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Medical Microbiology > Midterm #1 (session 2-8) > Flashcards

Midterm #1 (session 2-8) Flashcards

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1
Q

Define microorganism

A

Microorganisms are very small usually not seen by the naked eye, living or non-living organism. They can be cellular or acellular, autotroph, heterotroph, motile or sessile

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2
Q

Robert Hooke

A

was the first to see and describe a microorganism (fungus)

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3
Q

Antoni van Leeuwenhoek

A

first to see and describe bacteria

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4
Q

Louis Pasteur

A
  • developed vaccines for diseases like anthrax and rabies
  • developed methods to for controlling the growth of microorganisms called pasteurization
  • disproved the theory of spontaneous generation
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5
Q

Robert Koch

A
  • identified the similarity between microorganisms and infectious diseases
  • discovered causal agents for anthrax and tuberculosis
  • developed set criteria (called postulates) to identify the causal agents of an infectious disease
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6
Q

Koch cont.

A
  • koch developed the first pure culture techniqe
  • showed that using a solid media provided an easy way to grow microbes
  • observed masses of cells called colonies, they have different morphologies
  • began identifying microbes based on their colony morphology
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7
Q

Alexander fleming

A

discovered the antibiotic called Penicillin
from the fungus called penicillium chrysogenum
-the fungus would repel the bacteria

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8
Q

Joseph Lister

A
  • used phenol to sterilize surgical tools and wounds

- was the first to conduct an aseptic surgery

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9
Q

List the type of microbes

A 
bacteria
protists
prions
fungus
microscopic animals
viruses
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10
Q

Cellular microbes

A

bacteria- prokaryotic, unicellular
fungus-eukaryotic, uni or multicellular
protists-eukaryotic, uni or multicellular
microscopic animals-eukaryotic and multicellular

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11
Q

Acellular microbes

A

viruses and prions

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12
Q

Cellular microbe structures

A

contains the cell membrane, cytoplasm, ribosomes and the cell wall (excluding the microscopic animals)

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13
Q

Eukaryotic cell structure

A

contain the nucleus, endoplasmic reticulum and other membrane-bound organelles

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14
Q

Nucleus in eukaryotic vs prokaryotic

A

Eukaryotic have a nucleus that contains chromosomes that are linear shape. Prokaryotic DNA are circular shaped.

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15
Q

Plasmid

A

set of small and circular genetic material that carries genes responsible for antimicrobial drug resistance

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16
Q

Cell wall

A
  • rigid and thick
  • made of carbohydrates and proteins
  • purpose is to protect the cell
  • bacteria cell walls are made of peptidoglycan
  • eukaryotic cell wall in fungi is made of chitin
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17
Q

Cell membrane

A
  • soft and thin layer the surrounds the cell
  • controls what enters and exits the cell (regulates waste and nutrients)
  • made of phospholipid and proteins
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18
Q

Ribosomes

A
  • produces proteins
  • there are two subunits=large subunit and small subunit
  • uses an mRNA template to produce the proteins
  • Eukaryotic ribosomes are larger than prokaryotic
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19
Q

Mitochondria

A
  • the powerhouse of the cell
  • produces ATP
  • are modified bacteria because
    1. DNA is circular
    2. ribosomes are identical to bacteria
    3. the genes are very similar to bacteria
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20
Q

Endoplasmic reticulum

A

Smooth endoplasmic reticulum= involved in the process of the biosynthesis of lipids
Rough endoplasmic reticulum=involved in the production of glycoproteins

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21
Q

Endocytosis

A
  • the cell takes in macromolecules by forming vesicles from the plasma membrane
    1. Phagocytosis
    2. Pinocytosis
    3. Receptor-mediated
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22
Q

Phagocytosis

A

the cell taking in solids (cell eating)

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23
Q

Pinocytosis

A

the cell taking in liquids (cell drinking)

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24
Q

Receptor-mediated endocytosis

A

receptors that are specific to a certain molecule where they would bind together

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25
Q

Bacteria cell morphology

A 
coccus
diplococcus
streptococcus
staphylococcus
bacillus
spirillum 
spirochetes
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26
Q

The benefits of being small

A
  • greater surface area to volume ration
  • supports greater nutrient and waster exchange
  • tend to grow faster than larger cells
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27
Q

Cell Walls of bacteria

A
  1. Gram-positive

2. Gram-negative

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28
Q

Gram-positive

A

stains blue or purple

  • contains a thick cell wall (peptidoglycan)
  • contains only one membrane (cytoplasmic membrane)
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29
Q

Gram-negative

A

stains red or pink

  • contains a thin cell wall (peptidoglycan)
  • contains two membranes (an outer membrane and a cytoplasmic membrane)
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30
Q

Capsule and slime layer

A
  • can be thick, thin, rigid or flexible
  • help cell attach to surfaces
  • protects against phagocytosis
  • prevents water loss
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31
Q

Fimbria (fimbrae)

A
  • filamentous protein structure

- allows cells to attach to surfaces and eachother

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32
Q

Pilus (pili)

A
  • filamentous protein structure
  • helps cells attach to surfaces and each other
  • helps with genetic transfer between cells (ex. plasmids can move between two cells)
  • some involved in motility
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33
Q

Flagella

A

tail-like structure that helps the cell swim in liquids

-provides motility in water

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34
Q

Endospores

A
  • are highly resistant to high temperatures, harsh chemicals and radiation
  • can survive in 70% of alcohol
  • produces spores that can survive harsh conditions
  • only gram-positive bacteria can produce spores
  • contains many layers that help them survive the harsh conditions
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35
Q

Cell division in eukaryotic cells

A

mitosis

meiosis

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36
Q

Mitosis

A

diploid or haploid cells produce 2 identical daughter cells

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37
Q

Meiosis

A

diploid cells only produce 4 haploid cells

-only in sexual reproduction and it increases genetic diversity in a population

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38
Q

Cell division in bacteria

A

Binary fission

-do not have a nucleus and does not reproduce sexually

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39
Q

Binary fission

A
  1. bacterial DNA will replicate to produce two identical copies of chromosomes
  2. each will attach to a different part of the cell
  3. as the bacteria elongates they go to opposite ends of the poles
    - a septum will be produced to produce two identical daughter cells
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40
Q

How does bacteria increase genetic diversity ?

A
  • mutations

- horizontal gene transfer

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41
Q

Horizontal gene transfer

A

the movement of genes from one cell to another, this will increase the genetic diversity

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42
Q

Transduction

A
  • gene transfer between cells using a virus
    1. the virus infects the bacteria
    2. sometimes the virus will reproduce, part of the genome of the bacteria will package inside the capsid of the virus.
    3. This means when the virus reproduces it will have the genome of the bacteria not the virus
    3. When the virus infects another bacteria it will transfer the genome for the previous bacteria into the new bacteria
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43
Q

Transformation

A

free floating DNA that enters another bacterium

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44
Q

Conjugation

A

the gene transfer between cells using a structure called a pilus. The cell will attach to another cell using the pilus and the plasmid of the bacteria will transfer into the other bacterium

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45
Q

Autotrophs

A

bacteria that make their own food ex.photosynthesis in plants

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46
Q

Heterotrophes

A

bacteria that get their food from another source. An example would be humans

47
Q

Predatory bacteria

A

bacteria that prey on other microbes

48
Q

Obligate aerobe

A

bacteria that required oxygen to survive. It it doesn’t it will die

49
Q

Obligate anaerobe

A

Bacteria does not need oxygen to survive, if it is exposed to oxygen it will die

50
Q

Facultative aerobe

A

bacteria can survive with or without oxygen

51
Q

Fungi

A
  • are heterotrophs
  • mostly multicellular and and eukaryotic
  • cell wall is made of a disaccharide called chitin
  • body is made of thin and fibrous structure called hypha (hyphae) -haploid cells
52
Q

Mycelium

A

pure culture hyphae form compact tufts

53
Q

Protists

A
  • single celled protist

- multicellular protist

54
Q

Single celled protist

A
  • some are human parasites that causes disease in humans and animals
  • four different species of the genus Plasmodium = causes malaria in humans
55
Q

Malaria Life cycle

A
  • development of sporozoites in the female mosquito
  • the sporozoites are released, transmission by the bite of the mosquito
  • the sporozoites travel into the liver and mature into schizonts
  • the mature sporozoites will infect the red blood cells and will reproduce = symptoms will appear
  • the production of gametocytes and will transmit to a non-infected mosquito though a bite
  • the gametes will mature in the mosquito and undergo fertilization and growth
56
Q

Multicellular protists

A
  • structure and shape is very similar to fungi
  • cell wall is made of cellulose
  • can cause life-threatening diseases in humans and animals (pythiosis)
57
Q

Pythium

A

is the casual agent of pythiopsis and needs an aquatic environment to reproduce. The spores can infect the people who are exposed to contaminated water

58
Q

Chemoattractants

A

human and certain animal hair and skin are chemoattractants for the spores that swim using their flagella

59
Q

Helminths

A
  • multicellular
  • anaerobe animals
  • no cell wall
  • contains a protective layer called a cuticle
  • feed on living tissue that can cause damage
  • absorbs food from the host and uses most of it’s energy for reproduction
60
Q

Transmission of Helminths

A

fecal oral
intermediate host
transdermal
vector borne

61
Q

Fecal oral

A

larvae and eggs that are present in the feces.Transmits through the contamination of food and water

62
Q

intermediate host

A

eating of infected tissue from another host

63
Q

transdermal transmission

A

larvae penetrate and migrate through the tissue

64
Q

vector-borne

A

larvae transmit through bloodsucking vectors (mosquitoes)

65
Q

3 groups of helminths

A

tapeworm
roundworm
threadworm (pinworm)

66
Q

Challenges Helminths have on the immune system

A
  • they are constantly moving
  • some are covered in a protective layer
  • they are too large for phagocytosis
  • some are able to produce compounds that suppress the immune system
67
Q

Virus

A
  • genetic material that cannot reproduce independently
  • scientist do no consider them living
  • do not contain organelles = acellular elememts
  • cannot reproduce outside of the cell
68
Q

Virions

A
  • virus particles
  • extracellular form of viruses
  • exist outside of the cell and infects living cells, when it enters a living cell its activated and called a virus
69
Q

Viral components

A
  • can either be RNA or DNA genome
  • circular or linear
  • single stranded or double stranded
  • single stranded can be plus sense or minus sense
70
Q

Double stranded DNA

A
  • contains two strands of nucleotides
  • contains the bases (adenine, cytosine, guanine and thymine)
  • one of the strands can be a plus sense and the other will be a minus sense
71
Q

Single stranded DNA

A

contains only one strand of nucleotides

72
Q

Transcription

A
  • turning DNA into mRNA
  • RNA polymerase will pick one of the two strands of the DNA which will be called the DNA template strand that will be antisense, this will be used to produce the mRNA strand
73
Q

Translation

A
  • turning mRNA into proteins
  • ribosomes will use the mRNA strand to produce proteins
  • the virus that chooses the SS RNA gene that the genome used by the ribosome to produce proteins is called the mRNA strand
  • If there is no ribosomes, this process cannot happen
74
Q

Capsid

A

the protein shell that surrounds the genome of the virus particle

75
Q

Envelope

A

in many animal viruses they have an outer layer consisting of the phospholipid bilayer and virus specific proteins

76
Q

Naked virus

A

has no membrane = no envelope

77
Q

Capsomere

A

individual protein molecules arranged in a precise and highly repetitive patter surrounding the nucleic acid making up the capsid

78
Q

Viral shapes

A

spherical

rod shaped

79
Q

Enveloped viruses

A
  • have a lipoprotein membrane that surrounds the nucleocapsid
  • Envelope proteins attach to and infect an animal host cell
80
Q

Enzyme in virions

A

lysozymes

81
Q

lysozymes

A

creates a hole in the cell wall for nucleic acid entry and lyses the cell wall to release new virions

82
Q

Permissive cell

A

host cell that allows the complete replication cycle of virus to occur

83
Q

non-permissive cell

A

host cell does not allow the full life cycle to occur

-this causes cancer when it can’t reproduce

84
Q

Stages of viral replication in a permissive host

A
  1. attachment
  2. penetration
  3. synthesis
  4. assembly
  5. release
85
Q

Attachment stage

A

attachment of virions. Virons attach to specific molecules on the cell surface ( this is why viruses are specific to one cell type)

86
Q

Penetration stage

A

injection of the virions nucleic acid

87
Q

Synthesis stage

A

synthesis of virions nucleic acid and protiens by the host cell’s metabolism redirected by the virus

88
Q

Assembly stage

A

assembly of the capsids and packages the viral genomes into new virions

89
Q

Release stage

A

release of the mature virions from the host cell

90
Q

Bind specific host cell receptors

A
  • used for cell-cell contact or immune function

- different tissues and organs express different cell surface proteins

91
Q

Virus entry into animal cells

A
  1. phagocytosis
  2. receptor-mediated endocytosis
  3. Genetic injection (into the cytoplasm)
92
Q

Four lifestyles for animal viruses

A
  1. virulent infection
  2. latent infection
  3. persistent infection
  4. transformation
93
Q

Virulent infection

A

the virus reproduces inside the host cell and kills the host

94
Q

Latent infection

A

viral DNA exist in the host genome and virions are not produced=the cell is unharmed unless triggered

95
Q

Persistent infection

A

release of virions from the host cell by budding but does not result in the cell lysis, the infected cell remains alive and continues to produce virus

96
Q

Tansformation

A

conversion of normal cells into tumor cells (cancerous cells)

97
Q

Retroviruses

A
  • single stranded plus sense RNA genome
  • they are enveloped RNA viruses that replicate through a DNA intermediate
  • contains two enzymes= reverse transcriptase and integrase
98
Q

reverse transcriptase

A

an enzyme that converts viral RNA into viral DNA

99
Q

integrase

A

is an enzyme that integrates newly synthesized viral DNA into a host genome

100
Q

Life cycle of retrovirus

A
  1. entrance into the cell with the removal of the envelope at the membrane
  2. DNA is produced from the viral RNA using the enzyme reverse transcriptase
  3. DNA enters the host genome through the enzyme integrase and produces viral protiens and viral RNA genome (ss(+)RNA)
  4. new viruses are released from the cell through exocytosis (budding)
101
Q

Tumor viruses

A
  • some viruses (DNA viruses or retroviruses) can induce cancer
  • in permissive host the cell is killed and the virions are released after lysis
  • in nonpermissive host cell integration occurs in to host DNA resulting in transformation=the production of viral tumor-induction proteins causes loss of growth inhibition that results in a tumor
102
Q

Virome

A

the entire population of viruses present in a sample

103
Q

Bacteriaphages

A

viruses use bacteria as a host

  • it is the most abundant in human viromes
  • are believed to benefit baterail cells by transferring antibiotic resistance between bacteria
104
Q

Hepatitis D

A
  • very small RNA virus, it has a capsid but it’s genome lacks the genes encoding it’s own capsid
  • this is why it needs Hep B to produce a complete virus = it cannot replicate without it
105
Q

Prions

A
  • infectious proteins that contain no nucleic acid (no genome)
  • are considered faulty proteins
106
Q

Prions that are known to cause disease in animals (animal prion disease) is called…

A

transmissible spongiform encephalopathy

107
Q

Protein folding

A

polypeptides are formed by the ribosomes and need to be folded properly to produce a 3D shape that is critical for protein function
-if it is not folded properly it cannot function properly

108
Q

Misfolded protein

A
  • aggregate and produce insoluble plaques that can interfere with the cell’s normal functions
  • this can causes diseases by prions
  • accumulation of aggregation can produce insoluble prions that destroy brain and nervous tissue
109
Q

PrP^c

A

all mammal cells contain a gene that encodes a native form of prion protein that is found in healthy individuals for the proper function of the nervous system

110
Q

PrP^sc

A

prion victims that is due to genetic mutation or sporadically misfolded proteins

111
Q

Cruetzfeldt-Jakob Disease (CJD)

A
  • very rare disease

- 20% chance it happens though mutation and 80% happen sporadically through a misfolded protein

112
Q

Variant Cruetzfeldt-Jakob disease

A

linked to the consumption of eating contaminated meat with the agent of Bovine spongiform encephalopathy also known as mad cow disease

113
Q

MAVS

A
  • nonpathogenic prion in humans
  • human protein that converts into a prion like structure and becomes infected by the virus.
  • structure triggers interferon production in response to virus and helps immune system
  • MAVS eventually kills the cell so the virus does no have the ability to reproduce

Medical Microbiology (1 decks)

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