Prokaryotes, viruses, and protists Flashcards
(121 cards)
1
Q
Define microbiology.
A
The study of microscopic biology, (prokaryotes, viruses, and eukaryotes)
2
Q
Who is considered the Father of Biology and why?
A
Leeuwenhoek, because he was the first to identify and describe “animalcules” or unicellular organisms in the 1600s
3
Q
What are the two types of cells?
A
Eukaryote (multiple cells) and prokaryote (single cell)
4
Q
List some characteristics of prokaryotes
A
- Single cell
- No nucleus or membrane-bound organelles
- Small
5
Q
Briefly describe prokaryotic DNA.
A
- Chromosomal
- Concentrated in the nucleoid region
- Apart from the main chromosome, DNA is in separate rings called plasmids
6
Q
Briefly discuss the diversity of prokaryotes.
A
- some cause disease, but most are harmless or helpful
- found everywhere
- humans have the same number of bacterial cells as human cells in their body
7
Q
List the two domains of prokaryotes.
A
Bacteria and archaea
8
Q
What organisms are included in the third domain?
A
Eukaryotes
9
Q
Briefly describe archaea.
A
Look similar to bacteria, with a different cell wall structure, membrane lipids, and DNA sequences
10
Q
List some examples of archaea and their extreme lifestyle.
A
Archaea live in harsh environments and include:
- Thermophiles love heat
- Halophiles love salt
- Methanogens produce methane
11
Q
List three major characteristics of prokaryotes.
A
- Cell shape
- Cell wall structure
- Mobility or movement
12
Q
List and briefly describe the three basic shapes of prokaryotic cells.
A
- Cocci: spherical
- Bacilli: rod
- Spirilla: spiral
- also variations and combinations
13
Q
List two examples of prefixes used to describe common cell groups.
A
- Strep: chain of cells
- Staph: cluster o’ cells
14
Q
Briefly describe the prokaryotic cell wall.
A
There is an outer plasma membrane made of peptidoglycan and polymer of sugars linked by short polypeptides. Archaea do not have peptoglycan.
15
Q
Briefly describe the types of cell coverings that may be found in prokaryotes.
A
- Plasma membrane
- Supportive cell wall, different thicknesses
- Additional cell membrane
- Sticky protective capsule outside the wall
16
Q
What is the purpose of Gram staining?
A
To know the cell wall thickness. Gram- is a thinner wall and shows pink, Gram+ is a thicker wall and shows purple.
17
Q
Why is Gram staining important?
A
To determine the cell wall’s thickness and strength, and know which antibiotics to use depending on if it’s positive or negative.
18
Q
How do bacterial flagella differ from eukaryotic flagella?
A
Propellor movement (circular motion)
19
Q
List another form of prokaryotic mobility.
A
Pili: hairlike, shorter and thinner than flagella; secreted slimy threads
20
Q
What is a bacterial colony?
A
A group of bacteria; a visible mass of microorganisms that originate from one cell and are therefore clones of each other.
21
Q
List two possible sources of energy for organisms.
A
Sunlight or chemicals
22
Q
List two possible sources of carbon atoms for organisms.
A
Carbon dioxide or organic compounds
23
Q
Briefly describe the difference between aerobic and anaerobic bacteria.
A
- Aerobic require oxygen for metabolism of energy
- Anaerobic cannot grow in the presence of oxygen
24
Q
Define a facultative anaerobe.
A
Can live with or without oxygen; found in soil and foods
25
Give an example of photosynthetic bacteria and briefly describe its niche.
Cyanobacteria; live in moist soils and water, free-living or in symbiotic relationships with fungi to make lichens
26
Where does photosynthesis take place in cyanobacteria?
Thylakoids
27
Briefly describe binary fission.
Prokaryote asexual reproduction, DNA replicates and splits into two clones (basically mitosis)
28
Give an example of how quickly bacteria can reproduce.
They can double every twenty minutes (Td = double time)
29
List four ways that genetic variation can occur in prokaryotes.
Mutation, transformation, conjugation, transduction
30
Briefly describe conjugation.
Pilus used to make a bridge between two cells; donor cell copies plasmid and transfers one copy to recipient; cells separate
31
What is bacterial transformation?
Bacteria take DNA from the environment (usually from recently died bacteria), can also be done in a laboratory
32
Define transduction.
Viruses and bacteriophages inject genetic material into bacterial cells
33
Briefly describe endospores.
- Tough, dormant structures formed by bacteria when stressed
- Can survive extreme conditions, high/low temperature and lack of moisture or nutrients
- Will reactivate when conditions are good, develop into fully functional bacteria
34
Briefly describe bacteria's role as decomposers in ecosystems.
Break down dead organisms and recycle nutrients; regenerate soil by returning carbon and other nutrients
35
Briefly describe nitrogen-fixing bacteria.
Live in nodules on roots of plants called legumes; convert nitrogen gas from the atmosphere into a form usable by plants
36
List and briefly describe two human uses of bacteria.
- Biotechnology: baceria used with fungi for brewing, baking, making cheese and butter
- Genetic engineering: transformed bacterial cells used to make insulin and other pharmaceuticals
37
Define bioremediation.
Waste management; uses bacteria and other organisms to remove/neutralize pollutants (oil, pesticides, fertilizers, other toxic chemicals)
38
Briefly describe the symbiotic relationship between humans and E. coli.
E. coli lives in human intestines, where it receives food and produces vitamins K and B
39
List the two main structures that make up a virus.
- Short piece of nucleic acid, DNA or RNA
- Protein coat (capsid)
- Variety of structures; may have outer membrane
40
List some characteristics of viruses.
- Smaller than prokaryotes
- Not cells (not alive)
- Cannot reproduce on its own, must infect living cells to reproduce
- Pathogens: all are BAD
41
Briefly describe the process by which viral infections occur.
- Virus injects genetic material into host cell
- infected cell makes copies of virus or its structures
- Two majour ways
42
Briefly describe the results of the lytic cycle.
- Virus attaches to cell membrane
- Virus injects genetic material into host cell
- Viral DNA released, transcribed, translated into viral proteins
- Viral DNA replicated, DNA and proteins assembled into new viruses
- New viruses released from host cell as it ruptures
43
Briefly describe the results of the lysogenic cycle.
- viral DNA incorporated into host cell DN
- when cell reproduces, it also makes copies of the viral DNA
- virus reproduces without destroying the cell
- environmental triggers can cause the virus to leave the dormant cycle and enter active repoduction (lytic cycle)
44
Name two types of viral reproduction.
Lytic (dangerous) and lysogenic (dormant)
45
What is a retrovirus?
A virus with a singe strand RNA molecule; when injected into the host, DNA is transcribed from the RNA (the reverse of the usual pattern)
46
Define pathogen.
A microorganism that causes disease
47
List the most common ways pathogens are transmitted.
Touch, inhalation, sexual contact, contaminated food/water
48
Name the two ways that pathogenic bacteria cause disease.
- destroy healthy tissues and cells
- produce toxins that cause illness
49
List at least three bacterial diseases.
- pneumonia
- meningitis
- strep throat
50
Define anitbiotics.
Chemicals that slow/prevent bacteria growth; interfere with the bacterial cell wall
51
What was the first antibiotic, and whose work led to its development?
Penicillen; Alexander Fleming, 1928
52
What does it mean for bacteria to be "resistant"?
They adapt to resist antibiotics; survive and multiply even in the presence of antibiotics
53
How do viruses cause disease?
Insert genes into the host cell
54
List common viral diseases in humans.
- flu
- chicken pox
- herpes
- HIV
55
Name two common viral diseases in animals, and two in plants.
Animals: rabies, parvovirus
Plants: tobacco mosaic virus, tomato spotted wilt virus
56
Why are vaccines used instead of antibiotics to defend against viral infections?
Vaccines stimulate the immune system to defend against viral infections; antibiotics only work on bacteria and viruses are too simple
57
Who was Edward Jenner?
An English physician who developed the first successful vaccine for smallpox in the late 1700s
58
List some viruses that have been the subject of recent news headlines.
- Ebola virus
- Marburg virus
- Hanta virus
- Zika virus
59
List some facts about Coronavirus SARS CoV-2.
- similar to SARS, 2001
- now spreads more due to more global travel
60
Define viroid.
The smallest kind of pathogen; a single circular RNA strand with no caspid
61
Define prion.
An infectious agent made completely of protein
62
What is the most important factor in fighting infections?
Immune response; white blood cells
63
What is a protist?
A eukaryote that is not an animal, plant, or fungi
64
List some characteristics of protists.
- mostly unicellular
- heterotrophs or autotrophs
- most can move around
- live in freshwater, oceans, and moist land
65
List and briefly describe the three groups of protists based on their means of nutrition.
-animal-like, protozoans: heterotrophs
- plant-like: autotrophs
- fungus-like: external digestion; absorb nutrients
66
List three characteristics of animal-like protists.
- heterotrophic
- unicellular
- move
67
List the four major groups of protozoans.
- sarcodnes
- ciliates
- zooflagellates
- sporozoans
68
List some characteristics and examples of sarcodines.
- use pseudopods, "false feet", to move and trap food
- free living
- contractile vacuole collects and expells excess water
- e.g. amoeba, forams
69
Define pseudopods.
Temporary builges of cytoplasm; change shape
70
Briefly decribe phagocytosis.
How an amoeba engulfs food; surround it with pseudopods and package it in a vacuole
71
Briefly discuss amoebic dysentery.
Instestine infection that involves severe diarhhea; most often in the tropics
72
Briefly describe forams.
Hard calcium caronate shells; extend long, thin pseudopods through pores in the shell; have many shapes and sizes
73
Describe ciliates and list some examples
- hair-like projections called cilia allow to move and get food
- wave-like motion
- free-living
- e.g. paramecium, stentor, vorticella
74
List three structures found in a paramecium.
- oral groove similar to a mouth
- two nuclei
- anal pore
75
How do paramecia reproduce?
mitosis; use conjugation for genetic diversity
76
Define conjugation.
Two paramecia attach adn exchange genetic information, then reproduce using mitosis
77
Briefly describe the cilia of a stentor.
- around "mouth"
- move food toward mouth, also movement
78
Describe the shape of vorticella.
stalked, inverted bell shape
79
What do vorticella eat?
Bacteria and small protozoans
80
Briefly describe zooflagellates and list some examples.
- move with flagella
- free-living or parasitic
- giardia, trypanosoma, leishmania
81
Briefly discuss giardia.
An intestine parasite in humans that causes bad cramping and diarrhea, contracted by drinking water contaminated with animal feces.
82
Name the disease caused by Trypanosoma, and how it's transmitted.
African sleeping sickness; by a tsetse fly bite
83
Name the disease caused by another species of Trypanosoma that occurs primarily in South America, and how it's transmitted.
Chagas; by "kissing bug" bites
84
List three facts about Leishmaniasis.
- from sand fly bite
- causes skin ulcers and spleen and liver damage
- in Asia and Middle East
85
List some common characteristics and examples of sporozoans.
- all are parasitic
- unicellular
- can't move
- e.g. plasmodium, toxoplasma
86
Name the disease caused by plasmodium, and how it's transmitted.
Malaria; female anopheles mosquito
87
List some symptoms of malaria.
Headache, fever, chills, sweat, nausea, vomiting, muscle and back pain, fatigue, dry cough
88
Name the disease caused by toxoplasma and list the means of transmission.
Toxoplasmosis in humans and animals; caused by contaminated food, animals, and congenitally (mother to child)
89
Briefly describe algae.
Photosynthetic autotrophs that provide oxygen and food for other organisms; uni or multicellular, or in colonies
90
List six groups of plant-like protists.
- diatoms
- dinoflagellates
- euglenoids
- red/brown/green algae
91
List some characteristics of diatoms.
- unicellular
- glass-like cell walls with silica
- geometric
- cell wall "shells" of diatoms form diatomaceous earth
92
Briefly discuss diatomaceous earth.
- fossilized remains of diatom shells
- gritty texture, used in toothpaste and cleansers
93
List some characteristics of dinoflagellates.
- unicellular
- 2 flagella, move in a whirling motion
- stiff plates of cellulose around it
- live in oceans and freshwater
- photosynthetic
94
Describe the symbiotic relationship between dinoflagellates and coral.
- provide food for coral animals
- receive food from coral waste products and protection within coral skeletons
95
Define bioluminescence.
The ability of living organisms to produce light.
95
What is the possible function of light production by dinoflagellates?
To startle predators
96
When do red tides occur?
When a dinoflagellate colony grows out of control
97
List two ways that red tides may be harmful.
- produce toxins harmful to wildlife
- when organisms die, they deplete oxygen in the water
98
Describe plankton.
Microscopic floating organisms that form the base of the aquatic food chain; made of photosynthetic phytoplankton and heterotrophic zooplankton
99
List some examples of filter feeders that consume plankton.
Jellyfish, wales, coral
100
List some characteristics of euglenoids.
- same chlorophyll as plants
- unicellular
- mostly freshwater
- some conditions cause them to be heterotrophic
101
List two examples of euglenoids.
Euglena, trichilemmomas
102
List some characters of euglena.
- grow in pond water
- photosynthetic when light is available, otherwise heterotrophic
- one or two flagella
- stigma/eyespot detects light
103
List some characteristics of red algae.
- most are multicellular
- in warm coastal waters, tropical regions
- can live in very deep water
104
List some characteristics of brown algae.
- largest, most complex seaweeds
- anchored to the seafloor by root-like structures called holdfasts
- air bladders increase buoyancy
105
List some characteristics of green algae.
- chlorophyta
- can be unicellular, colony, or multicellular
- e.g. chorella, chlamydomonas, volvox, spirogyra, ulva
106
Describe kelp forests.
Largest form of brown algae; underwater forests that can grow up to 80m tall
107
How do sea otters use kelp?
Sleep in it to keep from floating out to sea
108
List some characteristics of chlamydomonas.
- common in freshwater
- unicellular, with two flagella
- sense light
- photosynthetic
109
Describe the symbiotic relationship of lichens.
Unicellular green algae with fungi become lichen; algae provides food through photosynthesis, and fungi provides a sheltered, moist environment
110
List two examples of colonial green algae.
- spirogyra
- volvox
- groups of individual cells that function together
111
Briefly describe multicellular green algae and give an example.
- mostly marine seaweeds, some freshwater
- ulva or sealettuce
112
What is a superfood?
Dense in nutritional content; proteins, vitamins, minerals; matcha and a variety of seaweeds
113
List two substances produced from algae that are used in commerical substances.
Algin in medicines, food, and beauty; carrageenan is a food additive often used in dairy
114
List some characteristics of fungus-like protists.
- heterotrophs, external digestion
- have cell walls
- reproduce with spores
- decomposers
- usually do not move
115
List some characteristics of slime moulds.
- slimy masses, 1-2cm or larger
- grow on rotting logs and other decaying stuff
116
Briefly discuss the two types of slime moulds.
- cellular: unicellular and multicellular stages
- plasmodial: single cytoplasm with many nuclei and no membranes or walls
117
List some characteristics of cellular slime moulds.
- feed on microorganisms in dead plant material
- usually in unicellular, amoeba-like feeding stage
- may clump together and move as one organism
118
List some characteristics of plasmodial slime moulds.
- have a mobile feeding stage and a nonmobile reproductive stage
- moves about 1mm per hour
- spores may remain dormant for several years before germinating
119
List some facts about water moulds.
- in freshwater or moist soil
- can be parasitic to plants and animals; feed on decaying organisms
- caused the Irish potato famine
120
List some facts about downy mildews.
- most are plant parasites
- spores spread by the wind
- infect grapes and vegetables
