Microbiology - Exam Two

2 ATP, 2 NADH, 2 pyruvate

Products of glycolysis

Nucleic Acids

Source of energy in cells that do not have access to carbohydrates

Biofilms

Bacteria growing as a community on a surface

Autoinducers

Signaling molecules that bacterial quorum sensing relies upon

Electron Carrier

The role of NAD+ in metabolic pathways

Barotolerant

Organisms that can grow at extreme pressures

Obligate Aerobes

Can only grow in the presence of oxygen; catalase positive

Obligate Anaerobes

Can only grow in the absence of oxygen; catalase negative

Facultative Anaerobes

Can grow using oxygen (best) or without it; catalase positive

Aerotolerant Anaerobes

Grows well without using oxygen even when it is present; small amounts of catalase

Microaerophiles

Use small amounts of oxygen; small amounts of catalase

Catalase

Enzyme that converts H₂O₂ into H₂O

Hydrogen peroxide

What catalase coverts into water

Extreme Thermophiles

Organisms in the highest temperatures

Psychrophiles

Organisms in the lowest temperatures

Lag

Phase where bacteria are acclimating to environment but not growing

Death

Phase where most bacteria cells are dead or dying due to low nutrients

Stationary

Phase where bacterial growth equals the amount of cells dying due to limited nutrients

Exponential (Log)

Phase where bacteria are dividing as fast as the environment allows

Phytoplankton

Photosynthetic organisms such as cyanobacteria and algae

Eutrophication

A massive increase in certain aquatic microbial populations which can result in oxygen depletion

ATP yield of aerobic cellular respiration

ATP yield of anaerobic cellular respiration

2 ATP

ATP yield of fermentation

Nitrogen Fixation

The conversion of nitrogen gas (N2) into ammonium

Mycorrhizal Associations

Associations between fungi (and certain bacteria) and the root system of plants

Electron Transport Chain

Uses the energy in protons to pump electrons across a membrane to create a motive force used to regenerate ATP

Alcohol Dehydrogenase

Enzyme that converts acetaldehyde to ethanol during alcohol fermentation

Catabolic Pathway

Break down complex molecules into smaller, simpler products; degradation

Anabolic Pathways

Build complex molecules out of simpler building blocks; biosynthesis

Amphibolic Pathways

Function as both catabolic and anabolic depending on the current energy and biosynthetic needs of the cell; dual nature

Adenosine Triphosphate

The common metabolic currency; consists of a ribose, adenine, and three phosphates

Oxidation

Lose an electron

Reduction

Gain an electron

Glycolysis

The first step of aerobic and anaerobic carbohydrate catabolism

Decarboxylation

Removal of CO₂

Krebs Cycle

Series of redox reactions and decarboxylation reactions

6 NADH, 2 FADH₂, 2 ATP, 4CO₂

Products of the Krebs Cycle (per glucose molecule)

34-35 ATP

Net gain of the electron transport chain

Chemiosmosis

Movement of ions across a semipermeable membrane, down their electrochemical gradient

Respiration

Uses the electron transport chain

Fermentation

Does not use the electron chain

Pyruvic Acid

What fermentation uses to sustain ATP production in absence of respiratory chain

Lactic Acid Fermentation

Occurs in muscle cells when oxygen is limited

Lactate Dehydrogenase

Enzyme used in lactic acid fermentation

Pyruvate dehydrogenase

Enzyme that converts pyruvate to acetaldehyde in alcohol fermentation

Photosynthesis

Creates molecules from carbon dioxide and hydrogen-containing molecules using sunlight as an energy source

C6H12O6 and 6O2

Products of photosynthesis

Heterotrophs

Harvest energy from organic molecules that are eaten or obtained

Autotrophs

Make their own molecules (self-feeders)

Generation Time

Growth Time / Number of Generations

Chemostat

System used to maintain cells at a particular growth phase

Aerobes

Have enzymes that detoxify reactive oxygen species

Anaerobes

Organisms that do not use oxygen

Acidophiles

Organisms that can survive acidic conditions; have proton pumps or specialized membranes to protect enzymes

Alkaliphiles

Organisms that can survive basic conditions; enrich plasma membrane with acidic compounds

Plasmolysis

Water rushing out of the cell caused by high-salt conditions

Establish electrochemical proton gradient

Purpose of pumping protons in one direction along the electron transport chain

Liposomes

Phospholipid containment units for RNA based organisms

Ribozymes

RNA with enzymatic properties

Artificial Selection

Humans guiding evolution by selecting traits; e.g. dogs

Vancomycin

Antibiotic that targets normal cell wall; drug resistance example

Ecology

Study of relationships of organisms to each other and to their environment

Biotic

Interactions between organisms

Abiotic

Environmental factors

Population

All members of a species living in defined geographical area

Ecological Community

Populations within a defined region

Ecosystem

Ecological populations and abiotic factors of specific area

Food Chain

Path of consumption; energy and nutrients

Food Web

More accurate description of the food chain

Microenvironment

Area immediately surrounding the organism; typically very small

Biofilms

Microbial community growing on a surface

Matrix

Network of sugar polymers secreted by microorganisms that encases cells in a biofilm

Quorum Sensing

Intercellular communication amongst bacteria

Topsoil

Mix of broken down rock and dead plant matter

Humus

Organic substances formed in soil when microorganisms break down plant/animal residues

Rhizosphere

Soil environment surrounding root systems

Phytoplankton

Photosynthetic organisms; mainly algae and cyanobacteria

Zooplankton

Protozoa, small crustaceans, other small organisms

Photic Zone

Extends to deepest sunlight penetration; high oxygen content; phytoplankton only producers

Littoral Zone

Photic zone where light hits the bottom (shores); multicellular aquatic plants also serve as producers

Profundal Zone

Oxygen limited; sunken organic matter; facultative anaerobes abundant

Benthic Zone

Deepest region including sediments; obligate anaerobes and methanogens abundant

Thermocline

Sharp demarcation in temperature in water

Oligotrophs

Can grow in relatively low levels of nutrients

Eutrophs

Require high nutrient abundance (bacteria in GI tract)

Algal Bloom

Excessive algae growth

Eutrophication

The over-enrichment of a body of water with nutrients; oxygen depletion

Pelagic Zone

Within the photic zone; in the open-ocean

Intertidal Zone

Shoreline exposed to sea at high tide and air at low tide

Near-Shore Littoral Zone

Rich in nutrients from shore; green due to abundant photosynthetic phytoplankton

Exobiology

Search for extraterrestrial life

Ammonification

Decomposers break down nitrogen-containing organic matter into inorganic ammonia (NH₃) or ammonium (NH₄)

Nitrification

Nitrate converted to nitrite (NO₂); Nitrite converted to nitrate (NO₃)

Root Nodules

Specialized plant organs formed through symbiosis between nitrogen limiting plants and nitrogen fixing soil bacteria

Genome

Entire collection of genetic material in a cell or virus

Gene

Heritable units of genetic material that define a particular trait

Gentotype

Genetic makeup

Phenotype

Physiological or physical traits