What are the basic characteristics of a virus?
Noncellular, Cannot reproduce on its own, and parasitic
What are the two viral structures?
Capsid; outer layer made of protein subunits
Nucleic Acid Core; DNA or RNA is stored
What are the three categorizes of viruses?
1-Type of Nucleic acid
-DNA or RNA
- Single stranded or double stranded
2. Size and Shape (threadlike-polyhedral, helical, isometric, icosahedron)
3. Prescence/Absence of outer envelope
Name the two cycles of Bacteriofages
Lytic and Lysogenic
Describe the Lytic cycle
Viral compenents synthesized, assembled, released. Cell dies as a result
Describe the Lysogenic cycle
Virus infects bacteria and viral DNA integrates with bacterial DNA.
What is a bacteriofage?
A virus that parasitizes bacteria
What is a Retrovirus?
•Retroviruses are RNA, animal viruses. They contain a special enzyme (Reverse transcriptase) which allows the genetic code of RNA to be copied (transcribed) to DNA.
Virus ruptures cell killing it - leads to
AIDS
–Formerly infected only apes/monkeys
–Mutation occurred allowing HIV to “jump” species
–First reported in 1981
AIDS – Acquired Immunodeficiency Syndrome (HIV)
outbreak in 2003, carried from SE Asia to Toronto, Canada
SARS (severe acute respiratory syndrome)
brought into US, infecting bird & mosquito poplulations
West Nile encephalitis
1993 outbreak, traced to deer mouse, transmitted to humans through fecal contamination Southwest US
Hantavirus
severe hemorrhaging & death (50-90% untreated). Outbreak confined to Africa
Ebola
spread through contact of infected person, vaccine 1995
Chicken Pox
last case 1977, vaccination wiped out
Smallpox
vaccine available, extremely contagious
Measles
major killer – 1918, 44 million died
Influenza
Epstein-Barr virus, spread by infected saliva
Mononucleosis
Infects CNS & leads to paralysis, often fatal. Vaccine has almost wiped it out
Polio
infectious protein particle
Prions
fatal neurodegenerative disorder
Kuru
Another example of prions
Mad Cows Disease
“ancient bacteria”
Extremophiles
Archaebacteria or
Domain: Archaea
What extremophile lives in an anaerobic enviroment?
Methanogen
What extremophile is found in hot springs,thermal vents, volcanoes (hot/acidic)
Thermoacidophiles
–salt loving
•Found Great Salt Lake & Dead Sea
*is an extremophile
Halophiles
“true bacteria”
Most of the bacteria today
More common type of prokaryote
Eubacteria
Domain: Bacteria
Is Eubacteria Prokaryotic or Eukaryotic?
Prokaryotic
Polysaccharide cross-linked peptide chains
Peptidoglycan
tail-like filament that allows bacteria to move
Flagella
unable to grow in the presence of oxygen (botulism, gas gangrene & tetanus)
Obligate Anaerobes
grow in presence or absence of oxygen
Facultative anaerobes
require oxygen (most bacteria)
Aerobic
self feeders
Autotrophic
What are the two types of Autotrophs?
Photoautotrophs (light/photosynthetic)
Chemoautotrophs (chemicals – hydrogen gas, hydrogen sulfide & ammonia)
Chemoheterotrophs = organic nutrients
Heterotrophic
breaks down large organic molecules into smaller one that can be absorbed (decomposers)
Saprotrophs
Bacteria are often
Symbiotic
Bacteria & host benefit
Mutualistic
Examples of Mutalism
Nitrogen-fixing bacteria in legumes
bacteria in digestive tracts
Bacteria benefits, host unharmed
Commensalistic
Commensalistic Example
E. coli uses up available O2 in intestines, allowing obligate ananaerobes to live there as well
Host is harmed
Pathogenic / diseases
Parasitic
(1) Produce toxins &/or
(2) adhere to surfaces and
(3) may invade organs or cells
Pathogens
How is Bacillus (pl. bacilli) shaped?
rod shaped
Examples of Bacillus
Coccobacilli, Pseudomonas
How is Coccus (pl. cocci) shaped?
round / spherical
Examples of Coccus
Staphylococci, Streptococci
How is Spirillum (pl. spirilli) shaped?
helical-shaped
Examples of Sprillium
Spirillum volutans
Thick peptidoglycan cell wall
Purple when stained
Gram-Postive
More common
Thinner peptidoglycan cell wall
pink when stained
Gram-Negative
small strand of DNA containing very few genes
plasmid
Two ways that bacteria can reproduce
Conjugation and Binary Fission
Bacterial sexual reproduction
Conjugation
Bacterial asexual reproduction
Binary Fission
Formerly - blue-green algae (Gram-negative bacteria)
Photosynthetic
Introduced O2 to primitive atmosphere
Some -fix nitrogen
food source for aquatic ecosystems
found - fresh water, soil, moist surfaces, hot springs
Cyanobacteria
Bacillus anthracis
Biological agent, flu-like symptoms, not contagious, treat w/ antibiotics
Anthrax
Clostridium botulinum
Caused by improperly canned foods, produces a toxin
Botulism
Vibrio cholerae
Found in areas of poor sanitation, digestive tract diseases
Cholera
Streptococcus
Caused by strep sticking to teeth, eating sugars, producing acid that rots teeth
Dental Caries
Mycobacterium leprae
Called Hansens disease – skin lesions
Leprosy
Borrelia bergdorferi
vector, - deer tick, bulls eye rash, joint pain, lethargy, treat w/ antibiotics
Lyme Disease
Helicobacter pylori
Treat w/ antibiotics
Peptic Ulcers
Yersinia pestis
Bubonic plague –bite of flea, pneumonic plague – inhaled. Major killer
Plague
Streptococcus
–Respiratory disease
( Streptococcus also causes sore throat, rheumatic fever)
Can be bacterial or viral
Pneumonia
Mycobacterium tuberculosis
–Respiratory infection, contagious, many strains are resistant to our antibiotics
Tuberculosis
“Silent STD”
Pelvic Inflamatory Disease (PID) – sterility
Chlamydia
can lead to PID and sterility
Gonorrhea
appears as blister / sores
End stage results in heart disease, mental deficiency, nerve damage, loss of motor function, and blindness
Syphilis
List the importance of Bacteria
Carbon cycle, nitrogen cycle, anibiotics, and clean enviromental pollutants
nucleus and organelles
Eukaryotic
Describes how a large host cell and ingested bacteria could easily become dependent on one another for survival, resulting in a permanent relationship. Over millions of years of evolution, mitochondria and chloroplasts have become more specialized and today they cannot live outside the cell.
endosymbiotic theory
Some scientist argue protist are not a
Kingdom
This group includes land plants and other photosynthetic organisms, such as green and red algae, that have organelles derived from endosymbiotic cyanobacteria
Supergroup: Archaeplastids
Majority are unicellular, but some are multicellular
Live in variety of moist environments (oceans, freshwater, treebark…)
Green Algae
Example of Green Algae
Chlamydomonas
Description of Chlamydomonas
- Unicellular
- 2 Flagella – front end, breaststroke
The chloroplast in Chlamydomonas contains
Pyrenoid and eyespot (stigma)
produces starch
Pyrenoid
bright red, sensitive to light (helps them find light for photosynthesis)
Eyespot (stigma)
Two flagella at the anterior end are used for
Locomotion
unicellular, common on tree bark and soil.
Chlorella
500 to 60,000 indiv. cells
Colonial green algae
¢Colonial green algae
w/ 500 to 60,000 indiv. cells
¢Flagella - produce directional movement
¢Daughter colonies will leave to form new colonies
¢Vegetative cells don’t reproduce
True division of labor Not all cells reproduce.
***Beginning of cell specialization***
Genus Volvox
¢Multicellular green algae
¢– sea lettuce
¢marine
¢2 cells thick
¢Up to 1 meter long
Genus: Ulva
¢filamentous green algae
¢Ribbonlike, spiralled chloroplasts
¢Asexual & sexual reproduction
Charophytes: Genus Spirogyra
¢DNA transfer between cells
Sexual: Conjugation tube
¢product of fertilization
Diploid Zygote
Most - multicellular
- Found shallow and deep waters
- Grow in warm seawater
- Economically important: agar: gel capsules, dental impressions, cosmetics, media for bacteria, foods (jellies & desserts)
- Genus Porphyra – Important Food crop for Japan – sushi roll wrapping.
The Red Algae
gel capsules, dental impressions, cosmetics, media for bacteria, foods (jellies & desserts)
Agar
Made of two large subgroups
- ) Stramenopiles- have flagella (or descended from organisms that had flagella)
- Brown Algae
- Diatoms
- Water Molds - ) Alveolates- Unicellular protist that habe alveoli (small sacs) just below their cell membrane.
- Dinoflagellates
- Ciliates
- Apicomplexans
Supergroup: Chromalveolates
¢responsible for most of the food production through photosynthesis. (up to 100m)
Kelp
¢grasping portion - attach themselves to rocks.
holdfasts
¢flat portion
Blade
¢give buoyancy
Air bladders
¢sometimes break off from holdfasts & form floating masses
Float due to airbladders
Genus Sargassum
¢Autotrophic
¢Unique double shells made of silica - fit togetether like a ”hat box” or petri dish
¢“diatomaceous earth” (remains) on ocean floor
used as an abrasive (silver & toothpaste)
Filtering agents & soundproofing
¢Reproduce asexually – each offspring gets one old shell, and a new shell grows until it is 30% size of the original
– then sexually reproduce
The Diatoms
Unique double shells made of silica - Shells are like boxes with lids, one half of the shell fitting inside the other
Chrysophyta
¢Most live in water
¢Parasites or saprotrophic – fish, insects, decomposing remains – form furry growths
¢Cellulose cell wall, not chitin like fungus
¢Phytophthora infestans – resp. for potato famine of Ireland in 1840
Water Molds
How do saprotrophics obtain their nutrients?
What water can they survive in?
Where can they also live?
obtains nutrients from dead material
Fresh or salt water
Also live in soil
¢photosynthetic
¢Contain cellulose and silica walls
¢2 flagella, 1 extends out while the other wraps around the organism
¢Symbiontic w/ jellyfish, sea anemones, mollusks and corals
- “red tide”- “blooms”
- Dinoflagellates undergo abnormal growth. This leads to an increase in toxin levels which kills fish in the environment. Can lead to human poisoning, if consumed
Dinoflagelletes
unicellular organisms that move by cilia
Ciliates(paramecium)
semi-rigid outer covering
Pellicle
barbed threads used for defense/capturing prey
Trichocysts
structure where food enters
Gullet
Wastes excreted – anal pore
Reproduction
Food Vacoule
causes malaria
Spread by mosquitoes (vector)
Invades RBC’s
Chills & fever occur when RBC’s rupture releasing toxins
Apicomplexans- Plasmodium
Nonmotile, spore-forming parasite Spores enter bloodstream of person and they make their way to the liver and reproduce asexuallySpores reenter bloodstream, rupture, releasing toxic substances.
The Sporozoans
autotrophic or heterotrophic (1/3 have chloroplast)
Pyrenoid – region of chloroplast – produces paramylon carbohydrate
Pellicle – flexible protein - shape
2 Flagella - movement
Stigma or eyespot - @ base of flagella - light sensitive
Contractile vacuole – rids body of excess water
Euglenoid
African sleeping sickness
- Lack of O2 to brain causes lethargy
- Tsetse flies - vector
Trypanosomes
responsible for hiker’s diarrhea
Giardia lamblia
Parasitic & free living
No definite shape
Locomotion pseudopods (Greek “false” and “foot”)
Feed – phagocytosis – digestion occurs in “food vacuole”
Ameobic dysentery , caused by amoeba, can be fatal if they infect the brain or liver.
The Amoebas
- Exist as a plasmodium:
- Plasmodium- mass of “Cell bodies” that are not separated into individual cells
- Creeps along -resembles slime –phagocytizing decaying plant material in forest
- Produce spores in dry environments, which will germinate when moisture returns
Plasmodial Slime Molds
- a non-walled multinucleate mass of cytoplasm that resembles moving mass of slime
Plasmodium
Exist as individual amoeboid cells
- Common in soil
- Moves through soil or substrate ingesting bacteria and yeasts
- When conditions are not favorable, they will aggregate and produce spores until conditions are more favorable.
Cellular slime molds
Related to sponges (greatly resemble the feeding cells of sponges)
Filter feeders: whipping their flagellum circulates the water through the collar, where microvilli take in nutrients
Choanoflagellates
Glassy silicon test (skeleton)
Many needles – like pseudopods
Radiolarians
Marine
- Tests – calcium carbonate skeleton
- Pseudopods - Cytoplasmic projections extend through openings in the test
- “White Cliffs of Dover” - Southern England - rich in foraminiferan deposits.
- Egyptian pyramids – foraminiferan limestone
Foraminifera