Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology II > Prokaryotes: Bacteria & Archaea > Flashcards

Prokaryotes: Bacteria & Archaea Flashcards

Chapter 22 in the book

1
Q

Why would prokaryotes be the first inhabitants of Earth?

A

Early Earth’s atmosphere contained less molecular oxygen, had strong volcanic activity & was subjected to strong solar radiation. So the first organisms (prokaryotes) would have flourished where they were more protected, such as the deep ocean or far beneath the surface. Also they would of been adaptive to withstand the harsh conditions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a Microbial Mat?

A

Multi-layered sheet of prokaryotes that includes mostly bacteria & archaeans. They are a few centimeters think, & typically grow where different types of materials interface, mostly on moist surfaces. Also these represent the earliest forms of prokaryotic life on Earth.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Prokaryotes in a microbial mat are held together by what?

A

Extracelluar Matrix, a glue-like sticky substance that they secrete.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What energy sources do prokaryotes in microbial mats use?

A
  1. Chemicals found near hydrothermal vents
  2. Sunlight
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a Hydrothermal Vent?

A

A breakage or fissure in Earth’s surface that releases geothermally heated water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a Stomatolite?

A

A sedimentary structure formed when minerals are precipitated out of water by prokaryotes in a microbial mat.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Stromatolites form layers of rocks made from what?

A

Carbonate or silicate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What kind of atmosphere did early Earth have?

A

Anoxic, there was no molecular oxygen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What kind of organisms would have been able to live during early Earth?

A

Anaerobic organisms b/c they are the only organism’s can grow without oxygen & live.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are phototrophs?

A

Autotrophic organisms that are able to make their own food by converting solar energy to chemical energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is Cynobacteria?

A

A.K.A “blue-green algae,” bacteria that evolved from early phototrophs & oxygenated the atmosphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do Cell Walls do for the prokaryotes that do have them?

A

They are a protective structure that allows them to survive in both hypertonic & hypotonic aqueous conditions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is an Extremophile?

A

Organism that grows under extreme or harsh conditions.
Meaning “lovers of extremes”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Are Bacteria & Archaea extremophiles?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How are different groups of extremophiles identified?

A

Based on the conditions in which they grow best

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is Radioresistant?

A

Organism that grows in high levels of radiation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are Koch’s postulates?

A

Guidelines that identify the organisms responsible for specific diseases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Koch’s postulates include that an organism can be identified as the cause of disease when it is?

A

Present in all infected samples & absent in all healthy samples, & it is able to reproduce the infection after being cultured multiple times.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Koch’s postulates can be fully applied to only organisms that can be what?

A

Isolated & cultured

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why can’t some prokaryotes grow in a laboratory setting?

A
  1. Lack of knowledge as to what to feed these organisms
  2. Lack of knowledge on how to grow them
  3. Some bacteria are obligate intracellular parasites & cannot be grown outside a host cell
  4. Stressful conditions
  5. Require the presence of other prokaryotic species
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is Viable-but-non-culturable (VBNC)?

A

Survival mechanism of bacteria facing environmental stress conditions. These organisms cannot be cultured & are not dead.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is Resuscitation?

A

Process by which prokaryotes that are in the VBNC state return to viability when environmental conditions improve.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Do most prokaryotes prefer to live in communities where they can interact?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a Biofilm?

A

Microbial community that is held together by gummy-textured matrix that consists primarily of polysaccharides secreted by the organisms, together with some proteins & nucleic acids.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Where do biofilms usually grow attached to?
Surfaces & are present almost everywhere.
26
What are biofilms difficult to destroy?
B/c they are resistant to many common forms of sterilization.
27
What are the 3 shape categories for prokaryotes?
1. Cocci (Spherical) 2. Bacilli (Rod-shaped) 3, Spirilli (Spiral-shaped)
28
What are Prokaryotes?
Unicellular organisms that lack membrane-bound organelles or other internal membrane-bound structures.
29
What does a prokaryote chromosome consist of?
(usually single) Consists of a piece of circular, double-stranded DNA located at the nucleoid.
30
What is a Cell Wall?
Located outside the plasma membrane. It functions as a protective layer, it is responsible for the organism's shape. Prevents osmotic lysis (bursting due to increasing volume)
31
What does a capsule outside the cell wall do for some of the bacterial species?
Enables the organism to attach to surfaces, protects it from dehydration & attack by phagocytic cells, & makes pathogens more resistant to our immune responses.
32
What does a flagella do for some of the prokaryotes?
Used for locomotion
33
What does a pili do for some of the prokaryotes?
Used for attachment to surfaces.
34
What is the Prokaryotic Plasma membrane?
A thin lipid bilayer that completely surrounds the cell & separates the inside from the outside.
35
What does the Prokaryotic Plasma membrane selectively permeable nature do?
Keep ions, proteins, & other molecules within the cell & prevents them from diffusing into the extraceullar environment, while other molecules may move through the membrane.
36
What occurs in archaea Cell membranes?
Isoprene (phytanyl) chains linked to glycerol replace the Fatty acids linked to glycerol replace the Fatty acids linked to glycerol in bacterial membranes. Some are lipid monolayers of bilayers.
37
Why is the osmotic pressure within the cell relatively high?
B/c the cytoplasm of prokaryotic cells have a high concentration of dissolved solutes.
38
What do bacterial cell walls contain?
Peptidoglycan
39
What is Peptidoglycan?
Material composed of polysaccharide chains that are cross-linked to unusual peptides containing both L- & D- Amino acids including D- glutamic acid & D- alanine.
40
What are also present on the outside of the cell walls of both Archaea & Bacteria?
S-layer (surface layer) proteins are also present on the outside of the cell wa
41
Bacteria are divided into what two major groups?
1. Gram Positive 2. Gram Negative
42
How are Bacteria divided into the two groups?
Based on their reaction to Gram staining, due to their cell wall structure.
43
Describe gram-positive bacteria.
Belongs to one phylum, typically lacks an outer membrane, & 90% of its cell wall is composed of pepetidoglycan, & most of the rest is composed of acidic substances (teiechoic acids). The teiechoic acids may be covanetly linked to lipids in the plasma membrane to form lipoteichoic acids. Lipoteichoic acids anchor the cell wall to the cell membrane.
44
Describe gram-negative bacteria.
Bacteria in the other phyla belong to this group (Proteobacteria, Chlamydias, Spirochetes, Cyanobacteria, & others). Has an outer membrane & has thin cell walls composed of few layers of peptidoglycan, surrounded by an outer envelope (Sometimes referred to as the second lipid bilayer) containing lipopolysaccharides (LPS) & lipoproteins. Also has porins, which are proteins in the cell membrane that allow substances to pass through the outer membrane.
45
Do Archaean cell walls contain peptidoglycan?
No
46
How many different types of archaean cell walls are there?
4, one type is composed of Pseudopeptidoglycan, which is similar to peptidoglycan in Morphology but contains different sugars in the polysaccharide chain. The other 3 types of cell walls are composed of polysaccharides, glycoproteins, or pure protein.
47
How does reproduction in prokaryotes take place?
They asexually reproduce by binary fission.
48
Does Binary Fission provide an opportunity for genetic recombination or genetic diversity?
No
49
What do prokaryotes undergo instead of mitosis?
The chromosome is replicated & the 2 resulting copies separate from one another, due to the growth of the cell. Then the prokaryote, now enlarged, is pinched inward at its equator & the 2 resulting cells, which are CLONES, separate.
50
What are the 3 mechanisms that prokaryotes use to share genes?
1. Transformation 2. Transduction 3. Conjugation
51
What is Transformation?
Process by which a prokaryote takes in DNA found in its environment that is shed by other prokaryotes.
52
What is Transduction?
Process by which a bacteriophage, a virus that infects bacteria, moves short pieces of chromosomal DNA from one prokaryote to another. The DNA may remain separate as plasmid DNA or be incorporated into the host genome. This results in a recombinant organism.
53
What is Conjugation?
Process by which prokaryotes move DNA from one individual to another using a pilus, which brings the organisms into contact with one another, & provides a channel for transfer of DNA. The DNA transferred can be in the form of a plasmid or as a composite molecule, containing both plasmid & chromosomal DNA.
54
Can reproduction for Prokaryotes be rapid?
Yes
55
What does rapid reproduction allow for?
B/C it allows for short generations with mechanisms of genetic recombination & high rates of mutations, it can result in rapid evolution of prokaryotes. This can allow them to respond to environmental changes very quickly.
56
What do prokaryotes need to live?
1. A source of energy 2. A source of carbon 3. Some additional nutrients
57
What are macromolecules? (Recall)
Produced by the polymerization of smaller units called monomers.
58
What are nutrients?
Essential substances for growth, such as carbon & nitrogen.
59
What are Macronutrients?
Nutrients that are required in large amounts.
60
What are Micronutrients?
Nutrients that are required in small amounts.
61
What elements are considered macronutrients?
Carbon Hydrogen Oxygen Nitrogen Phosphorus Sulfer (Acronym: CHONPS or SPONCH)
62
What is the major element in all macromolecules (Protein, Nucliec Acids, Lipids, & Carbohydrates)?
Carbon
63
What form is nitrogen most available in nature?
Atmospheric Nitrogen (N2) or another inorganic form.
64
Can Diatomic/atmospheric Nitrogen be converted into a organic form?
Yes, by nitrogen-fixing organisms.
65
Are hydrogen & oxygen a part of many organic compounds & water?
Yes
66
Is phosphorus required by all organisms for the synthesis of nucleotides & phospholipids?
Yes
67
What other elements are important for the structure & function of prokaryotic cells?
Potassium (K), magnesium (Mg), calcium (Ca), & sodium (Na).
68
What are phototrophs?
Organisms that are able to make their own food by converting solar energy to chemical energy.
69
How do phototrophs trap light energy?
Chlorophylls or bacterial rhodopsin.
70
What are Chemotrophs?
Organisms that obtain energy from chemical compounds
71
What are Chemoorganotrophs?
Chemotrophs that use ORGANIC compounds as energy sources.
72
What are Chemolithotrophs?
Chemotrophs that use INORGANIC compounds as a source of energy.
73
What two pathways of energy-producing?
1. Aerobic 2. Anaerobic
74
What is Aerobic?
Organisms that grow with oxygen. Oxygen is used as the terminal electron acceptor.
75
What is Anerobic?
Organisms that grow without oxygen. Use simple inorganic compounds or organic molecules as the terminal electron acceptor.
76
How do autotrophic prokaryotes obtain carbon?
By synthesizing organic molecules from carbon dioxide.
77
How do heterotrophic prokaryotes obtain carbon?
From organic compounds.
78
How do photoautotrophs obtain carbon & energy?
Carbon from carbon dioxide & water. Energy by coverting light energy (sunlight) to chemical energy.
79
How do chemoherterotrophs obtain carbon & energy?
From an organic chemical source.
80
How do chemolithoautotrophs obtain carbon & energy?
From carbon dioxide. From inorganic compounds.
81
How do photoheterotrophs obtain carbon & energy?
Organic compounds. From light.
82
What is the carbon cycle?
The movement of carbon from inorganic to organic compounds & back again.
83
What is carbon cycled through?
Earth's major reservoirs: land, the atmosphere, aquatic environments, sediments and rocks, & biomass.
84
How does the carbon cycle function?
Carbon dioxide is removed from the atmosphere by land plants & marine prokaryotes, & is returned to the atmosphere via the Respiration of chemoorganotrophic organisms.
85
Who participate in the carbon cycle?
1. Producers 2. Consumers 3. Decomposers of organic compounds
86
What are the primary producers of organic carbon compounds from CO2?
1. Land plants 2. Photosynthetic bacteria
87
What are decomposers?
Organisms that carry out the decomposition of dead organisms.
88
Who collectively carry out the breakdown (decomposition) of plants & animals & their organic compounds?
Decomposers
89
What is the largest pool of nitrogen available in terrestrial ecosystems?
Gaseous Nitrogen (N2)
90
Can gaseous nitrogen(N2) be used by plants ?
No, instead this gas is "fixed" into available forms, such as ammonia (NH3).
91
What is Nitrogen Fixation?
A process by which gaseous nitrogen is transformed, or "fixed" into more readily available forms, such as ammonia.
92
What is Ammonification?
Process by which ammonia is released during the decomposition of nitrogen-containing compounds.
93
What is Nitrification?
Ammonium ion is progressively oxidized by different species of bacteria.
94
Explain the process of Nitrification.
Begins with the conversion of ammonium to nitrite (NO2), & continues with the conversion of nitrite to nitrate.
95
Most nitrogen in soil is in the form of what?
Ammonium (NH4+) or Nitrate (No3-).
96
Can ammonia & nitrate be used by plants or converted to other forms?
Yes.
97
What reverses the process of nitrification?
Denitrifying Bacteria, reduces the nitrate from soils to gaseous compounds such as N2O, NO, & N2.
98
When does abiotic nitrogen fixation occur?
During physical processes such as lightning or by industrial processes.
99
What is Biological Nitrogen Fixation?
Conversion of atmospheric Nitrogen into ammonia exclusively carried out by prokaryotes (soil bacteria, cyanobacteria, & Frankia spp). This the second most biological process on Earth ( The first being photosynthesis).
100
What are nodules?
Novel structures on the roots of certain plants (legumes) that results from the symbiotic interaction b/w the plant & soil bacteria, & is the site of nitrogen fixation.
101
What is Nitrogenase?
The enzyme that fixes nitrogen.
102
What occurs when Nitrogenase is inactivated by oxygen?
The nodules provide an oxygen-free area for nitrogen fixation to take place. The oxygen is sequestered by a form of plant hemoglobin called leghemoglobin, which protects the nitrogenase, but releases enough oxygen to support respiratory activity.
103
What is Symbiotic Nitrogen Fixation?
A process that provides a natural & inexpensive plant fertilizer. It reduces atmospheric Nitrogen to ammonia, which is easily usable by plants.
104
Through using symbiotic Nitrogen fixation, plants benefit from what?
Using an endless source of nitrogen (the atmosphere).
105
Through using symbiotic Nitrogen fixation, bacteria benefit from what?
Using photosynthesis (carbohydrates produced during photosynthesis) from the plant & having a protected niche.
106
Through using symbiotic Nitrogen fixation, soil benefit from what?
Being naturally fertilized.
107
What is Bioremediation?
Use of microbial metabolism (or prokaryotes) to remove pollutants.

Biology II (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions