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186 Cards in this Set
- Front
- Back
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Bacteria--what are they, what size are they typically?
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Single-celled prokaryotic organisms, about 0.5-2 um large.
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Archea
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Prokaryotic cells that lack the polysaccharide, peptidoglycan in the cell walls.
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Eukaryotic cell
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Contains a "true nucleus," also has membranous organelles and includes animal cells, plant cells, fungi, and protozoa.
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Prokaryotic cell
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Has no true nucleus, its DNA is found on chromosomes in the cytoplasm and does not contain membranous organelles. This is unique to bacteria and archea.
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List the three domains:
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Bacteria--prokaryotes
Archea--prokaryotes Eukarya--eukaryotic cells |
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Types of Eukaryotic organisms:
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Fungi
Protozoa Helminths |
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Fungi
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Can be single-celled yeasts or multicellular molds and are heterotrophic .
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What are fungal diseases called?
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Mycoses
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What can fungal diseases affect?
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Respiratory tract,skin, systemic infections.
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What organisms cause a number of GI diseases?
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Protozoa
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Helminths
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Worms (not really microbes)
Includes tapeworms, flukes, and roundworms that can attack different organs. |
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Viruses
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Acellular organisms that consist of nuclear material (DNA) surrounded by protein coat.
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How do viruses grow?
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By changing the metabolism of the cells they invade.
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Contagion
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Believed that something was transmitted to cause disease (coined in 1500s).
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Spontaneous generation
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Believed that living organisms can from non-living material (late 1700s).
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Give an example of spontaneous generation:
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Old meat left out will produce maggots.
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Who is considered the "Father of Microbiology?"
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Leeuwenhook (Late 1600s) credited with observing first live microorganisms.
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Who coined the term "cell" and was credited with creating the concept of a microscope?
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Robert Hooke
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Semmelweis
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First stressed the importance of hand-washing after realizing that doctors that went straight from autopsies to delivering babies transmitted life-threatening diseases. (Mid 1800s)
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Lister
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In addition to Semmelweis, also contributed to controlling infection. Credited with the creation of modern-day microscopes. Put phenol on bandages and tools to reduce infection.
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Pasteur
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Defeated the idea of spontaneous generation by developing flask where air could enter and microorganisms could not. Pasteurization--heating liquid at high temperatures to kill microbes.
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Who created the vaccination against rabies?
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Pasteur
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Koch
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Developed ways of studying bacteria in a lab (Agar and pure cultures)
Also discovered the cause of anthrax and tuberculosis. |
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Koch's postulates:
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a. Agent must be found in every case
b. Isolated in pure culture c. Inoculation should produce the same disease in another animal d. Should be able to isolate organism again from diseased animal. |
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Jenner
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Vaccination against small pox using cowpox.
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Fleming
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Discovery of penicillin in 1920s from mold penicillin.(Began field of chemotherapy).
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Mycology
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Scientific study of fungi.
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Example of a fungal disease:
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Ringworm (skin, fungi overgrowth)
Thrush (mouth, candida) |
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Bacteriology
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Study of bacteria, identification, classification, and characterization of bacterial species.
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Parasitology
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study of parasites
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Virology
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Study of viruses
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Microbial genetics
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Study of genetics of microorganisms.
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Medical microbiology
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Study of microorganisms that are capable of causing infections and diseases in humans.
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Bioremediation
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Use of microorganisms to metabolize toxins in environment to reclaim soils and waterways.
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Industrial microbiology
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Use of microorganisms in the manufacture of food or industrial products.
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Non polar covalent bonds
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Bonds where electrons are shared equally.
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PH
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Hydrogen ion concentration.
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Buffer
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Solution that is resistant to large changes in PH.
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Monosaccharide
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Simple sugar--the basic subunit of a carb.
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Disaccharide
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Two monosaccharides joined together
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Triglyceride
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Three fatty acid tails and a glycerol backbone.
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Fatty acid
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Long carbon chain carboxylic acid
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Hydrophilic
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Affinity for water.
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Sterol
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Lipid with no fatty acids
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Peptide bond
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Bond that links amino acids in proteins
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Enzymes
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Protein catalyst for specific reactions
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Histones
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Protein molecule around DNA tightly coiled in chromatin.
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Gene
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Unit of inherited information in DNA.
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Hydrolysis
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Breaking down molecules by addition of water
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Polar covalent bonds
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Unequal sharing of electrons
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Specific heat
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Amount of heat required to raise temperature of 1g of substance to 1 degree Celsius.
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Acidity
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Concentration of H+ ions.
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Alcohol
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Substituted hydrocarbon that contains
one or more hydroxyl groups. |
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Carbohydrate
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Organic molecule composed of carbon, hydrogen, and oxygen
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Polysaccharide
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Polymers with up to thousands of monosaccharides linked in dehydration synthesis.
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Steroid
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Lipids that play a role in metabolism.
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Amino acid
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Monomers, basic building blocks of proteins
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denaturation
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Protein loses structure because of physical or chemical factors.
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Nucleic acid
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Polymers, nucleotides linked by covalent bonds.
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How much of a cell is water?
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About 65-75%
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Importance of water in cells:
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Important solvent
Temperature regulation Plays a role in chemical reactions |
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What is a by product of a cell's metabolism?
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Heat is a by product
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What does it mean to say that water has a high specific heat, and how does this benefit the cell?
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It takes alot of heat to raise the temperature of water to one degree--this benefits the cell because a major by product of a cell's metabolism is heat.
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How does water play a role in chemical regulation?
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By hydrolysis and dehydration, adding water to break bonds and removing water to make bonds.
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What range of PH can most bacteria tolerate?
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6.5-8.5
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What type of PH can Helicobacter Pylori tolerate, and what does it cause?
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Can tolerate very low PH as low as 1.5--causes stomach ulcers.
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Name three polysaccharides:
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Starch, Glycogen, and Cellulose.
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Main function of carbohydrates:
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Provides a source of energy.
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If starch is broken down by bacteria, what would be the end result?
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Monosaccharides
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Key functions of fat:
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Stores energy, catabolize to provide energy
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What elements do fats contain?
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Carbon, Hydrogen, Oxygen.
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Are fatty acids polar or non-polar?
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Non-polar tail, polar head.
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Do triglycerides dissolve in water?
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No.
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Types of steroids:
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Made from cholesterol, Estrogen, Progesterone, and testosterone.
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Waxes
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One chain fatty acid, completely insoluble in water.
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What elements are proteins made of?
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Nitrogen, Carbon, Hydrogen, and Oxygen.
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Main functions of proteins:
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Catalysts, transportation, defense, regulation (cell function), structure.
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Levels of protein structure:
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Primary structure
Secondary structure Tertiary structure and Quaternary structure |
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What are the primary and secondary structures of proteins?
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Amino acid sequence and folded structure/pleated sheet.
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Tertiary and quaternary structures of proteins:
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Complex three-dimensional shape and two or more polypeptide chains linked.
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Two basic types of nucleic acids:
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DNA and RNA
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Characteristics of enzymes:
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Reaction-specific
Can be used repeatedly Catalysts Protein PH/Temperature sensitive |
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Three parts of a nucleotide:
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Phosphate group
Sugar Nitrogenous base |
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Four bases in RNA:
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Adenine, Guanine, Cytosine, Uracil.
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Four bases in DNA:
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Adenine, Guanine, Cytosine, and Thymine.
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How does structure of RNA differ from that of DNA?
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It contains ribose instead of deoxyribose, has nitrogenous base uracil rather than thymine, and has single helix rather than double.
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Do Eukaryotes have histones? What about prokaryotes/archea?
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Eukaryotes and archea have histones. Prokaryotes do not.
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Resolution
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Whether or not two objects can be distinguished as separate objects under the microscope.
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What does high resolving power mean?
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Two objects very close together can be distinguished.
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Microscopy
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Using electrons or light to magnify objects.
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Light microscopy
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Using light waves to view specimens.
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Electron microscopy
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Beams of electrons rather than light rays, only way to view images less than 1 um (0.2 um).
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Types of electron microscopy:
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Scanning electron microscopy (3d images of surface)
Transmission electron microscopy (inside of cells) |
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Staining
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Using colored dyes in light microscopy to make organisms easier to identify.
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Steps involved in staining:
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1. Make a smear
2. Heat fix them 3. Add a dye and rinse |
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Types of simple stains:
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Crystalline violet, methylene blue
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What is the purpose of heat fixing bacteria onto a slide?
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Attaches the microorganisms to the surface.
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Simple stain
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One dye is used to color the bacteria
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Negative stain
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Repelled from bacteria, and the background is stained (does not mean gram negative).
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What type of charge do bacteria generally have? What type of charge will a simple dye usually have?
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A negative charge/positive charge.
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How does staining work?
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Because bacteria has a negative charge, it attracts the positively charged dye, which colors the bacteria. In the case that the dye is acidic or negatively charged, the negatively charged bacteria repels the dye, and the background is colored instead, creating a halo around bacteria (Capsule staining).
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Differential stain
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Uses more than one stain to differentiate between bacteria or structures.
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Types of differential stains:
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Ziehl Neelsen acid-fast stain and Gram stain.
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What is the Ziehl Neelsen stain used for?
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Used for mycobacterium tuberculosis--it retains red stain because of lipid in the cell wall, other bacteria will be blue.
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Gram stain
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Bacteria divided into gram positive and negative based on cell wall structure.
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Why are endospores difficult to stain?
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Because of their impermeable walls.
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How many steps are involved in gram staining? What are they?
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4 steps
Primary stain Mordant Decolorizer Counterstain |
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Shapes of bacteria
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Coccus--round
Bacillus--rod-shaped Spirilla (spirochete)--wavy/corkscrew |
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Staphylo--
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Arranged in clusters
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Strepto--
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Arranged in chains
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Diplo--
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Two bacteria (together)
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Pleomorphic
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Ability of some bacteria to change/morph shape depending on the circumstances.
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External structures of prokaryotic cells:
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Glycocalyx
Pili Fimbriae Flagella |
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Do prokaryotes have cell wall and membrane?
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Yes?
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What is the cell envelope?
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Often glycocalx + cell wall + cell membrane.
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Flagella
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Long structures that extend beyond surface of the cell and glycocalyx and propel cell throughout the environment.
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Fimbriae
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Bristle-like projections to adhere to one another and environment.
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Pili
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Type of fimbriae longer than other fimbriae but shorter than flagella, only a few per cell when present.
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Cell wall in prokaryotes
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Provides structure and shape and protects from osmotic forces.
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Cell membrane of prokaryotes
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Beneath cell wall and glycocalyx, 8 nm thick and composed of phospholipids.
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Glycocalyx
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Layer of polysaccharides and peptides external to cell wall that keeps cells from drying out.
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Capsule
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Dense gel bound tightly to the cell, anti-phagocytic.
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Slime layer
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Thin and not bound tightly , binds cells together and traps nutrients.
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Structure of flagella
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Basal body + hook + filament
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Types of flagellation:
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Monotrichous
Lophotrichous Peritrichous Amphitrichous |
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Monotrichous flagella
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One flagella on one side of organism.
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Lophotrichous flagella
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Group of flagella on one side of organism.
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Peritrichous flagella
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Flagella on all sides, around organism.
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Amphitrichous flagella
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Flagella on both sides of organism.
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What shape of organisms have "internal flagella" and what are they called?
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Spirochetes have axial filaments (internal flagella).
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Possible movements of flagella:
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Rotation, runs and tumbles, and taxis.
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Conjugation pili
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Transfers DNA from one bacterium to another.
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How do fimbriae help create biofilms?
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Can act as electrical wires, conducting electrical signals among cells in a biolfim.
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Why would Neisseria gonorrheae have fimbriae?
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Allows it to attach to host cell and cause disease (gonorrhea).
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Main functions of cell wall:
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Structure and shape
Attachment Resistance to antimicrobial drugs |
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What does it mean to say cell wall protects bacteria from osmotic pressure?
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Keeps too much water from diffusing passively in or out of the cell.
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Peptidoglycan--structure
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Functions like chain-link fence
Made of alternating sugars (NAM and NAG) cross-linked through peptide bonds. |
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Gram positive bacteria
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Up to 90% of the cell wall is peptidoglycan network, also has glycerol-sugar compound called techoic acid.
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Acid-fast bacteria
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Cell wall is 60% fat (mycolic acid--waxy fat) will stain positive with gram reaction.
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Gram negative bacteria
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Only up to 20% peptidoglycan
Has outer membrane of fat that contains lipopolysaccharides that can act as endotoxins. |
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Endotoxic shock
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Condition characterized by fever and blood vessel dilation, caused by release of endotoxins when large numbers of bacteria killed.
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Periplasm
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Space between inner membrane and outer fat membrane in gram negative bacteria. Contains peptodiglycan and many enzymes.
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Significance of lipolysaccharide layer:
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Phospholipid layer with sugars that can act as antigens and allow for differentiation between stains of bacteria.
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What substance plays an important role in endotoxic shock?
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Lipid A.
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Name a bacteria with no cell walls:
What does it contain instead of a cell wall? |
Mycoplasma (cell membrane with sterols).
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Would it be easier for antibiotic to reach peptidoglycan layer of gram positive or negative bacterium?
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Gram negative, because it only has one or two peptidoglycan layers in comparison to gram positive.
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What types of compounds can pass through cell membrane?
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Fat-soluble compounds.
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Which end of phospholipid bilayer is hydrophobic? Hydrophilic?
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The tails/the head
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Integral and peripheral proteins
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Proteins that penetrate the cell wall and those that just loosely attach to membrane.
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Simple diffusion
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Molecules move down electrochemical gradient through phospholipid bilayer , no ATP required.
Ex. Oxygen, CO2, lipid-soluble chemicals |
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Facilitated diffusion
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Molecules move down electrochemical gradient through channels/carriers, no ATP required.
Ex. Glucose, Fructose, Urea |
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Osmosis
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Water molecules move down concentration gradient across selectively permeable membrane.
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Active transport
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Cell expends energy in the form of ATP to move substance against electrochemical gradient, yes requires ATP.
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Shock
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Sudden drop in blood pressure.
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Nucleoid
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No nuclear membrane, one circular chromosome attached to cell membrane.
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Plasmids
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Other smaller circles of DNA that code for plasma membrane proteins--carries genes for antibiotic resistance.
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Inclusions
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Found in cytoplasm, not membrane-bound
Ex. lipids, starch, compounds containing sulfur, phosphate, and nitrogen. |
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Endospores
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Dormant form of bacteria, resistant to extreme/harsh conditions and environments.
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Sporulation
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Formation of an endospore
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Why is an endospore dehydrated?
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To allow it to remain dormant--the presence of water would allow enzymes and chemicals to cause reactions to occur and would not allow the bacteria to remain dormant.
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Parts of the endospore:
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Core (has calcium and dipicolinic acid)
Cortex (double layer of cell membrane with spore coat of keratin) |
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Can endospores divide?
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No, they are not reproductive structures. One bacteria forms one endospore.
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Two bacteria that can undergo sporulation:
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Clostridium and Bacilus.
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What is the advantage for bacteria that can form endospores?
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They can survive harsh conditions/extreme environments and for long periods of time.
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Cytoskeleton
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Forms cell's basic shape, simple structure in bacteria.
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Function of ribosomes
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Protein synthesis
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Do archea have glycocalyx?
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Yes, composed of polypeptides or polysaccharides.
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Do archea have flagella?
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Some do (are usually 10-14 nm in diameter) They grow at base and rotate both clockwise and counterclockwise.
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Do archea have fimbriae?
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Yes, proteinaceous used for attachment and formation.
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Do archea have the same cell membranes as bacteria?
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No, the membranes in archea are composed of polysaccharides or proteins, not peptodiglycan.
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Do eukaryotes have glycocalyx?
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Some do.
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Which Eukaryotes have cell walls?
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Plants, algae, and fungi.
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Can eukaryotic cells have flagella? How is it different from bacteria?
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Yes, they are usually within the cytoplasm, internal and push cytoplasmic membrane out around them, and generally only found at one end of the cell.
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Is the cell membrane of eukaryotes similar to bacteria?
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No, composed of polysaccharides, not peptidoglycan.
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Nucleus
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Often largest organelle in cell, "control center of cell," contains most of genetic information (DNA).
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Mitochondria
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Have two membranes, phospholipid bilayer, "power house" of the cell, most of the ATP produced in cristae of mitochondria (folds of membrane).
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Ribosomes
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Responsible for protein synthesis, can be free floating or attached to endoplasmic reticulum.
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Rough ER
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Contains ribosomes of surface, synthesizes and transports proteins.
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Smooth ER
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No ribosomes, involved in lipid synthesis and transport.
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Golgi apparatus
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Receives, processes, packages, large molecules for export from cell.
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Lysosomes
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Contains catabolic enzymes for self-destruction of old damaged/diseased cells, also digests phagocytized nutrients.
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Peroxisomes
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Vesicles derived from ER that contain oxidase/catalase that degrade poisonous metabolic waste.
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Nonmembranous organelles
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Nucleolus
Ribosomes Cytoskeleton Centrioles/centrosome |
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Nucleolus
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Specialized region, synthesizes RNA
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Cytoskeleton
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Anchors organelles, functions in cytoplasmic streaming and movement of organelles within cytosol, composed of tubulin microtubules, actin microfilaments, and intermediate filaments.
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Centrosomes
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Area containing centrioles, role in mitosis, cytokinesis, flagella and cilia formation in animals.
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