MICRO - LEC EXAM 1 - 8/30/18 lecture

Cellular respir (gylcolysis/cellular respirtion, Krebbs Cycle and Electron transport chain) EUKS vs. Proks

EUKS - glycolysis happens in cytosol (outside organelles - cytoplasm in Euks is inside organelles) krebs and electron transport chain happens in mitochondria, bec enzymes that catalyze the glycolytic pathway are in mitochondra. PROK - can do cellular respiration in cytoplams w/o organelles bec all enzymes are dissolved in cytoplasm.

how is genetic material held in Euk and Prok?

Euk - in nucleus Bacteria - usually single circular chromosome ssDNA

What is Endosymbiosis

Euks are thought to be made of primitive cells that came tog via Endosymbiosis - Prok cells that came together and formed a symbiotic relationship

PROKARYOTE STRUCTURE - Cell Wall

FUNCTION - to provide/define shape - protect from Osmotic lysis - impt as live in hypoosmotic envt; no cell wall = bacterial cells would expand and lyse - contains Peptidoglycan

what is the first descriptor of biological and organic molecules? and why is this crucial to understanding biological cell structure?

First descriptor of biol and org molecules is whether they are hydrophobic or hydrophilic. This is crucial to understanding biol cell structure bec cells don't get made, they FORM, they grow. They take on those forms and structures bec that's what the chem adn phys environment dictate. They FORM through Spontaneous Assembly of substructures in a cell.

G+ vs. G-

G+ - simple, THICK peptidoglycan G- - complex, thin peptidoglycan - cell wll much more complex structurally; consists of peptidoglycan in THIN layer, and add'l layer the "Outer Membrane" - the outer membrane of G- bacteria is actually a portion of the cell wall itself! Has lipid and other material in it that are similar to what we find in plasma and cell membrane.

How might you tell that you might have an inclusion in cell observed?

Gram stain of cytoplasm not stained 100% or not uniform. Patches of no stain can mean some storage structure or inclusion body.

in lab, how might you be able to tell with naked eye if microbe has a capsule?

If you lift up the loop and it's gummy. That gummyness is from the thick layer of polysaccharide outside the cell wall.

what can affect ability to make or not make an endospore?

a simple mutation

what is a virulence factor?

a substance produces by pathogen that promotes the establishment and maintenance of the disease. Or a cell part that helps them to invade other organisms better.

why is knowing the fx of a cell impt?

important in identification of bacteria

where does all chemistry of Proks happen?

in aq soln, because everything is dissolved in water.

what is virulence vs. pathogenicity

A bacterial pathogen is usually defined as any bacterium that has the capacity to cause disease. Its ability to cause disease is called pathogenicity. Virulence provides a quantitative measure of the pathogenicity or the likelihood of causing disease. Pathogenicity vs Virulence. Pathogenicity refers to the ability of an organism to cause disease (ie, harm the host). ... Virulence, a term often used interchangeably with pathogenicity, refers to the degree of pathology caused by the organism.

Prokaryotes - Endospores

- Formed under adverse conditions: resting survival structures formed inside cell under adverse conditions such as extreme heat, dehydration, toxic chemicals, radiation - it's a form of CELL DIFFERENTIATION - Can SURVIVE 100's of years: generates a copy of genome of the original organism and is incredibly resistant with many layers of material; allowing it to survive 100's of years (existing spores found in tombs regenerated with nutrient broth, germinate and give rise to vegetative cells immediately!) - NOT reproductive; encapsulation of organisms genetic structure., - ability of bacteria to make an endospore is considered to be a genetically stable characteristic as an endospore can survive conditions not favorable for growth.

proof of Endosymbiosis

- mitoch and chloroplasts of plant cells both contain 70s ribosomes (which are found in bacteria alone). We believe mitoch and chloroplasts were once free living bacteria that developed a symbiotic relationsihop with another cell and gave rise to mitochondria in 1 case adn chloroplasts in the the other.

Eukaryotes - morphology, multi-cellular life, organelles

- much more complex morphologically than euks - development of one single cell Euk organism to multicellular life - organelles - "little organs" because they are compartments in cell with certain jobs that in a prok must occur in cytoplasm.

characteristics of FW microbes?

- no morphological complexity - simple, no nucleus, tiny - looking at them and studying them is very diff than Euk cells

Euk cells in class

- not going over structure of Euk cells - don't encounter specifics of those structures often except in broader circumastances. - in light microsc. work we looked at Euk organisms in hay infusion (protazoa).

what can limit what a cell can produce?

- perhaps genetic composition, because certain things can only be made if it has a GENE to make it!

How does mutation affect Prok vs. Euk?

- prokaryotes/Bacteria have only 1 copy of genes; only 1 chromosome. If mutated, gene may not be able to make a protein. And as only 1 chromosome a mutated gene is ALWAYS expressed. - Euks have 2 copies of every gene, therefore we have a backup for each gene if mutation occurs.

formation of an endospore is seen to be...

- simple cell differentiation

How do cell fatty acids allow individual cells to regulate some characteristics of their membrane?

- the degree of FA's affects the FLUIDITY of the membrane (why things like fish don't freeze in cold weather). - Sat fat - solid at room temp - Unsat fat - liquid at room temp

what happens when a cell is infected with a virus

- virus gets in cell - cell taken over; molecular components of virus override normal host cell activity and cell starts making virus parts. - when those genomes (DNA, RNA, protein) are present in right amt, in the right env't, virus particles SPONTANEOUSLY ASSEMBLE.

PROKARYOTE STRUCTURE - Cytoplasm

- Cytoplasm is the aq soln inside prokaryotes, and inside membranous organelles in euks (cytosol in Euks is what organelles sit in) - 70-90% water - site of metabolism (cellular respiration: glycolysis, krebb's, e- tport chain) - nucleoid - where DNA is found in single circular ssDNA - same fx in Prok and Euk - Aq soln containing functionally dissolved proteins and enzymes that catalyze the rx's of prok cells (to make enzymes, they must have a gene to make the particular enzyme!)

best way to kill something?

- Dehydrate: bec life consists of activities that happen in an aq. soln., quickest way to kill something is to dehydrate it (if a cell or organism)

More info on Prok and Euk

- Difference: ability to interact w/ other cells to form multicellular organisms

Prokaryote Cell Structure

- Appendages on outside - Capsule and Envelope > outer membrane (some) > periplasmic space > cell wall (most) > cytoplasmic membrane - Cytoplasm > nucleoid > ribosomes > storage granules composite cells - model shows all potentially in a cell but not all nec in a cell - cell wall outside the plasma membrane which responsible for differential stainging in Gram Staining procedure. - maintains cell shape and prevents lysis in hypotonic solns - electron microsc shows their structure - phospholipid bilayer w/ membrane proteins - selective membrane (bact membranes work like Euk's membranes) - most bacteria have Peptidoglycan (Euks don't)

Info on Stains

- INCREASES CONTRAST: makes things more easily visible under micros. - SAMPLES MUST BE FIXED - most tissues are fixed; fixed before staining; insures sample will stick to slide; chemical (usually alcohol) or heat fixation. heat fixing - dehydrating of org and coagulates proteins so they stick to slide and only stain will wash away; can't heat fix Euks as would destroy structures, so usually fixed to preserve and then sliced to observe in preserved state. - TYPES OF DYES: acidic and basic - SIMPLE STAINS: make cells visible with one dye, easy, quick - DIFFERENTIAL STAINS: enables you to distinguish b/w types of microbes. Best Ex: Gram Stain - G+ or G-; fundamentally impt technique; bacteria so small you cacn't see internal structure and range in shapes is also limiting, so Gram stain split all bacteria into 2 groups according to difference in cell wall structure ** Living, unst material is challenging to view as low contrast, due to org being largely water in an aque cytoplasmic soln; most stains kill living orgs so use "vital stains" -

PROKARYOTE STRUCTURE - Ribosomes Prokaryotes have little particulate matter - does have Ribosomes like Euks - info on Prok ribosomes...

- NOT membrane bound organelle - complex non-membranous macromolecule made up of protein and rRNA (1/2 is rRNA involved in transcription of DNA) - visible by EM - must have these to synthesize proteins! - in Bact - 70s, in Euk - 80s - size difference matters for things like Antibiotic mechanisms of action (the work better on 70s ribosomes than 80s), which explains how we can take drugs that kill cells and not harm ourselves. - ribosomes are made of 2 subunits. Catalyzes and synthesizes proteins; at intiation of translation they are separate subunits; mRNA combines with the small subunit, then whole thing comes together; 2 unit structure + mRNA then carries out protein synthesis.

PROKARYOTE STRUCTURE - APPENDAGES on Outside - Appendages on outside - Capsule and Envelope > outer membrane (some) > periplasmic space > cell wall (most) > cytoplasmic membrane - Cytoplasm > nucleoid > ribosomes > storage granules

- Pili or Fimbriae - Flagella

How do pili transfer genetic material to another cell?

- The pili are small projections of the cell membrane that can form physical channels with the pili of adjacent cells. - In addition to a single large piece of chromosomal DNA, many prokaryotic cells also contain small pieces of DNA called plasmids. - The transfer of plasmids between one cell and another is often referred to as "bacterial sex." Sounds dirty. - The genes for antibiotic resistance, or the gradual ineffectiveness of antibiotics in populations, are often carried on plasmids. If these plasmids get transferred from resistant cells to nonresistant cells, bacterial infection in populations can become much harder to control. For example, it was recently learned that the superbug MRSA, or multidrug-resistant Staphylococcus aureus, received some of its drug-resistance genes on plasmids4.

Sporulation - aka Endospore Formation

- Vegetative cell that is actively growing/metabolizing, dividing - Once it starts to form and Endospore it's no longer called a vegetative cell. It's called and Endospore - Under good conditions, it will germinate (reactivate the genome, then endospore layers are modified, and cell grows again and is called a Vegetative cell)

what is peptidoglycan?

- a fundamental component of primarily bacterial cell wells (prokaryotes, but NOT in archaea)

what are genetically stable characteristics for bacteria?

- ability of bacteria to make an endospore is considered to be a genetically stable characteristic as an endospore can survive conditions not favorable for growth.

what is cell theory?

- all life is made of cells, and cells come from other cells - Impt dvlpmt of Golden Age of Micro (1850-1920) - we were then able to look at the stability and variability in cell structure in understanding their fx and fundamental differences

What are thebacterial virulence factors? things that help the bacteria invade the host, cause disease, evade host defenses...

- attachment via adhesins - pili (fimbriae) - inhibition of phagocytosis by having a capsule - invasive enzymes - invasion of host cells - via tissue damage by enzymes produced by bacteria cell wall - Toxins

PROKARYOTE STRUCTURE - Storage Granule (storage inclusions)

- big red dots (the smaller specs are Ribosomes) - bacteria's way of storing certain material in cytoplasm that bacteria need (visible storage centers in cell) - can have structure w/in cytoplasm - usually unstained and look like dots/bubbles when rest of cell is stained - NOT an organelle - Do NOT have a typical lipid bilayer, but has a lipid - gas vacuoles - uncommon

Prok and Euk - similarities

- chromosomes - DNA as genetic material - that are organized in genes expressed through transcription and translation - ribosomes - cytoplasm - cell membrane - vacuoles - have same metabolic fxs, with Prok actually having more diversity.

PROKARYOTE STRUCTURE - Cytoplasmic (cell plasma) Membrane aka Plasma Membrane - the Sangor or Fluid Mosaic model

- contains the cytoplasm - EVERY cell, Prok and Euk, has a plasma membrane - regulates passage in/out of cell - components are: Phospholipid bilayer and proteins (transmembrane, cytoplasmic, peripheral) - "fluid mosaic" - membrane is fluid and proteins move about. - NOTE: if cell can make a protein, then it must have a GENE to make that protein!

what are Archaea?

- free living organisms not associated with disease or infection - prokaryotic cell structure - includes extremophiles

how does renal physiology relate to cells and water permeability?

- hormones can modify H2O permeability of kidney tubules; no cell walls known yet, so how does that happen? AQUAPORINS. If the cell limits the number of proteins that allow the passage of water, you can limit permeability of cell membrane to water. - so water not sneaking through the PL bilayer, it is going through Aquaporins!

proteins in plasma membrane

- in Euks and Proks - if a cell can make a protein, it has a GENE to make that protein - before looking at DNA for a cell, we look at protein compositions in different bacteria, as that look at gene expression. Looking at the occurrence of proteins helps assess genetic capability of the organism. - cells are able to regulate some characteristic of their membrane through the type and composition of proteins they make

LIST OF THINGS TO BE INCLUDED!

- know which organisms have the capability of making endospores as that is a stable genetic trait to be noted! - Ex: G+ endospore forming rod or cocci"

what is peptidoglycan composed of?

1) short, peptide chains - Petido (AA compound) 2) N-containing sugars (NAM and NAG) - glycan (sugars)

what is a free living organism?

An organism that is not directly dependent on another organism for survival. Bacteria: Single-celled microorganisms that can exist either as independent (free-living) organisms or as parasites (dependent on another organism for life).

bacteria vs. virus

Bacteria are living things. They can reproduce all by themselves and do not need a host to survive. They are single-celled and reproduce by duplicating themselves. ... A virus cannot multiply outside a living host cell.

PROKARYOTE STRUCTURE - Capsule - Appendages on outside - Capsule and Envelope > outer membrane (some) > periplasmic space > cell wall (most) > cytoplasmic membrane - Cytoplasm > nucleoid > ribosomes > storage granules

CAPSULE - slime layer - slimy, mostly polysaccharides (muco); a genetic trait; need a gene to have this. Usually a thick layer of mucopolysaccharide FUNCTION... 1) Protects cell .....A) from phagocytosis by WBC .....B) protects from drying out. helps Hydrate cells. Polysachs (sugars) are hydrophilic so soluble in aq. solnl. and able to interact wtih water molecules easily...therefore CAPSULES HAVE HIGH water content. 2) Adhere to surface 3) Pathogenesis - Capsule is a virulence factor for some bacteria if the bacteria has NO capsule! if no capsule it can be phagocytized. Virulence factors are involved with how easily they can infect and cause disease.

How are Prokaryotes diverse compared to Euks?

Diversity is largely seen in metabolic capability. They carrou out every kind of energy metabolism ever discovered. Many that are NOT found in any euk organism. What Proks lack in morphological diversity they more than make up in chemical diversity.

How do antibiotics work?

Osmotic lysis used to destroy some bacterial cells with defective cell walls, made defective by antibiotics! Ex: Penicilin - incorporated into newly synthesized bacterial cell walls and as soon as exposed to hypotonic soln they swell, rupture and effectively die.

Prok vs. Euk - cell basic structure?

PROKARYOTES - smaller than Euk - simple, but not primitive in their ability to metabolize. They can carrout out metabolic processes that no euk can carry out. - plasma membrane - cell wall that contains peptidoglycan - outer plasma membrane - lacks membrane bound organelles - no nucleus, nucleoid - single circular DNA/chromosome - ssDNA in cytoplasm, containing most of the genes needed for cell growth, survival, and reproduction - binary fission for reproduction - anaerobic and aerobic - 70s ribosomes EUKARYOTES - bigger - complex cell structures - no cell wall (but if plant there is cell wall) - plant cells walls made of Cellulose, fungi cell walls are Chitin - ** NO peptidoglycan in euk cells walls - animal cells - NO cell wall - plasma membrane - nucleus with complex dsDNA - paired chromosomes - membr bound organelles - mitosis (involves nuclear division, not cellullar division - cell div is part of cell cyle not mitosis) and meiosis for reproduction - complex - 80s ribosomes

What do both G- and G+ have in cell wall?

Petidoglycan

PROKARYOTE STRUCTURE - Nucleoid

Prok - mass at center of cell called nucleoid. Ex: E. coli - chromosome highly compacted and wound inside; only visible with EM

what are the 2 types of cell structures?

Prok and Euk - they have different cell structures

prokaryotic plasma membrane

Prokaryotic Plasma Membrane Prokaryotic cells can have multiple plasma membranes. Prokaryotes known as "gram-negative bacteria," for example, often have two plasma membranes with a space between them known as the periplasm. As in all cells, the plasma membrane in prokaryotic cells is responsible for controlling what gets into and out of the cell. A series of proteins stuck in the membrane (poor fellas) also aids prokaryotic cells in communicating with the surrounding environment. Among other things, this communication can include sending and receiving chemical signals from other bacteria and interacting with the cells of eukaryotic organisms during the process of infection. Infection, by the way, is the kind of thing that you don't want prokaryotes doing to you. Keep in mind that the plasma membrane is universal to all cells, prokaryotic and eukaryotic. Because this cellular component is so important and so common, it is addressed in great detail in its own In Depth subsection.

PROKARYOTE STRUCTURE -Envelope

The envelope is the structure that surrounds the cytoplasm of the organism which includes: - cell membrane - cell wall (peptidoglycan) - outer cell membrane (if present)

Bacteria and movement

While bacteria are simple, theydisply directional movement and responsive movement.

why is the relationship b/w prok and euk impt in micro?

bec we are going to look at host organisms that are euk and infectious agents, or parasites that are prokaryotic. Therefore minor differences do have significance. But functionally Bacteria has NO problem carrying out all the same activities of Euk cells that are much larger and structurally complex.

how do virulence factors help bacteria?

helps - invade the host - cause disease - evade hosts defenses

bacteria and archaea differ only at

molecular level, otherwise both have prokaryotic structure

The vast majority of cells on earth are

prokaryotic; humans carry about 20 times more bacterial cells than euks.And 20 times more proks than euks on earth

gram stain slide outcomes

purple = G+ pink = G-

what is a simple stain?

single dye; all stained one color; easy and quick

PROKARYOTE STRUCTURE - Periplasmic Space

space b/w cell membrane and cell wall

What are pili or fimbriae?

structures/attachments of prokaryotes - Pili - involved in genetic transfer between bacterial cells by direct cell-to-cell contact; small projections of the cell membrane that can form physical channels with the pili of adjacent cells. - Fimbriae (attachment pili) - thinner and shorter than flagellae, assoc with ability to attach to surfaces. Fimbriae are used by bacteria to adhere to one another and to adhere to animal cells and some inanimate objects. A bacterium can have as many as 1,000 fimbriae. Fimbriae are only visible with the use of an electron microscope. They may be straight or flexible.

flagella in bacteria -

they are a locomotion structure in most motile bacteria - for Locomotion - propeller like motion; if bacteria are motile they have one or more flagella. - Structure: helical shaped filament

what are we doing with a cell once found?

we look at stability and variability of structure to understand fx and fundamental differences

Bacteria vs. Euk cells - can bacteria carry out life processes?

yes, even w/o complex cell structure that Euks have