Biol 202 Exam 3 Flashcards
Final population equation (What is it?)
N0 x 2^n
- N0: initial number of cells
- n : amount of generations
Bacterial phylogenies (what are they often based off of?)
They are often based on the 16s rRNA subunit gene - highly conserved
How can we tell which species is more closely related to one another?
(WHEN COUNTING WHICH ARE MORE CLOSELY RELATED WE MUST)
1. count the number of turns it takes to get to each other
2. whichever are further are less closely related
How many phyla of bacteria is there?
There are 30 phyla of bacteria from which species can be cultured
Firmicutes (Characteristics)
○ Firmicutes (not many G,C in DNA sequence)
- Gram +
- “tough skin”
- Layers of peptidoglycan
- Low “G+C” (guanine and cytosine) content
- Often found in human intestines
- Creates a fatty acid (butyrate) that helps keep us healthy
Actinobacteria (Characteristics)
○ Actinobacteria (lots of G,C in DNA sequences)
- Gram +
- Peptidoglycan with an additional thick waxy coat
- High “G+C” content
- Important in the soil and aquatic ecosystems; some can be human pathogens
What two bacteria affect our gut physiology most?
The balance between FIRMICUTES and BACTEROIDETES affects our gut physiology.
What bacteria have endospores?
Some species of firmicutes form endospores
Tetanus and botulism are both caused by what phyla and what genus?
- Firmicutes include the genus Clostridium, which are strict anaerobes
○ Club shaped
○ Clostridium species include the causative agents of
§ Tetanus (C. Tetani) = jaw muscles contract
§ Botulism (C. Botulinum) muscles are weak (cannot contract)
Lactic acid and listeria are both from what phyla?
- Firmicutes also include Gram positive, non endospore forming bacilli
○ Heroes
§ Lactic acid bacteria, such as Lactococcus and lactobacillus, ferment milk to make yogurt and cheese
○ Villains
§ Listeria spp. Are intracellular pathogens causing diseases affecting the GI tract and nervous system
□ Often on undercooked or unpasteurized foods
How are species of enterococcus, streptococcus, and staphylococcus distinguished?
- Species of enterococcus, streptococcus, and staphylococcus may be distinguished by patterns of hemolysis on blood ager plates
Actinobacteria (characteristics)
- Actinobacteria (gram +)
○ Includes antibiotic producers, decomposers and pathogens
○ Cell wall includes unusual cell wall lipids, such as mycolic acid
○ Are acid-fast staining bacteria
§ Resist decolorization by acids -> make them easy to ID
○ They have a layer of mycolic acid (THIS IS UNIQUE TO ACTINOBACTERIA)
§ The acid stain binds to this
Actinobacteria (What two diseases is it known for?)
- Actinobacteria (Gram +) (purple under the scope)
○ Mycobacterium tuberculosis (tuberculosis)- infects lungs
○ Mycobacterium leprae (leprosy) - damages peripheral nerves; affects limbs and ENT
Proteobacteria (characteristics?)
- Proteobacteria
- Gram -
- Super diverse! Lots of metabolic properties
○ Can be autotrophic
○ Can be heterotrophic
○ Most are chemolithoautotrophs - Is the largest phylum of bacteria
Proteobacteria (Enterobacteria - Characteristics)
- Bacillus and gram -
- Facultative anaerobes
- Motile
- Many live in our guts
- Commensals and pathogens
Proteobacteria (Enterobacteria - What two diseases is it known for?)
- Famous example of Enterobacteriaceae (both gram - bacilli):
○ Yersinia pseudotuberculosis
§ Causes GI disease that can mimic appendicitis + is transmitted from animals to humans by contaminated food or water
○ Yersinia pestis
§ Causes the pneumonic/bubonic plague
Pseudomonads (Characteristics)
- Bacillus shaped, G-
- Motile
- Many marine species - responsible for seafood spoilage
- Some (opportunistic) human pathogens
○ Pseudomonas aeruginosa - Most are saprophytic
○ Get food from absorbing dissolved organic material (osmotrophic - type of heterotrophy) - Many produce pigments
Bacteroidetes (Characteristics)
- Bacteroidetes
○ Bacteroides spp. Are major inhabitants of the human colon
○ G-, obligate anaerobes, ferment indigestible sugar derivatives, and break down toxins
§ PSA and T-cells
○ Produce communication molecules to communicate with and direct the immune system
○ We like these guys, they’re often in our yogurt
Spirochaetes (Characteristics)
- Spirochetes are spiral-shaped bacteria
- They are gram - and chemolithoautotrophic
Spirochaetes (Borrelia bergdorferi - what is it and its symptoms)
○ Borrelia bergdorferi (Lyme disease)
§ Currently uncurable (but symptoms can be treated);often lead to rheumatoid arthritis and other auto immune diseases
§ Causes lots of symptoms like
□ Muscle spasms
□ Headaches
□ Arthritis
□ Immunodeficiencies
Spirochaetes (Treponema pallidum - what is it and its symptoms)
○ Treponema pallidum (syphilis)
§ Sexually transmitted bacterium
§ Contact with any of the chancres (spores) can transmit the bacterium
Chlamydia’s (Characteristics)
- Chlamydia’s
○ Absent or diminished cell walls
○ Chlamydia’s are obligate parasites or pathogens
§ This means that they cannot reproduce without a host
○ Persistent infection with C. trachoatis can lead to pelvic inflammatory
○ They are more common in females, but males can exhibit inflammation of the testes and discharge
What is unique of Chlamydia’s?
- They cannot reproduce without a host cell
- They cannot be gram stained
Is Chlamydia more common in females than males?
yes
