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MCAT TPR Biology > Microbiology > Flashcards

Microbiology Flashcards

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1
Q

Viruses are obligate intracellular parasite. what does that mean?

A

they are only able to reproduce within cells

it relies on host machinery

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2
Q

T/F

Viruses on their own are able to synthesis ATP and other chemical reactions.

A

False

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3
Q

T/F

Viruses are not cells or living organisms.

A

True

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4
Q

How can some viruses have ATP stored in their capsid? What can they use it for?

A

they got it from the last host

they can use it for penetration into the next host

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5
Q

When a virus is not inside a host cell, what does it contain?

A

only its own genome which could be single stranded or double stranded, linear or circular

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6
Q

If the ratio of adenine to thymine in a DNA virus is not one to one, what can be said about the genome of this virus?

A

the genome must be single stranded DNA, or RNA which has no T

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7
Q

A disease agent that is isolated from a human cannot reproduce on its own, but it can reproduce when put in a culture of human cells. In its pure form it contains both RNA and DNA, is it a virus? Why?

A

no because a virus can only have DNA or RNA but not both

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8
Q

What is a bacteriophage?

A

virus that infects bacteria

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9
Q

What limiting factor affects all viral genomes?

A

size

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10
Q

What happens if a viral genome triples in size?

A

it will no longer fit within the normal viral structure and therefore will not be packaged in infectious viral particles

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11
Q

How does the virus adapt to its size constraint?

A
  • carries only a few genes and relies mostly on host encoded proteins for transcription, translation, and replication
  • ability to encode more than one protein in a given length of genome by utilizing more than one reading frame within a piece of DNA so that genes overlap
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12
Q

How do ribosomes used to translate viral proteins compare to host ribosomes?

A

they are the same because viruses use the host ribosomes

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13
Q

What is the protein coat that surrounds the viral nucleic acid genome which is also used to classify viruses?

A

capsid

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14
Q

Helical capsids?

A

rod shaped

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15
Q

Polyhedral capsids?

A

multiple sided geometric figures with regular surfaces

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16
Q

What is the capsid shape of Bacteriophage T4?

A

Helical and Polyhedral

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17
Q

What is the host for the Bacteriophage T4?

A

E. coli

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18
Q

Where on the capsid is the genome located?

A

in the capsid head

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19
Q

What do the tail fibers and the base plate of the capsid do?

A

attach to the surface of the host cell

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20
Q

What does the sheath of the capsid do?

A

contracts using energy of stored ATP, injects the genome into the host

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21
Q

Why might a bacteriophage inject its DNA, while animal viruses do not?

A

a phage must puncture the bacterial cell wall, while animal viruses can be internalized whole because there is no cell wall

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22
Q

The entire viral capsid is composed of _______ while the viral genome is composed of ______.

A

proteins

nucleic acids

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23
Q

In animal viruses, what surrounds the capsid?

A

the envelope

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24
Q

What is the envelope?

A

membrane on the exterior of the animal virus derived from the host membrane

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25
Q

How do animal viruses acquire an envelope?

A

budding

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26
Q

What are viruses without an envelope?

A

naked viruses

-plant viruses and phages are all naked because they do not bud through the membrane, they puncture the cell wall

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27
Q

T/F

Viruses are very specific, not random.

A

True

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28
Q

What is the first step in infection?

A

virus binds to a specific receptor on the cell surface

-attachment or adsorption

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29
Q

After binding, how does the virus become internalized?

A

fusion with the plasma membrane or receptor mediated endocytosis

-penetration(animal) or eclipse(plant, bacteria)

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30
Q

If antibodies to a viral capsid protein are ineffective in blocking infection, what might this indicate about the virus?

A

the virus is enveloped, so the antibody cannot reach its epitope on the capsid surface

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31
Q

In the Lytic cycle, what happens as soon as the phage genome has entered the host cell?

A

host polymerases and ribosomes begin to rapidly transcribe and translate it

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32
Q

What is one of the first viral gene products made in the lytic cycle?

A

hydrolase- degrades entire host genome

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33
Q

Early genes?

A

a group of genes that are expressed immediately after infection and which includes any special enzymes required to express viral genes (ex. hydrolase)

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34
Q

What happens after hydrolase degrades the host genome in lytic cycle?

A

multiple copies of the phage genome are produced (using dNTPs resulting from degradation) as well as capsid proteins

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35
Q

What happens after copies of the phage genome are produced in the lytic cycle?

A

each new capsid assembles itself around a new genome

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36
Q

What happens after the new capsids form in the lytic cycle?

A

enzyme called lysozyme (late gene) is produced which destroys the bacterial cell wall, the host bursts (lyses) releasing hundreds of the new capsids to repeat the cycle

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37
Q

If lysozyme were an early gene, would this be advantageous to the virus?

A

no the host would burst before the phage had time to replicate and assemble

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38
Q

When phage are first added to a bacterial culture, the number of infective viruses initially decrease before it later increases, why?

A

many phage have injected their genomes into host cells and are no longer infectious, then the cells lyse and release a bunch of capsids

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39
Q

Bacteria culture in the presence of S-cysteine and P-phosphate are infected with T4, what will be found in the interior of newly infected bacteria?

A

only P because nucleic acids contain no S and proteins contain no P, when the virus infects bacteria their nucleic acids are injected while the proteins remain on the outside

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40
Q

A bacteriophage with an important capsid gene deleted infects the same cell as another virus (co-infection) with a normal copy of the same gene. What will happen at the time of lysis?

A

all released viruses will be capable of infecting new hosts, but only some of these new infections will give rise to phage capable of infecting new hosts.

some of the bad genome will be covered by good capsid, which can infect another cell but once in the cell the bad genome will code for bad capsid and its progeny will not be able to infect a host

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41
Q

Advantage and disadvantage of the lytic cycle?

A
  • efficient way for a virus to rapidly increase its numbers

- all host cells are destroyed, eventually all will run out

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42
Q

In the lysogenic cycle, what happens after infection of the host?

A

the phage genome is incorporated into the bacterial genome and is now referred to as a prophage, host is called a lysogen

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43
Q

What is a prophage in lysogenic cycle?

A

silent, genes are not expressed, viral progeny not produced

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44
Q

Why is the prophage dormant in lysogenic cycle?

A

transcription of phage genes is blocked by a phage encoded repressor protein that binds to specific DNA elements in phage promoters (operators)

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45
Q

Why is the lysogenic cycle clever?

A

every time the host reproduces itself, the prophage is reproduced too

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46
Q

What happens when the prophage becomes activated in the lysogenic cycle?

A

removes itself from the host genome (excision) and enters the lytic cycle

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47
Q

What is a potential consequence of the lysogenic cycle?

A

when the viral genome activates, excising itself from the host genome, it may take part of the host genome with it and could integrate that DNA into future infections (transduction)

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48
Q

Why would a bacterial gene, carried with a virus and integrated with viral genes into a new bacterial genome, not be repressed along with the viral genes during lysogeny?

A

viral repressor proteins bind to a specific sequence on viral DNA, this sequence is not present on the bacterial gene, so the bacterial gene can be expressed while the viral genes are repressed.

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49
Q

What does the virus bind to on animal cells?

A

animal cells have proteins on the surface of the plasma membrane that serve as specific receptors for viruses

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50
Q

What is one of the first steps in HIV infection?

A

HIV virus protein gp120 binds to a T cell membrane protein called CD4

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51
Q

Would treatment of an HIV infected person with a soluble form of CD4 protein affect the infectivity of the virus?

A

yes, the CD4 protein would bind the virus CD4 receptors and block attachment of the virus to the T cells

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52
Q

Mutation of the cell surface receptor that viruses attach to would be a means for an organism to become resistant to viral infections. Why is this mechanism not common?

A
  1. the receptor has a specific role in the normal function of the host, which might be compromised
  2. viruses can evolve rapidly to keep up with the changes of the host
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53
Q

What is the next step in the infection of the animal cell after the virus has been bound to the plasma membrane?

A

penetration- many animal viruses enter by endocytosis

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54
Q

Endocytosis in animal virus infections?

A

the host cell engulfs the virus and internalizes it

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55
Q

Once inside the host cell, the viral genome becomes ______.

A

uncoated (released from capsid)

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56
Q

What are the three possible cycles of an animal virus?

A

lytic
productive
lysogenic

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57
Q

What is the difference between the productive and lytic cycles?

A

productive doesnt destroy the cell

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58
Q

How is the cell not destroyed in the productive cycle?

A

the enveloped virus exits the host by budding through the host’s cell membrane, the cell membrane can reseal itself so the cell doesnt die

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59
Q

What is a provirus in animal cells?

A

the dormant form of the viral genome in the animal virus lysogenic cycle

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60
Q

What is an example of a provirus in animal cells?

A

Herpes Simplex I is the virus that causes oral herpes

it can remain dormant until stress reactivates it

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61
Q

What is + RNA?

A

a piece of single stranded viral RNA which serves as mRNA

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62
Q

What happens when a + RNA virus in injected into the cell?

A

it acts as mRNA and host ribosomes immediately begin to translate it, creating viral proteins

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63
Q

Infective?

A

injecting an isolated genome into the host cell will result in virus production (+RNA)

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64
Q

What protein is needed for +RNA virus to replicate itself?

A

RNA dependent RNA polymerase

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65
Q

What is the role of RNA dependent RNA pol?

A

to copy the RNA genome for viral replication

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66
Q

What are some examples of +RNA viruses?

A

common cold, polio, rubella

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67
Q

If a viral genome is + strand RNA, what is used as a template by the RNA dependent RNA pol?

A

it needs the - strand RNA as a template so it first produces a - strand intermediate before generating new + strand genomes

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68
Q

What happens when a -RNA virus enters the cell?

A

it codes for and carries the RNA dependent RNA pol, unlike +RNA viruses, so when it enters the cell the enzyme creates a + strand from the - strand, then the cycle can continue

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69
Q

What are some examples of -RNA viruses?

A

rabies, measles, mumps, flu

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70
Q

What is a retrovirus?

A

+RNA viruses that undergo lysogeny

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71
Q

How can a retrovirus integrate into double stranded DNA genome if it enters the cell as RNA?

A

they undergo reverse transcription to make DNA from an RNA template, this is done by RNA dependent DNA polymerase (reverse transcriptase) encoded by the viral genome

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72
Q

Even though retroviruses carry the enzyme, RNA dependent DNA pol, they are theoretically not required to carry it, why?

A

the viral genome can be translated by host ribosomes so it only needs to encode for the enzyme

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73
Q

What are the three main retroviral genes and what do they code for?

A

gag- codes for viral capsid proteins
pol- codes for reverse transcriptase
env- codes for viral envelope proteins

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74
Q

After integration of a retrovirus into the cellular genome, a reverse transcriptase inhibitor is added to the cell, will the production of new viruses be blocked?

A

no because the reverse transcriptase is only required for the copying of the viral RNA genome into DNA, this will have already taken place so it is not needed anymore, so an inhibitor wouldnt block anything

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75
Q

What do double stranded DNA viruses often have?

A

large genomes that include genes for enzymes involved in dNTP synthesis and DNA replication

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76
Q

Why do double stranded DNA viruses carry around genes for enzymes that are possessed by the host cell?

A

if the virus wants to reproduce, it doesnt have to wait for the host cell to do it

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77
Q

Why dont RNA viruses carry the genes for dNTP synthesis or replication?

A

transcription is always occurring in all cells, so NTPs (not dNTPs) are always present

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78
Q

What factor likely limits the size of RNA genomes?

A

the error rate is much higher in RNA synthesis as opposed to DNA synthesis, so if the RNA genome was too large every copy would suffer too many errors that no infectious virus would be produced

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79
Q

What is the advantage for DNA viruses to induce host cell division?

A

to produce the ingredients needed for DNA synthesis if it does not already possess them

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80
Q

What is a virus that complements another virus?

A 
helper virus (one virus provides one thing necessary, the other virus provides the other thing necessary, 
ex. adenoviruses)
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81
Q

What is the primary feature that distinguishes prokaryotes from eukaryotes?

A

prok do not have membrane bound organelles

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82
Q

What are three examples of prokaryotes?

A

bacteria
archea (extremophiles)
blue green algae (cyanobacteria)

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83
Q

Taxonomy?

A

classification of living organisms

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84
Q

What are the three recognized domains of taxonomy?

A

bacteria
archea
Eukarya

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85
Q

Domains can be subdivided into what?

A

kingdoms

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86
Q

What are the three Euk kingdoms?

A

Animalia
Plantae
Fungi

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87
Q

What is the prok genome like?

A

single double-stranded circular DNA chromosome (not in a nucleus and no nucleosomes)

88
Q

What is a polyribosome?

A

many ribosomes translating a single piece of mRNA

89
Q

Is the free end of mRNA that has already been transcribed 3’ or 5’?

A

5’ because DNA is transcribed 5’ to 3’

90
Q

What is the free end of the polypeptide that has already been translated?

A

N terminus because proteins are made N to C

91
Q

Why is important that bacterial ribosomes are different than our ribosomes?

A

the differences allow us to prescribe various antibiotics which interfere with bacterial translation without disrupting ours

92
Q

What is the plasmid in prok?

A

circular piece of double stranded DNA which is smaller than the genome, referred to as extrachromosomal genetic elements

93
Q

Why are plasmids important?

A
  • they encode advantageous gene products, such as antibiotic resistant genes
  • they orchestrate bacterial exchange of genetic info (conjugation)
94
Q

What is the proper name of round shaped bacteria?

A

cocci (plural)

coccus (singular)

95
Q

What is the proper name of rod shaped bacteria?

A

bracilli (plural)

bracillus (singular)

96
Q

What is the proper name of spiral shaped bacteria?

A

spirochetes or spirilla (plural)

spirochete, spirillum (singular)

97
Q

What prevents lysis due to osmotic pressure in bacterial cells?

A

cell wall

98
Q

How can animal cells deal with osmotic pressure if they lack a cell wall?

A

they continuously pump ions across the cell membrane

99
Q

What is the bacterial cell wall composed of?

A

peptidoglycan- complex polymer unique to prok

100
Q

What is peptidogylcan composed of?

A

cross linked chains made of sugars and amino acids, including D-alanine(not found in animal cells, we have L configuration)

101
Q

What enzyme is found in tears and saliva which is also made by lytic viruses?

A

lysozyme

102
Q

What is target of many antibiotics, including penicillin?

A

bacterial cell wall

103
Q

What is a protoplast?

A

an osmotically fragile structure due to the cell wall (peptidoglycan) being destroyed by lysozyme

104
Q

Would a protoplast moved from salt water to fresh water shrivel or burst?

A

burst because concentration inside the cell is higher than outside so fresh water would rush through osmosis (hypotonic)

105
Q

Gram staining?

A

method of classification derived from the extent to which bacteria turn color in a procedure

106
Q

Gram positive?

A

stain strongly dark purple color

107
Q

Gram negative?

A

stain weakly light pink color

108
Q

What is the difference in cell wall between gram positive and gram negative bacteria?

A

positive- thick peptidoglycan layer outside the cell membrane and no other layer beyond this

negative- thinner layer of peptidoglycan in the cell wall and an additional outer layer containing lipopolysaccharide

109
Q

What is the periplasmic space in gram negative bacteria?

A

intermediate space between the cell membrane and the outer layer which sometimes contain enzymes to degrade antibiotics

110
Q

Which bacteria would be more susceptible to lysis when treated with lysozyme, positive or negative?

A

positive because it has a thicker peptidoglycan layer and no other layer, lysozyme hydrolyzes linkages in the peptidoglycan to weaken the cell wall

111
Q

What are endotoxins in gram negative bacteria?

A

normal components of the outer membrane that arent poisonous unless when many bacteria die and their outer membranes are released into circulation, the immune system will release chemicals which send the patient into septic shock causing a drop in blood pressure

112
Q

What are exotoxins found in both gram positive and negative bacteria?

A

very toxic substances secreted into the surrounding medium, exotoxins help the bacteria compete with other bacteria which could be normal to the body (ex. botulism, tetanus)

113
Q

What is the capsule that only some bacteria have?

A

glycocalyx, sticky layer of polysaccharide goo surrounding the bacterial cell wall and often an entire colony of bacteria making it more difficult for the immune system to eradicate them and allows bacteria to stick to smooth surfaces

114
Q

What are flagella in bacteria?

A

long whip like filaments involved in motility

115
Q

Can viruses move via flagella propulsion to find host cells?

A

no viruses lack any means of energy production or movement on their own, they rely on diffusion into host cells

116
Q

Monotrichous? Amphitrichous? Peritrichous? (bacteria)

A

Mono- flagella at only one end

Amphi- flagella at both ends

Peri- multiple flagella

117
Q

What are the three parts of the flagella?

A

filament, hook, basal structure

118
Q

What does the basal structure of flagella do?

A

anchor flagella to the inner and outer membrane for a gram negative bacteria and serve to rotate the rod and the rest of the attached flagella either clockwise or counterclockwise

119
Q

How does a bacteria supply the large amount of ATP needed to rotate the rod of a flagella?

A

supplied by the diffusion of H+ down the proton gradient generated across the inner membrane by electron transport

120
Q

Chemotaxis?

A

bacterial motion directed towards attractants, such as food,

or away from toxins, such as acid

121
Q

What does the connection between chemotaxis and flagellar propulsion depend on?

A

chemoreceptors on the cell surface that bind attractants or repellants and transmit a signal which influence the direction of flagellar rotation, depends on the change in concentration

122
Q

What are pili in bacteria?

A

long projections on the bacterial surface that attach to different surfaces

123
Q

What is the sex pilus in bacteria?

A

special pilus attaching F+ male and F- female bacteria which facilitate the formation of conjugate bridges

124
Q

What are fimbriae in bacteria?

A

smaller structures involved in adhering to surfaces

125
Q

What are mesophiles?

A

bacteria that love moderate temperatures

126
Q

What are thermophiles?

A

bacteria that love heat, live in hot springs or geothermal vents in the ocean floor

127
Q

What are psychrophiles?

A

bacteria that thrive in cold temps

128
Q

Autotrophs?

A

utilize CO2 as their carbon source

129
Q

Heterotrophs?

A

rely on organic nutrients created by other organisms (glucose)

130
Q

Chemotrophs?

A

get their energy from chemicals

131
Q

Phototrophs?

A

get their energy from light

132
Q

What are the 4 types of bacteria? (trophs)

A

chemoauto
chemohetero
photoauto
photohetero

133
Q

Chemoautotroph?

A

build organic macromolecules from CO2, using the energy of chemicals, obtain energy by oxidizing inorganic molecules like H2S

134
Q

Chemoheterotrophs?

A

require organic such as glucose made by other organisms as their carbon source of energy (humans)

135
Q

Photoautotrophs?

A

use only CO2 as a carbon source and obtain their energy from the sun (plants)

136
Q

Photoheterotrophs?

A

get their energy from the sun but require an organic molecule made by other organisms as their carbon source

137
Q

A bacteria that causes an infection in the bloostream of humans is most likely to be classified as what? (trophs)

A

chemoheterotroph because there is no sun involved and most likely uses some of our chemicals

138
Q

What category best describes an organism that uses sunlight to drive ATP production but cannot incorporate CO2 into sugars?

A

photoheterotroph

139
Q

In the lab, what is the most common solid medium that bacteria grow?

A

agar- firm transparent gel made from seaweed

140
Q

Plating?

A

process of putting bacteria on a petri dish

141
Q

Minimal medium?

A

contains nothing but glucose and agar

142
Q

Wild type bacterium?

A

possesses all the characteristics normal to that particular species

143
Q

Lawn?

A

dense growth of bacteria seen in lab petri dish

144
Q

Plaque?

A

clear area in the lawn which are the result from death of bacteria and are caused by lytic viruses or toxins

145
Q

What is the doubling time of E. coli?

A

20 minutes

146
Q

Examples of slow growing bacteria?

A

bacteria in TB or leprosy

147
Q

What factors determine doubling time?

A

availability of nutrients and other environmental factors

148
Q

Auxotroph?

A

bacteria that cannot survive on minimal medium, needs the certain substance to live (arginine)

149
Q

Oxygen metabolism is _____ metabolism.

A

aerobic

150
Q

Bacteria which require oxygen are called ______.

A

obligate aerobes

151
Q

Bacteria which do not require oxygen are called _______.

A

anaerobes

152
Q

What are the three subcategories of anaerobes?

A

Facultative
Tolerant
Obligate

153
Q

Facultative Anaerobes?

A

will use oxygen when it is around, but do not need it

154
Q

How much more ATP can be made if oxygen is around?

A

16 times more

155
Q

Tolerant Anaerobes?

A

can grow in the presence or absence of oxygen but do not use it their metabolism

156
Q

Obligate Anaerobes?

A

poisoned by oxygen because they lack enzymes necessary for the detoxification of free radicals which form when oxygen is around

157
Q

What is the main difference between respiration and fermentation?

A

respiration uses O2 while fermentation doesnt

158
Q

What is anaerobic respiration?

A

glucose metabolism with electron transport and oxidative phosphorylation relying on an external electron acceptor other than O2, such as nitrate

159
Q

In an experiment, facultative anaerobic bacteria that are growing on glucose in air are shifted to anaerobic conditions. If they continue to grow at the same rate while producing lactic acid, how much will the rate of glucose consumption increase or decrease?

A

increase 16 fold

160
Q

How do bacteria reproduce?

A

asexually, there is no meiosis, no gametes

binary fission- bacteria grows in size until it has enough for two and then splits

161
Q

In prok, does reproduction increase genetic diversity?

A

no all of the daughter cells are identical

without meiotic recombination, there is no diversity

162
Q

How is asexual production in Euk different than Prok?

A

Euk undergo mitosis, Prok do not

163
Q

Bacterial population growth is ______.

A

exponential (log phase)

164
Q

If 10 bacteria in log phase are placed in ideal growth conditions and the doubling time is 20 mins, how many bacteria will there be after 4 hours?

A

4 hours = 240 mins

240 mins = 12 cycles

answer: 10 * 2^12

165
Q

Log phase vs Lag phase?

A

Log- bacteria experiences exponential growth

Lag- prior to log phase where cell division does not occur even if conditions are ideal

166
Q

If growth conditions are ideal, why wouldnt cell division occur immediately?

A

during the lag period, bacteria are producing new cellular components so that they can divide, but they are not ready to divide

167
Q

Will bacteria that are transferred from a culture that is in log phase to a fresh new culture show a lag phase?

A

no because all the gear necessary for population growth is ready

168
Q

Stationary phase?

A

cells cease to divide because of lack of nutrients, cells may die

169
Q

Carrying capacity?

A

max population at the stationary phase

170
Q

If bacteria are grown in a medium with glucose as the main source of energy, when will the glycolytic pathway be more active: during the lag phase or the stationary phase?

A

the bacteria will use glucose during the lag phase to produce ATP and cell machinery so glucose will be abundant at this time, during the stationary phase the glucose will be depleted and glycolysis rate will have decreased

171
Q

What are endospores?

A

Gram positive bacteria form endospores under unfavorable conditions, they have tough outer shells made of peptidoglycan and can survive harsh conditions, it is dormant until germination activates it

172
Q

What is germination?

A

reactivation of endospores

173
Q

When are bacteria most likely to form endospores?

A

during the stationary phase when times are bad for the bacteria, it is like hibernating, there is no reproducing

174
Q

What are the three mechanisms of acquiring genetic material in bacteria?

A

Transduction
Transformation
Conjugation (most common)

175
Q

What is transformation in bacteria?

A

pure DNA is added to a bacterial culture, the bacteria internalize the DNA in certain conditions and gain any genetic info in the DNA

176
Q

What is conjugation in bacteria?

A

bacteria make physical contact and form a bridge between cells, one cell copies the DNA and transfers it through the bridge to the other cell

177
Q

A key to bacterial conjugation is the _____ ______.

A

F(fertility) factor

178
Q

Bacteria that have the F factor are _____ or _____.

A

male
F+
males transfer the F factor

179
Q

Bacteria that do not have the F factor are _____ or _____.

A

female
F-
females receive the F factor and become male

180
Q

If all cells in a population are F+, will conjugation occur?

A

no, it only occurs between male and female

181
Q

Which cell will produce sex pili in bacteria?

A

the male cell contains the F factor that encodes the genes for pili

182
Q

T/F

DNA transfer between F+ and F- occurs in one direction.

A

True

male to female

183
Q

High frequency of recombination cell?

A

a cell with the F factor integrated into its genome

184
Q

Will an Hfr cell undergo conjugation with an F- cell?

A

yes it contains the F factor

185
Q

If bacteria contain only one copy of the bacterial genome, how can recombination occur?

A

when a Hfr cell conjugates with an F- cell and transfers a portion of the bacterial chromosome, the F- cell will have two copies of some genes

186
Q

Conjugate mapping?

A

technique in the lab by allowing Hfr cells to conjugate in time intervals to see what order the genes are in

187
Q

T/F

Most fungi are nonmotile, multicellular Prokaryotes.

A

False
Eukaryotes
Yeast are unicellular

188
Q

Chitin?

A

rigid cell wall of fungi

also found in the exoskeleton of insects

189
Q

T/F

All fungi are chemoheterotrophs.

A

True

190
Q

Most fungi are either saprophytes or parasites.
Saprophytes?
Parasites?
Mutualists?

A

Sapro- feed off dead plants and animals

Parasites- feed off living organisms doing harm to the host

Mutualists- live in a symbiotic relationship where both benefit (lichen)

191
Q

Most fungi are obligative aerobes. Yeast are ______.

A

facultative anaerobes

192
Q

The method of nutrition used by fungi is called ______.

A

absorptive- digestion takes place outside the cell, molecules are absorbed across the cell wall

193
Q

Can yeast use CO2 as a carbon source?

A

no they are chemoheterotrophs

194
Q

Hypha in fungi?

A

long filament of cells joined end to end

195
Q

Septate hyphae in fungi?

A

cells separated by walls called septae

196
Q

Aseptate hypha in fungi?

A

cells joined together in a long tube where contents are shared

197
Q

Haustoria?

A

hyphae that are specialized to digest and absorb nutrients in parasitic fashion

198
Q

Mycelium?

A

meshwork of hyphae

199
Q

Thallus?

A

large fungal structure which is visible to the naked eye, meaning body

200
Q

Vegetative portion of thallus? Fruiting body?

A

Veg- involved in obtaining nutrients

Fruit- functions in reproduction, makes spores
ex. mushrooms

201
Q

What is the difference is spores from fungi to bacteria?

A

fungi- may produce many spores, reproduction

bacteria- produces only one endospore, wait out bad times

202
Q

T/F

Fungi reproduce both sexually and asexually.

A

True

203
Q

Three types of fungal asexual reproduction?

A

Budding
Fragmentation
Spore formation

204
Q

Budding in fungi?

A

new smaller hypha grows outward from an existing one

205
Q

Fragmentation in fungi?

A

the mycelium can be broken into smaller pieces and develops into smaller mycelium

206
Q

Asexual spore formation in fungi?

A

mitosis to generate many spores from one cell

207
Q

Sporangia?

A

specialized structures of spores found elevated in stalk like hypha

208
Q

Haploid? Diploid?

A
  • cell species with only one copy of each chromosome

- Diploid has two copies (ex. humans)

209
Q

In humans, _____ gametes are produced from diploid cells through _______. Fusion of two gametes results in ______ _____ which then divides through ______ to produce a diploid adult.

A

haploid
meiosis
diploid zygote
mitosis

210
Q

Fungal adults are ______. (hap/dip)

A

haploid

211
Q

Summary of life cycle of fungi?

A

haploid cells derived from haploid adults fuse to produce a diploid zygote which quickly enters meiosis to produce haploid cells again which will divide through mitosis to produce a haploid adult

212
Q

Gametangia?

A

part of fungi specialize to reproduce asexually

213
Q

Dikaryon?

A

cell with two nuclei occurs when fusion of gamete nuclei does not occur right after the two haploid gametes join together

214
Q

In a bacterial medium, if a culture is cloudy, what does that mean? Clear?

A

cloudy- stationary phase

Clear- not growing or in lag phase

215
Q

What prok process does not introduce new material but creates more?

A

binary fission

MCAT TPR Biology (7 decks)

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