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lecture exam 2 Flashcards

1
Q

Why is it possible to say LUCA may have been a community?

A

Horizontal gene transfer -
LUCA may have been an interbreeding community, so natural selection could not be possible because heredity was not established

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2
Q

What is horizontal gene transmission?

A

The movement of genes from one genome to another, complicates efforts to build a tree of life.

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3
Q

Who was Lynn Margulis?

A

She suggested that eukaryotes arose as an endosymbiosis between bacterium and archaea.

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4
Q

Who is Carl Woese?

A

He used rRNA sequences to draw phylogenetic trees instead of morphology.

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5
Q

Who was Norm Pace?

A

He used cloning techniques to allow identification of microbes without having to grow them

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6
Q

Why did Woese use ribosomal RNA to study the tree of life?

A

rRNA genes evolve slowly

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7
Q

What are the three domains of life?

A

Bacteria, Archaea, and Eukarya

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8
Q

What types of environments can extremophile Archaeans be found in?

A

Extreme environments - hypersaline water, strongly acidic water, very hot water, deep sea vents, and anaerobic environments

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9
Q

What do Archaeans and Eukaryotes have in common?

A

They are genetically and metabolically similar to each other.

RNA polymerase
Initiator amino acid for protein synthesis

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10
Q

What do Archaeans and bacteria have in common?

A

Their structures and shapes are similar - spheres, rods, spirals, and plates

Membrane lipids
Response to the antibiotics streptomycin and chloramphenicol

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11
Q

Who discovered Archaeans, when, and using what data type?

A

Woese discovered them in 1977 when they were separated from bacteria using the phylogenetic taxonomy of rRNA

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12
Q

Describe Deinococcus radiodurans. Why is it like that?

A

It is an extremophile and radio-resistant.
They have multiple storages of their genetic material so if one gets damaged there is always a backup.

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13
Q

Describe the three shapes that prokaryotes can have.

A
  1. Cocci (sphere)
  2. Bacilli (rod)
  3. Spiral
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14
Q

How is the cell wall of a bacterium unique with respect to the other 2 domains?

A

Bacterial cell walls contain peptidoglycan, a network of sugar polymers cross-linked by polypeptides.

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15
Q

Describe how gram-staining works.

A

Scientists can classify bacterial species by gram-staining into Gram-positive and Gram-negative bacteria. Gram-negative bacteria have less peptidoglycan and an outer membrane that can be toxic.

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16
Q

Who developed gram-staining?

A

It was developed by Hans Christian Gram

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17
Q

A bacteria stains purple, is it gram-negative or positive?

A

Positive

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18
Q

Describe and be able to label the two types of bacteria cell walls.

A
  1. Eukaryote cell walls - made of cellulose or chitin
  2. Bacterial cell walls - contain peptidoglycan
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19
Q

T or F: Bacteria can be found as high as 25 miles and as deep as a half mile underground

A

True

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20
Q

What, specifically, does penicillin attack?

A

The peptidoglycan of bacterial cell walls

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21
Q

What’s a capsule and what is it good for?

A

It is a polysaccharide/protein layer that covers prokaryotes.

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22
Q

What’s a fimbria?

A

Fimbria are attachment pili that allow bacteria to stick to their substrate or other individuals in a colony.

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23
Q

What’s a pilus?

A

A pilus or sex pili are longer and allow exchanging of DNA.

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24
Q

What is taxis?

A

Taxis is the ability to move toward/away from certain stimuli.

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25
If chemotaxis means moving toward a specific chemical. What do you think negative chemotaxic means?
Negative chemotaxis would mean to move away from a specific chemical.
26
Label the flagella mechanism of a bacteria and describe how it works.
Flagella are what bacteria use to propel themselves for motility.
27
Are all archaeans extremophiles?
No, some are methanogens that live in anaerobic habitats.
28
What are two types of interior membranes that can be found in some bacteria?
1. Respiratory membranes 2. Thylakoid membranes
29
Describe the two types of DNA in a bacterium.
1. Plasmid - delivers DNA 2. Nucleiod - main DNA material
30
Bacterial generation times are about how long?
Bacteria divide every 1-3 hours by binary fission, sometimes even 20 minutes.
31
What's an endospore? How can you kill it?
An endospore is a resistant asexual sport that develops inside some bacteria cells. It can be killed when heated to 121ºC UNDER PRESSURE.
32
What are the three ways that bacteria generate so much genetic diversity?
1. Rapid reproduction 2. Mutation 3. Genetic recombination
33
About how many mutations occur in your E. coli fauna every day?
A milliion
34
What is the F-factor?
A piece of DNA that is required for the production of sex pili and can exist as a separate plasmid or as DNA within a bacterial chromosome.
35
What is an R-plasmid?
They carry genes for antibiotic resistance.
36
What is an Hfr cell?
High-frequency recombination cell is a bacterium with a conjugative plasmid (donor cell)
37
What two things are required to kill an endospore?
Heat and pressure
38
Why might a doctor cycle a drug treatment with a short period of no drugs?
Use antibiotics to knock down bacteria, but there is a resistant bacteria that does not get touched. Cycling.
39
Where (what bacterial group) did your mitochondria come from?
Rhizobium
40
Why are alpha proteobacteria like Rhizobium important to plants (and us)?
Internal cell membranes (ancestors of our mitochondria) Cellular respiration
41
What is binary fission?
A kind of asexual reproduction and the most common form of reproduction. Splits into 2 and can divide every 1-3 hours
42
What is a leading hypothesis for chlamydia causing infertility?
It affects the reproductive pathway.
43
Beans provide a home for Rhizobium in their roots. The bacteria provide usable nitrogen. Living together like this is termed ...
mutualistic symbiosis
44
Lyme disease and syphilis are caused by ...
parasites
45
Why are cyanobacteria considered so important?
They generate oxygen. Plant chloroplasts likely evolved from cyanobacteria by the process of endosymbiosis. Earth changed into an aerobic planet.
46
What was the Great Oxygen Event? When did it happen?
It was covered in methane. The appearance of free oxygen in the Earth's atmosphere. It happened 2.4 billion years ago
47
What are the three types of symbiotic relationships?
1. Mutualism 2. Commensalism 3. Parasitism
48
A disease-causing bacteria is called a...
pathogen
49
Describe how Lyme disease is transmitted
A deer tick bites into human and insets a toxin. Muscles expands and pathogenic prokaryotes cause diseases by releasing exotoxins and endotoxins
50
What are the 4 major nutritional modes in bacteria?
1. Photoautotrophs 2. Chemoautotrophs 3. Photoheterotrophs 4. Chemoheterotrophs
51
Describe the three bacterial modes concerning oxygen use/tolerance.
1. Obligate anaerobes - don’t like oxygen 2. Obligate aerobes - like oxygen 3. Facultative aerobes - do either
52
What is nitrogen fixation?
Prokaryotes convert atmospheric nitrogen to ammonia
53
Give an example of a nitrogen-fixing bacteria and where it lives.
Soybeans - lives on the root
54
What's a biofilm?
In some prokaryotic species, metabolic cooperation occurs in surface - coating colonies called biofilms
55
What is a eukaryote?
A unicellular protist
56
What are the five major eukaryote groups?
1. Excavata 2. Chromalveolata 3. Rhizara 4. Archaeplastida 5. Unikonta
57
What are the three nutritional strategies of eukaryotes?
1. Photoautotrophs - contain chloroplasts 2. Heterotrophs - absorb organic molecules or ingest large food particles 3. Mixtrophs - combine photosynthesis and heterotrophic nutrition
58
Describe the primary endosymbiosis of plastids. What two groups arose this way?
The plastid-bearing lineage of protists evolved into red and green algae. Archeoplastids and Chromalveolates arose this way.
59
Describe secondary endosymbiosis. What 3 groups arose this way? How do we know it was secondary?
On several occasions during eukaryotic evolution, red and green algae underwent secondary endosymbiosis in which they were ingested by a heterotrophic eukaryote. Chromalveolates, Rhizarians, and Excavates arose this way.
60
What are the 3 groups within the Excavata?
1. Diplomonads 2. Parabasalids 3. Euglenozoans
61
What basic properties do the excavates share?
A cytoskeleton They have modified mitochondria and protists with unique flagella
62
If an excavate has a plastid, where did it originate?
From red or green algae
63
What is the main distinguishing feature of a Euglenozoan?
A spiral/crystalline rod of unknown function within the flagella
64
What two groups make up the Euglenozoa?
1. Kinetoplastids 2. Euglenids
65
What two diseases are caused by Trypanosoma infections?
1. Sleeping sickness 2. Chagas' disease
66
What 2 groups make up the Chromalveolates?
1. Alveolates 2. Stramenopiles
67
What distinguishes alveolates? What is that for?
They have membrane-bound sacs (alveoli) under the plasma membrane, function is unknown
68
Dinoflagellates gain nutrition by either being...
mixotrophs or heterotrophs
69
Dinoflagellates release toxins and blooms may result in...
toxic red tides
70
Malaria is caused by the apicomplexan...
Plasmodium
71
About how many people contract malaria each year?
350-500 million
72
How many people die each year from malaria?
1-3 million
73
T or F Humans have evolved in response to malaria?
True
74
Where do merozoites develop in your body?
Merozoites develop in the liver cells and then the red cells in the blood.
75
Where do gametocytes develop in your body?
Gametocytes develop in the blood marrow.
76
Ciliates have cilia and two types of nuclei...
Macronuclei and micronuclei
77
How do paramecia become recombinant?
Conjunction
78
How do paramecia reproduce?
via meiosis
79
Stramenopiles are characterized by what type/s of flagella?
A hairy flagellum and a smooth flagellum
80
Diatoms of skeletons made of hydrated...
silica
81
Golden algae get their color from yellow and brown...
cartenoids
82
Some golden algae are ... in addition to being autotrophic
heterotrophic
83
An example of brown algae is...
seaweed/kelp
84
Are brown algae (protists) multicellular?
yes
85
How many feet can brown algae grow in one day?
1-2 feet
86
What are the three parts of a brown algae and what do they do?
1. Holdfast- anchors the algae 2. Stipe - stemlike, supports blades 3. Blades - photosynthetic, leaflike
87
What group caused the Irish Potato famine and why was it so devastating to the potatoes?
Phytophthora infestins caused the Irish Potato famine
88
What’s the genus of that bacteria in the bobtail squid?
Vibrio fischeri

OD (4 decks)

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