CH 4 - Micro

Streptococci

if there is tonsillitis or inflammation in throat you will know is caused by this if you see it

Diplococci

if you see this when your taking a sample, you can then be sure this is what is causing the problem

Coccobacillus

in between a cocci and bacillus (one of few that breaks the rule), round and bar shaped

Whats the significance of Botox when it comes to eubacteria?

it is a toxin produced by a bacteria which is so dangerous that it could kill people very easily—but we extract such tiny amounts of the toxin that we use it to relax muscles (maybe for people with muscle spasms) so if too much it is relaxing all muscles in the body eventually killing them

Vibrio

"comma shaped" diseases of the stomach, etc

Streptobacilli

(strepto related to throat)

Fimbria (Fimbriae=plural)

-an appendage on a bacterial cell used for attachment

Single bacillus

"bar shaped"

Glycocalyx

-(coat of sugar) sometimes known as extracellular polymeric substance -either Capsules(compact), or slime layer(loose) - made of polysaccharides ( can be compact and attached to cell wall// or can be very loose) -huge role in biofilms -----Eg Streptococcus.mutans(oral cavity), Streptococcus.pneumonia(pneumonia causing)

Gram positive cell wall

--Dense interconnected network, enormous sac, 90% of cell wall is peptidoglycan --Techoic acids - glycerol or ribitol + phosphate molecules and sugars --Lipotechoic acid (anchored to the lipid cell membrane) Gives the cell its negative charge (Gram positive don't have periplasm because they are so dense and tight that they don't have the space)

Gram negative

--Outer membrane - lipid bilayer --Porin protein - 3 identical subunits --LPS: lipopolysaccharide, made up of 3 components: (1.Core polysaccharide/2. Lipid A/3. O specific polysaccharide side chain) --Lipoprotein = small protein , anchor between the OM and peptidoglycan layer. --Outer membrane provides a strong negative charge and helps in evading phagocytosis, and action of the complement. It also acts as a barrier. --Periplasm = space between OM and Cell membrane --Hydrolytic enzymes, binding proteins and chemoreceptors

Function of Glycocalyx

--Resists phagocytosis (important in defense and inflammation of body)— (the presence of the capsule is what makes it so strong, avoiding phago, and can cause pneumonia going to lungs) --Adherence to surfaces—(have ability to take up lots of water, and also to attach to surfaces) --Also suggested in the role of resistance to desiccation(dryness)

Axial filament

--Sets of flagella, enclosed in the space between the cell wall and cell membrane also called endoflagellum. --Rotation of the flagella within the confines of outer membrane causes the cell to move like a corkscrew. --found in spirochaetes --corkscrew movement!

Capsule

-an outer, viscous covering on some bacteria composed of a polysaccharide or polypeptide -this is the version of glycocalyx if the cell secretes the substance and it is organized(compact), and firmly attached to the cell wall -its presence can be determined by using negative staining

What arrangements are possible for Flagella?

-Peritrichous(all over cell; ecoli) -Monotrichous(single flagella/polar end), -Polar(at one or both ends of the cell) -Amphitrichous(at two ends of cell), -Lophotrichous (tuft/bunch at one end) -Atrichous(without any flagella)

Peptidoglycan

-a macromolecular network that a bacterial cell wall is composed of -combo of sugars and amino acids -NAM and NAG joined together(two amino sugars similar to glucose)

Biofilm

-a microbial community that usually forms as a slimy layer on a surface -Glycocalyx plays a big role in bacteria attaching to each other and working as a unit to form these -Examples would be plaque forming on teeth, or ones that form over burns, making it hard to treat burn victiims

Plasmid

-a small circular DNA molecule that replicates independently of the chromosome -extra pieces of DNA in prokaryotes that gives them advantages for survival but is not essential for living

Mycoplasma

-atypical cell wall -have no cell walls because they are so small (smallest known bacteria that can grow and reproduce outside living host cells) ---no peptidoglycan! but sterols in the cell membrane (how does it have structural integrity? It has sterols. So doesn't respond to the staining)

Pilus (pili=plural)

-gives ability to exchange genetic info (DNA transfer/conjugation); which is what can allow them to be different from one another even though they all divide from themselves and are all of the same population -also involved in motility(twitching or gliding)

What is important about Runs and Tumbles of bacteria?

-it is the taxis of bacterium -in response to stimuli, information is passed to the flagella. If the signal is positive (attractant), the bacteria move toward the stimulus with more runs(movement forward) than tumbles, but if the signal is negative (repellent) there are more tumbles as bacteria move away from the stimulus. --arrangement of flagella depend on runs and tumbles

Haploid

-meaning an organism with one of each type of chromosome -daughter cell is identical to original cell -1 splits into 1 -there is no sexual reproduction

Binary Fission

-prokaryotic cell dividing process where DNA is copied, and the cell splits into 2 daughter cells (involves fewer structures and processes than eukaryotic cell division)

Histones

-proteins in eukaryotic cells that package and order the DNA into structural units (NOT FOUND IN PROKARYOTES)

Spirillum

-rigid, not very flexible but still moves like cocscrew; common in tics and lime disease; with their motion propelle through body fluids; -used to say stomach ulcers were by stress and acids, but they have discovered lots of the population has certain bacteria in their stomach

Mycobacteria

-waxy outer lipid coat -has Mycolic acid lipid layer (could contain two collagens, of which one can cause terrible diseases such as leprosy) (acid-fast=similar to staining but you use acid as a way of destaining)

What are characteristics of a prokaryotic cell?

1) DNA not enclosed, single, circular, haploid, double stranded. 2) DNA not associated with histones 3) Lack of membrane enclosed organelles 4) Presence of peptidoglycan in their cell walls 5) No sexual reproduction, division by binary fission

What amount of microbes is actually harmful to human health?

15 % (most are actually pretty helpful)

Which statement best describes what happens when a gram-positive bacterium is placed in an aqueous solution of lysozyme and 10% sucrose? a) No change will result; the solution is isotonic b) Water will move into the cell c) Water will move out of the cell d) the cell will undergo osmotic lysis e) Sucrose will move into the cell from an area of higher concentration to one of lower concentration

A) No change will result; the solution is isotonic

You have isolated a motile, gram-positive cell with no visible nucleus. You can assume this cell has: a) ribosomes b) mitochondria c) an endoplasmic reticulum d) a Golgi complex e) all of the above

A) Ribosomes

What is another name for endoflagellum?

Axial filament

Which statement best describes what happens when a gram-negative bacterium is placed in distilled water and penicillin? a) No change will result; the solution is isotonic b) Water will move into the cell c) Water will move out of the cell d) the cell will undergo osmotic lysis e) Sucrose will move into the cell from an area of higher concentration to one of lower concentration

B) Water will move into the cell

The antibiotic amphothericin B disrupts plasma membranes by combining with sterols; it will affect all the following cells except: a) animal cells b) gram-negative bacterial cells c) fungal cells d) Mycoplasma cells e) plant cells

B) gram-negative bacterial cells

Which of the following pairs is mismatched? a) glycocalyx -- adherence b) pili -- reproduction c) cell wall -- toxin d) cell wall -- protection e) plasma membrane -- transport

B) pilli -- reproduction (wrong; pilli are involved in motility and DNA transfer)

What makes the cell membrane so important in prokaryotic cells?

Because these cells lack membrane enclosed organelles, the cell membrane ends up compensating for all the functions of these organelles it is lacking

Which of the following statements best describes what happens to a cell exposed to polymyxins that destroy phospholipids? a) in an isotonic solution, nothing will happen b) in a hypotonic solution, the cell will lyse c) water will move into the cell d) intracellular contents will leak from the cell e) any of the above might happen

D) Intracellular contents will leak from the cell

Which statement best describes what happens when a gram-positive bacterium is placed in distilled water and penicillin? a) No change will result; the solution is isotonic b) Water will move into the cell c) Water will move out of the cell d) the cell will undergo osmotic lysis e) Sucrose will move into the cell from an area of higher concentration to one of lower concentration

D) the cell will undergo osmotic lysis (meaning the cell will burst)

Which of the following pairs is mismatched? a) metachromatic granules -- stored phosphates b) polysaccharide granules -- stored starch c) lipid inclusions -- poly-β-hydroxybutyric acid d) sulfur granules -- energy reserve e) ribosomes -- protein storage

E) Ribosomes -- protein storage (ribosomes function as the sites of protein synthesis)

Which of the following is not a distinguishing characteristic of prokaryotic cells? a) they usually have a single, circular chromosome b) they lack membrane-enclosed organelles c) they have cell walls containing preptidoglycan d) their DNA is not associated with histones e) they lack a plasma membrane

E) they lack a plasma membrane (their plasma membrane is actually a very important part of their cell)

Which of the following is false about fimbriae? a) they are composed of protein b) they may be used for attachment c) they are found on gram-negative cells d) they are composed of pilin e) they may be used for motility

E) they may be used for motility (used more for attachment/adhering, especially in forming biofilms)

The human body always has microbes coexisting on/in us, including vaginal acidic microbes to keep the vaginal pH low. Related to this, why do we have to worry about being on antibiotics?

Having a low pH keeps the bad microbes and pathogenic bacteria out, but when on antibiotics the good and bad bacteria in the body get killed, allowing the pH to rise and yeast infections to occur

Staphylococci

MRSA is this; responsible in many infections; found in nasal cavity of 40% of population; important for medical practice; in puss sometimes; very resistant to treatments, antibiotics, antiseptics;

Inclusion

Material held inside a cell, often consisting of reserve deposits

L forms

Prokaryotic cells that lack a cell wall; can return to walled state (bacteria naturally with no cell wall, or something synthesis a cell wall, if no cell wall they are very fragile)

What shape of bacteria always have flagella?

Spirilla

Arrangements of prokaryotes

Streptococcus, Staphylococcus, Tetrads, Diplococcus, Sarcinae

Taxis

The movement of a bacterium toward or away from a particular stimulus (chemotaxis or phototaxis)

Flagella

Thin appendages from the surface of cells; used for cellular locomotion; composed of flagellin

Spheroplasts

a gram-negative bacterium treated to damage the cell wall, resulting in a spherical cell (gram - without peptidoglycan/cell wall)

Protoplasts

a gram-positive or plant cell treated to remove the cell wall (by lysozyme) (gram + where peptide-/cell wall is stripped off making them sensitive to pressure)

Shapes of prokaryotes

bacillus, coccus, coccobacillus, vibrio, spirillum, spirochaetes, prosthecate, pleomorphic

pleomorphic

bacteria that genetically can have many shapes, not just one

Monomorphic

bacteria that maintain a single shape (most bacteria)

Chemotaxis

movement of a bacterium toward or away from a particular stimulus of chemicals (such as oxygen, ribose, and galactose)

Phototaxis

movement of a bacterium toward or away from a particular stimulus of light

Spirochete

syphilis,, a lot more flexible than spirillum, can make it through body fluid very easily and fast so syphilis is common with this and easily passed

Conjugation

the passing of DNA (transfer) through cell to cell contact (through sex pili, latch on to adjacent bacterial cell, make a channel, and transfer DNA through the channel)

Slime layer

the version of glycocalyx if the cell secretes the substance and it is unorganized and only loosely attached to the cell wall