Chapter 5&6 – Flashcards
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| Binary Fission |
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| An asexual process in bacterial and archaeal cells by which a cell divides to form two new cells while maintaining genetic constancy |
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| Generation Time |
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| The time interval for a cell population to double in number |
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| Incubation Period |
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| The time that elapses between the entry of a pathogen into the hose and the appearance of signs and symptoms |
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| What are the phases of a population growth curve? |
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| Lag Phase- no cell divisions occur Log Phase- active stage of growth-primary metabolites are being synthesized Stationary Phase- reproductive and death rates equalize and plateau- environmental resistance is factors that limit population growth/secondary metabolites are produced these are chemicals not necessary for growth Decline Phase- nutrients become low and cells start dying off |
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| Vegetative Cell |
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| Cells that actively metabolize and obtain nutrients |
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| Endospore |
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| A dormant structure that persist during periods of unfavorable conditions |
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| Dipocolinic Acid |
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| A chemical found in endospores that stabilizes its proteins and DNA |
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| Sporulation |
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| Bacterial chromosome is replicated, One chromosome condenses, Asymmetric cell division partitions prespore from mother cell, Transverse septum forms and prespore is engulfed by mother cell, Cortex develops around the prespore followed by a piece of spore coat, Spore wall is complete; vegetative cell disintegrates, Free spore is released |
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| Psychrophile |
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| A microbe that grows in cold temperatures |
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| Mesophile |
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| A microbe that grows in moderate temperatures |
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| Thermophile |
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| A microbe that grows in hot temperatures |
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| Obligate Aerobe |
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| Requires O2 (Oxygen) |
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| Obligate Anaerobe |
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| Cannot grow in the presence of O2 (Oxygen) |
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| Facultative |
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| Can grow in the presence or absence of O2 (Oxygen) |
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| Microaerophile |
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| Requires low concentrations of O2 (Oxygen) |
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| Capnophile |
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| CO2 (Carbon Dioxide) loving organisms |
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| Aerotolerant |
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| Anaerobe that can tolerate O2 (Oxygen) however does not derive any benefit from it |
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| Halophile |
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| Lives in environments rich in salt |
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| Hypotonic |
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| Solute concentration is lower than the cell. Water enters by osmosis. Cell becomes bigger |
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| Isotonic |
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| Solute concentration is equal to that of the cell. Water is neither gained nor lost. |
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| Hypertonic |
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| Solute concentration is higher than the cell. Water leaves by osmosis and the cell becomes smaller. |
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| Synthetic Medium |
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| Chemically defined; contain highly purified organic and inorganic compounds. |
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| Non-Synthetic Medium |
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| Also known as complex media contains at least one ingredient that is not chemically defined such as blood, serum, meat extract etc.. |
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| Carbon |
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| Serves as the backbone of organic molecules |
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| Carbon Cycle |
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| Carbon enters the ecosystem by photosynthesis or chemoautotrophy and leaves by cellular respiration |
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| Nitrogen |
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| Used for synthesizing proteins, DNA, RNA, and ATP |
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| Nitrogen Cycle |
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| Nitrogen enters the ecosystem by nitrogen fixation and leaves by denitrification |
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| Oxygen |
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| Major constituent of organic molecules, Required for aerobic cellular respiration |
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| Hydrogen |
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| Major constituent of organic molecules, Involved in maintaining pH, Important for hydrogen bonding in macromolecules, Prime force in oxidation-reduction reactions of cellular respiration |
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| Phosphorus |
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| Constituent of DNA, RNA, nucleotides, ATP, phospholipids, and coenzymes, PO43- is the primary inorganic source of the element |
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| Sulfur |
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| Constituent of proteins, Cysteine and methionine are amino acids that contain sulfur |
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| Microelements |
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| Compounds or substances needed in small amounts for proper functioning in the body. |
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| Growth Factors |
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| Substances that cannot be synthesized and must be obtained as a nutrient such as temperature, oxygen, ph, hydrostatic and osmotic pressure |
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| Fastidious Organism |
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| Require special growth factors |
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| What are two major solidifying agents for media? |
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| Agar and gelatin |
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| Which solidifying agent has the most disadvantages? |
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| Gelatin, it will not stay solid like agar it will melt |
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| Synthetic Media |
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| Chemically defined; contains highly purified organic and inorganic compounds |
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| Non-synthetic Media/Complex Media |
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| Contains at least one ingredient that is not chemically defined such as blood, serum, meat extract, infusions, milk, yeast extract, malt extract, soybean digests, and peptone |
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| General Purpose Medium |
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| Designed to grow a broad spectrum of microorganisms such as TS broth, TSA, nutrient broth, and nutrient agar |
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| Enriched Medium |
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| Enriched with blood, serum, hemoglobin, or special growth factors, Promotes the growth of fastidious organisms, Chocolate agar is an example |
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| Selective Medium |
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| Contains a chemical that inhibits the growth of certain organisms, but promotes the growth of others, Lowenstein-jensen medium contains malachite green; this medium promotes the growth of mycobacterium while inhibiting other bacteria |
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| Differential Medium |
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| Can grow several types of microorganisms, but can distinguish among them due to different appearances on the medium such as color of the colonies or color of the medium where the microorganisms are growing, Different types of gram-negative intestinal bacteria can be identified on chromacult agar due to the imparting of color to the colonies |
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| Fermentation Medium |
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| Determines whether a microorganism can ferment a particular carbohydrate, Fermentation is an anaerobic process that often generates acids, If the carb is fermented acid is produced and can be detected by a ph indicator dye, Phenol red fermentation tubes turn yellow if the organism can ferment the sugar if it can’t it stays red |
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| How can we isolate microorganisms in a mixed culture? |
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| By using the pour-plate method where the mixed culture is incubated on molten agar and after 24-48 hours the cells divide and form discrete colonies, or the streak-plate method where a series of streaks is made on the surface of nutrient agar of one area of the plate and dragged through all four sides after incubation each cell will grow to form a discrete colony on the plate |
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| Turbidity |
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| Medium becomes cloudy as the number of microorganisms increase, this is measured with a spectrophotomer |
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| Direct Count |
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| Involves counting the number of cells in a sample microscopically this is done with a cytometer |
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| Viable Plate Count |
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| Determines the colony forming units of serially diluted samples using pour plate technique or spread plate technique |
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| Most Probable Number |
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| A statistical estimation of the number of microorganisms by counting the number of tubes that demonstrate either turbidity or gas production |
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| Filtration |
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| A known volume of liquid or air is passed through a filter that traps the microorganisms, A filter is placed on an agar medium and incubated the colonies are counted after the incubation period |
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| What is are the differences between anabolism and catabolism? |
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| Anabolism is reactions that build up- buildup of small molecules, products are large molecules, mediated by enzymes, energy-requiring, Catabolism is reactions that break down- breakdown large molecules, products are small molecules, mediated by enzymes, energy releasing |
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| What is a catalyst? |
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| A catalyst is a chemical agent that changes the rate of a reaction without being consumed in the reaction |
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| What are the characteristics of enzymes? |
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| Enzymes are proteins that catalyze biochemical reactions, Enzymes are not consumed or permanently altered by the reaction, Enzymes are reusable, Enzymes exhibit specificity for their particular substrate, Enzymes are effective in low concentrations, Enzymes lower the energy of activation of a biochemical reaction, The names of enzymes typically end in the suffix -ase |
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| Why are cofactors important for conjugated enzymes? |
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| Cofactors are organic or inorganic molecules that are required for the activity of a certain conjugated enzymes |
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| Why is the active site important for enzyme function? |
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| An active site is the part of an enzyme that directly binds to a substrate and carries a reaction. It contains catalytic groups which are amino acids that promote formation and degradation of bonds. By forming and breaking these bonds, enzyme and substrate interaction promotes the formation of the transition state structure. Enzymes help a reaction by stabilizing the transition state intermediate. This is accomplished by lowering the energy barrier or activation energy- the energy that is required to promote the formation of transition state intermediate |
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| What is an allosteric site? Why are they important for the regulation of metabolic pathways? |
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| An allosteric enzyme has a regulatory site as well as an active site. An inhibitory substance binds to the regulatory site and changes the shape of the enzyme distorting the active site. This prevents the substrate from binding to the active site inhibiting the enzymatic reaction. |
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| Distinguish between competitive and non-competitive inhibitors. |
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| Competitive inhibitor is an inhibitor that binds to the avtive site it competes with the substrate for the active site but no product is made, Non-competitive inhibitor is an inhibitor that binds to another site where binding is irreversible |
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| How do sulfa drugs work? |
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| Sulfa drugs act as competitive inhibitors of a bacterial enzyme. Bacteria need PABA in order to make metabolites leading to the making of folic acid which is necessary for DNA replication. Sulfa drugs out compete PABA. Since no product is made, no folic acid is made. The bacteria stop dividing because they are unable to perform DNA replication. |
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| What factors can denature an enzyme? |
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| Denaturization occurs when there is an extreme change that causes the enzyme to become unstable and change its shape. The factors that can cause denaturization are temperature, pH, and osmotic pressure |
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| Distinguish between exergonic and endergonic reactions |
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| Exergonic reaction is an energy releasing reaction- downhill to release energy to make ATP- catabolic, Endergonic reaction is an energy requiring reaction- uphill reaction- ATP needed for energy- anabolic |
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| What are oxidation-reduction reactions? |
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| How cells transfer energy from one compound to another- always occurs in pairs- if one is oxidized a second is reduced- To remember oxidation and reduction; LEO the chemistry lion says GER! LEO: lose electrons oxidation, GER: gain electrons reduction |
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| Explain the ATP cycle |
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| ATP is made by the phosphorylation of ADP: energy released from the oxidation of nutrient molecules provides the energy to make ATP |
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| What is the role of coenzymes in cellular respiration? |
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| Coenzymes carries energy from the broken chemical bond of the substrate to the formation of the high energy bond of ATP Coenzymes act as mobile electron carriers, Coenzymes transport electrons to the electron transport chain where most of the ATP is made Most important coenzyme is NAD+ |
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| Summarize glycolysis |
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| Is a sugar splitting reaction that occurs in the cytosol of eukaryotic cell |
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| Summarize the bridging step |
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| Step between glycolysis and citric acid cycle, Occurs in cytosol of eukaryotic cells, occurs twice for each molecule of glucose, pyruvic acid is converted into acetyl CoA, carbon dioxide is generated |
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| Summarize the citric acid cycle |
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| Occurs twice for each molecule of glucose, occurs in the matrix of the mitochondrion or the eukaryotic cell and cytosol of the prokaryotic cell, carbon dioxide is generated, GTP is converted in ATP, the NADH and the FADH2 go to the electron transport chain |
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| Summarize the electron transport chain |
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| A series of electron carriers bound to a membrane, occurs on the cristae of the mitochondrion of the eukaryotic cell and the mesosome of the prokaryotic cell, coenzymes drop off their electrons in the ETC, electrons are passed along a series of 9 carriers, oxygen is the terminal electron acceptor and is converted into water, as electrons are passed along the electron acceptors, energy is released to produce ATP |
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| How many ATP molecules are made aerobically? |
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| 38 ATPs for Prokaryotic 36 ATPs for Eukaryotic |
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| Summarize how ATP is made by chemiosmosis |
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| Energy released in the electron transport chain is used to pump hydrogen across the membrane from the matrix into the intermembrane space. |
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| What is anaerobic respiration? How many ATP molecules are made? |
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| Anaerobic respiration Is an energy releasing process that does not require oxygen, Anaerobic respiration is fermentation, only 2 ATPs are made |
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| What is the function of fermentation? |
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| Fermentation pathway recycles coenzymes for ongoing glycolysis |
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| Alcohol Fermentation |
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| Performed by fermentative yeasts, alcohol and carbon dioxide are produced |
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| Homolactic Fermentation |
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| Produces lactic acid, performed by many bacteria, performed by our muscle tissue when oxygen levels fall |
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| Heterolactic Fermentation |
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| Occurs in many bacteria, produces a comination of acids, also H2 and CO2 |
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| What is the methyl red test? |
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| Tests for acid products |
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| What is the Voges-Proskauer test? |
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| Tests for neutral products |
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| What is the difference between light-dependent and light-independent reaction? |
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| Light dependent needs light to react; light independent does not need light to react |
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| Photoautotroph |
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| Needs co2 and light |
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| Chemoautotroph |
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| Needs co2 and inorganic chemicals |
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| Photoheterotroph |
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| Need organic molecules and light |
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| Chemoheterotroph |
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| Need organic molecules and organic chemicals |
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| What is the difference between a saprobe and a parasite? |
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| Saprobes feed on dead organic matter Parasites feed on living organic matter |
