Micro Final Exam Flashcards
What is microbiology?
Microbiology is the study of organisms which are usually seen by a microscope, not the unaided eye.
Prokaryotic vs. Eukaryotic
Prokaryotic cells came into existence before the eukaryote. They do not have membrane bound organelles or a nucleus. Eukaryotic cells have a nucleus and membrane bound organelles
Carl Woese
He created Domain, which is used as a classification system. It showed 2 distinct types of groups, Bacteria and Archaea
Prokaryotes
Majority have cell wall with peptidoglycan. Reproduce by binary fission. About 0.3-5 nanometers.
Significance of Cyanobacteria
produces significant amounts of oxygen; photosynthetic
Are virus’ considered organisms
No, they are considered infectious agents
Viroid and Virusoids
Consist of only RNA; no protein coat
Prions
consists only of protein, no DNA or RNA ex: Mad cow disease
Why did RNA exist before DNA?
RNA was first because it could store information and was catalytic and DNA is NOT catalytic, only a storage molecule
The Endosymbiotic Theory
The theory that states that mitochondria and chloroplasts were acquired to the eukaryotic cell by endosymbiosis from a prokaryotic cell.
Antony Van Leeuwenhoek
improved microscopy Increased magnification 50-300x
Who challenged spontaneous generation and what did he do?
Fransesco Redi challenged spontaneous generation and he did this with the meat and maggots experiment
What is Koch’s Postulate?
- Present in every case of the disease. absent in healthy organisms 2. Must be isolated and grown in pure culture 3.Same disease must result upon infection of healthy organism 4.Same microorganism must be isolated again
What are some application of microbiology?
Sewage Treatment Bioremediation (ex. oil) Produce useful products (ex. insulin, ethanol, amino acids, pesticides) Genetic Engineering Food (lactic acid, fermentation reactions)
Rank microorganisms smallest to largest
virus, bacteria, protist, eurkaryote
Resolution
the ability to distinguish between separate objects
Contrast
light intensity difference between a sample and its background
Relationship between oil and glass
They have the refractive index
Wavelengths relation to resolution
Short wavelengths increase resolution because they can fit where longer wavelengths cant
What are stains composed of?
A chromophore Charged salt- negative dye = acidic pH positive dye = basic pH
Which type of dye is used as a negative stain?
Acidic
Differential Stains
Distinguishes between different types of bacteria Gram stain and Acid Fast stain
What makes something Gram+ or Gram-
Gram positive indicates a thick cell wall, the crystal violet and iodine mixture is not able to escape from the thick peptidoglycan layer. The opposite is true for Gram-
What is the composition of the cytoplasmic membrane?
It is made up of a bilayer of phospholipids. It is amphipathic- there is a different chemical feature on both sides. There is also a lipid bilayer with hydrophilic heads and hydrophobic tails
What is the fluid mosaic model?
The word fluid tells us that the membrane is not static, it can more and adjust or else cells pop. It has LATERAL movement and rotation. Mosaic tells us it is not uniform throughout the membrane.
What is flip-flop?
It is a rare occurance when the fluid mosaic model moves up and down. The enzyme that makes this happen is flippase. The reason this is rare is because there is a lot of resistance from the non-polar tails to move to the other size of the cell
Describe an Integral protein
Goes through both sides Makes up 70-80% of protein in the cytoplasmic membrane Not easily extractable Insoluble in water Have some hydrophilic regions
Describe a Peripheral protein
On the inside or outside of the membrane but never both. If on the inside they are normally helping another protein and if they are on the outside they are working as receptors 20-30% Easily Isolated Soluble in Water May attach to integral proteins
What is true about both a peripheral protein and a integral protein?
The both function as receptors for cell signaling. Both may interact with cell wall. Both are transporters of nutrients
Functions of the cytoplasmic membrane
Selective Barrier Site of Transport Systems Site of Crucial metabolic processes Site for special receptors to decent environmental conditions
What compounds are passive transport limited to?
H2O, O2, CO2, and small nonpolar molecules
Describe Facilitated Diffusion
Controlled by shape, depends on a concentration gradient, less important in prokaryotes
Describe the two types of active transport
Primary- utilizes ATP and are uniporters Secondary- utilized gradients and are symporters and antiporters
Primary Active Transport
ATP Binding Cassette Transports Found in bacteria, archaea, and eukaryotes. If it is gram negative the protein will attach to the periplasm but if it is gram positive it will attach to the lipids
What are the 3 types of electrochemical gradients?
Uniport- 1 thing, 1 direction Symport- 2 things 1 direction Antiport- 2 things, opposite directions
What are mycoplasma?
hey live in environments that are friendly to their outer membranes. They use hopanoids to deal with turgor pressure They DO NOT handle environmental changes well!!
What is peptidoglycan?
Strands of polysaccerides that are weaved together of the cell membrane. This is unique to bacteria. This weaving provides strength to the cell wall. A tetra peptide provides the crosslinking
What is the backbone of the cell wall?
Alternating Monomers of NAG and NAM which pack into each other in numerous layers
How are NAG and NAM related to glucose?
The OH is replaced with an acetyl group NAM picks up the acetyl group NAG picks up the acetyl group as well as a lactyl group
Describe Gram - cell wall
Has DAP Has direct D-ala binds to Dap Starts link with D-ala Very thin cell wall, about 2-3 layers Periplasm is more defined Has 2 periplasms
Describe Gram + cell wall
Has L-lysine Does not have a direct link. 5 glycine residues in a row connect D-ala to L-lysine. This is the peptide interbridge called penta glycine Starts link with D-ala Thick cell wall, 30 or more layers Periplasm is harder to see Does not have an outer membrane Only 1 periplasm More resistant to osmotic pressures Has teichoic and lipteichoic acids
What is the LPS?
The LPS is a lipid attached to a polysaccharide or series of sugars.
What 3 areas can the LPS be broken up into?
The lipid- disaccharide of glucosamine with 3 FA attached The Core Polysaccharide- Carbohydrates attached to lipid by KDO 0-Specific Polysaccharide- Species and strain specific
What is an endotoxin?
When the macrophages in the bodies immune system target the LPS, it can tear apart the lipid A from the sugar tail, and if the body doesn’t handle it it is very toxic, like anaphylactic shock
What is endotoxin’s benefit to bacteria?
It works as a protective layer It functions as virulence (survival in humans)- rise in temperature can be a better environment, breakdown of cells is food. It confers negative charge in the bacteria
What is a channel protein?
diffusion of small hydrophilic molecule, can be different sizes based on selective entry of differently sized molecules
What is Braun’s Lipoprotein?
Connects the outer membrane to the cell wall. Works kind of like techoic acid. It really is focused on anchoring the outer membrane.
What are beta-lactam antibiotics?
An example of these antibiotics is penicillin. These type of antibiotics do NOT break down the cell wall, but they prevent the cell wall from growing. This antibiotic prevents cross linking. The weakened cell wall then ruptures and falls apart.
What is the structure of the flagella?
Basal Body –> Hook –> Filament
What are some components of the external structure of prokaryotes?
Glycocalyx Fimbriae and Pili Flagella
