Q

What are 6 methods of prokaryotes used in research?

A

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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