Exam 1 Flashcards
Describe the 4 major processes of living cells.
- Growth- increase in size and complexity
- Reproduction- production of new cells or of a new individual. sexual/asexual
- Responsiveness- ability to detect changes (stimuli) in external or internal environment and respond to them.
- Metabolism- all chemical reactions that occur within a cell- all living things transform matter and energy to live
How are prokaryotic and eukaryotic cells the same?
- Both are surronded by a plasma membrane (phospholipid bilayer) that defines their boundaries.
- Both encode genetic information in DNA molecules.
How are prokaryotic and eukaryotic cells different?
Eu has nucleus and Pro does not Eu has nucleolus and Pro does not Eu has cytoskelton and Pro does not Eu divides by mitosis or meosis and Pro divides by binary fission Eu has histones and Pro does not
Describe the function of the glycocalyx.
– Enables certain bacteria to resist phagocytic
engulfment by white blood cells
– Enables some bacteria to adhere to
environmental surfaces to colonize and resist
flushing (rocks, human teeth)
– Protects against dehydration (dessication)
Describe the clinical significance of the glycocalyx.
Streptococcus pneumoniae
– Pathogenic with capsule
– Nonpathogenic without capsule
What are flagella?
Long filamentous
appendages that
function in propelling
the bacterium
What are the 3 basic parts of the flagella?
-Filament – rigid, extends from cell surface (flagellin protein)
– Hook – flexible coupling between filament and basal body
– Basal body – a rod and series of rings that anchor the flagellum and the cytoplasmic membrane molecular motor that enables flagellum rotation
Flagella arrangements:
Monotrichous-single flagellum, at one pole
Amphitrichous- single flagellum, at both poles
Lophotrichous- two or more flagellum at one or both poles
Peritrichous- flagella over entire surface
Flagellar Function
• Locomotion (for most of bacteria capable of
motility)
Clinical Significance of Flagella
H pylori (the causative agent for some forms of gastric ulcers in humans.
Describe positive chemotaxis, negative chemotaxis, positive phototaxis and negative phototaxis in relationship to a microbe’s motility.
Positive chemotaxis- move toward chemical ex pheromoes
Negative chemotaxis- move away from chemical ex fart on elevator
Positive phototaxis- move toaward light ex. photosynthesis or food
Negative phototaxis- move away from light ex. so it doesnt harm it or somethng moving toward light doesnt harm or kill organism
Fimbriae (Attachment Pili)
attachment pili, hair-like projections found in many gram-neg bacteria, used for attachment not movement, found at poles to hlep bacteria adhere to surfaces.
- Contribute to pathogenicity
- Clinically significant in N gonorrhoeae and E coli
Pili
Conjugation (sex) pili
– Found only in certain groups of bacteria
– Attaches two cells to provide a pathway to
transfer genetic material (conjugation)
– Important mechanism of transferring antibiotic
resistance.
The extra gene is used for antibiotic resistance. Can make hospital antibiotic resistance
Axial Filament
- cork screw motion, screw into skin
- extend from both ends of bacterium between outer membrane and cell wall.
- Clinically significant: can bore through tissue as in Treponema pallidum (causative agent of syphilis) and B burgdorferi (lyme disease)
Describe the chemical composition of peptidoglycan
- 10-65 NAG/NAM molecules joined in chain (glycan)
- Parallel chains held together by peptide cross bridges
- sugars in the body are in D form/ amino acids are in L form
Gram –Positive Cell Walls
- Very thick peptidoglycan
- Lipoteichoic acid (link to plasma membrane)
- Teichoic acid (linked to peptidoglycan)
- Stains purple
Gram- Negative Cell Walls
- Very few layers of peptidoglycan
- Outer membrane – LPS, lipoproteins, phopholipids
- Fluid-filled space between outer and plasma membrane
- Contains digestive enzymes and transport proteins
Lipid A
Endotoxin
toxicity or poisining to patient seen as flu symptoms/ DIC
Describe the differences of the cell walls of bacterial, archaeal, mycoplasma and L-forms.
Bacteria: semi rigid, lies outside of cell membrane, often porous, does not regulate the entry of materials into or out of the cell, composed of peptidoglycan
Archaea: lack cell walls or unique cell walls (no peptidoglycan)
Mycoplasma: do not have cell walls- unique plasma membranes (sterols)
L-forms: can live with or without their cell walls- they have cell walls and then lose their ability to make them
Clinical significance of L-forms
- they turn gene genesis off making it difficult to treat.
- may play a role in recurent chronic disease
- often results from treatment or antibiotics specific for cell destruction
Describe the function and clinical significance of biofilms.
Function: impede or inibit antimicrobial drugs and allow bacteria to retain nutreints
CS: make treatment much more difficult and prolonged
Explain the fluid mosaic model of cytoplasmic membrane structure.
Selectively permable conduit, both hydrophillic and hydophobic, highly dynamic and organized, loaction of variety of critical metabolic processes
Describe the prokaryotic cytoplasm and its basic content
- 80% water
- Proteins, carbohydrates, lipids
- Inorganic ions
- Inclusions
- Ribosomes
- Nuclear area
Describe the basic structure, function and clinical significance of prokaryotic ribosomes.
- translation and proteins synthesis*
- protein and rRNA
- Streptomycin inhibits protein synthesis by attaching to 30S subunit
Identify the functions and clinical significanceof the nucleoid in the prokaryotic cell.
Chromosome genes for structure and function
Describe the function and clinical significance plasmids
- Spead antibiotic resistant genes
- Organisms resistant to more than one antibiotic
Describe the function and clinical significance of endospores
Spread disease-very hard to get rid of
The bacterial cell wall is important because it
Protects the cell from the environment
The primary substance making up the bacterial cell wall is
Peptidoglycan
Peptidoglycan is made up of
repeating NAG NAM molecules
Gram-positive cell walls differ from Gram-negative cells in that the Gram positive ones contain
Teichoic acids
Wall teichoic acids
go only halfway through the cell wall
Lipoteichoic acids
go completely through the cell wall
Teichoic acids
are involved in respiratory infections
Gram-negative organisms differ from Gram-positive organisms in that Gram-negative
have an outer membrane
Gram-negative organisms contain
translocation proteins
Mycoplasma is an organism that
has no cell wall
Mycolic acid
is found only in certain Gram-positive bacteria
Lipid A is
part of the endotoxins of gram-negative bacteria
O polysaccharides are
used to identify certain bacteria
All of the following are associated with the exterior of the bacterial except:
Fimbriae Phospholipid bilayers pili flagella axial filaments
Phospholipid bilayers
Slime layers and capsules are part of
the glycocalyx
The presence of a capsule
causes bacteria to become more infective
Fimbriae are involved with
staying in the host
Pili are responsible for what?
immune response
movement of bacteria
transfer of genetic info
Axial filaments are
same as flagella
flagella located around an entire bacterial cell are called
Peritrichous flagella
The plasma membrane is composed of
a phospholipid bilayer
Integral proteins
go all the way through the membranes
Plasmids are
- circular DNA particles within a micro organism that is not part of the main DNA of the cell.
- it carries many information that allows adaptation of the cell to particular enviroments.
- plasmids are also used as vectors to introduce certain traits into cells that do not naturally have that triat.
Bacterial ribosomes
are involved in protein synthesis
Bacterial ribosomes are clinically important because they
are resistant to antibiotics
Bacterial endospores are
resistant to heat
Define atrichous
bacteria without flagella (cocci rarely have flagella)
Microbiology
is the scientific study of microorganisms
Exaplain what a microorganism is
microbes are living organisms that are usually to small to be seen with the naked eye
6 main classes of microorganisms
Viruses Bacteria Archaea Fungi Protozoa Algae
Helminths
not microorganism
Parasitic worms of mecical importance. Use microbiology techniques to identify-usually looking for eggs in feces. They feed off of host, when somebody is about to die the worms will come out of the body anyway possible
Arthropod Vectors
not microorganism
Animals that carry disease from one host to another. Ex. Mosquitoes, ticks, lice, fleas, mite, ect
Properties of Viruses
Very small, acellualr, DNA or RNA gentic core, does not have cell wall
How Viruses differ from all other microbes
Acellular, virus is fragment for DNA and RNA an dit needs a cell to reproduce
Which domain is “obligate intracellaur parasite”
Virus–which means it must live within the cell, cannont multiply outside a living cell, cannot replicate inside a specific host
Properties of bacteria
Prokaryotic, complex cell wall made of peptidoglycan, diverse lifestyles, unicellular
-spirical, rod, or spiral shaped
Eubacteria
types of bacteria that make up dangerous disease “true bacteria”
belongs to bacteria domain
Archaebacteria
composed of single-celled organisms lacking organelles or a nucleus (prokaryotic).
- cell wall without peptidoglycan
- live in extreme environments
- belongs to archaea domain
importance of peptidoglycan
makes up the cell wall of bacteria
determines if bacteria is Gram-negative or Gram-positive
Properties of Algae
Eukaryotic
Cell wall-Cellulose
Unicellular or multicellular
Photosynthetic- fresh or salt water
Properties of Protozoa
Eukaryotic No cell wall Free or parasitic lifestyle Many shapes and movement Unicellular
Properties of Fungi
Eukaryote Cell wall- Chitin Absorbs organic material for nutrition unicellular-yeast multicellular- molds
Reasons why microorganisms are studied
- Large numbers found everywhere
- On and in our bodies- normal microbiota
- Human host 1500 different microbes
- Pathogenic- cause disease
- Air, soil, water in and on plants and animals
- Perform fuctions essential for life on earth
- -decompose plant and animal waste
- -nutrient cycling
- -food for higher organisms
- -photosynthesis
Good things microbes are used for
- Soil-nitrogen fixation
- Medicine-antibiotics (penicillin and tetracycline) and vaccines
- Industrial- nail polish remover, acetone, vinegar
- Make 50% of oxygen in atmosphere
Bad things microbes do
- Diesease; flu cold, leasles, plague, food poisoning
- Food spoilage
- Destruction of buildings and statues
- Bioterrorism
Pathogen
any microbes that causes disease
opportunistic pathogen
opportunistic pathogen is a microbe that doesnt normally cause disease but can under the right circumstances
normal microbiota
microbes that exist in the bodies of all humans
Bioremediation
to use biological organisms to solve an enviromental problem such as contaminated soil or groundwater
Bioterrorism
the use of viruses, bacteria, fungi, or their toxins for threatening or harmful purpose. Bacillus anthracis- bacterium that causes anthrax. Smallpox- virus
Acellular
not consisting of, divided into, or containing cells.
Obliagate
restricted to a particular function or mode of life
Probiotics
are living microbes (mostly bacteria) that are similiar to beneficial microbes found in the human gut. “Friendly or good bacteria” Available to consumers mainly in the form of dietary supplements and food
genome
nucleoid (DNA)
chromosomes genes for structure and function
plasmid
organism resistant to more than one antibiotic
Conjugate pili
exchange of DNA
Pili clinical significance
spreads antibiotic resistance
Endotoxin
Gram-negative bacteria infection
get into circualr tissure
blood clotting
controls what comes in and out of cell
cell membrane
maintains cell shape
cell wall
Glycocalyx
enables certain bacteria to resist phagocytosis by WBC
protects against dehydaration
Bacteria under stressful times will shares genes or DNA randomly
Conjuction
Cytoplasmic Membrane
- Phospolipid bilayer embedded with protiens
- Barrier between the cytoplasm and outside environment
- Selectivevly permeable conduit
- Defines the boundry of the cell
- Hyrophillic and Hydrophobic components
Gram-negative cell wall
few layers of peptidoglycan
outer membrane made of LPS, lipoproteins, phospholipids
periplasmic space
DIC
gram-neg inf randomly blood clot throughout stream
Gram-positive cell wall
Very thick peptidoglycan
Teichoic acid
porins
let stuff in and out of cell in the cell membrane
What as no nucleus and peptidoglycan in the cell wall
Bacteria
Eukaryotic and Chitin in cell wall
Fungi
Eukaryotic and cellulose in cel wall
Algae
Eukaryotic and no cell wall
Protozoans
Acellular and no cell wall
Virus
Prokaryotic and chemically simple cell wall with no peptidoglycan
Archaea
Live in extreme environements
Archaea
Absorbs orgain material for nutrition
Fungi
Photosynthetic and lives in fresh or salt water
Algae
3 Unicellular classes are
Bacteria
Archaea
Protozoans
Can be with unicelluar or multicellular
Fungi and Algea
Neither unicellular or multicellular
Virus
Pili are absent in what type of cell
Eukaryotic
Polysaccaride and Polypeptide subunits
Glycocalyx
rigid, extends from cell surface
filament of flagella
flexible coupling between filament and basal body
hook of flagella
molecular motor that enables flagellum rotation
Basel Body
