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MCB2000 Exam 2 Notes
Genetics
GMO genetically modified organism, manipulating a seed or bacteria to have a desired effect
Eukaryotic Cell: more complex, has 2 or more chromosomes, mitochondria & chloroplasts have their own DNA that carries additional genes
Prokaryotic Cell: simpler, DNA is THE genetic material
Bacteria: has 1 chromosome
Extra chromosome is available on DNA
Virus: Acellular, have DNA or RNA, only viruses can have one or the other, may have single stranded DNA (always the exception)
DNA is a polymer of Nucleic Acid Nucleic Acid is made up of Nucleotides, double stranded, connected together by hydrogen bonds, its helix shape makes it compact
Don't forget about the age old question of mkt 327 msu exam 1
Duplicating DNA: relax DNA, separate two strands, make a copy for each one, then have two
Nucleotide: sugar, phosphate, nitrogen base (ATCG)
All cells have double stranded DNA, including plasmid, chloroplasts, and mitochondria Don't forget about the age old question of Hellenism refers to what?
Genes
segments of chromosome code for a specific protein called a gene not all DNA are genes, only segments of genes If you want to learn more check out cdae uvm
some genes made code for an RNA molecule that is not coded for a protein Virus few hundred genes
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Bacteria couple thousand genes
Humans tens of thousands of genes (in Eukaryotes)
every gene has a start and an end We also discuss several other topics like precification
If you want to learn more check out afst 212 study guide
every gene has to be expressed, this happens in the form of RN every gene copes for one molecule of RNA
more complex the organism is, the more genes it has We also discuss several other topics like the writers of the constitution justified different methods of selection and varying terms of office for the president, senate, and house as a means of
Vertical Gene Transfer: from parent gene directly to daughter gene
Horizontal Gene Transfer: in bacteria, conducted through conjugation, transformation, and transduction
Conjugation: there is direct contact, DNA is copied from the daughter and the copy of DNA is transferred to the recipient, there is a Vector that carries the DNA the plasmid, diseasecausing genes are passed on through this conjugation, virulence genes, antibiotic resistance genes/pathogenic genes
Transformation: pick up DNA from the environment (naked DNA), no direct contact, DNA comes from other cells that die and cause DNA to be free, this process isn't very common, use this in lab to introduce genes into bacteria can be in the form of plasma, also is a lab technique to introduce DNA into a host
Transduction: virus, attack one hostpicks of DN fragment transfer to another host, happens very naturally, carry toxic genes from one bacteria to another, involved in spreading resistant genes, do not kill the host just carry the genes from one host to another
Reverse Transcript: take RNA and copy it to DNA
Bacteriaphage, take from one bacteria into the new bacteria—> then has a piece of gene from another bacteria
Virus do exactly what plasmid does, one virus attacks one host—>picks up DNA from that host and carries to another
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Exotoxins: contribute to the diseases, they kill human cells, genes encoding these toxins are carried by phage, they go from one bacteria to another and carry these genes with them,
Transposons carry genes from one bacteria to another, can jump from chromosome to plasmid or from plasmid to chromosome, help plasmid to carry gene from chromosome also, sometimes called jumping genes, when these genes reach the chromosome they are more permanent
NakedDNA, Cellfree DNA
Replication of DNA
Binary Fission: the cell doubling, replication (exact copy of the DNA)
Enzymes involved in replication: Helicase unwinds the DNA and opens it up, PrimateSynthesizes the RNA primer & is required to start replication, DNA polymerase adding bases to the new DNA chain; proofreading the chain for mistakes & removes primercloses gapsrepairing mismatches, Ligase final binding of nicks in DNA during synthesis and repair, Topiosomerases supercoiling and untangling
Bacterial DNA circulator:
Duplicating DNA: relax DNA, separate two strands, make a copy for each one, then have two
3 Prime side of strand, and 5 prime side of strand, the replication always goes from 5 to 3, DNA polymerase always synthesizes in one way
Replication always starts at one point ORI, it is Bidirectional it goes both ways, goes from 53 direction
Replication is semiconservative (one strand is old from the parent cell, one strand is new)
the two strands are complimentary, G —> C, C —> G (3 hydrogen bonds), A —> T, T —> A (2 hydrogen bonds), two strands are antiparallel (53, then 35)
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You can tell one strand from the other by regarding the Antiparallel aspect and the complimentary aspect
To start replication you need a Primer, RNA
during replication one strand is segments and one strand is in one piece
Replication SUMMARIZED: Double stranded, one chromosome, circulator, super coiledcompact molecule, always starts at ORI, moves in both directions, goes 5’—3’ direction, needs a RNA primer to start, semiconservative, the two strands are complimentary, are antiparallel, LIGASE&SIMPLE DIAGRAM OF RE
Genomic: the study of genes and structures
Bioformatic: the science of comparing DNA
Transcription
from DNA to RNA, read DNA and then make RNA
transcription:
making copy of DNA in form of RNA
has multiple forms, tRNA mRNA rRNA
all microbes in protein synthesis
segments of DNA that code for RNA segment is called a gene
some RNA molecules are made to make protein, some are not
mRNA: codes for protein, where info comes from to make a protein, CODON used as a template for making the protein
tRNA: help synthesize the protein coded for by mRNA
RNA polymerase uses DNA as a template, it then reads the gene, and then synthesizes RNA
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Translation
Protein synthesis/translation, end result is a protein molecules
the size and composition of ribosome in human is different from those in bacteria
some antibiotics target bacterial ribosomes instead of human ribosomes because they are different
happens at the Ribosome (every cell must have a ribosome)
Ribosome is a complex molecule made of proteins plus RNA
mRNA transcript reads the mRNA and uses it as a template to
mRNA carries Codon for Amino Acid, a strand of molecule made of GCUA, every 3 base pair is one Amino Acid—> a polypeptide
Codons are triplets each Codon for a different Amino Acid, different combinations code for different things
Ribosome hooks the tRNA and Amino acid together
tRNA has a matching codon, an anticodon, binds to an amino acid and brings them to the Ribosome
Initiation: first step of translation, mRNA is sandwiched between two ribosome
Elongation: second step of translation, a new amino acids and the polypeptide chain is growing
UNDERSTAND CONCEPT OF EACH STEP
Termination:
Point Mutations
Spontaneous Mutations: mistakes naturally made by DNA polymerase, key is to have mistakes fixed
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Fidelity of Mutation: DNA polymerase will go and correct itself and repair anything that went wrong
Frameshift happens halfway through where you either add a base pair or remove a base pair
Sequencing DNA
GCAT……
Human Genome Project: has all human genes/mitochondria/chromosome sequenced, we know the sequence of DNA all the way from the first humans
Studying DNA
Gel Electrophora: Run it through gel and observe it, put DNA on the gel, run it through electricity, then turned from negative to positive, this technique visualizes DNA for you
RFLP: a friendly technology, used by law enforcement agency, takes human DNA runs it through enzyme restriction, then runs it through the gel, every human has a different pattern,used by forensic scientists to identify DNA from different sources
Restriction Endonucleases: enzymes that cut DNA at certain points, cut DNA into segments
Restriction Enzymes: cut DNA with the enzyme, Restriction enzyme cuts the DNA at different placesthis is a natural source, take plasmids and cut them the same as DNA connect them together to create Recombinant DNA (DNA from at least 2 sources)
Polymerase Chain Reaction
every cycle the DNA is doubled
the key is what type of primer to use to perform the PCR
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no matter how small it is we are now able to extract DNA from it
DNA has to denature and open up and synthesize in this process Prokaryotes to Eukaryotes
Ti plasmid: bacteria that attacks plant, this has been tamed, now able to be put into Eukaryotesplants, introduced genes from other plants
Some Mutagens and their Affects
Base Analaog: structured, GCAU
Alkylating agent: example nitrosoguanidine incorrect pairing—>point mutation Some chemicals damage
Ames Test
FDA will require any new product to be testes through this for carcinogen (can cause cancer)
every chemical in the new product has to be tested
Simple test: bacteria grown on a plate, in the plate their is a missing amino acid, the bacteria cant grow, you then add the amino acid to the plate to trick the bacteria, some chemicals can cause that bacteria to grow even without amino acid
Cancer: unregulated growth, whatever cancer you have: your cells keep growing uncontrollably, each cell has a control gene
DNA Repair
DNA constantly repairs itself
DNA polymerase is an enzyme that replicates
Exonuclease Activity: chopping the DNA, cutting it back
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if damage is not fixed, it becomes a mutation
Recombinant DNA technology
Labs have been able to adjust DNA
intentionally modifies genomes of organisms, by natural and artificial processes, for practical purposes
Work with DNA, extract it, through genetic engineering
phenotype: a gene that is expressed
Tools of Recombinant DNA technology
Reverse Transcriptase: converts RNA to DNA, comes from HIV, good for us when we have to take a copy of RNA into the DNA form
Restriction Enzymes: use to cut your DNA and cut your vectors (plasmid, viruses, manmade plasmid)
gene libraries: collection of Bacteria that each carry 2 DNA
Protoplast fusion: two cells—> membrane fuses together—> become one cell, if they have cell wall it has to be dissolved
Applications of Recombinant DNA technology
take pieces of pathogen, put it into another bacteria to grow
taken protanes from different pathogens but into new bacteria
RFLP: patterns of restriction enzyme, cutting DNA
it is possible to express pathogens/genes into humans, to produce protein in your body
plants, animals, fungi, parasites, protozoans —> Eukaryotes
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Endosymbiosis
Monera—> unicellular, prokaryotes
not everyone has cell wall, bacteria does—> peptidoglycan
fungi and plants have cell wall
Viruses
Acellular, no hallmarks of the cell
lots of activity, but not alive, has an automatic pilot, is functional, works and does what its supposed to do
Smaller than all else, nanometers (nm)
need Electron Microscopy to see them
can’t be grown on a plate, always need a host
Flask used to grow virus is a host, monolayer destructed when virus attacks
make monolayer by taking host (animal tissue, human/plant tissue) homogenize it, grows for few days and dies off primary culture comes straight from source, fuse normal cell with cancer cell and that cell will grow forever
plaques: one virus got in, killed the host, cleared it out, bacteria colonies—> viruses plaque
fewer genes than others, has few hundred
obligate intercellular parasite, always need host, have to be inside host cant just attach to host
Virus can recognize skin as a host or respiratory system as a host, go straight to that portion of host and cause issues there
eating food with Hepatitis A gives you Hepatitis Astraight to liver, Hepatitis C blood or sex goes to specific liver to attack
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Archaea attacked by viruses
made of piece of protane and a piece of nucleic acid
Capsid (protein), these proteins assemble automatically
Nucleic Acid DNA and RNA, singlestranded or doublestranded, one or the other but all possible
cell “envelope” made of lipids, not membrane but similar to membrane
spikes needle embedded into the envelope of the virus molecule, allows attachment to a specific host, additional layer
not a lot of cure, not a lot of treatment
when attacking a human, the virus takes your polymerase & ATP to attack you and your system, they take control of your movement
smallest of all molecules, some 1520 nanometers
unique structure Icosohedron multi face shape, covers the nucleic acid, due to shape of the capsid
Viral Replication
set of steps to make sure virus gets into host
attaches with capsid or spikes
inject DNA or RNA into the host through penetration, the capsid remains outside sometimes gets in with the DNAcapsid then needs to get out of the hosthappens through Uncoating (additional step) target to stop virus from initiating suffocation
Synthesize make virus pieces, make all components of the virus, made inside the host
Assemble put the pieces together at the same time, aka packaging or maturation, made of Preformed components
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Release rupturing the cell to release all the viruses, lysis of the host, host is disrupted, one virus gets into the host hundred get out
using host polymerase the cells make more of themselves
as the virus squeezes out of the host they carry a piece of membrane with them which becomes their envelope, spikes develop later
this describes a typical Human virus (DNA)
when viruses come in as an RNA virus and needs to go through a process to convert RNA into DNA involves an enzyme called reverse transcription—> RNA copy to DNA —> DNA inserted into host for replication
HIV is a Retrovirus has to be converted to DNA first, take RT inhibiters
when virus is inserted into the chromosome of the host stage of life called ProVirus refers to the DNA of the virus embedded into the chromosome of the host
as host replicates, DNA replicates, make more viruses
One Step Growth Curve
After attachment and penetration and start of assembly there is a period of time where no virus is detectable
during this period it is called Biosynthesis and Maturation—> Eclipse Period once assembly stops they viruses are coming and keep showing up at the same time
Viral Syndromes
oral and respiratory tract infections
flulike (body ache, feeling under the weather, heaviness on your system) and systematic symptoms
congenital, neonatal and perinatal viruses
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infections of the CNS
Hepatitis liver
Important Human Virus Families
viruses herpes variety family of possible types
chicken pox viruses
Pollo virus
families: groups of viruses that have similar characteristics
Animal defenses against viral infection
fever: speeds up the immune system, slows down bacteria, viruses get killed, beneficial immune system response
interferon: antiviral proteins, effect RNA viruses
antibioties: proteins produced by immune system that recognizes viruses and neutralizes them
targeting viruses for cure are difficult because you have to target human cells
Few Successful Drugs: need a drug that targets the viral mechanism instead of the host machinery/system—> tamiflu: attack influenza virus A and B, amantadine, acyclovir, ribovirin
viruses are obligate intracellular pathogens, this means they must have a host to replicate or multiply, use the hosts machinery (metabolism, synthesis system, transcription, translation, etc)
Properties of viruses
obligate intracellular parasites of bacteria, protozoa, fungi, algae, archaea must use host machine
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ultramicroscopic submicroscopy Electron Microscope
made of same polymers of others
acellular, no cell membrane, not selfregulated, no regulation of their activities RNA or DNA as their genetic material (not both)
could be single or double stranded
Host specific
must have capsid, must have nucleic acid, matrix proteins (spikes) may or may not have
oncogene: cause uncontrollable growth, this causes a tumor formation, example of this type of virus is the Retroviruses
virus brings gene with them that takes over the gene of the human cell, takes control of the hosts cell division
Virus Induced Changes in Cells
Virus gets in, starts multiplying and making more viruses Acute infection
Permissive or productive infection: results in acute infection and host cell lysis (break up), typical outcome of virus infection
Abortive or nonproductive: no viruses produced, no harm to the host
Persistent infection: keep producing viruses at low level, host survives but keeps making viruses, not good for the host, turns your system into a virus making machinery, form of chronic infection
Latent: virus lives in you, stays in you, one day may flare up and cause problems, also chronic, no virus produced, just hosted with possible flare up at any point
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transforming: cancer, transformation into malignant cells
cytopathic effects (CPE): visual effects of the virus on the host, you can see from eyes or under a microscope, cell lysis is a form, causes damages to the cell that can be visualized, results in different infections (latent infection)
Latent Infections
virus lives with the host
Herpes virus: HSV1 oral, HSV2 genital
Chicken Pox
CMV: causes mono
EBV: Burkitt’s lymphoma type of cancerHIV
Chronic Infections
Hepatits B & C: effects liver, plasmasalivagenital secretions
can cause cancer
- cirrhosis- makes liver spongy, cells damaged
carcinoma: cancer
Rubella virus: congenitalpass onto the fetus
Viruses & Cancer
Cell division is a highly regulated process
Neoplasia uncontrollable cell division
mass of neoplastic cells is a tumor
Benign vs. Malignant tumors: metastasis, cancers
HPV: genital warts, can result in tumor
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Characteristics of Prions
Acellular, noncellular structures
MadCow disease
Alpha helixnormal
Beta sheet abnormal
accumulation of Beta sheet protein results in neurological damage
Microbial Pathogenesity
CDC keep in touch with this website, updated information
microbes can possess molecules and structures that cause disease Survival of the fittest
very simple structures, no internal organelles no nucleus no mitochondria, grow rapidly allows exchange of waste and brining in nutrients
survive harsh conditionsproduce endospores, attachment devices help thispili capsule fibre
Capsule protects it against the immune system
Symbiosis: Normal Flora symbiotic relationship with us, bacteria, no virus, no parasite, this changes as your age changes
no association of microbes in areas like middle, inner ear, sinuses, circulatory system, glands, organs, brain and spinal cord, ovaries and testes
Epidermis constantly growing and shedding off dead cells, top layer of skin, covers a large portion, cooler, lower pH, salt
Staph can live on the skin
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The Infectious Triangle
Host—> Microbe —> Environment
number of how much you get exposed to microbes is important
ID50 & LD50: the number of microbes that cause disease, lower the number the lower the ID50 the more virulence
Immunocompromised Individuals: have some form of immune system deficiency, receive immune suppressant drugs, receiving radiation or cancer qualifies, diabetes, HIV
low ID50: get sick more often, come into contact with low amount of bacteria this will get you sick
LD50: lower the lethal dose, the more vicious the bacteria is, a certain level will kill you
Intracellular pathogens: the virus most go into the host to multiple, must go inside obligate and intracellular to use the host machinery, protected when the immune system try to fight off the pathogen
Biggest difference from bacteria bacteria uses its own system
Extracellular systems: have more room to spread and move
Produced toxins will send throughout the system by transportation by things like living under the nails
Bacterial Pathogens
Usual pathogen: go there and touch it, you get sick
Opportunistic pathogen: have to have a certain environment to infect you Endotoxin Gram negative bacteria
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Focal infections: start at one point but spread of other locations from that point Chronic infection: slow but long process, progresses over time
Virulence Factors
attachment devices: pili, fimbrae, capsule, glycocalyx
Virulence Factors can be an enzyme, a structure, a toxin, even simply just being able to grow and invade
Extracellular enzymes: use to breakdown host barriers
Toxins: exotoxins/endotoxins, produced by both Gram positive and Gram negative, it is both produced and secreted, LPS only gram negative
Phagocytosis: white blood cells engulf and remove bacteria from the body
Exotoxins & Endotoxins
LPS outer membrane of gram negative bacteria, endotoxin, part of Lipid A most toxic part of LPS, causes inflammation, fever, drop in blood pressure, coagulation, released when bacteria is dead, weakly toxic
Endotoxins: LOS & LPS
Exotoxin: almost all gram negative, affects many things, made of proteins, extracellular, highly toxic, enters body with high immune response, one can inactivate exotoxin and convert to toxoid (inactivated endotoxin, can be used as vaccine)
Endotoxins: proteins
Examples: Hyaluronidase enzyme bacteria produces that allows the bacteria to spreadmakes an invasive bacteria facilitates movement for bacteria to go further into the system, Hemolysin kills RBC, Leukocidin: kills WBCs, Alpha Toxin: kills all kinds of cells, Streptokinase: blood clots, blocks bacteria from entering your system, Coagulase: molecule forms clot around bacteria to protect it from the immune system to get into
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Respiratory tract is a main area where bacteria accesses into the system
Endotoxins are always gram negative, toxic in high does, LPSLOS part of structures of bacteria, a small amount released when the bacteria is goring
Exotoxins made of proteins secreted to the outside and they cause damage outside, make toxoid with this not endotoxins used for vaccine production, highly toxic
Sources and Transmission of Infectious Agents
Soil not easy to survive in, not much nutrients, lots of composition, worry about Endospores in soil bacterial, dormant, inactive, survive harsh conditions, Clostridium causes Tetanus, fungal spores as well, not lots of viruses or parasites
People who work with livestock are at risk of Bacilles, causes skin problem, Antrax disease, in the form of endospore in the soil
Portals of Entry
1) Skin: staph relatedcauses skin infection, strep flesh eating bacteria, herpes virus
2) Mucous Membrane: includes digestive tract, urogenital tractHIVchlamydia, respiratory tractfungibacteriafungi, opening your mouth, inside body cavities, most common entry
3) Parenteral route: cutting your skin, Genital Tract, bit by an insect, bypass conventional layers, surgery, cuts/bruises
Placenta can allow pass through to the fetus, congenital birth defect something happened when fetus was developed in the womb
use the same routes for exit as well, can enter through one route and exit through the other as well
capsule antiphagocytic
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Modes of Transmission
Communicable diseases:
Direct contact: touching, sexual
Indirect: airborne diseasetravel more than a meter distance, droplet, sneezing, famine: nonliving means of transmission through non direct contact drink from the same glasssame razortowels
Vehicle transmission: food and water
Vector transmission: flies, mosquitos, other insects
Arthopod borne disease
no bacteria inside the womb, as fetus passes through birth control it accesses bacteria, bacteria then becomes part of the normal flora of the body
kids need some exposure to bacteria while growing up and developing to build immunity to them
Normal Flora
bladder urethra bacteria here, kidney, if you hold bladder to long, bacteria will travel up and give you a kidney infection, flushing with urine gets the bacteria out
respiratory tract lung has antibacterial action to kill bacteria
reproductive system no bacteria in uterusovariesfallopian tubes
Incubation periodtime for bacteria to grow and multiply exposed to the disease and where symptom start to show up can be hours or months, rabies is several weeks to months
Prodromal Stage: flulike symptoms
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Convalescent period: final stage, recovery
you are infectious through any stage of this process ^^
signs someone else cans seerashesreddness,
symptoms feel but cannot seepainflulike symptoms,
syndrome collection of signs and symptomsEx: AIDSnot just one thing
Reservoir infection: where disease is found on a regular basis, could be through nature, lakes, animals, humans
carrier: carries disease and can transport it to another, healthy person can do this, chronic carrier: carries disease for a long period of time, nonliving or living
Zoonotic disease: disease from animal to human, only get from animals, rabies from bites of animals west nile virus through mosquito bites, plague rodents bite humans
malaria human to human from mosquito, not zoonotic
Arthropod borne diseases: carried through mosquitos
Koch’s Postulates observation, isolation, Inoculate second subject, observe same as original, reisolate, compare , found one microbe one disease—> this doesn't apply to all diseases
only infectious diseases are caused by microbes
not possible to isolate in pure culture in some agents
Nosocomial Infections
diseases acquired at a healthcare facility, staff, doctor, bathroom, being exposed to elements of being sick
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- Epidemiology
study of the origin and spread of disease
everything about the disease, how what when where why, all info besides treatment they collect data and analyze the results and experiment
CDC
Pandemic: worldwide, passed through several countries
Epidemic: in a region
Endemic: ongoing disease, in population all the time, like a cold
less infectious diseases now because of antibiotics, treatments, etc
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