exam 1 final Flashcards
what are the size ranges of prokaryotes
Size: 0.20 to 2.0 um in diameter 2-8 um in length
1735 – Carolus (Carl) Linnaeus
established the system of nomenclature (naming) for organisms which assigns each organism 2 names…
A. Genus is the 1st name and is always Capitalized and underlined or italicized.
B. Specific epithet or species is the 2nd name and is not capitalized, but is underlined or italicized.
Example:
1. Staphylococcus aureus or
- Staphylococcus aureus*
2. Escherichia coli or Escherichia coli
1867 - Joseph Lister
English surgeon
initiates aseptic surgical techniques.
He began soaking surgical dressings in a mild solution of carbolic acid (phenol) which kills bacteria.
This reduced the incidence of infections and deaths in surgical patients.
Founder of aseptic surgery
1876 -83 Robert Koch
proved the germ theory of disease
discovered a rod-shaped bacteria now known as Bacillus anthracis in the blood of cattle that had died of anthrax.
He cultured the bacteria and injected samples of the culture into healthy animals which became sick and died.
Koch isolated the bacteria in the blood and found it to be the same as the original bacteria isolated.
Experimental procedure used to relate specific microbe to a specific disease is known as Koch’s postulate
1881 - developed pure culture and staining techniques.
• 1882 - discovered Mycobacterium tuberculosis, the causative agent of
tuberculosis.
• 1883 - discovered Vibrio cholerae, the
causative agent of cholera.
1880 - Louis Pastuer
developed immunization techniques based on Edward
Jenner’s work with smallpox (vaccination)
• Avirulent form of bacterium causing fowl cholera can induce immunity against subsequent infections by virulent counterpart.
Vaccine: cultures of avirulent microorganism used for preventative inoculations
also discovered Streptococcus pneumoniae (1881), the causative agent of pneumococcal pneumonia.
1885 - Theodor Escherich
of Germany discovered Escherichia coli, the
causative agent of urinary tract infections and traveler’s diarrhea.
1887 - Richard Julius Petri
of Germany introduced a covered dish for growing microorganisms on a solid medium. (petri dish)
1890 - Paul Ehrlich
of Germany proposed a theory of immunity in which antibodies are responsible for immunity.
- Discovery of chemotherapy—treatment of disease by use of chemical substances (i.e. synthetic drugs & antibodies)
- Magic bullet — substance that could target and destroy the pathogen without harming the host
- Salvarsan (arsenic derivative; 1910)— chemotherapeutic agent against syphillis
1892 - Dmitri Iwanowski
of Russia discovered a filterable organism (virus) caused tobacco mosaic disease.
- What determines whether a person will contract a disease?
a. the disease producing properties of the microorganism
b. the resistance of the body.
1928 - Alexander Fleming
Scottish physician and bacteriologist
discovered the antibiotic, penicillin, by accident
Thus he discovered a mold (fungus), Penicillium chrysogenum which could inhibit the growth
of bacteria.
Adenosine Triphosphate = ATP
is the principal energy-carrying molecule (potential form of energy).
- is composed of adenine, ribose, and 3 phosphate groups
- energy is released when a phosphate is removed ATP———–>ADP + Pi + Energy
Algae:
DIVERSITY OF MICROORGANISMS - are photosynthetic eukaryotes. - wide varieties of shapes. - are members of the kingdom Protista. - reproduction is sexual or asexual.
Beneficial Activities of Microorganisms
1. Microorganisms degrade dead plants and animals and recycle chemical elements such as nitrogen, carbon, oxygen, sulfur, and phosphorus.
Example - bacteria and fungi return carbon dioxide to the atmosphere when decomposing organic matter…carbon cycle
Example - Nitrogen fixation - converting nitrogen gas into ammonia (i.e. Rhizobium species)
2. Microorganisms are used to decompose
organic matter in sewage…recycle water and prevent pollution (bioremediation) of rivers and oceans
Bioremediation: use of microorganisms to remove environmental pollutant
(Zoogloea ramigera).
3. Microorganisms (i.e. Bacillus thuringiensis) cause disease in insects and thus can be used as a biological control in insect pests (instead of pesticides which harm the environment).
-
Microorganisms can be used to produce food such as:
a. soy sauce (Aspergillus oryzae (fungi) b. yogurt (Streptococcus thermophilus)
for acid production,
Lactobacillus bulgaricus for flavor and aroma).
- Using biotechnology and recombinant DNA technology, bacteria, can be used to produce human proteins:
a. insulin
b. factor VIII
c. tissue plasminogen activator d. growth hormone
e. use in gene therapy
Carbohydrates
- Are sugars and starches (chain of glucose)
- Basic building block = Monosaccharide (simple sugars) - General composition: (CH2O)n
- 3 major groups:
- monosaccharides: contains 3-7 C atoms;
i. e. glucose, fructose, galatose, deoxyribose, ribose - disaccharides: formed by the bonding of 2 monosaccharides in a dehydration synthesis reaction
i. e. glucose + fructosesucrose glucose + galactoselactose
glucose + glucosemaltose
conjugated proteins
modified protines
ex
- glycoproteins contain sugars
- nucleoproteins contain nucleic acids 3. metalloproteins contain metal atoms 4. lipoproteins contain lipids
Edward Jenner
1798
developed the first vaccine for smallpox
milkmaid couldn’t get smallpox because she had already been sick with cowpox, a much milder disease
Jenner decided to test this story:
collected scrapings from cowpox blisters and made inoculations with this material by scratching the arm of a healthy volunteer with the cowpox contaminated needle.
The person became mildly sick but recovered and never
contracted either cowpox or smallpox
Francesco Redi
Opposition to spontaneous generation: 1668
expirament:
3 jars with decaying meat and sealed them tightly, no maggots
• 3 jars with decaying meat and left them open, maggots • There were doubter still…magical substance in fresh
air was needed for spontaneous generation to occur…
Functions of carbohydrates:
a. provide a source to produce energy, mainly ATP, for the cell.
b. function as food reserves
c. Deoxyribose sugar is backbone of DNA (deoxyribose nucleic acid).
d. are components of cell walls of bacterial cells
Functions of proteins
- Structural proteins
- microfilaments for movement of cells
- cell membranes or cell walls
- carrier proteinstransport molecules into and out of cells - Enzymes: catalyze chemical reactions 3. signaling molecules
- Toxins are produced by certain bacteria;
Bacteriocins: proteins produced by some bacteria that kill other bacteria.
- Hormones for regulatory function (i.e. insulin) 6. Antibodies for immune function
Fungi
- are eukaryotes. - are members of the kingdom Fungi. - are unicellular (yeasts) or multicellular (mushrooms). - True fungi have cell walls composed of chitin. - Yeasts are oval-shaped microorganisms larger than bacteria. - Molds are typical fungi. - reproduce sexually (meiosis) or asexually (mitosis).
give at least 3 examples of microorganisms and the food product they are make.
a. soy sauce (Aspergillus oryzae (fungi) b. yogurt (Streptococcus thermophilus)
for acid production,
Lactobacillus bulgaricus for flavor and aroma).
c. cheese (Propionibacterium species produce holes in Swiss cheese by producing carbon
dioxide. )
d. bread (San Francisco sourdough bread requires
Saccharomyces exiquus and Lactobacillus
sanfrancisco) .
e. alcoholic beverages (wine requires the yeast
Saccharomyces cervisiae ).
43
hydrophilic amino acids
- basic
- lysine (lys)
- argininine (arg)
- Histidine (his)
- acidic
- asparate (asp)
- glutamate (glu)
- polar amino acids
- serine (ser)
- threonine (thr)
- asparagine (asn)
- Glutamine(gln)
- thyrosine (tyr)
hydrophobic amino acids
- Alanine (ala)
- valine (val)
- Isolucine (ile)
- Lucine (leu)
- Methinonine (met)
- Phenylalanine (phe)
- Tryptophan (Trp)
John Needham
Proponent of spontaneous generation 1745
He heated nutrient fluids (chicken broth and corn broth), cooled it, and then poured it into covered flasks, the solutions were teeming with microorganisms.
Needham claimed that the microbes developed spontaneously from the fluids.
Lazzaro Spallanzani
1765
disproved Needham conclusion
- suggested that microorganisms from the air probably entered the solutions from the air after they were boiled.
- showed that nutrient fluids heated after being sealed did not develop microbial growth.
Lipids
Are “fat”
- Lipids
- Are composed of C, H, O
- Are nonpolar molecules; can’t dissolve in water
- F(x)s: energy source
- constituent of plasma membranes and cell walls
Types of lipids:
Triglycerides = simple lipids or fats
Complex lipids
- Steroids
Louis Pasteur
1861 demonstrated that microorganisms are present in the air and that they can contaminate sterile solutions, but air itself does not create microbial life.
During a job on understanding why wine and beer sour, discovered that microorganisms called yeasts convert sugars to alcohol in the absence of air.
This is called FERMENTATION (1857).
Discovered pasteurization (1864)…process of
heating to kill bacteria to reduce/prevent spoilage
This was the first link that microorganisms can cause changes in organic materials.
that microorganisms might cause disease
introduced germ theory of disease
nucleic acids
Nucleotides are the basic building blocks of nucleic acids (DNA and RNA molecules—genetic material)
• Are composed of
– Phosphate group
– Pentose: 5-carbon sugar molecule
-deoxyribose vs ribose – Nitrogenous Base
Deoxyriboucleic Ribonucleic Acid Acid
Peptide bond
joins the amino end of one aa to the carboxyl end of another aa
phospholipids
(glycerol, 2 fatty acid, phosphate group)
- has polar and non-polar ends
- is major constituent of cell membranes—phospholipid bilayer
Prions
(Proteinaceous infectious particles) infectious proteins. Unlike bacteria or viruses, prions do not require any DNA or RNA infectious. A prion is a misfolded protein has lost its normal conformation and function while acquiring the ability to convert other molecules of the same protein from the conformation into the abnormal prion form. This form of self propagation explains the infectious nature of prions. In all of the prion proteins
studied, the transformation between the normal and prion forms occurs through a dramatic change in the protein’s three-dimensional structure. Prions cause diseases such as Creutzfeldt-Jakob disease (CJD; Kuru) in humans, in sheep (scrapie), and bovine spongiform encephalopathy (BSE or mad-cow disease).
prokaryotes
(“prenucleus”)Its genetic material is not enclosed in a nuclear membrane
Protein chain (polypeptide)
is formed by amino acid monomers joined together by covalent peptide bonds
Protein: Structure
Primary (1o) structure:
– The linear sequence of amino acid
– Also known as the protein sequence
- Secondary (2o)structure:
– It is the regularly repeating conformation of the
peptide backbone
– Helix; Strands sheets; turns
– A polypeptide usually has different secondary structures at different regions
– Is dependent on the amino acid sequence of the different regions.
– Structure is stabilized by H-bonds
- Tertiary (3o) structure:
– Is the 3D arrangement of all the polypeptide’s amino acid residues
– Is formed by packing various combinations of 2o structures
– Structure is stabilized by a variety of non- covalent bonds between aa side chains (i.e. hydrophobic)
- Quaternary structure:
– The overall structure and organization of more than one polypeptide chain
– Each polypeptide chain in this protein is referred to as a subunit.
Amino acids (aa)
are the monomeric building blocks of proteins
There are 20 different aa.
All organisms on earth have the same 20 aa.
Each protein being synthesized are made from the different arrangements of the aa.
Each aa monomer has 4 different groups attached to the central carbon atom (C)
The nature of an aa is based on the composition of its side chain.
- 20 different aa20 different side chains
- Each side chain differ in: – Size
Hydrogen
– Shape
– Charge
– Hydrophobicity
Protozoans:
- unicellular eukaryotes - are members of the kingdom Protista - are classified according to their means of locomotion 1. cytoplasmic streaming (amoebas) 2. flagella 3. cilia - shapes vary - can live free or as parasites. - reproduction is sexual or asexual. (Fig. 1.1c)
1884 - Hans Christian Gram
developed a differential staining technique
called the Gram stain which differentiates bacteria into 2 groups, gram (-) and gram (+).
Rudolf Virchow
1858 Theory of biogenesis: living cells can arise only from preexisting living cells
special amino acids
cysteine (cys)
glycine (gly)
proline (pro)
Theory of biogenesis:
living cells can arise only from preexisting living cells
There are five different nitrogenous bases:
Triglycerides
are formed by the dehydration reaction of one glycerol with 3 fatty acids.
- glycerol have 3 hydroxyl (-OH) groups attached to 3 C atoms
- fatty acids are composed of long hydrocarbon (H-C) chains ending with carboxyl (-COOH) group.
Viruses :
- are so small that they can only be seen with an
electron microscope.
- are not cellular.
- are parasites which require a host cell to replicate itself.
- simple structure:
- Core contains the nucleic acid (DNA or RNA)
- Protein coat surrounds core
- Lipid envelope may surround coat
Complex lipids:
- contains elements (i.e. phosphorus, nitrogen, sulfur) in addition to C, H, O
- Examples are waxes and glycolipids.
- cell walls of bacteria belonging to the genus
Mycobacterium contain waxes & glycolipids; provides distinguishing staining characteristic
(acid-fast stain)
- example: phospholipids (glycerol, 2 fatty acid, phosphate group)
has polar and non-polar ends
- is major constituent of cell membranes—phospholipid bilayer
Which nucleotide is present in DNA?
gram stain procedure
- Apply crystal violet which colors all bacteria purple (primary stain)
• Wash off w/ddH O. 2
- Apply iodine, a mordant, all bacteria still purple.
- Wash with ethanol or ethanol- acetone solution, a decolorizing agent
- Gram + bacteria will be purple; Gram - bacteria will be colorless
- wash off w/ddH2O
- stain with safranin, a counterstain.
- Gram (-) will be pink; Gram (+) will be purple - wash off w/ddH2O
- blot dry 19
- examine microscopically
Gram-positive
no membrane covering peptidoglycan wall
Gram (+) bacteria have a thicker cell wall composed of peptidoglycan than gram (-) bacteria
Gram-negative
outer membrane covers peptidoglycan wall
Gram (-) bacteria have a thin layer of peptidoglycan and outside of that, a layer of lipopolysaccharide
Negative Staining for Capsules
- capsule: a gelatinous covering of some microbes;
confers virulence(polysacharide or polysacharide protine)
- is more difficult than other types of staining procedures because capsules are soluble in water and may be removed during washing.
Negative staining for capsuls: Procedure
a. Mix bacteria with Nigrosine, an acidic dye which provides a
dark purple background.
b. Spread dye as in negative staining.
c. Stain slide with crystal violet, basic dye to stain bacteria (purple)
d. Capsules will appear as colorless halos surrounding purple bacterial cells against a dark purple background.
Schaeffer-Fulton Endospore Stain
a. Apply malachite green to heat-fix smear on slide and steam heat for 5 minutes. Spores will stain green and cells will be colorless.
b. Wash
c. Counterstain with safranin, which will stain the cells
pink. Spores will be green. d. Wash
- Flagella Staining
Flagella are structures of locomotion.
- Staining flagella involves using a mordant and carbolfuchsin to build up the diameters of the flagella until they become visible under the light microscope.
- It is a tedious and delicate staining procedure.
TransmissionElectronMicroscopy (tem)
- can resolve objects as close as 2.5 nm
- Magnification is from 10,000X to 100,000X.
- Only a very thin section (about 100 nm) of a specimen can be studied effectively
- can’t obtain 3D image
- Specimens must be fixed, dehydrated, and viewed under vacuum; therefore, shrinkage and distortion may occur; may get artifacts
Fluorescence microscopy:
- uses an ultraviolet source of illumination that causes fluorescent compounds to emit light.
- Some organisms fluoresce naturally.
- Other organisms can be stained with fluorescent dyes called fluorochromes.
- Specimens appear as luminescent objects against a dark background
Combine a fluorochrome to a
specific antibody for a specific antigen.
Allow the antibody to combine with the specific antigen
Wash to remove non-specific binding
Thefluorochrome-antibody- antigen fluoresces under UV light
- is useful in diagnosing syphilis and rabies or detecting specific cell types, tissues, or structures
(Fig. 3.6a)
7
Scanning Electron Microscope: (sem)
- Image is 3-dimensional
- It can study surface structures of intact cells & viruses
- resolves objects as close as
20 nm
- Magnification is 1000X to 10,000X
Power of resolution of human eye, light microscope, and electron microscope:
Prokaryotes: Shape
-1. Spherical or coccus (pl. cocci)
- Diplococci = two cocci
- Streptococci = cocci in chains
- Tetrads = cocci that divide in two planes and remain in groups of four
- Sarcinae are cocci that divide in 3 regular planes and produce a cube- like group of 8
- Staphylococci are those that divide at random planes and form grape like clusters or broad sheets
Prokaryotes: Shape
- Rod-shaped, bacillus (bacilli, pl.)
- divide only across their short axis.
- Diplobacilli appear in pairs after division.
- Streptobacilli occur in chains. - Some have tapered ends like
cigars.
- Coccobacilli are oval and may look like cocci.
- Most appear as single rods.
- bacillus means:
a. bacterial shape
b. genus (i.e. Bacillus anthracis)
Flagellum: structure
- Three basic parts:
a. Filament is the long outermost region which is constant in diameter and contains the globular protein flagellin - not covered by membrane or sheath
b. Hook is the structure to which the filament is attached
c. Basal body anchors the flagellum to the cell wall and the plasma membrane.
(Fig. 4.8)
- It is composed of a central rod inserted into a series of rings.
Axial Filaments:aka endoflagellum
- are bundles of fibrils that arise at the ends of the cell
beneath the outer sheath and spiral around the cell.
- used as a form of locomotion by spirochetes such as Treponema pallidum, the causative agent of syphilis.
3. Rotation of filament causes spiral motion that resembles the movement of a corkscrew
Structure of peptidoglycan:
