Midterm #1 (session 2-8) Flashcards
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
2
Q
Robert Hooke
A
was the first to see and describe a microorganism (fungus)
3
Q
Antoni van Leeuwenhoek
A
first to see and describe bacteria
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
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
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
7
Q
Alexander fleming
A
discovered the antibiotic called Penicillin
from the fungus called penicillium chrysogenum
-the fungus would repel the bacteria
8
Q
Joseph Lister
A
- used phenol to sterilize surgical tools and wounds
- was the first to conduct an aseptic surgery
9
Q
List the type of microbes
A
bacteria protists prions fungus microscopic animals viruses
10
Q
Cellular microbes
A
bacteria- prokaryotic, unicellular
fungus-eukaryotic, uni or multicellular
protists-eukaryotic, uni or multicellular
microscopic animals-eukaryotic and multicellular
11
Q
Acellular microbes
A
viruses and prions
12
Q
Cellular microbe structures
A
contains the cell membrane, cytoplasm, ribosomes and the cell wall (excluding the microscopic animals)
13
Q
Eukaryotic cell structure
A
contain the nucleus, endoplasmic reticulum and other membrane-bound organelles
14
Q
Nucleus in eukaryotic vs prokaryotic
A
Eukaryotic have a nucleus that contains chromosomes that are linear shape. Prokaryotic DNA are circular shaped.
15
Q
Plasmid
A
set of small and circular genetic material that carries genes responsible for antimicrobial drug resistance
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
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
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
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
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
21
Q
Endocytosis
A
- the cell takes in macromolecules by forming vesicles from the plasma membrane
1. Phagocytosis
2. Pinocytosis
3. Receptor-mediated
22
Q
Phagocytosis
A
the cell taking in solids (cell eating)
23
Q
Pinocytosis
A
the cell taking in liquids (cell drinking)
24
Q
Receptor-mediated endocytosis
A
receptors that are specific to a certain molecule where they would bind together
25
Bacteria cell morphology
```
coccus
diplococcus
streptococcus
staphylococcus
bacillus
spirillum
spirochetes
```
26
The benefits of being small
- greater surface area to volume ration
- supports greater nutrient and waster exchange
- tend to grow faster than larger cells
27
Cell Walls of bacteria
1. Gram-positive
| 2. Gram-negative
28
Gram-positive
stains blue or purple
- contains a thick cell wall (peptidoglycan)
- contains only one membrane (cytoplasmic membrane)
29
Gram-negative
stains red or pink
- contains a thin cell wall (peptidoglycan)
- contains two membranes (an outer membrane and a cytoplasmic membrane)
30
Capsule and slime layer
- can be thick, thin, rigid or flexible
- help cell attach to surfaces
- protects against phagocytosis
- prevents water loss
31
Fimbria (fimbrae)
- filamentous protein structure
| - allows cells to attach to surfaces and eachother
32
Pilus (pili)
- 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
33
Flagella
tail-like structure that helps the cell swim in liquids
| -provides motility in water
34
Endospores
- 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
35
Cell division in eukaryotic cells
mitosis
| meiosis
36
Mitosis
diploid or haploid cells produce 2 identical daughter cells
37
Meiosis
diploid cells only produce 4 haploid cells
| -only in sexual reproduction and it increases genetic diversity in a population
38
Cell division in bacteria
Binary fission
| -do not have a nucleus and does not reproduce sexually
39
Binary fission
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
40
How does bacteria increase genetic diversity ?
- mutations
| - horizontal gene transfer
41
Horizontal gene transfer
the movement of genes from one cell to another, this will increase the genetic diversity
42
Transduction
- 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
43
Transformation
free floating DNA that enters another bacterium
44
Conjugation
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
45
Autotrophs
bacteria that make their own food ex.photosynthesis in plants
46
Heterotrophes
bacteria that get their food from another source. An example would be humans
47
Predatory bacteria
bacteria that prey on other microbes
48
Obligate aerobe
bacteria that required oxygen to survive. It it doesn't it will die
49
Obligate anaerobe
Bacteria does not need oxygen to survive, if it is exposed to oxygen it will die
50
Facultative aerobe
bacteria can survive with or without oxygen
51
Fungi
- 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
Mycelium
pure culture hyphae form compact tufts
53
Protists
- single celled protist
| - multicellular protist
54
Single celled protist
- some are human parasites that causes disease in humans and animals
- four different species of the genus Plasmodium = causes malaria in humans
55
Malaria Life cycle
- 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
Multicellular protists
- 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
Pythium
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
Chemoattractants
human and certain animal hair and skin are chemoattractants for the spores that swim using their flagella
59
Helminths
- 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
Transmission of Helminths
fecal oral
intermediate host
transdermal
vector borne
61
Fecal oral
larvae and eggs that are present in the feces.Transmits through the contamination of food and water
62
intermediate host
eating of infected tissue from another host
63
transdermal transmission
larvae penetrate and migrate through the tissue
64
vector-borne
larvae transmit through bloodsucking vectors (mosquitoes)
65
3 groups of helminths
tapeworm
roundworm
threadworm (pinworm)
66
Challenges Helminths have on the immune system
- 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
Virus
- 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
Virions
- 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
Viral components
- 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
Double stranded DNA
- 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
Single stranded DNA
contains only one strand of nucleotides
72
Transcription
- 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
Translation
- 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
Capsid
the protein shell that surrounds the genome of the virus particle
75
Envelope
in many animal viruses they have an outer layer consisting of the phospholipid bilayer and virus specific proteins
76
Naked virus
has no membrane = no envelope
77
Capsomere
individual protein molecules arranged in a precise and highly repetitive patter surrounding the nucleic acid making up the capsid
78
Viral shapes
spherical
| rod shaped
79
Enveloped viruses
- have a lipoprotein membrane that surrounds the nucleocapsid
- Envelope proteins attach to and infect an animal host cell
80
Enzyme in virions
lysozymes
81
lysozymes
creates a hole in the cell wall for nucleic acid entry and lyses the cell wall to release new virions
82
Permissive cell
host cell that allows the complete replication cycle of virus to occur
83
non-permissive cell
host cell does not allow the full life cycle to occur
| -this causes cancer when it can't reproduce
84
Stages of viral replication in a permissive host
1. attachment
2. penetration
3. synthesis
4. assembly
5. release
85
Attachment stage
attachment of virions. Virons attach to specific molecules on the cell surface ( this is why viruses are specific to one cell type)
86
Penetration stage
injection of the virions nucleic acid
87
Synthesis stage
synthesis of virions nucleic acid and protiens by the host cell's metabolism redirected by the virus
88
Assembly stage
assembly of the capsids and packages the viral genomes into new virions
89
Release stage
release of the mature virions from the host cell
90
Bind specific host cell receptors
- used for cell-cell contact or immune function
| - different tissues and organs express different cell surface proteins
91
Virus entry into animal cells
1. phagocytosis
2. receptor-mediated endocytosis
3. Genetic injection (into the cytoplasm)
92
Four lifestyles for animal viruses
1. virulent infection
2. latent infection
3. persistent infection
4. transformation
93
Virulent infection
the virus reproduces inside the host cell and kills the host
94
Latent infection
viral DNA exist in the host genome and virions are not produced=the cell is unharmed unless triggered
95
Persistent infection
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
Tansformation
conversion of normal cells into tumor cells (cancerous cells)
97
Retroviruses
- 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
reverse transcriptase
an enzyme that converts viral RNA into viral DNA
99
integrase
is an enzyme that integrates newly synthesized viral DNA into a host genome
100
Life cycle of retrovirus
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
Tumor viruses
- 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
Virome
the entire population of viruses present in a sample
103
Bacteriaphages
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
Hepatitis D
- 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
Prions
- infectious proteins that contain no nucleic acid (no genome)
- are considered faulty proteins
106
Prions that are known to cause disease in animals (animal prion disease) is called...
transmissible spongiform encephalopathy
107
Protein folding
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
Misfolded protein
- 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
PrP^c
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
PrP^sc
prion victims that is due to genetic mutation or sporadically misfolded proteins
111
Cruetzfeldt-Jakob Disease (CJD)
- very rare disease
| - 20% chance it happens though mutation and 80% happen sporadically through a misfolded protein
112
Variant Cruetzfeldt-Jakob disease
linked to the consumption of eating contaminated meat with the agent of Bovine spongiform encephalopathy also known as mad cow disease
113
MAVS
- 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
