Exam 1 Flashcards
the supposed production of living organisms from nonliving matter
Spontaneous generation (abiogenesis)
it asserts that living things can only be produced by another living thing
Biogenesis
free from reproductive spores or germs; as, a sterile fluid.
Sterile
is a method designed to prevent contamination from microorganisms
Aseptic techniques
states that many diseases are caused by microorganisms
Germ theory of disease
discovered bacteria, and invented the microscope. Known as the “father of microbiology.”
Antonie van Leeuwenhoek
discovered that microbes were responsible for souring alcohol and came up with the process of pasteurization, where bacteria is destroyed by heating beverages and then allowing them to cool. His work in germ theory also led him and his team to create vaccinations for anthrax and rabies
Louis Pasteur
American physician First documented recommendation of hand washing by healthcare workers to prevent disease
Oliver Wendell Holmes
Hungarian physician who first instituted to wash hands with bleach having tremendous results
Ignaz Semmelweis
made surgery much safer with the use of phenol to kill micro-organisms on skin of patients and surgical tools
Joseph Lister
also the most important microbiologist developing the bacteriological techniques (agar, petri dish) proving micro-organisms caused harm. Experimental verification of the “germ theory of disease” Proved anthrax was caused by micro-organisms and discovered mycobacterium tuberculosis.
Robert Koch
Describe the structure of DNA -
DNA is made up of six smaller molecules – a five carbon sugar called deoxyribose, a phosphate molecule and four different nitrogenous bases (adenine, thymine, cytosine and guanine).
Describe the structure of RNA -
The basic components of RNA are the same than for DNA (see the DNA page) with two major differences. The pyrimidine base uracil replace thymine and ribose replace deoxyribose (see the sugars, purines and pyrimidines pages).
The process that causes a protein to lose its shape
denaturing the protein
prokaryotic cells, live in temperate climates.
Bacteria
ancient bacteria, live in unusual or hard environments
Archaea
Eukaryotic, single celled, classified by motility , many free living, some cause disease
Protozoa
eukaryotic, yeasts (unicellular), molds (multicellular)
Fungi
eukaryotic, multicellular, parasitic worms, adults macroscopic, eggs and larva microscopic.
Helminths
eukaryotic, microscopic plants, unicellular or multicellular, does not cause disease, photosynthesis.
Algae
acellular, insert outside host cell, made of a protein coat and nucleic acid, most common cause of human infection
Viruses
acellular, abnormally folded proteins, infects cells and causes normal proteins to fold abnormally, causes spongiform encephalopathies (mad cow)
Prions
acellular, single stranded pieces of RNA that are infectious and can cause disease, usually infects plants, potato spindle tuber and apple scar skin are a product of this microbe.
Viroid
microbes that live on or in the body and do not cause harm and are often beneficial to the body. (when they are in the correct location)
Normal Flora
used to produce products or to improve organisms.
Biotechnology
manipulation of the genes of organisms.
Genetic engineering
transferring genetic material from one organism to another.
Recombinant DNA technology
using microbes to stabilize ecosystems or clean up waste or pollution.
Bioremediation
cause disease in all people.
Primary Pathogen
cause disease in immunocompromised people or when put in the wrong place or when normal flora is lost.
Opportunistic pathogen
bacteria and archaea, 10x smaller than eukaryotic cells, lack organelles, can still have complex structure, can engage in all activities a eukaryotic cell can, all microorganisms.
Prokaryotic cells
animals/plants/fungi/protozoans, have organelles (ribosomes, nucleus, mitochondria), some microorganisms, some macroorganisms.
Eukaryotic cells
the science of classifying living things.
Taxonomy
the assignment of scientific names to various taxonomic categories and to individual organisms.
Nomenclature
prokaryotic, modern bacteria
Bacteria
prokaryotic, ancient bacteria
Archaea
eukaryotic, Protista/fungi/plantae/Animalia
Eukarya
Protisita -
protozoans
Fungi -
molds, and yeasts, not photosynthetic
Plantae -
algae, are photosynthetic
Animalia -
Helminths
variation in the size and shape of cells of a single species due to nutritional and genetic differences.
Plemorphic
aggregated groups of microbes that form as a layer with associated organic materials.
Biofilms
Coccus shapes >
single (1), diplococci (2), streptococci (long chains), tetrads (four), sarcina (eight), staphylococci (irregular groups)
Bacillus shapes >
single (1), diplobacilli (2), streptobacilli (long chains)
comma shaped
Vibrio
ridged, corkscrew shaped cells, motile through flagella
Spirillum
flexible, corkscrew shaped cells, motile with axial filament
Spirochete
branching
Filamentous
Structure: Capsule: tight fitting coating of molecules external to cell wall/ or Slim layer: loose fitting and diffuse coating of molecules external to cell wall. Function: Adherence, protection, and receptor. Clinical Significance: Infection, but only with capsule form. The capsule inhibits phagocytosis. Genes can also be transferred between the organisms.
Glycocalyx
Structure: Fine hair like bristles extending from the surface of the cell. Function: helps in adhesion to other cells and surfaces. Clinical Significance: Potential target for antibiotics. They form fragments that bind antibody molecules & inactivate them.
Fimbriae
Structure: An appendage. Function: Used for drawing another bacterium close in order to transfer DNA to it. Clinical Significance: They often contain genes that allow bacteria to become more virulent.
Pili
Structure: An appendage. Function: Motility. Clinical Significance: since flagella is motile it helps opportunistic infections, escape from host defense, and systemic infection.
Flagella
Structure: Appendage that is enclosed in the space between the cell wall and the cytoplasmic membrane. Function: Motility which is corkscrew like movement. Clinical Significance: It can corkscrew into tissues normal bacteria cannot get to, and it can get into the blood. Both of these abilities help cause infection
Axial filament
Structure: Thin sheet of lipid and protein that surrounds the cytoplasm. Function: Controls that flow of materials in and out of the cell pool. Clinical Significance: Susceptibility. Primary target for antibiotics. Inhibits DNA replication. Destroys the ability to produce energy. Causes loss of membrane integrity and destruction of the cell.
Plasma membrane
Structure: Composed of dense DNA molecules. Function: DNA directs all genetics and heredity of the cell and codes for all proteins. Clinical significance:
Nucleoid and bacterial chromosome -
Structure: Double stranded DNA circle. Function: Contains extra genes. Clinical Significance: Carry genes for toxins, and is antibiotic resistant.
Plasmids
Structure: Tiny particles composed of protein and RNA. Function: Protein synthesis. Clinical Significance: Major target for antibiotics, because they will cause inhibition of protein synthesis which is lethal to the cell.
Ribosomes
Structure: Dense crystal or particle. Function: Stores nutrients such as fats, phosphates, or glycogen that can be used when needed. Clinical Significance: NONE
Inclusion bodies
Structure: Dormant body formed within some bacteria. Function: Allows for survival in adverse conditions. Clinical Significance: Infection. Resistant to antibiotics, and heat. Is also resistant to almost all disinfectants, and antiseptics.
Endospores
Atrichous
no flagella
Monotrichous
single flagellum
Lophotrichous
small branches or tufts of flagella emerging from the site.
Amphitrichous
flagella at both poles of the cell.
flagella are dispersed randomly all over the surface of the cell.
Peritrichous
Structure: a semirigid casing. Function: support and shape for the cell. Clinical Significance: Target for antibiotic, which ends up disrupting the integrity and causing cell lysis
Cell wall
- Thick, homogenous sheet of peptidoglycan made of many layers.
- Contains teichoic acid and lipoteichoic acid that joins the layers.
Gram-positive cell walls
- Single sheet of peptidoglycan
- Thinness gives gram-negative cells great flexibility and sensitivity to lysis.
- Contain an outer membrane – made of lipoproteins and lipopolysaccharides. Lipid A (endotoxin), and porin proteins (they only allow certain chemicals to penetrate.)
Gram-negative cell walls
Mycobacterium
• Cell walls contain mycolic acid.
• Mycolic acid – a waxy material that contributes to the pathogenicity of the bacteria, due to its resistance to certain chemicals, dyes, and to digestion by phagocytic cells.
Acid-fast bacteria
Mycoplasmas
• Naturally lack a cell wall
• Sterols in the plasma membrane stablilze the cell against lysis.
• Mycoplasma pneumoniae – “walking pneumonia”
Cell-Wall-Deficient Bacteria
body or colony of mold.
Mycelium
threadlike cells that form from the bodies of molds.
Hyphae
have cross walls between cells.
Septate
have no cross walls between cells.
Aseptate
are responsible for visible mass of growth.
Vegetative
produce spores
Reproductive
reproductive structures that disperse via air, water or living things. Will germinate when favorable substrate is found.
Spores
reproductive hyphae that hold the mold spores away from the body.
Aerial
have colonies much like bacteria.
Yeasts
cottony, hairy, or velvety texture.
Molds
can take either form
Dimorphic
acquire nutrients from a wide variety of organic substrates.
Heterotrophic
obtain nutrients from the remnants of dead plants and animals in soil or aquatic habitats.
Saprobic
grow on the bodies of living animals or plants.
Parasitic
Who am i?
- A number of species are pathogenic to corn and grain
- rot fresh produce during shipping.
Fungi
Protozoan
Skin (cutaneous mycosis)
•Tinea causes?
i. Ring worm
ii. Jock itch
iii. Athletes foot
Protozoan
Mucous membranes
•Candida albicans
i. Vaginal yeast infection
ii. Thrush
I am a Protozoan that
• Enters through the lungs
• Spreads through blood or lymph
• Causes lung infections, skin lesions, and organ lesions.
• Most are molds, but grow in the human body as a yeast.
- Systemic or deep infections
Who am i?
- Most are harmless, free-living inhabitants of water and soil.
- A few are parasites, and are responsible for hundreds of millions of infections each year.
- Heterotrophic
- Single cells, Eukaryotic
- Some exist in only tropozoite phase
- Asexual - Mitotic cell division or multiple fission (schizogony)
Protozoan
motile feeding stage requiring ample food, and moisture to stay active
Protozoan - Trophozoite
Dormant, resting stage when the conditions are unfavorable.
Protozoan - Cyst
What are the four classes of parasitic protozoans?
- Amoebas (sarcodina)
- Ciliates (Ciliophora)
- Flagellates (Mastigophora)
- Sporozoa
move through pseudopods, and form cysts
Amoebas
i. Amoebic dysentery
ii. Many cases are asymptomatic
iii. 10% result in disease – symptoms include blood in diarrhea
Entamobea
i. Causes fatal infection of the brain
Naegleria
Name the two amoebas.
Entamobea
Naegleria
only one causes disease in humans.
Ciliates
i. Causes intestinal infection
ii. Transmitted by pigs or contaminated food that has pig fecal matter in it.
iii. Asymptomatic, but if symptoms arise they are nausea, vomiting, and diarrhea
Balantidium
Balantidium belongs to which protozoan group?
Ciliates
The group of protozoans that are motile with flagella
Flagellates
Causes intestinal infection and problems in uptake of fats that persists even after infection is cleared
Giardia
What is protozoan is responsible for these?
i. African sleeping sickness
ii. Chagas disease
Trypanosoma
spread by tsetse fly, causes central nervous system infection, coma and death
African sleeping sickness
spread by the kissing bug, varying symptoms but chronic disease results in damage to the heart.
Chagas disease
i. Spread by sand fly
ii. Causes cutaneous and visceral infections
Leishmania
i. Causes sexually transmitted infection such as: vaginitis in female and urethritis and prostatitis in males
Trichomonas
not mature in motile form.
Sporozoans
What protozoan causes this:
•malaria
i. Spread by Anopheles mosquito
ii. Fever, anemia, and circulatory changes.
iii. Marial paroxysm – feeling very hot and very cold
Plasmodium
What protozoan causes this: toxoplasmosis i. Spread by cat feces or raw beef ii. Asymptomatic in healthy individuals iii. Can damage or kill a fetus
Toxoplasma
Who am i
- Adult specimens can be seen with the naked eye.
- Diagnosis through eggs and larvae.
- Multicellular animals that are equipped with organs and organ systems.
- Most developed organs are the reproductive tract.
- Complete lifecycle includes the fertilized egg, larval, and adult stage.
Helminths
Who am i?
two groups Intestinal & Tissue. Sexes are separate and different in appearance
Nematodes
What group do I belong to? Enterobius (pin worms) Ascaris Necator (hook worm) Trichinella
Intestinal Nematodes
What group do I belong to?
i. Dracunculus (Guinea worm)
ii. Onchocerca
Tissue Nematodes
pin worm or seat worm. Common infestation of the large intestine
i. Microscopic eggs are swallowed
ii. Eggs hatch in the intestine
iii. Larvae mature into adults with in one month
iv. Female and male worms mate
v. Female migrates to the anus to deposit eggs
vi. Intestine itching ensues
vii. Scratching spreads the eggs
Enterobius
the largest nematode to infect humans
• Eggs are found in soil and are ingested with unwashed plants or can become airborne and swallowed
• Larvae hatch in the large intestine and adults can travel through the body
• Low worms loads cause no symptoms
• High worm loads can cause malnutrition, abdominal discomfort, and intestinal blockage.
Ascaris
– the hookworm
• Transmission is through the soil contaminated with human feces
• Causes anemia and loss of nutrients in the digestive tract
Necator
infection occurs through in ingestion of larvae contaminated tissue.
• Usually pork or bear meat
• Larvae live in the intestine but travel to the muscle tissue and encyst there.
Trichinella
the guinea worm
• Larvae enter the digestive system with contaminated water.
• Male and female worms mate in the intestine
• Males die and females then travel to the skin where they encyst, this causes a burning sensation
• The infected person goes to the water to relieve the burning, and the female releases the larvae into the water.
• Treatment can be to wrap the worm around a stick and slowly extract the worm. This takes several days.
• This may be the origin of the Rod and Asclepius – symbol of healing and medicine
Dracunculus
causes river blindness
• Can cause skin and eye lesions
Onchocerca
These are all? • Trematodes i. Paragonimus (lung fluke) ii. Clonorchis (liver fluke) iii. Schistosoma (blood fluke) • Cestodes i. Taenia (pork or beef tapeworm) ii. Diphyllobothrium (fish tapeworm)
Flatworms
the lung fluke
i. Spread by infected person coughing up sputum and spitting in the water.
ii. Eggs hatch into larvae that infect snail > snails release a different larval stage that infect crustaceans > human eats undercooked crustaceans and are infected and the larvae produce adult worms which lay eggs in the lungs.
Paragonimus
spread by eating under cooked fish
i. Causes abdominal pain nausea, diarrhea and bile duct obstruction.
Snail is intermediate host
Clonorchis (liver flukes)
no treatment for this worm
i. Larvae from contaminated water penetrate the skin > larvae are release back into the water via urine and feces >
Causes infection in the blood vessels, digestive and urinary tracts. Can cause kidney failure from UTI’s, and seizures if the worms are in the CNS
Schistosoma
tapeworms
i. Have a head (scolex), with hooks and or suckers.
ii. Have a regenerative neck.
iii. Proglottids are segments that contain ovary and testes that produce fertilized eggs
iv. Infections occur from eating undercooked meat
v. Proglottids are excreted and contaminate soil and plants.
vi. Patients with low worm load are normally asymptomatic, but high load patients can have malnutrition, and intestinal obstruction may occur.
Taenia and Diphyllobothrium
the study of inheritance
Genetics
sum total of genetic material of an organism.
Genome
a segment of DNA that code for a functional part
Gene
the sum of all gene types; an organisms distinctive genetic make up.
Genotype
The expression of the genes to create certain traits.
Phenotype
• DNA condensed into a packet with proteins. (not histone proteins)
Single, circular chromosome
Prokaryotic Chromosomes
- DNA wound around histones
- Located in the nucleus
- Diploid - two of each type of chromosome
- Haploid – one of each type of chromosome
Eukaryotic Chromosomes
Nucleotide - unit of DNA structure
• Phosphate
• Deoxyribose sugar
• Nitrogenous base
• Sugar-phosphate linkage that becomes the backbone of each strand.
1. Nitrogenous bases attach along a stand by covalent bonds to the sugar:
• Purines and pyrimidines join with complementary bases on the opposite strand using weak hydrogen bonds.
• Easily unzipped
2. Paring of bases
• Guanine, Cytosine, Adenine, Thymine
3. Nature of the double helix
• Antiparallel arrangement – one side of the helix runs in the opposite direction of the other.
DNA Structure
Begins at the Origin of Replication > topoisomerase unwinds the supercoils and larger coils of DNA > helicases unwind and separate the helix by breaking the hydrogen bonds that hold the two sides together creating an area called a replication fork > DNA an antiparallel the two sides are called the lagging stand and the leading strand > leading strand primase creates an RNA primer > DNA polymerase is able to attach to the RNA primer and synthesize DNA in the direction of the opening replication fork > Rnas H eventually removes the RNA primer > DNA polymerase fills in the gap > DNA ligase the covalently bonds the two pieces together > lagging strand antiparallel the direction of the DNA replication run in the other direction > Primase will create RNA primers and the helix opens > DNA polymerase will synthesize DNA > Okazaki fragments are left > Rnas H removes RNA primers and DNA polymerase replace them with DNA for each Okazaki fragment > ligases move along the lagging strand to remove fragments.
DNA replication –
- Single stranded molecule
- Can assume secondary and tertiary levels of complexity
- Contains Uracil instead of Thymine
- Contains ribose instead of deoxyribose
- Structure of RNA
Three types of RNA involved in translation are?
rRNA
mRNA
tRNA
makes up the ribosome along with associated proteins.
rRNA
a copy of genetic code of a gene.
i. Contains codons – each codes for an amino acid.
mRNA
carry the amino acids to the ribosome during the process of translation.
has an anticodon that corresponds to a codon on the mRNA
tRNA
the process of making an RNA copy of a gene
Transcription
Transcription consists of three steps:
i. Initiation
ii. Elongation
iii. Termination
RNA polymerase blinds to a section of DNA at the beginning of a gene called a promoter.
Initiation
RNA polymerase moves along the template side of the DNA, and makes an RNA copy of a gene.
Elongation
RNA polymerase reaches a terminator and drops off, releasing newly made RNA.
Termination
the process of using mRNA and tRNA’s and ribosome to produce a protein.
Translation
Translations three steps:
i. Initiation
ii. Elongation
iii. Termination
three types of RNA come together and start a codon. Small subunit of the ribosome bind to the mRNA at the start codon. First tRNA carrying the amino acid methionine blinds to the start codon.
Initiation
the ribosome moves along the mRNA reading one codon at a time, adding the amino acids. This step is where the protein is made.
Elongation
ribosome continues moving along until a stop codon is reached. Enzyme attaches and releases all the components – the ribosome, the last tRNA, the mRNA and the finished protein.
Termination
consist of a coordinated set of genes regulated as a single unit. (only in bacteria)
Operon
code for proteins needed all the time.
Constitutive genes
Induced by the substrate of the enzyme(s) for which the structural genes code.
• Only produce the enzyme when the substrate is present
Inducible (catabolic) operon
Anabolic enzymes
• Turned off by the product synthesized by the enzyme.
Repressible operons
it is off unless lactose is present and then it can be activated
The lac operon is an inducible operon
• Three features of the?
Regulator: composed of the gene that codes for the protein capable of repressing the operon (repressor). This repressor is usually active but can be inactivated by lactose
Control region:
Promoter: recognized by RNA polymerase (same promoter as in transcription)
Operator: on/off switch
Structural region made up of three genes coding for a different enzymes needed to catabolize lactose
lac operon
- In a repressible operon, genes are
• An example of a repressible operon is
usually transcribed and translated but they can be repressed (turned off)
the trp operon that contains genes used in the synthesis of tryptophan.
Mode of genetic exchange in which a plasmid or other genetic material is transferred by a donor to a recipient cell via a direct connection
Conjugation
is a conservative process in which the donor bacterium retains (conserves) a copy of the genetic material being transferred.
Conjugation
Which conjugation am i?
• Fertility (F’ factor) allows the synthesis of a conjugative pilus
• Recipient cell has a recognition site on its surface for the pilus.
• F+: cell that has the plasmid
• F-: cell that lacks the plasmid
Gram-negative conjugation
Which conjugation am i?
• An opening is created between two adjacent cells (no pili)
• Hfr:
• Replicated DNA passes across from one cell to another
• In high frequency recombination (Hfr) donors the plasmid is integrated into the bacterial chromosome
• When Hfr cells conjugate with recipient cells some of the Hfr cell’s genes may be transferred along with the plasmid genes
• Creates even more recombination
Gram - positive conjugation
involves the transfer of naked DNA (DNA in solution) from a donor cell to a recipient cell.
Transformation
Transfer of DNA from a donor cell to a recipient cell inside a bacteriophage (virus that infects bacteria) is?
Transduction
- Bacteriophage serves as a carrier from a donor cell to a recipient cell
- Random fragments of disintegrating host DNA are taken up by the bacteriophage
- Virtually any gene from the bacterium can be transmitted
Generalized Transduction
• Highly specific part of the host genome is regularly incorporated into the virus.
Specialized Transduction
are segments of DNA capable of moving from one part of the genome to another
• Can be transferred from a chromosome to a plasmid, or vice versa; or from one cell to another in bacteria and some eukaryotes
• Some replicate themselves before jumping to the next location and some simply move
Transposon (Jumping genes)
any change to the nucleotide sequence in the genome.
Mutation
a random change in the DNA arising from errors in replication (not common)
Spontaneous mutation
result from exposure to known mutagens, which are primarily physical or chemical agents that disrupt DNA
• Radiation: UV light, X rays, Gamma rays
• Chemicals: nitrous acid
Induced mutations
alters a base, but does not change the amino acid, and has no effect
Silent mutation
- One or more bases are inserted or deleted
- Changes the reading frame of the mRNA
- Nearly always results in a nonfunctional protein
Frameshift mutation
- A change in the code that leads to the placement of a different amino acid
- Can create a faulty, nonfunctional protein
- Can produce a protein that functions differently
- Can cause no significant alteration
Missense mutation
one nucleotide change that changes a normal codon into a stop codon. Produces an incomplete protein.
Nonsense mutation
¥ DNA polymerase has a proofreading mechanism to repair mistakes made during replication.
¥ The cell has additional systems for finding and repairing DNA that has been damaged outside of replication.
¥ UV damage repair:
i. Photoactivation/light repair through photolyase.
ii. Successful only for a small number of UV mutations
Mutation Repair
i. Enzymes break the bonds between the bases and the sugar-phosphate strand at the site of the error.
ii. A different enzyme removes the defective bases one at a time.
iii. The remaining gap is filled in by DNA polymerase I and ligase.
Excision repair
Allows biotechnologists to cleave DNA at desired sites
Restriction endonucleases -
Produces a readable pattern of DNA fragments.
• Creates a genetic finger print.
Gel electrophoresis -
Rapidly increases the amount of DNA using heat to separate DNA strands and DNA polymerase to replicate them followed by cooling
Polymerase Chain Reaction -
Primary intent is to deliberately remove genetic material from one organism and combine it with that of a different organism
• Bacteria can be genetically engineered to mass produce:
i. Hormones
ii. Enzymes
iii. Vaccines
Recombinant DNA technology -
Creating identical copies of DNA, cells or higher organisms through asexual means.
Genetic clones/cloning
collections of DNA clones that represent the entire genome of numerous organisms
Genomic libraries:
Small, well characterized, easy to manipulate
Can be transferred into appropriate cells through transformation
Plasmids
have the natural ability to inject DNA into bacterial hosts
Bacteriophages:
What typically contain a gene that confers drug resistance to their cloning host.
• Cells can be grown on drug-containing media.
• Only those cells that harbor a plasmid will be selected for growth.
• Vectors
