Exam 1 Flashcards
Microbiology
The study of small microscopic organisms.
What does Microbiology include?
Eukaryotes, Viruses, Bacteria, Algae, Protists
How many categories in the tree of life?
3
What are the categories of the tree of life?
Bacteria, Archaea, Eucarya
What is the Tree of Life?
The evolutionary relatedness of organisms.
Almost all biology is “Microbiology”. What are the ones inside the circle called?
Microbial
What are the ones that are rarely visible?
Animals, Fungi, and Plants
What are bacteria?
Evolutionarily separate form of life.
How small are bacteria?
Eukaryotes are 100x bigger. 1 um long. (1/1000 of a millimeter)
Bacteria lack…
Organelles.
What are organelles?
Membrane-enclosed subcompartment
Bacteria have…
Nucleoids.
What is a nuceloid?
There is no membrane. A nucelus is something that is membrane-enclosed.
Bacteria and Archaea are …
Prokaryotes (Have Nucleiod)
Eukarya are …
Eukaryotes (Have Nucleus)
Chromosomes in Bacteria vs Eukaryotes
Eukaryotes have multiple, linear chromosomes. Bacteria have single, circular chromosome.
What bacterial ribosomes are in Eukaryotes and Bactera?
Eukaryotes are 80S (60S+40S) Ribosomes. Bacteria have 70S (50S+30S) Ribosomes
How do drugs work?
We can have drugs target certain cells by focusing on the chromosomes.
Bacteria have a unique..
Cell Wall
Cell wall for Animals?
None
Cell Wall for Plants?
Cellulose
Cell wall for Fungi?
Chitin
Cell wall for Bacteria?
Peptidoglycan
What do bacteria do?
They consume, and they grow
What do some bacteria consume?
Sugars, Lights, Toxins, some make alcohol, and some breathe uranium
Many bacteria grow in conditions we would consider…
extreme. This includes hot springs, arctic ocean, strong acid, and deep in earth.
What do bacteria do?
Cycle most carbon, make most oxygen. Some make us sick, and they build communities.
Structural of Eukaryotes
Large Membrane-Bound Nucleus Membrane-bought organelles No wall or Cellulose Wall 80S Ribosomes
Bacteria Structural
Small Nucleoid No Organelles Peptidoglycan 70S Ribosomes
Metabolic of Eukaryotes
Fairly limited metabolism Fairly limited tolerance
Metabolic of Bacteria
Diverse Metabolism Extremophiles
Genetic of Eukaryotes
Linear Chromosomes Single Genes So Sigma Factors
Genetic of Bacteria
Circular Chromosomes Operons of Genes Sigma Factors
How much bacteria are there?
5 x 10^30 bacteria
Bacterial Colonies can be large, in class example?
“Milky Seas”
What is the Vibrio Fischeri
Marine Bacterium with squid symbiont.
What enzyme does the Vibrio Fischeri use?
Luciferase
What does the Vibrio Fischeri do?
Produces light only at high cell density using quorum sensing
How does the Squid/Vibrio relationship work?
Chemical recognition between squid and bacteria. Squid feeds the bacteria and bacteria give off light
What is the term used for when bacteria emits light?
Counter-Illumination.
Bacteria + Animal
Symbiosis (Tube Worms)
Bacteria + Plant
Symbiosis (Root Nodules)
Bacteria + Fungi
Symbiosis (Lichens)
Bacteria + Bacteria
Symbiosis (BIofilms)
What year and Who was credited with discovering microorganisms
1676, Antony Van Leeuwenhoeks
What did Antony van Leeuwenhoek discover?
Discovered microorganisms.
What did Robert Hookie do?
Studied TB using his own microscopes in 1670
What was the Voynich Manuscript?
Was possibly the first biology textbook. The drawings on them resemble telescopes from the time.
Who was the creator of the early microscope?
Cornelius Drebbel (1572-1633)
How many requirements for Microscopy?
Four
What are the four requirements for Microscopy?
Magnification Resolution Light Quality Contrast
Magnification (Microscopy)
Relative increase in image size
Resolution (Microscopy)
The ability to distinguish two points that are close together
Light Quality (Microscopy)
Sets limit of resolution
Contrast (Microscopy)
The ability of detect objects against a background
Most common type of microscope?
Bright Field Microscopes
Refraction definition
Light bends when it passes from one medium to another
Why does bending occur?
Because light travels more slowly in a denser medium
What do Lenses do?
Refract light to focus light onto a single point
What is the Refractive Index?
A measurement of how much lens will bend light
How do you get an increase in apparent image size?
Decreased focal length and increased magnification
What does a decreased focal length and increased magnification cause?
Increase in apparent size of image
What is empty magnification?
When you zoom in on a product and it is blurry.
How do you get the ability to distinguish two adjacent points?
Increase in numerical aperture and increase in resolution
What does an increase in numerical aperture and resolution do?
Increases ability to distinguish two adjacent points
What do stains do in terms of Contrast?
Enhance Contrast Fixes (Kills) Cells Specialized/Diagnostic Stains
Gram Stain in terms of Contrast?
Detects kind of cell envelope
What does flagellar stain do in terms of Contrast?
Detects Flagella
What is Phase Contrast Microscopy?
Uses diffraction and interference to generate contrast. No staining necessary Gives off a bright halo vs a black background
What is Light Microscopy?
Light passes through the specimen.
Florescence Microscopy?
Light does not pass through specimen Light excites fluorescent molecules which emit light themselves
Gene Fusion to GFP?
Fuse two gene sequences to make a hybrid protein. Combines minJ and GFP so that it’s always dragged along
Flourescence
Emits light after photoexcitation
Example of Fluorescence
GFP
Luminescence
Produces light by chemical reaction
Example of Luminescence?
Luciferase
Resolution is ultimately limited by light quality by having
decreased wavelength and increased resolution
What is Electron Microscopy?
Uses a beam of electrons with a very short wavelength. Allows very high resolution
What are the two types of Electron Microscopy?
Transmission and Scanning
Scanning Electron Microscopy
Uses electrons to scan specimen. Cells are strained and dead
Transmission Electron Microscopy
Allows for very detailed inside looks. Cells stained and kills
Electron Cryotomography (Transmission EM)
Freeze sample in ice. Take pictures as you tilt the stage. Cells are still alive
Light Microscopy
Fluorescence Microscopy
Transmission Electron Microscopy
Scanning Electron Microscopy
Atomic Force Microscopy (AFM)
A type of microscopy that does not use light! (kinda) An ultra-fine probe taps over objects.
Name of microscopy that probe taps over objects?
Atomic Force Microscopy
More facts about AFM
Emitter light bounces into detector.
Cells are still alive.
Probe can damage soft objects
Limit of Light Microscopy?
1000x
Limit of Electron Microscope?
1,000,000x
Microscopy must colve
Magnification
Resolution
Light Quality
Contrast
How long have bacteria been here for?
3.5 billion years ago
What are stromatolites?
Ancient, Fossilized Microbial Mats. Look like modern day Cyanobacteria.
Taxonomy
Placing organisms in groups
What is Nomenclature?
A system of naming
What did Carolus Linnaeus declare?
That Biological Nomenclature must be consistent and meaningful.
Abbrevation for Biological Nomenclature
Kingdom Phylum Class Order Family Genus Species
Definition of Species
An interbreeding population that is reproductively isolated
Biological Nomenclature is organized from..
bottom to top
Classification strategies for bacteria?
- Numberical Taxonomy (traits)
- DNA-DNA Hybridization (Genome Comparison)
- Phylogenetics (Molecular Chronometer)
- Polyphasic Approaches (Combination)
- Naming by disease
Numerical Taxonomy
Name bacteria based on trait similarity. Traits are assigned yes/no to each one. Need 100 traits.
Problems with numerical taxonomy?
If two strains share enough “important” traits then they are the same species
Advantages of Numerical Taxonomy
Trait information is very useful and meaningful
Disadvantages of Numerical Taxonomy
Traits are arbitrary
All weighted equally
Some simple, some complex
Traits are necessarily related to one another
Same trait may rise through different mechanisms
DNA-DNA Hybridization
Compares entire genome. DNA is heated and untwisted. They’re then cooled and retwist with one another.
What percentage of DNA-DNA Hybridization needed to be same species?
>70% DNA/DNA Hybridization
Advantages of DNA-DNA Hybridization?
Extremely accurate and relevant Only formal definition of bacterial species today is >70% DNA-DNA Hybridization
Disadvantages of DNA-DNA Hybridization?
Two organisms being compared must be genetically similar for this to work. Impractical and only close comparsions work.
What are Phylogenetics?
Comparing sequences of a chosen macromolecule.
What is a chosen molecule in Phylogenetics called?
Molecular Chronometer
Phylogenetics is
classification based on evolutionary relatedness by sequence similarity
Phylogenetics explained
You choose sequence of protein or gene and the organisms with fewer changes in sequence more closely related.
Molecular chronometers must meet how many criteria?
Four
Molecular Chronometers must meet the following criteria:
Found in all represesntatives of the groups studied
Function must be the same in all representatives
Sufficient Similarity between molecules so that the sequences can be aligned
Sufficent differences such that each sequence has its own signature
Molecular Chronometers in Animals?
Hemoglobin; O2 Carrier
Molecular Chronometers in Aerobes
Cytochrome C (Protein); Respiration
Molecular Chronometers in Animals/Plants/Microbes?
ATPase (Protein) ; ATP Synthesis
Molecular Chronometers in Almost All Organisms?
RecA; Homologous Recombination
Molecular Chronometers in All Cellular Life?
16S rRNA; Ribosome Structure
16S rRNA
Nucleic Acid Sequence
Found in all living things
Part of Ribosomes
Relative Constant Regions
Highly variable regions
Consequences of 16S rRNA Phylogeny
The old tree with five kingdoms got replaced with new tree of three kingdoms. Bacteria were now parallel and equal to Eukaryotes
Old thoughts about Photosynthesis?
Photosynthesis was thought to be narrowly distributed
After thoughts of Photosynthesis
Photosynthesis is widely distributed
Old thoughts about bacteria?
There was some unusual bacteria present in the body
After thoughts about bacteria?
Some unusual bacteria wasn’t bacteria at all., it was Archaea instead
How was Microbial Ecology REvolutionized?
Harvest and sequence an environmental mixture of 16s rRNA
Steps behind Microbial Ecology
- Quickly assess microbial members of an environment
- Deduce properties of environmental by bacteria groups
Microbiome
Determining all the organisms in a particular region of body. Bacteria population associated with health and disease
Problem with Endosymbiotic Theory?
Mitochondria and Chloroplasts have 16S rRNA. These organelles were once bacteria.
16S rRNA Sequence Advantages
Eay in the “sequencing age”. Massive data sets accumulating and great for higher order comparisons.
16s rRNA Sequences Disadvantages
Poor at species designation with no direct trait information
Bacteria cannot be organized by
the traditional species concept
Recap of Numerical Taxonomy
Compare organisms based on similar traits (informative but too artbitrary)
Recap of DNA/DNA Hybridization
Compare organisms based on total geneome similarity (precise but too specific)
Recap of 16S rRNA Sequencing
Compare organisms based on evolutionary relatedness (Universwal but doesn’t tell you about the properties of the organism)
Polyphasic Approach
Naming by a combination of approaches. Isolate and grow new bacterium.
First Step of Polyphasic Approach
Sequence 16s rRNA and compare to database to find closest relative (Molecular Chronometer)
Second step of Polyphasic Approach
Then compare physiological traits to closest “type strain” (Numerical TAxonomy)
Third Step in Polyphasic Approach
Compare genome to the type of strain to determine same of diferent species (DNA-DNA Hybridization)
What is a bacterial species?
A collection of strains that share important traits and 70% DNA/DNA genome hybridization with a type strain
What is a type strain?
An arbitrarily selected bacterial stran that has all of the hallmark traits of the species to which it belongs
Comparing to Type Strains
Compare traits of new isolate to type of strain. You then confirm species with DNA-DNA Hybridization >70%.
Organism of Week - Epulopiscium Fishelsoni
Enormous bacteria, can be seen by the human eye. Found in gut of surgeon fish.
Cell Division in Epuloiscium Fishelsoni?
New daughter cells grows inside mother cell. Mother cell killed when daughters released
Naming by Disease
Pathogen species are named based on the disease they cause
Complications of Naming Bacteria?
Characterization long and difficult
Traits can be hard to observe
Some cant be grown in lab
What are Phages
Phage are viruses that infect bacteria. Viruses are just proteins and nucleic acids.
Phage Strategy: Lysogeny
Phage inserts genome into genome of E Coli
E Coli repliacates phage gene like its own
Now expresses phage gene as its own
E Coli now secretes Shiga Toxin that damages human cells
Serotyping
Naming pathogens based on antigen variation. Antibodies bind to target anitgens.
What is the O-Antigen?
Unique sugar pattern on LPS of each Gram Neg.
What is the H-Antigen
Flagellin
What is the K-Antigen?
Capsule
What is the subunit of Polysaccharides?
Carbohydrates
What is the subunit of Nucleic Acids
Nucleotides
What is the subunit of Proteins?
Amino Acids
What is the subunit of Lipids?
Fatty Acids
What is the Macromolecule Polymer of Carbohydrates?
Polysaccharides
What is the Macromolecule Polymer of Nucleic Acids
Nucleotides
What is the Macromolecule Polymer of Amino Acids
Proteins
What is the Macromolecule Polymer of Fatty Acids
Lipids
What are Polysaccharides?
Polysaccharides are polymers of carbohydrates.
AKA “Sugars”
What are carbohydrates?
They are hydrated Carbons. For every C, there is H2O
What are sugar names determined by?
Number of Carbons
Orientation of Hydroxyl Groups
Glucose; Know that this is a Sugar
Allose
Glucose - Six Carbon Sugar
Know that this is a Sugar!
How do you connect two molecules?
You remove a molecule and link relative to one another. (Dehydration)
What are polysacchardies in terms of polymers?
They are large polymers with many monosaccharides
Polysacchardies contain information in
Type of Sugars
Linking between sugars (Alpha or Beta)
Branches
Which linkage is easier to break?
Alpha linkages are easiter to break than Beta
What are A linked Polysaccharides?
Starch and Glycogen, common energy storage molecules
What are B linked Polysaccharides?
Lactose (Lactose Intolerance) and Cellulose (PLant Cell Walls) difficult to digest
Beta Linked Polysaccharides
Beta Linked Polysaccharides
Alpha Linked Polysaccharides
Alpha Linked Polysaccharides
How many carbohydrate functions are there?
Three
What are the carbohydrate functions
Structural Component
Energy Source
Information
Carbohydrate Function - Structural Component
Cell Wall Material
“Capsule”
Carbohydrate Function - Energy Source
Found in the environment and intracellular storage molecules
Carbohydrate Function - Information
Sugar pattern on cell surface can identify bacteria
Intracuellular trafficking and recognition in eukaryotes
Where are polysaccharides found?
In the capsule beyond the boundry of the cell wall
Pentose
Pentose
Deoxyribose
Deoxyribose
What is the Sugar-Phosphate backbone of DNA?
Deoxyribose
What is the Sugar-Phosphate backbone of RNA?
Ribose
How did Nucleic Acids get its name?
Because they were isolated from the nucleus of eukaryotic cells
What are Nucleic Acids?
Carry genetic information and are polymers of nucleotides
Do bacteria have nucleic acids?
Yes
DNA and RNA are
Polymers of nucleotides
RNA are for
short term information storage
DNA are for
long term information storage
RNA
DNA
Polymerization
The mechanism of chain growth
How is Polymerization activated?
Nucleotides are activated with tri-phosphate
What end of a chain is added in Polymerization?
3’ End
Chains Polymerized in a
5’ to 3’ direction
What are the two Purines?
Adenine and Guanine
What are the two Pyrimidines?
Thymine and Cytosine
Adenine
Guanine
Thymine
Cytosine
Which base pair features two hydrogen bonds?
Adenine -Thymine (Slightly Weaker)
Which base pair features three hydrogen bonds?
Guanine-Cytosine (Slightly StrongeR)
Base pairing aligns two strands of DNA that are
Antiparallel strands
“Sides” of DNA bases carry
Information
More information is found in
major groove
Less information found in
minor groove
What does Hydrogen Bonding of bases do in DNA Structure?
Sets alignment of double strand
What does the Hydrophobic Base do in DNA?
Stacking stabilizes the macrostructure
What does Electron Repulsion do in DNA Structure?
Electrial Repulsion of Phosphates destabilizes structure
What do Divalent Metals do in DNA Structure?
Neutralize charge and repulsion to stabilize
What makes RNA more unstable?
It has an -OH (Hydroxyl) Group in 2’
What base does RNA have instead of DNA?
It has Uracil instead of Thymine
How many strands does RNA have?
One
Exception of single strand of RNA?
tRNA and rRNA
How many functions does Nucleic Acid have?
Three
What are the functions of Nucleic Acid?
Information Storage
Structure
Energy Intermediate
Nucleic Acid Function - Information Storage
Genetic Material, Dna Chromosome
Information Conversion
Signaling
What does mRNA do?
Transcription
What does tRNA do?
Translation
What does signaling contain?
cAMP, ppGpp, c-di-GMP
Nucleic Acid Function - Structure
Ribosomal rRNA
Nucleic Acid Function - Energy Intermediate
Energy “Currency” (ATP/NADH)
Shape of a protein determines..
what function it has
Proteins are made of
amino acids
All information for protein folding is
contained in the specific order of amino acids
Proteins are polymers of
amino acids
Amino Acid
Amino Acids differ based on
R Groups
What is Hydrophobic?
They avoid water
How can amino acids be linked together
They can be linked together via peptide bonds to make polypeptides
Peptide bonds are very
strong
Polypeptides have an
orientation
Primary Structure (1 Degree)
A linear series of amino acids that forms a protein expressed N to C terminus.
What does a Primary Structure contain?
Contains all the information for protein folding and function
What does Secondary Structure (2 Degree) do?
The primary sequence instructs folding of two basic motifs. Stabilized by Hydrogen.
Alpha Helix role in Secondary Structure?
Backbone of hydrogen bonding between adjacent amino acids
Beta Sheet in Secondary Structure
Backbone hydrogen bonding between non-adjacent amino acids
Tertiary Structure (3 Degrees)
3D folding of a 2D structure
Tertiary Structure folding is
driven and stabilized by hydropobic interactions of amino acid R-GRoups
Quaternery Structure (4 Degrees)
Multiple proteins assemble to form super structure. Multiple proteins must cooperate in a complex.
What is the Goal of Structures?
To take the 1 degree and predict everything about it
Protein Naming
Bacteriology uses common system. Three letter prefix, one letter sufix.
How many protein functions are there?
Two
What are the protein functions?
Enzymes
Structural
Protein Functions - Enzymes
Proteins do almost all work in cell
Diversity of structure/function
Catalyze reactions
Synthesize cell parts
Protein Functions - Structural
Internal and External Structure
Cytoskeleton in Eukaryotes
Lipids are hte primary component of
Cell Membranes
Represents membrane bi-layer
What are lipids made of?
One glycerol (head group) and up to three fatty acids attach to Hydroxyl with R hanging off end
Fatty Acids can vary by
Carbon Chain Length
Number of double bonds
Position of Double Bonds
What do X and Y represent in CX:Y
X = Number of Carbons
Y = Number of Double Bonds
Saturated means
No Double Bonds
Unsaturated means
One or more double bonds
Fatty Acids are Amphipathic
Both Hydrophillic (Associates with water) and Hydrophobic (Avoids Water)
Fatty acids can also form
Miceles
What are miceles?
Fatty acids that arrange themselves in a spherical form.
What is on the outside and inside in a micele?
Hydrophillc on the outside, hydrophobic on the inside.
What happens as more fatty acids are added to a micele?
It starts to destabilize into smaller miceles.
Phosopholipids carry multiple …
fatty acid chains linked together by glycerol, phosphate, plus head group
Phospholipids can form
bilayers
Fatty acids occupies a
conic space
Phospholipids occupies a
cylindrical space
Many phospholipids make a
vesicle
Lateral Diffusion
Transverse Diffusion
What does Fluid in Fluid Mosiac Model of Biological Membranes mean?
“Fluid” because lateral diffusion is rapid
What does Mosaic in Fluid Mosiac Model of Biological Membranes mean?
Mosaic of proteins embedded throughout the membrane. Integral and peripheral. Transport, sensory systems, energetics
Membrane Proteins - Integral
Passes through the membrane
Membrane Proteins - Peripheral
Associated with surface of membrane
What percentage is water is a bacteria cell?
70%
Proteins contribute the ___ ____ and are the ___ ____ macromolecule
most mass
most diverse
What is the largest macromolecule in the cell?
DNA
Does DNA or RNA have more weight?
RNA
What is the most numerous macromolecule?
Lipids
Cell structure is defined by the
cell membrane
Cell membrane has what type of barrier?
Permeability
Thermal Damage - What happens when it gets too hot?
It causes it to break down into smaller vesicles
Thermal Damage- What happens when it gets too cold?
Too cold causes it to shatter
Saturated fatty acids ___ to one another
stick
What can happen to membranes at low temperatures?
They can freeze
Cells adjust fluidity by doing what?
Increasing “space” to increase bilayer fluidity.
What does heat do to a membrane?
Heat speeds up molecular motion so cell compensates with saturated fatty acids
What does cold do to a membrane?
Cold slows down molecular motion so cell compensates with modified fatty acids
Less molecular freedom =
Less fluid
More molecular Freedom =
More Fluid
Membranes are slightly permeable to
water
Name of membranes protecting themselves from water damage?
Osmotic Damage
What happens when too much water gets past the membrane?
Cell bursts
Peptidoglycan is a combination of what two components?
Sugar and Protein Component
Peptidoglycan - Sugar Component a polymer of
NAG and NAM joined by B-Linkage to form chains
Peptidoglycan - Protein Component chains crosslinked by?
Amino Acids
What is Peptidoglycan?
An exoskeleton that protects cell from bursting
Polysaccharides are ____ to long axis
perpendicular
Peptide Crosslinks are ___ to long axis
Parallel
Peptidoglycan surrounds ____
Plasma Membrane
What B-Linked Glucose is used in Plants?
Cellulose, used in Cell Walls
Use of D-Amino acids ____
increass peptidoglycan resistance to proteases
What are L-Form amino acids?
They are used to make proteins
Where are D-Form amino acids found?
Found in peptidoglycan
Diaminopimelic Acid “DAP”
“Unusual Amino Acid
Not found in proteins
Permits crosslinking
Forms 2 Peptide Bonds
DAP
What is Penicillin?
Antibiotic that prevents chain crosslinking (Incomplete Structure)
What is Lysozyme?
Enzyme in tears that cleaves B-Linkage between sugars of the chain
What happenes in Chemical Damage?
Hydrophobic molecules will insert themselves into membrane and destabilize the bilayer
What is the name of the thing that causes harm in Chemical Damage?
Detergents
How to bacteria act behave to the presence of heat?
Adapt by moving fatty acids in membrane depending on the heat
What does a Gram Positive place in the presence of Detergents?
Negatively Charged Teichoic Acids
What does the Gram Negative place in the presence of Detergents?
Negatively Charged Lipopolysaccharides
Structure of a Gram Positive?
Only one plasma membrane with a lot of peptidoglycan
Structure of Gram Negative?
An outermembrane
Peptidoglycan
Plasma Membrane
Gram Positive
Gram Negative
Thin or Thick layer of Peptidoglycan in Gram Positive Cell?
Thick Layer
Components of Gram Positive Cell?
Peptidoglycan
Plasma Membrane
Is the Plasma alive in Gram Positive?
Yes
Is the outer membrane alive in Gram Positive?
No
Gram Positive - Teichoic Acids
Negatively charged glycerol phosphate polymers
Teichoic Acids in Purple
Teichoic Acids
What do Teichoic Acids do?
Protect the membrane. They repel hydrophobic detergents from inserting into membrane
Components of Gram Negative Cell Wall?
Outer Membrane
Peptidoglycan
Periplasm
Plasma Membrane
What does the outermembrane do in Gram Negative?
Shids plasma membrane and peptidoglycan
LPS is located where?
On the outer membrane of Gram Negatives
Definition of LPS?
Negatively charged to repel hydrophobic molecules. Charger barrier for chemical defense.
Lipopolysaccharide is ___
amiphipathic
How many domains in LPS Structure?
Three
What are the three domains in LPS Structure?
O-Antigen
Core
Lipid A
O-Antigen on LPS
Core in LPS
Lipid A in LPS
What is the LPS “O-Antigen?
Repeating pattern of highly variable sugars. Function unknown
What is the LPS “Core”
A series of sugars that is highly conserved in all Gram negative bacteria. Is the charge barrier against detergents
What is the LPS “Lipid A”
Anchors Lipid A to outer membrane. Phospho-Sugar backbone instead of glycerol. 6 fatty acids instead of 2.
Is Lipid A Hydrophillic?
No, it is Hydrophobic1
What does Braun’s Lipoprotein do?
Attaches outer membrane to peptidoglycan.
LPS
Brauns Lipoprotein
Porin
What are porins?
Permeability gates.
Allow small molecules to diffuse into cell.
What is the Porin Structure?
Passive “pores” that let molecules move through the outer membrane
Periplasm
What is a Periplasm?
Not a structure, but a space. Contains thick gel spanning plasma and outer membranes
Periplasm chemical defense
Containing detox enzymes and chemical binding proteins
Gram Positive
The solution to Thermal Damage?
Adjust fatty acid content
Solution for osmotic pressure?
Peptidoglycan (Exoskeleton)
Solution for Chemical Damage?
Charge Barrier (LPS or Teichoic Acids)
What are the two different cell architectures?
Gram Positive and Negative
What is Mycoplasma Pneumoniae?
Causes “Walking Pneumonia”
Small bacteria
Only 500 genes.
No peptidoglycan
Cholestrol stabilizes membrane
What do Eukaryotes have to buffer membrane fluidity?
They use cholesterol. This can either increase or decrease molecular space. This in bacteria is rare
This is an increase in fluidity
This is a decrease in fluidity
Mycoplasma is an
Attachment Organelle
Mycoplasma has what in the dense core of protein in neck?
“Leg Proteins”
What is a Mycoplasma considered to be?
A Misnomer
Coccus
Rod
Vibrio
Prosthecate
Spirillum
Spirochete
Filamentous
What makes a rod, rod-shaped?
MreB
MreB Information
Actin homolog, forms filaments
Coupled to PG Biosynthesis
How do cells grow in a rod?
Cells grow outward from where the peptidoglycan synthesis machine is at
What makes a vibrio, vibrio-shaped?
CreS
Where is CreS found?
FOund only in some vibrio. May contain some MreB movement
What makes a coccus spherical?
Nothing. It lacks MreB and CreS
What is the name of the area around the molecules?
Hydration Shells
In a Fluorescence Microscope shot, what color is the membrane and nucleoid?
Membrane is Green
Nucleoid is Red
Information about Chromosome
It is single, closed circular chromosome. Contains 500-10,000 genes
Nucleoid Structure
Well-defined structure but is not membrane bound. Structure constrained by proteins.
What does SMC stand for?
Structural Maintenance of Chromosomes
Why do we have organelles?
They reduce volume.
Restrict diffusion
Concentrate reactants
isolate imcompatible reactions
By compartmentalizing, eukaryotes attempt to…
regian the efficiency of bacteria
Do bacteria need organelles?
No , bacteria already have a high surface area to volume ratio
Do eukaryotes have organelles because they are multicellular?
No, not the case.
Closest relative of Mitochondria?
Midichoria
Closest relative of Chloroplast?
Cyanobacteria
What does the periplasm do with the membrane?
Increase surface area and decrease volume
How many storage granules are there?
Three
What are the three storage granules?
Energy Storage
Element Storage
Damaged Proteins
In energy storage
PHB is excess fat. Glycogen is excess carbon. Also contain polyphospahte
What is in element storage?
Sulfur and Iron
What is in Damaged Proteins?
PRotein Inclusion Bodies. Storage granules can be mistaken for organelles
Megnetospirillum Magnetotactum
Once thought to be true organelles but disproven, used to orient motibility in magnetic field
What are Magnetosomes?
Storage granules composed of magnetite (Fe3O4)
What organizes magnetosomes inside of the cell?
MamK
Are magnetosomes surrounded by the membrane?
Not completely
Advantages of Nucleoid
Rapid Signaling. Signaling is simplier and immediate. Also allow for coupled transcription and translation
