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139 Cards in this Set
- Front
- Back
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Glycocalyx |
Thick sticky layer of a polysaccharide extending from the surface of bacteria |
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2 types of glycocalyx |
1) CAPSULE-glycocalyx FIRMLY ATTACHED to the cell wall 2) SLIME LAYER- glycocalyx LOOSLEY ATTACHED |
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Advantages of a glycocalyx |
Capsule contributes to protection against PHAGOCYTOSIS
Capsule contains a lot of water protecting bacteria AGAINST DESICCATION (extreme drying) |
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Advantages of a glycocalyx 2 |
Glycocalyx AIDS bacterial ATTACHMENT TO SURFACES of solid objects such as teeth or tissue surfaces |
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Fimbriae |
Short fine hairlike appendages that are used for attachment, NOT MOBILITY Gram negative bacteria |
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Pili |
Used for exchange of genetic information during CONJUGATION (Pilus,singular) |
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Axial filaments AKA periplasmic flagella |
-Emerge from the end of the cell and wrap around the bacterium -rotation of the filaments gives the bacterium a corkscrew movement |
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Spirochetes |
The major bacterial genus that commonly have AXIAL FILAMENTS |
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3 parts bacteria flagellum is composed of |
Filament, basal body, hook |
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Filaments (Bacteria flagellum) |
Long portion extending from body to tip -hollow rigid cylinder composed of flagellin protein |
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Basal body (Bacteria flagellum) |
Embedded in the cell wall and plasma membrane Gram - basal body has 4 rings (2CW, 2PM) Gram+ have only the inner pair of basal body rings |
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Hook (Bacteria flagellum) |
A short curved segment links the filament to its basal body |
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Bacteria appendages Flagella plural Flagellum singular |
Threadlike appendages extending outward from the plasma membrane and cell wall |
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Monotrichous bacteria |
1 polar flagellum |
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Amphitichous bacteria |
Single flagellum at each end or organism |
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Lophotrichous bacteria |
A cluster of flagella at one or both ends |
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Peritrichous bacteria |
Many flagella around |
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Endospores |
A number of gram + bacteria can form a special resistant dormant structure called endoscope. |
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Endospores develop with in which vegetative bacterial cells |
bacillus, clostridium, and sporosarcina |
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Endospores are resistant to... |
Environmental stress such as heat, uv Rays, chemical disinfectants and desiccation |
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Prokaryotic vs. eukaryotic |
Prokaryotic cells are simple structures and do not have organelles -DNA is not contained in the nucleus -peptidoglycan makes up the cell wall Eukaryotic cells are complex structures with organelles -DNA in nucleus -plant cell wall is made of cellulose -fungal cell made up of chitin |
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PCP (pneumocystis carinii) Pneumonia |
Causative agent-pneumocystis carinii -the primary opportunistic infection in AIDS patients -forms secretions in the lungs and can be fatal rapidly |
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Candidiasis |
Causative agent: Candida albicans -this yeast is a normal part of the flora in the oral cavity, genitalia and large intestine; on the skin of approximately 20% of humans -pregnancy, drug therapy (antibiotics), immunodeficiency or trauma all allow the pathogen to flourish -AIDS Patients: Thrush-white, patchy appearance in oral cavity -vulvovaginal - "yeasties" female genatalia, ulceration and white yellow discharge |
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3 major human pathogens make up Opportunistic mycoses |
Candida-yeast Pneumocystis-yeast Aspergillus-filamentous fungus |
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Major subcutaneous mycosis |
These invade just beneath the skin (traumatized skin allows entry) Mycentoma (Madura foot) Causative agents: pseudallescheria or madurella -cause large fungal tumor like structures of limbs, primarily the hands and feet; systemic when spreads to bones or muscles |
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Types of dermatophytoses (Cutaneous mycoses) |
Scalp- tinea capitis Beard- tinea barbae Body- tinea corporis Groin- tinea cruris Foot (athletes foot)- tinea pedis Hand- tinea manuum Nail- tinea unguium |
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Types of fungal infections |
Superficial cutaneous Subcutaneous systemic |
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Superficial fungal infection |
Involve outer epidermis Cosmetic only |
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Cutaneous fungal infection |
Infections restricted to the non living areas of the skin |
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Systemic fungal infecion |
Infections occurring from inhalation and becoming circulating |
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Ringworm (tinea) |
Causative agent: Tricophyton, microsporum, and epidermophyton
Term used due to the circular, scaly patches of skin Not life threatening but a serious concern due to discomfort stress and pain |
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Agents to treat fungal infections |
Amphotericin B- oral or vaginal Micronazole- vaginal Flucystosine- systemic mycoses |
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Target where agents treat fungal infections |
Fungal cells have chitin in their cell walls which is a good target
Fungal cells are eukaryotic and thus these chemotherapeutic agents will offer be toxic to host cells as well as fungal cells |
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Aspergillosis |
Causative agent: aspergillus Niger The spores of this mild found in high concentrations in dust from granaries, barns, and silas
Inhaled spores can cause "fungus balls" in the lungs |
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Structures internal to the cell wall |
Selective permeable membrane Mesosomes - membrane folds internally inside the cytoplasm to form pouches; acts as site for metabolic activities |
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Prokaryotic cell wall |
Most bacteria have strong walls that give them shape and protection from osmotic lysis |
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Plasmolysis |
Water loss from the bacterial cell placed in a hypertonic solution cause the plasma membrane to pull away from the cell wall. |
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What is Plasmolysis useful for? |
Useful in food preservation because many microorganisms cannot grow in dried food and jellies as they cannot avoid plasmolysi |
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Inclusions |
Type of material reserve |
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Metachromatic granules |
Inorganic Pi that can be used to make ATP |
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Polysaccharide granuales |
Formed from glycogen or starch |
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Gas vacuoles |
Common in aquatic bacteria they provide buoyancy |
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Name two inclusions that some bacteria have |
Lipid-inclusion Sulfur granules which they oxidize to obtain energy |
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Group translocation |
Unique to prokaryotes A substance is chemically altered as it is transported across the plasma membrane |
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Name an example of group translocation |
Glucose is phosphorylated as a carrier protein moves it across the membrane |
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Structures of the cell wall |
Plasma membrane composed of phospholipid bilayer Proteins embedded in functions such as transport |
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Gram negative |
Alcohol dissolves the lipids from the gram negative wall so the purple crystal violet iodine complex is LOST from gram bacteria GRAM NEGATIVE CELLS ARE PINK AFTER THE PROCEDURE |
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The mechanism of gram staining |
Gram positive bacteria are decolorized with ethanol which shrinks the pores of the thick peptidoglycan. The DYE-IODINE COMPLEX is RETAINED during the shirt decolorization step and the bacteria remain purple |
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The mechanism of gram staining |
Gram positive bacteria are decolorized with ethanol which shrinks the pores of the thick peptidoglycan. The DYE-IODINE COMPLEX is RETAINED during the shirt decolorization step and the bacteria remain purple |
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What color are gram positive cell after gram staining procedure? |
Purple |
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Gram negative cell wall "Oreo cookie" |
Bottoms later - plasm membrane phospholipid bilayer |
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Gram negative cell walls outer layer "Oreo cookie" |
Lipopolysaccharides (LPS) 2 important characteristics- Lipid A aka endotoxin O polysaccharides |
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Gram negative cell walls outer layer "Oreo cookie" |
Lipopolysaccharides (LPS) 2 important characteristics- Lipid A aka endotoxin O polysaccharides |
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Lipid A (aka endotoxin) |
Bacteria toxic when it infects the hosts blood or GI tract |
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O polysaccharide |
Act as antigens (substance which is foreign and triggers the immune system) |
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Gram negative cell wall "Oreo cookie" middle layer |
Has a thin 1-3nm peptidoglycan layer Located in the periplasmic space along with many hydrolytic enzymes and proteins involved in transport of material into the cell |
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Gram positive cell walls |
Cell wall contains of single thick 20-80nm peptidoglycan or mureim layer lying outside the plasm membrane
Contains large amount of trichroic acids 2 types- wall teichoic acids (connected to peptidoglycan) Lipoteichic acids (connected to plasma membrane lipids) |
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Composition of the cell wall for both gram negative and gram positive |
Peptidoglycan (aka murein) Enormous polymer made of sugar and protein |
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Prokaryotic cell wall protein part |
Peptido part- peptide chains Protein chains link across to connect one long chain of sugars to another chain of sugars 2 amino acids found in these polypeptide are unique to bacterial cell walls D-glutamic and D-alanine Proteins normally use the L-isomers of the amino acids |
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Name the three genera of ringworm |
Tricophyton Microsporum Epidermophyton |
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Mycetoma (Madura foot) |
Pseudallescheria or madurella |
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How many rings does the Basel body of the flagellum in gram positive and gram negative bacteria have ? |
Gram positive has 2 in the inner part Gram negative has four rings, 2 CW and 2PM |
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Axial filaments (periplasmic flagella) |
Emerge from the end of the cell and wrap around the bacterium like a corkscrew type movement |
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Axial filaments (periplasmic flagella) |
Emerge from the end of the cell and wrap around the bacterium like a corkscrew type movement |
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Spirochetes |
Major bacterial bacterial genus that commonly have axial filaments |
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Peptidoglycan layer of gram positive and negative is how thick? |
Positive- VERY THICK Negative- thin |
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Gram positive cell walls contaib |
Teichoic acids 1 wall teichoic acids connected to peptidoglycan 2 lipoteichoic acids connected to plasma membrane lipids |
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Gram negative cell walls contain |
Lipid heavy outer membrane Sitting on top of thin peptidoglycan membrane -lipid A- endotoxin-trigger to immune system to spike a fever -O polysaccharide-antigen |
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Name 3 endospores that develop within a vegetative state. |
Bacillus Clostridium Sporosarcina |
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Name the endospores shape (Morpholoogies) |
Bacilli -rods Cocci-roughly spherical Spiral-varies greatly |
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Common prefixes of naming endospores |
Diplo- form pairs Strep- long chains -strip Sarcinae- cubical packets of 8 Staph- irregular |
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Catabolic reaction |
Break down molecules Energy releasing (Degradative) |
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Anabolic reactions |
Build molecules Synthetic reactions |
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Two types of metabolic reactions |
Endergonic-gain of energy Exergonic-loss of energy |
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Apoenzyme (Apoprotein) |
Enzyme without the cofactors Not active |
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Holoenzymes |
The active form of the enzyme=cofactors or coenzyme |
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Coemzymes |
Organic molecule such as vitamins |
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Cofactors |
Metallic ions such as iron or copper |
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Types of enzymes |
Exoenzyme- released outside the cell Edoenzyme- remain inside the cell to work Constitutive enzymes- enzymes that are present in constant amounts in the cell(amylase) Induced enzymes- present in trace amounts but increased by the addition of substrate (lactase-> lactose to glucose and galactose) |
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Energy hill diagram |
Explains how enzymes speed up the rate of reactions |
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Energy hill diagram 4 steps |
Initial state Activated state-top of energy hill Energy of activation-Ea=the amount of energy needed to get the transition state( top of the hill) |
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Enzymes |
Speed up reactions by LOWERING THE ENERGY OF ACTIVATION |
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Denaturation of enzymes |
Occurs because the shape of the protein is changed by high temperature or change of pH -hydrogen bonds are broken -active site is altered and CANNOT BIND WITH SUBSTRATE |
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Competitive inhibition |
The inhibitor competes with substrate by binding to the active site instead of substrate |
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Allosteric control |
Non competitive inhibition Feedback inhibition |
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A major cutaneous mycosis |
Dermatophytoses These occur in the non living epidermal tissue (stratum corneum) |
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Causative agent for Thrush |
Candida albicans |
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PCP (pneumocystis carinii-pneumonia) |
The He primary opportunistic infection in AIDS patients Forms secretions in the lungs and can be rapidly fatal |
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Front (Term) |
Glycocalyx Bacterial chromosome or nucleotide Pilus Mesosome Flagellum Fimbriae Inclusion/granule Cell wall Cell membrane Ribosomes |
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Mesosome |
An extension of the cell membrane that fold into the cytoplasm and increases surface area -function: acts as sites for metabolic activities |
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Bacterial chromosome or nucleoid |
The site where the large DNA molecule is condensed into w packet. |
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Most bacteria have strong walls that give them shape and protect the from _____? |
Osmotic lysis |
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Composition of the cell wall for both gram positive and negative |
Peptidoglycan (also called murein) composed of two major parts: Sugar portion: the Glycan part=NAG, NAM Protein portion: peptido part |
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NAG and NAM |
N-acetylglucosamine N-acetylmuramic acid |
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Two amino acids found in the protein portion of the peptide chains which are unique to the bacterial cell walls |
D-glutamic D-alanine |
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Lipopolysaccharides LPS |
These are large, complex molecules that contain both lipid and carbohydrate abs they have two important characteristics: lipid A and O polysaccharide |
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The mechanism of gram staining Gram positive Gram negative |
Gram + bacteria are decolorized with ethanol which shrinks the pores of the thick peptidoglycan. The DYE-IODINE complex is retained during the short decolorization step and the bacteria remain purple
Gram - alcohol DISSOLVES THE LIPIDS from the gram negative wall so the purple crystal violet iodine complex is LOST from gram negative. Gram negative cells are PINK after the procedure |
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Prokaryotic plasma membranes are composed primarily of ? |
Phospholipid bilayer |
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Proteins play an important role in the cell membrane by ? |
Regulating cell functions such as transport |
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Selective permeability |
In the plasma membrane Only allow passage of certain molecules and ions |
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Simple diffusion |
Net movement of molecules and ions from an area of high concentration to low concentration |
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Facilitated diffusion |
Carrier proteins are used to transport some molecules such as glucose across the plasma membrane Membrane is also DOWN THE CONCENTRATION GRADIENT and does not require ATP energy input |
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Osmosis |
Water moves across selectively permeable membranes -solution consists of solvent and solute |
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Hypotonic Hypertonic Isotonic |
Less solute More solute Equal spouted
Water flows into whatever solution is hypertonic |
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Active transport |
Carrier proteins are used to move molecules or ions AGAINST (UP) A CONCENTRATION GRADIENT this process requires energy in the form of ATP |
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Group translocation |
Unique to prokaryotes A substance is CHEMICALLY ALTERED AS IT IS TRANSPORTED ACROSS THE PLASMA MEMBRANES example-glucose is phosphorylated as a carrier protein moves it across the membrane |
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Endospores |
A number of gram positive can form a special resistant dormant structure called an endospores Endospores develop within vegetative bacterial cells of several genera: BACILLUS, CLOSSTRIDIUM, and SPOROSARCINA |
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Most commonly encountered bacteria have one of three basic shapes (MORPHOLOGIES) |
BACILLI-rods COCCI-are roughly spherical cells SPIRAL- greatly very |
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Common prefixes for morphologies |
Diplo- pairs Strep- long chains results when cells adhere after repeated divisions in one plane; a classic example is the genera Sacrinae- cubical packets of eight cells Staph- irregular grapelikeclumps |
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Essential growth nutrients |
Carbon Nitrogen, sulfur, and phosphorus Trace elements Organic growth factors |
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Carbon |
50%of the dry weight of a cell is carbon |
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Nitrogen, sulfur, and phosphorus |
Nitrogen-needed for DNA, RNA, Protein Sulfur-needed for amino acids (met and cys) Phosphorus- needed for DNA, RNA, phospholipids |
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Trace elements are needed for? |
Are needed, such as iron, copper, and zinc |
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Organic growth factors |
Many bacteria synthesize all essential nutrients from basic salts and a carbon source Some microbes and most other organism-need at least some vitamins, growth factors, essential amino acids, etc that must be obtained directly from the environment |
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What are autotrophs? |
Living things capable of feeding themselves by either photosynthesis or chemosynthesis -chemosynthesis autotrophs -photosynthetic autotrophs |
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What are heterotrophs? |
Obtain nourishment from compounds assembled by other living things They eat the plants directly or eat the herbivores etc. |
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Psychrophiles grow at what temperature |
Grow at 0C with optimal of only about 15C |
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What temperature does psychrotrophs grow |
Also grow at 0 C but have a higher optimal temperature 20-30C. These are more likely to be found in your REFRIGERATORS |
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What temperature does mesophiles grow |
Moderate temperatures; the temperatures we like37C |
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What temperature does thermophiles grow |
Grow at high temperature 50-60C Extreme thermophiles 80-110C |
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What are the most common bacteria? |
Mesophiles Adapted to live at moderate temps often in the bodies of animals Optimal temp is 37C Most common |
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What pH do bacteria prefer |
Narrow range centered around neutral 6.5-7.5 |
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Acidophiles pH? |
Grow at a pH of less than or equal to 4 (pH<=4) |
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Plasmolysis occurs when? |
Cells in a hypertonic medium lose water by osmosis and the plasma membrane of the contracting cell pulls away from the cell wall |
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Microbial growth in foods is prevented? |
With a high sugar or salt concentration |
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Extreme halophiles |
Can grow in a high salt concentration |
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Obligate halophiles |
Require a high salt concentration |
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Facultative halophiles |
Can grow in a high salt environment, but it is not a growth requirement |
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Which organisms are found in the refrigerator |
Psychophiles 0-15C Psychrotrophs 20-30C |
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Superoxide free radicals |
O2- are highly reactive by products of aerobic respiration |
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Cells require _____ enzyme , which converts the free radical O2- to oxygen and hydrogen peroxide |
Superoxide dismutase |
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What does catalase do? |
Degrades hydrogen peroxide to water and oxygen |
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What does peroxidase do? |
Degrades hydrogen peroxide to water |
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Microbial antagonism |
Microbes are in competition with each other |
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What is symbiosis? |
Two organisms live in close partnership |
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Commensalism |
One organism benefits while the other is unaffected |
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What are the phases of bacterial growth? |
Lag phase-bacteria adjusting to new environment Log phase- exponential phase constant growth, more sensitive to antibiotics Stationary phase-nutrients are limited, waste products accumulate Death phase- cell population of viable cells begins to decline rapidly |
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What are the phases of bacterial growth? |
Lag phase-bacteria adjusting to new environment Log phase- exponential phase constant growth, more sensitive to antibiotics Stationary phase-nutrients are limited, waste products accumulate Death phase- cell population of viable cells begins to decline rapidly |
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What is chemostat? |
Special growth chamber that removes old medium and replaces it with fresh medium. A bacterial population can then be kept in log phase indefinite |
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