intro to micro
cell structure
viruses
metabolism
microbial growth and control
100
what are the 3 domains of life according to Woese?
bacteria, archaea, eukarya
100
what is the main difference between bacterial and archaeal cell walls?
bacterial: contain peptidoglycan
archaea: contain pseudomurein or S layer
100
what are prions, how are they acquired, and why are they so hard to get rid of?
prions are misfolded proteins that can accumulate in the brain, they are acquired through ingestion of infected meat, since they are folded proteins, they have a relatively stable structure that is not easily denatured (except for with extreme heat beyond cooking temperatures)
100
what are the words used to describe:
energy source?
electron donor?
carbon source?
energy source: photo- (sunlight) and chemo- (preformed molecules)
electron donor: organo- (organic compounds) and litho- (inorganic compounds)
carbon source: hetero- (organic compounds) and auto- (carbon dioxide)
100
what is the difference between a batch culture and a continuous culture?
batch: fixed culture that is not constantly replenished
continuous: always being filled with fresh medium and being slowly drained to remove dead cells
200
what are the key differences between prokaryotic and eukaryotic cells?
1. nucleus vs nucleoid region
2. membrane bound organelles vs no membrane bound organelles
200
explain the difference between virulence and pathogenicity
pathogenicity: ability to cause disease
virulence: severity of disease
200
explain antigenic drift vs antigenic shift and provide an example
antigenic drift: seasonal changes due to small mutations, immune system can still respond but not fully
antigenic shift: more drastic changes that can produce new strains, may be completely foreign to the immune system
example: influenza vs swine flu
200
what is the difference between substrate level and oxidative phosphorylation
substrate level: an energy-rich substrate (single molecule) hydrolyzed to drive ATP formation, not much ATP produced
oxidative: outside electron donor, produces more ATP, requires an energized membrane or electric potential
200
what are the four main environmental growth requirements?
temperature, pH, water activity, and oxygen
300
what are the properties of all cells vs some cells?
all: genomes, cell membranes, ribosomes, cytoplasm, metabolism, growth, evolution
some: differentiation, communication, movement, gene transfer
300
fungal spores vs endospores
fungal spore: easily moved around by wind, used for fungal (eukaryotic) reproduction
endospore: hardy, dormant state of a bacterial cell that acts as a shell to protect the cell in times of extreme or unfavorable conditions
300
draw the structures of a naked virus vs an enveloped virus and explain which is easier to control and why
enveloped easier to control, since once the evelope is broken down the virus is already destroyed
300
what parts of the normal respiratory process (glycolysis --> krebs cycle --> ETC) are not actually necessary for survival?
an organism can survive on just glycolysis (no krebs cycle or ETC) as long as there is a fermentative mechanism to regenerate NAD+ (a limiting factor)
300
draw a batch culture growth curve and explain what is happening in each part
lag phase: fluctuating, where cells are adapting to new conditions, synthesis of necessary growth enzymes
log phase: growth phase
stationary phase: cells dividing = cells dying (lack of oxygen, nutrients, or space)
death phase: no more new growth, all cells die out
400
why does life have upper and lower limits?
SA / vol ratio (more SA needed for transfer as volume increases, but since volume increases faster than SA, it cannot keep up with this increase)
400
what is the difference between capsules and slime layers and what are the similarities and difference in their usages?
capsules: tighter outer coverings
slime layers: loose, sugary outer layers
similarity: both help in attachment
difference: capsules are more important in preventing immune responses
400
what is replicase and how does it relate to the difference between positive and negative RNA viruses? why don't humans need replicase?
replicase: RNA dependent RNA polymerase
+ RNA viruses: can be translated right away by the host cell since their genome acts as the mRNA
- RNA viruses: cannot be translated right away since their genome is the antisense / complementary strand, so must bring replicase with them
humans do not need replicase since they do not need to synthesize RNA from more RNA, but rather DNA from DNA or RNA from DNA
400
there are two cultures of yeast. culture A is open to the air, while culture B is capped tightly. what type of respiratory process will each culture be undergoing? which will have more growth and why? which will have less glucose in it and why?
culture A: aerobic respiration (glycolysis --> citric acid cycle --> ETC)
culture B: fermentation (glycolysis --> fermentation)
culture A will have more growth due to the higher efficiency of aerobic respiration
culture B will have less glucose since fermentation produces less ATP per glucose consumed, so to generate the same amount of ATP, more glucose will need to be used
400
classifications of organisms that can survive at different temperatures
psychrophile (loves cold), psychrotroph (can grow in cold and room temperature), mesophile (likes human temperatures), thermophile, hyperthermophile
500
are viruses alive? why or why not?
no - since viruses do not contain many of the necessary elements for living cells (they do not have their own metabolism, they do not possess ribosomes, they do not have a cytoplasm, and their only means of existence and replication are within a host)
500
if, after applying the first (purple) stain to my organism and washing it off with alcohol, the organism appears to be colorless, what could be the possible gram reaction or cell wall structure assuming I did the gram staining procedure correct? (and why)
gram negative - the initial stain was not able to be retained due to the small amount of peptidoglycan and a large periplasmic space, allowing for it to be washed away
acid fast - the waxy mycolic acid layer was unable to hold onto the initial stain and it easily washed away
500
compare and explain the processes of attachment, entry, assembly / replication, and exit of bacteriophages vs animal viruses
bacteriophage: attach on cell wall, enter by injecting genetic material, synthesize inside cell cytoplasm, and exit via lytic or lysogenic cycle
animal virus: attach on cell membrane, enter either via endocytosis or fusion if enveloped, synthesize in nucleus, cytoplasm, or golgi body, and exit via lysis, exocytosis, or budding
500
draw out the general respiration pathway and express what parts are oxidative and what parts are substrate level phosphorylation
glycolysis: substrate level phosphorylation
krebs / citric acid cycle: substrate level phosphorylation
electron transport chain: oxidative phosphorylation
500
what are the classifications and descriptions of organisms that survive in different oxygen conditions? why can oxygen be toxic?
oxygen can be toxic due to its ability to form reactive oxygen species, which can be deadly to a cell if not broken down
obligate anaerobe: doesn't have enzymes to break down toxic O2 byproducts, must grow without oxygen
aerotolerant anaerobe: anaerobe that can tolerate oxygen but does not prefer it, mostly ferment
facultative aerobe: can use but also doesn't have to use oxygen, can respirate and ferment
microaerophile: can tolerate oxygen but not full atmospheric levels
obligate aerobe: must grow in oxygen and must use oxygen as an electron acceptor