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Biology 30 > Unit 5- Microbiology > Flashcards

Unit 5- Microbiology Flashcards

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1
Q

What are viruses?

A
  • They are non-living particles which infect every form of life in every kingdom (comes from latin meaning posion)
  • are not classified into a domain because they do not possess all of the traits of living things
  • does not grow, respire, or respond to stimuli but it does reproduce
  • are named after the disease they cause (ex. Rabies virus) or organ or tissue they infect (ex. Meningitis)
  • They are not the smallest infections particles around (viroids and prions)
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2
Q

Explain the structure and shape of a virus

A
  • are very small
  • all viruses are made of at least 2 parts
    1. An inner core of nuclear material (DNA or RNA)
    2. Enclosed in a protein shell called a capsid (about 95% of the virus)
    3. Some also contain a fatty lipoprotein envelope
  • viruses do not contain the organelles of a cell
  • the capsid gives the virus its shape
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3
Q

Explain the function and reproduction of a virus

A
  • viruses are strict parasites and function only when inside of a host cell
  • when outside of a host cell, viruses can crystalize and remain inert for long periods of time
  • crystals become infectious when the viral particles they contain come in contact with and invade host cells
  • viruses are specific to the species and cell-type they infect (ex. polio infects only human intestinal and nerve cells )
    once it enters a host cell the virus takes over the cell’s processes to produce more viral material killing the original cell and infecting others
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4
Q

What is a virulent virus?

A
  • reproduction starts immediately after entering the host cell
  • lytic cycle (viruses are being produced)
  • ex) cold, flu
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5
Q

What is a latent virus?

A
  • after entering the host cell, the virus may go through a ‘resting stage’ before something triggers reproduction to begin
  • lysogenic cycle
  • ex) AIDS, Shingles
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6
Q

What happens in the lytic cycle?

A
  1. The new phage binds to the bacterium
  2. The phage DNA enters the host cell
  3. The host DNA is digested
  4. The new phage DNA forms using nucleotides from the former host DNA
  5. The host cell transcribes and translates the phage DNA producing phage proteins
  6. Assembly of new phages is complete. A phage encoded enzyme causes the cell to lyse
  7. New phages are released to start the cycle again
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7
Q

What happens in the lysogenic cycle?

A
  1. The phage binds to the bacterium
  2. The phage DNA enters the host cell
  3. The phage DNA integrates into the bacterial chromosome and becomes a non-infective prophage
  4. Chromosome with integrated prophage replicates. This can continue through many cell divisions
  5. In rare cases, the prophage may separate and the cell will enter the lytic cycle
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8
Q

Significance of Viruses- How are viruses harmful and helpful?

A

Ways they are harmful:
- cause sickness and disease
- cause some forms of cancers
Ways they are helpful:
- further our understanding of genes and DNA replication
- transmit a specific gene to engineer cells for a specific purpose
- destroy resistant bacteria and control insects and pests
- control pandemics through the creation of vaccines and antiviral drugs
- treat cancer

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9
Q

What are the theories of viral evolution?

A
  • there is no fossil evidence as to the origin of viruses but many theories
    a) ancestors of viruses were parasitic cells that lost their cellular components
    b) viruses came from detached fragments of genetic material belonging to other cells
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10
Q

How do we treat viruses?

A
  • As viruses are nonliving they cannot be killed using antibiotic so alternate methods must be present
    a) Prevent primary infection (vaccination)
    b) Treat symptoms
    c) Localize the infection (Antivirals)
    d) Immunoglobulin therapy- synthetic antibodies used to identify and neutralize viruses
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11
Q

What is a retrovirus?

A

A retrovirus is any family of RNA viruses that have an enzyme (reverse transcriptase) capable of making a complimentary DNA copy of the viral RNA, which is then integrated into the host cell’s DNA. The family includes a significant number of pathogens, typically causing tumors or affecting the function of the immune system (ex. HIV) They are infectious particles consisting of an RNA genome packaged in a protein capsid surrounded by a lipid protein envelope. This envelope contains polypeptide chains including receptor binding proteins which link to the membrane receptors of the host cell, initiating the process of infection.

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12
Q

What is a viroid?

A
  • RNA molecules with no protein capsid or fatty envelope
  • disease causing
  • only infect plants
  • ex) potato spindle tuber
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13
Q

What is a prion?

A
  • naked pieces of protein molecules, no nucleic acid involved
  • normally exist in cells and are shaped like a coil
  • When mutated prions are shaped like a piece of paper folded many times (cause disease)
  • ex) Mad cow disease, chronic wasting disease
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14
Q

What are prokaryotes?

A
  • prokaryotes are divided into two domains: Archaea and Bacteria
  • are the most numerous organisms on Earth. There are more bacteria on or in your body than there are people in the world
    -Members of this domain are very similar differing only in molecular structure
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15
Q

What are the general characteristics and structure of prokaryotes?

A
  1. are prokaryotic lack a nuclear membrane
  2. are unicellular existing singly or in colonies
  3. lack a cytoskeleton and have few organelles
  4. Have a single free-floating strand of DNA nucleoid chromosome carrying the majority of the organism’s genetic information
  5. Have a cell wall containing peptidooglycan (Bacteria) or membrane lipids (Archaea)
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16
Q

Structures that help ensure prokaryotes can survive in hostile environments?

A
  • Capsule (Slime layer): help evade immune systems and adhere to surfaces
  • Pili: Hair-like structures used for anchorage and ‘docking’
  • Endospore: Protective coating formed when conditions are unfavourable
  • Flagellum: Tail-like structure used for movement
  • Plasmid DNA: - Small rings of extra-chromosomal DNA carrying non-essential genes which are copied independently of the chromosome inside the cell
  • can be transferred to other prokaryotes spreading genes that are beneficial for survival (antibiotic resistance)
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17
Q

Name all of the ways prokaryotes reproduce

A
  1. Asexual Reproduction
    - bianary fission
  2. Sexual reproduction
    a) conjugation
    b) transformation
    c) transduction
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18
Q

Explain asexual reproduction in prokaryotes

A
  • most common form of reproduction (bianary fission)
  • 1 organism divides into 2, both genetically indentical to the parent (clones)
  • can do this every 20 minutes if conditions of food and space are ideal
  • warmth, moisture, and prefer darkness
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19
Q

Explain conjunction in prokaryotes

A
  • 2 cells line up side by side and exchange nuclear material before dividing
  • offspring have new genes (and new traits)
20
Q

Explain transformation in prokaryotes

A
  • living bacteria absorb and integrate genes from dead bacteria into their own DNA
  • gain new characteristics
21
Q

Explain transduction in prokaryotes

A
  • a virus attacks a bacterial cell and enters it
  • the bacterial cell incorporates the new gene the virus is carrying
  • this method is used in biotechnology to create bacteria to produce valuable products (ex. insulin)
22
Q

Explain classification of prokaryotes

A

Currently identified using DNA but historically identified and named based on: Respiration, nutrition, and shape and arrangement

23
Q

Explain respiration in prokaryotes

A

Prokaryotes can be grouped based on their need for oxygen
a) obligate anaerobes- cannot live in the presence of O2 (poisoned by it)
b) obligate aerobes- need O2 (obligated to use it)
c) facultative aerobes- can live without O2

24
Q

Explain Nutrition in Prokaryotes

A

Autotrophic (create their own food)
- photosynthesizer: use sunlight to convery CO2 and H2O to O2 and glucose
- chemosynthesizer: change inorganic materials into organic materials
Heterotrophic (ingest food via absorption)
- saprophytes: feed on dead plant and animal matter (decomposers)
- parasites: feed on living cells (pathogenic organisms)

25
Q

Explain shape and arrangement in prokaryotes

A

Shape:
- Coccus (plural cocci)- spherical
- Bacillus (plural bacilli)- rod-shaped
- Spirillum (plural spirilla)- twisted/ spiral
Arrangement (use prefixes):
- diplo: two
- staphyl: clusters
- stepto: chains

26
Q

General explanation of the Domain/ Kingdom Bacteria

A
  • most are aerobic
  • subdivided into many groups called divisions
  • all can be classified as either gram positive or gram negative based on whether or not it absorbs gram’s dye
  • thicker peptidoglycan cell wall will absorb the gram’s dye
  • determines which type of antibiotic to use against it
  • includes the Cyanophyta DIvision (aka blue green algae)
    -have chloroplasts containing chlorophyll and phycocyanin (blue pigment)
  • large numbers may cause O2 depletion (kill fish)
27
Q

General explanation of the domain/ kingdom Archae

A
  • thought to be more ancient than bacteria and yet more closely related to eukaryotes (have some of the same proteins)
  • live in environments similar to those when life first evolved on planet Earth
28
Q

Name and explain the 3 types of Archae

A

a) Methanogens
- decompose sewage, garbage dumps, ect. producing methane gas
- obligate anaerobes
b) Halophiles
- salt loving bacteria (the dead sea)
-photosynthetic
c) Thermoacidophiles
- heat and acid loving bacteria (deep ocean volcanoes) - chemosynthetic

29
Q

What are the benefits of prokaryotes?

A
  • make vitamens in humans
  • fix nitrogen for plants (nitrogen cycle)
  • produce oxygen and food (yogurt, cheese, vinegar)
  • recycle dead things and wastes (Bioremediation)
  • genetically engineered to make drugs, antibiotics and hormones
30
Q

What are the harmful effects of prokaryotes?

A
  • de-nitrogen fixing bacteria
  • tooth decay
  • causes diseases and illnesses in all organisms ( ex) tetnus and food poisoning)
  • decomposers (spoil food, etc)
  • damage crops
31
Q

Explain the domain eukarya

A
  • Kingdoms in the domain eukarya include protista, fungi, plantae, and anamilia
  • all contain organisms composed of eukaryotic cells (cells containing an organized membrane-bound nucleus and organelles which perform a variety of functions)
  • Most members of this domain are multicellular and macroscopic. However, there are a few unicellular, microscopic groups
32
Q

Explain the Protista kingdom and gives its general characteristics

A
  • contains “plant-like” , “animal like” and “fungi-like” organisms
  • the junk drawer of taxonomy
    General characteristics
  • eukaryotic (true nucleus)
  • microscopic
  • contain specialized ‘organelles’
  • most are aquatic (fresh water or marine)
  • most are unicellular but may live in colonies
33
Q

What are the 3 groups of protists and what are the based off of?

A

The kingdom protista is made up of three distict groups based on nutrition
- Animal-like protists (protozoans)- heterotrophs (take in food)
- Plant-lie protists- autotrophs (contain chlorophyll and photosynthesize. Contains many of the algae phyla
- Fungi-like protists- Heterotrophs (saprophytes or parasites) They have reproductive structures like fungi ex. slime molds

34
Q

What are the groups of Animal-like protists and what are they based off of?

A

There are four groups of animal-like protists based on movement:
- Ciliphorans
- Sarcodinians
- Zooflagllates
- Sporozoans

35
Q

Explain the Cilliphoran

A
  • is an animal-like protists
  • use hair-like cilia beating in unison to feed and move
  • ex) Paramecium
36
Q

Explain the Sarcodinian

A
  • is an animal-like protist
  • move using cytoplasm pushing against cell membrane
  • psuedopod: extension of the cytoplasm used to move and obtain food
  • ex) Amoeba
37
Q

Explain Zooflagllates

A
  • is an animal-like protists
  • moves using a whip-like flagella
  • ex) trichonympha
38
Q

Explain Sporozoans

A
  • is an animal-like protists
  • no structure for movement, uses host to survive
  • ex) plasmodium (causes malaria)
39
Q

Explain types of plant-like protists

A

a) Unicellular algae
i) Dinofalgellates- algae with two flagella, usually marine
ii) Diatoms- Cell walls have silica, abundant in oceans
iii) Euglenoids- no cell walls, perform photosynthesis and are heterotrophic
b) Multicellular algae
- similar to land plants but different because of its reproduction
- grouped based on colour
(all have chlorophyll, but masking pigments affect colour)
a. green algae
b. red algae
c. brown algae

40
Q

What are the roles of protists?

A

a. Food for others (plankton)
b. Some eat bacteria
c. Help produce oxygen
d. Breakdown dead plants and animals (decomposers)
e. some cause diseases

41
Q

Bacteriophage?

A

Virus that infects bacteria

42
Q

Bacteriophage?

A

Virus that infects bacteria

43
Q

What features of Euglena would make the organism difficult to classify?

A

All euglena have chloroplasts and can make their own food by photosynthesis. They are not completely tree my autotrophic though m, euglena cab also absorb their food from their environment (usually quiet ponds and puddles)

44
Q

PCR?

A

Sometimes called “molecular photocopying” the polymerase chain reaction is a fast, inexpensive technique used to amplify (copy) small segments of DNA. Most mapping techniques in the human genome project (HGP) relied on PCR.

45
Q

What causes red tide?

A

Toxic micro algae blooms turn waters red and are lethal to birds and marine creatures

Biology 30 (3 decks)

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