Infectious organisms- bacteria Flashcards
Exercising anaerobically
Exercising without oxygen. You would do some sort of high intensity training— body runs out of oxygen temporarily and has to resort to fermentation
Why is aenerobic respiration less efficient for metabolism
Produces less ATP per glucose molecule
What is the key dif between aerobic and anaerobic metabolism
Wether or not oxygen is used
What are bacteria
Prokaryotic cells
No nucleus at all
Everything floats around without compartmentalizations
Bacteria and archaea
Eukaryotic cells
Us, plants, fungi, etc
Prokaryotic cells have
Cell wall Cell envelope Protiens Nucleic acids Ribosomes
Condensed region of DNA! NueclOID
Glycocalyx
Slime layers outside of cell walls
Can help form biofilms
Can help resist antibiotic
Make the bacteria more virulent (more able to cause disease)
Bacterial cell wall
One very king molecule that encloses entire cell
Gives cell rigidity and structural support
Cell must maintain or it it can unravel like a sweater
Gram positive vs gram negative cell walls have what in common
Made of the same thing- peptitoglycan (complex sugar)
Cell envelope
Similar to cytoplasmic/cell membrane except that it has lipopylsaccharide among the phoshpholipids
If it’s released it triggers endotoxins and immune responses
Inside bacterial cells
No nucleus
Ribosomes in cytoplasm
Cytoskeleton
Various specialized compartments
Plasmids and bacterial chromosomes usually in a condensed structure
The nucleoid
One big circle of DNA
Bound together by proteins
Forms chromosomes called domains
Cytoskeleton
Composed of long protein filaments and provides support and structure
Similar to eukaryotic cytoskeleton
Ribosomes
BITH consist of 2 subunits but the density is different
Bacterial ribosomes have a density of 70S, eukaryotic ribosomes are 80S
Inclusion bodies
Distinct collections of substances inside prokaryotic cells
Insoluble granules
Sometimes bound in a membrane
Examples of inclusion bodies
Carboxysomes- contain carbon fixing enzymes
Magnetosomes- accumulate magnetic iron
Specialized structure of bacteria attachment in prokaryotic cells
Pili are made of pilin protein
Fimbriae
Attachment to Lili attache cells to surfaces
Conjugation pilus
Facilitates transfer of DNA between cells
Stalks
Membranous extensions of cytoplasm that secrete cytoplasm that secrete adhesion factors
Specialized structure of bacteria survival
Endoscores
Dormant bodies
Produced by some bacteria (bacillus, sporoearcina)
Life involves 2 phases: vegetative cell and endospore inside
Environmental conditions induce sporulation
Sporulation is triggered by what
Environmental conditions like a lack of carbon or nitrogen
Sporulation will begin and is complete in
6-8 hours
Endospores can withstand
Hear Drying Radiation Freezing Chemicals Harsh
Does disinfection kill endospores
No
Specialized structures of bacteria for adaptation
Thylakoids- allow them to photosynthesise
Gas vesicles- aquatic bacteria inflate/deflate for buoyancy
Storage granules- storage of nutrients such as sulfur, phosphate, or PHA
Magnetosomes
Allows them to pursue things that are magnetic
Bacilli
Rod shaped
Escherichia coli abbreviated to what
E. coli
Capitalized to not capitalized
Cocci (coccus)
Spherical cells
Vibrio
Comma shaped
Stella
Star shaped
Spirochetes
Spiral shaped, corkscrew motion
Spirrilum
Twisted like a cheese puff
Branching filaments
Filamentous shaped
Diplococcus
Two paired coccus
Strepdococcus
Chain of circular bacterium
Staphylococci
Group or cluster or circle shaped bacterium
Palisades
Largest organization for bacillus like lined up pills
Other shapes for bacterium
Spirochete Stella (star) Filamentous Pleomorphic (blobs) Spirochete
Most bacteria are between ___ microns
1-2
All bacteria have
Cell membrane Cytoplasm Ribosomes Cytoskeleton Nucleoid/chromosome
Bacteria a more diverse in the way they obtain nutrients:
All living cells must get carbon from the environment.
But bacteria can be autotroph or heterotrophs
Autotroph
Created complex carbon molecules from CO2
Heterotrophs
Take in complex carbon molecules from the environment
Phototroph
Organism creates something- light absorption captures energy
Chemotroph
Chemical electron donors are oxidized
Lithotroph
Inorganic molecules donate electrons (iron, plasma, etc) molecules
Organotropj
Organic molecules donate electron
Every single bacteria is a heterotrophs because (in class)
All need something from environment
Saprobes
(Detrivores): feed one nutrients from dead organisms, decaying matters
Parasites:
Microorganisms that derive nutrients from living hosts
Obligate parasites
Food sources can sometimes be substituted with other stuff (nutrient agar) but some microbes won’t eat ourside cells (obligate parasites)
In hypotonic solutions (fresh water) cells need to
Manage water rushing in
In hypertonic solutions (salt water) cells need to
Keep their water from rushing out
Osmosis
The movement of water molecules
Osmotic pressure
The effect on the membrane when water moves in or out of the cell
Isotonic solution
Water enters and exits in a free and balanced way
How do cells deal with osmotic pressure
Their cell wall makes them more resistant to water moving in
Still vulnerable to water leave the cell
Mesophile
What most bacteria are
Survive at the same optimum temp as humans
Thermofile
Organisms that survive well in high temps
Psychotroph
Low temp tolerant
Psychofile
Can survive well in extremely cold temps (survive in antartjca)
Why might body initiate fever to fight infection
The bacterial function rapidly drops off at higher temp
We have a heat response because it’s more effective to denaturing and killing bacteria than when bacteria are in cold temps
Obligate aerobe
Must have oxygen to survive
Microaerophiles
Use a little bit of oxygen but don’t grow at normal o2 levels
Many blood and GItrwcy dwelling microbes
Facultative anaerobes
Do not require oxygen but use it when it’s present
Many intestinal microbes
Anaerobes
Cannot use oxygen, some die in its pretense
Many oral and intestinal bacteria
Fluid thioglycolsye medium
Create a gradient of oxygen concentration to help us determine the oxygen preference of bacterial species
Where the bacteria grow in he tube indicates which kind of bacteria they are
(If they grow at the top they are aerobes— need or thrive wirh oxygen)
If the bacteria is growing in the middle of the tube
Somewhere between aenorbic and aerobic
Humans have a narrow PH tolerance
We like our cells to be at PH 7.2-7.4
UV rays and X rays effect on bacteria
Kill most of them
Most bacteria live in groups or on their own
Mostly on their own
As a group how do bacteria form
Colonies
Biofilms
Prokaryotic Bacteria reproduce by what
Binary fission
Binary fission
DNA is copied
Cell grows
Copied chromosome is drawn to opposite ends of the cell
Septum begins to form at midpoint
Septum eventually walls off the resulting two daughter cells from one another
Bacterial growth is not logorithmic its
Exponential
At wht rate does bacteria grow
2x every generation
Bacteria won’t grow forever because
They get crowded
Run out of nutrients
Run out of gases
Interactions with others can be limiting (competitive) or enabling to growth
Lag phase to log phase to stationary phase (plateau)
Newly inoculated broth and add a single bacterium, reproduces at its most rapid phase but then it eventually slows down to the plateau
Last stage of bacterial growth
Senescence
Endospores may form, they mainly die off
Direct methods of counting bacteria
Plating methods
Growth series
Serial dilution
Flow through
Manual counting
Indirect methods of studying bacteria
Turbidity based methods
Fluorescence based methods
PCR based methods
PCR testing
Method of testing nucleic acids
Benefits of biofilms
Immune cells can’t penetrate
Antibiotics can’t penetrate
Biofilm enhances sharing of virulence plasmids
Why must we dilute samples
To get individual colonies
