Chapter 6 & 7 Collaborative Flashcards
What is microbial nutrition?
A process by which chemical compounds (nutrients) are acquired from the environment to sustain life
What are essential nutrients?
A substance (element or compound) an organism must get from a source outside of its own cells
What are macronutrients?
Required in large quantities
What are micronutrients or trace elements?
Required in small amounts
What are organic nutrients?
Contain carbon and hydrogen atoms only
What are inorganic nutrients?
Contains a combination of atoms other than carbon and hydrogen
What do all living things need, nutritionally?
Carbon source and energy source
What is a heterotroph?
An organism that gets organic carbon from other organisms
What is an autotroph?
An organism that gets inorganic carbon (CO2) from the atmosphere and is not dependent on other organisms for it
What is a chemotroph?
An organism that gains energy through chemical compounds
What is a phototroph?
An organism that gains energy through photosynthesis
How do substances move across a cell membrane?
Passive or active transport
What is passive transport?
Does not require energy
What is osmosis?
Water moves through a semi-permeable membrane
What does hypertonic mean?
High solute concentration inside cell, water exits and cell shrivels
What does hypotonic mean?
Low solute concentration inside cell, water enters and cell bursts
What does isotonic mean?
Solute concentration inside and outside of cell is equal, net 0 movement
What is plasmolysis?
What happens in a hypertonic solution, when a cell shrinks
What is plasmoptysis?
What happens in a hypotonic solution, when a cell pops
What is active transport?
Requires energy to transport substances
What is endocytosis?
A form of active transport. Bringing substances into a cell through a vesicle or phagosome
What is phagocytosis?
A form of active transport. Ingesting substances or cells
What is pinocytosis?
A form of active transport. Ingesting fluids
What environmental factors influence microbes and their growth?
Niche and adaptations to temperature
What is niche?
Totality of adaptations organisms make to their habitat. Environmental factors affect the function of metabolic enzymes
Factors include temperature, oxygen requirements, pH, osmotic pressure, and barometric pressure
What are minimum, maximum, and optimum temperatures?
Minimum - lowest temp that permits microbes growth and metabolism
Maximum - highest temp that permits a microbes growth and metabolism
Optimum - promotes fastest rate of growth and metabolism
What is a psychrophile?
Optimum temperature is cold
What is a mesophile?
Optimum temperature is medium, like regular room temp-ish
What is a thermophile?
Optimum temperature is hot
What is an anaerobe?
Something that does not utilize oxygen
What is an obligate anaerobe?
Lacks the enzymes to detoxify oxygen, therefore cannot survive in an oxygenated environment
What is an aerotolerant anaerobe?
Does not utilize oxygen, but can survive and grow in its’ presence
What is an aerobe?
Something that utilizes oxygen and can detoxify it
What is an obligate aerobe?
Something that cannot grow without oxygen
What is a facultative anaerobe?
Something that utilizes oxygen but can grow in its absence
What is a microaerophile?
Something that requires only a small amount of oxygen
What is a capnophile?
A microbe that needs higher than normal levels of CO2
Effects of pH?
Neutrophiles - grow between 6-8 neutral pH, majority of organisms
Acidophiles - grow at acidic pH
Alkalinophiles - grow at basic pH
What is a symbiotic relationship?
2 organisms grow together, which is required by one or both
What is a mutualistic relationship?
Both members benefit
What is a commensalism relationship?
The commensal benefits, the other member is not harmed
What is a parasitic relationship?
Parasite is dependent and benefits, host is harmed
What is a syntrophy relationship?
Metabolic products of 1 organism is food for another
What is a binary fission?
Reproduction where a cell splits into 2 of itself. 1 into 2, 2 into 4, 4 into 8, etc. Causes exponential growth
Stages of a growth curve?
Lag phase, exponential growth phase, stationary phase, death phase
What does the growth curve look like during the lag phase?
The line may be flat or slightly curved. Period of adjustment, cells are preparing to divide
What is turbidity?
A way to analyze population growth; measure of cloudiness in a substance. More cloudiness means more growth
What is enumeration of bacteria?
A way to analyze population growth; manually or automated counting the number of cells in a sample microscopically
What is a capsid?
The protein coat of a virus. Along w/ the nucleic acid, it forms a nucleocapsid
What is an envelope?
Found around some viruses after leaving a host, and unstable outside of a host. Spikes on the outside allow for attachment of the virus to a host cell. Cells lacking an envelope are naked and more stable than enveloped viruses
Structures of a virus?
Capsid (protein coat), envelope (sometimes, not always), nucleic core (DNA/RNA)
What are the 2 structural capsid types?
Helical - continuous helix
Icosahedron - 3D symmetrical polygon with triangular faces
What are some atypical viruses?
Povxiruses and bacteriophages
What is the structure of DNA most viruses?
Usually double-stranded except for Parvoviridae
What is the structure of RNA viruses?
Usually single-stranded except for Reoviridae
Nomenclature of viruses?
Families end in -viridae
Genus end in -virus
What does in vitro mean?
Outside the body - in a test tube, culture dish, or elsewhere outside a living organism
What does in vivo mean?
Inside the body - taking place inside a living organism
What is medically significant about viruses?
They are the most common cause of acute infections, there are several billion viral infections per year, some have high mortality rates, and viruses may have a contribution to chronic afflictions. Major participants in the earth’s ecosystem
Steps of virus replication?
Attachment, penetration, uncoating, synthesis, maturation, release (enveloped - budding, naked - lysis)
What are saprobes?
Organisms that gain energy from dead organisms, such as bacteria and fungi
What are growth factors?
Anything the organism needs that it cannot produce on its own if it wants to grow
What is diffusion?
Movement of a substance from an area of high concentration to an area of low concentration
What does growth for cells look like?
Division, growth in numbers
The human body is a good environment for growth of what?
Normal flora
What happens during the log phase?
Exponential growth of organisms
What happens during the stationary phase?
Rate of cell birth = rate of cell death due to depleted nutrients, only in closed systems where nutrients are limited and wastes can pile up
What happens during the death phase?
As limiting factors intensify, cells die exponentially. More cells dying than dividing
Ways to measure growth?
Turbidity, cell counts, and dry weight
What are 3 acellular organisms?
Viruses, viroids, and prions. All nonliving
What are viruses?
Obligate intracellular parasites
What are some obligate intracellular parasites?
Viruses, along with rickettsia and chlamydia
How would you view viruses?
Using an electron microscope
What is the core of a virus?
The nucleic core of DNA or RNA
What are the shapes of bacteria vs shapes of viruses?
Viruses - helical and icosahedral
Bacteria - coccus, bacillus, coccobacillus, vibrio, spirillum, spirochete
What is the bacterial equivalent of spikes on viruses?
Fimbriae
Structure of bacteriophages?
Like spiders, with an icosahedral shape at top
What are bacteriophages?
Viruses that only infect bacteria
What is reverse transcriptase?
An enzyme that turns RNA into DNA
Do viruses have metabolic functions?
No, they’re not living
Why is there no uncoating step in the multiplication cycle of bacteriophages?
The genome of bacteriophages directly penetrates, while for viruses, it’s in the nucleocapsid, which has to be uncoated to release the genome
Where do DNA viruses replicate?
In the nucleus of the host
Where do RNA viruses replicate?
In cytoplasm
Where is Hepatitis B?
Human liver cells
Where is poliovirus?
Nerve and intestinal cells
Where is rabies?
Mammals
What are cytopathic effects?
Effects caused by viruses on host cells which can be seen using a regular microscope, not necessitating an electron microscope
How long does herpes last?
Forever, but if it’s not currently presenting, it’s latent
What does oncogenic mean?
Cancer-causing
Steps of multiplication in bacteriophages?
Attachment, penetration, synthesis, maturation/assembly, release
What do all viruses need to grow?
A living host cell
What do transformed cells do?
They lack contact inhibition and programmed cell death, and therefore cause cancer (rapid cell growth)
What are prions?
Misfolded proteins. No nucleic acid
What are transmissible spongiform encephalopathies?
Dangerous, harmful prions. Cause fatal neurogenerative diseases
How are prions transmitted?
Through ingestion (eating), parenteral (skin), iatrogenic (operations gone wrong), and hereditary means
What is significant about prions?
They affect the brain but do not trigger an immune response - meaning there are no symptoms and, more importantly, no immune response
What does scrapie affect?
Sheep and goats
What does bovine spongiform encephalopathies (BSE) affect?
AKA mad cow disease, cows
What does wasting disease affect?
Elk
What prions can humans get?
Kuru, Creutzfeldt-Jakob syndrome (CJS), vCJD, and Fatal Familial Insomnia (FFI)
Who is Stanley B. Prusiner?
The scientist that discovered prions
What is the shape of good and bad prions?
Good - alpha-helix
Bad - beta-pleated
How do prions reproduce?
They don’t, they turn good prions into them
What are viroids?
Short pieces of RNA with no protein coat. They only cause disease in plants
What did each scientist do?:
Koch
Lister
Pasteur
Linneais
Semmelweis
Koch - Germ theory
Lister - aseptic techniques
Pasteur - father of microbiology, food spoilage
Linneais - taxonomy
Semmelweis - correlated illness of new mothers with doctors coming from morgue
What is each flagellar arrangement?
Monotrichous - flagella at 1 end
Lophotrichous - 1 end has multiple
Amphitrichous - flagella at 2 ends
Peritrichous - flagella all around
What is the dung beetle photo representing?
A syntrophy relationship
What do special stains reveal?
External structures, such as capsules, flagella, and endospores
What dye is used to look at endospores?
Malachite green dye
