1) break down complex organic compounds to simpler ones

2) Degradation reactions

3) Generally hydrolysis reactions

4) Enzyme regulated chemical reactions

5) Exergonic reactions (energy-releasing)

1) building complex organic compounds from simpler ones

2) Biosynthesis reactions

3) Generally dehydration synthesis reactions

4) Enzyme regulated chemical reactions

5) Endergonic reactions (energy-requiring)

A sequence of enzymatically catalyzed chemical reactions in a cell.

Enzymes

Apoenzyme-protein, inactive

Cofactor-non-protein component, activator

1) Temperature

2) pH

3) Substrate concentration

4) Enzyme inhibitors-prevent the substrate from binding to the active site of the enzyme (competitive and noncompetitive)

1) glycolysis

2) Kreb's cycle

3) Electron transport chain

What is the net gain and the end product from glycolysis?

Net gain: 2 ATP molecules

End product: pyruvic acid

1) Pentose phosphate pathway

2) Entner-Doudoroff pathway

1) operates with glycolysis

2) net gain: 1 ATP

3) uses pentoses and produces NADPH

examples: Bacillus subtilis; E. coli

1) Produces NADPH and 1 ATP

2) does not involve glycolysis

3) generally found in gram-negative bacteria, i.e. Pseudomonas, Rhizobium, Agrobacterium

4) generally not found in gram-positive bacteria

Aerobic respiration-final electron acceptor is oxygen

Anaerobiv respiration-final electron acceptor is an inorganic molecule

1) Tricarboxylic acid (TCA) cycle

2) Citric acid cycle

Acetyl coenzyme A enters the Kreb's cycle

NADH and 2 molecules of ATP are produced

A series of carrier molecules are, in turn, oxidized and reduced as electrons are passed down the chain.  

First step: transfer electron from NADH

Oxygen: last electron acceptor

Energy released can be used to produce ATP by chemiosmosis.

1) flavoproteins (proteins+flavin)

2) cytochromes (proteins+iron)

3) ubiquinones or coenzyme Q (non-protein)

Prokaryotes: 38 ATP molecules (2+2+34)

Eukaryotes: 36 ATP molecules (2+2+32)

1) Releases energy from oxidation of organic molecules

2) Does not require oxygen; can take place in the absence or presence of oxygen

3) Does not use the Kreb's cycle or ETC

4) uses an organic molecule as the final electron acceptor

5) 1 or 2 ATP molecules are made

Homolactic fermentation: lactic acid only

Heterolactic fermentation: lactic acid and other compounds

Phototrophs: sun light for energy

Chemotrophs: chemicals for energy

Autotrophs: self-feeders

Heterotrophs: other feeders

1) metabolic pathways that have both catabolic and anabolic functions

2) anabolic and metabolic reactions are joined through a group of common intermediates

3) these pathways can be seen in glycolysis and Kreb's cycle

1) temperature

2) pH

3) osmotic pressure

1) source of C, N, S, P trace elements

2) oxygen, organic growth factors

1) Psychrotrophs: 0-30 degrees C, cause food spoilage

2) Psychrophiles: cold-loving

3) Mesophiles: moderate temperature loving

4) Thermophiles: heat-loving microbes

5) Hyperthermophiles: 70-110 degrees C

Bacteria grow in what pH?

Molds and yeast?

Bacteria: 6.5-7.5

Molds and yeast: 5-6

Acidophiles: acid-loving bacteria

1) complex polysaccharide

2) used as solidifying agent for culture media in petri plates, slants and deeps

3) generally not metabolized by microbes

4) liquefies at 100 degrees C

5) solidifies at about 40 degrees C

Extracts and digests of yeasts, meat or plants

Example: nutrient broth, agar

Differential; if bacteria ferments the carbohydrate to acid while growing, the media will turn yellow

if bacteria cannot ferment the carbohydrate to acid while growing, media will stay red

p=# of cells in a population

m=# of cells at the beginning

n=# of generations

Lag phase: little or no growth

Log phase: exponential growth; sensitive to adverse conditions

Stationary phase: slow growth rate; stabilized population

Death phase: decline phase; cells die in a logarithmic scale

1) Lack of sufficient nutrients: with time bacteria will use up all the nutrients in the media

2) Accumulation of waste: with time bacteria can produce toxic substances, acids that can inhibit growth

3) Changes in pH

1) Plate counts: each colony represents a bacterial cell in the original sample

2) Filtration: useful when the original sample has very small number of bacterial cells

3) Direct microscopic count: count the number of bacterial cells directly using the microscope

1) Turbidity: indicates the amount of bacteria growing in the medium; more turbid means more bacteria; measured using spectrophotometer

2) Metabolic activity: amount of acid production or CO2 production indicates the amount of bacteria growing in the medium

3) Dry weight: bacteria are removed from the growth medium and dried in a desiccator and weighed

1) Number of microbes

2) Environment

3) Time of exposure

4) Microbial characteristics

1) Damage to proteins and lipids in the plasma membrane causes cellular contents to leak

2) Damage to the cell wall: denatures the proteins so they can no longer function in the cell wall

3) Damage to nucleic acids: cells can no longer replicate

Moist heat: denatures proteins

Dry heat: oxidation

Pasteurization: 63 degrees C for 30 min or 72 degrees C for 15 seconds-sterilization (stored without refrigeration) 140 degrees C for <1 second

1) the concentration of the disinfectant

2) organic matter contaminations

3) pH of the disinfectant

4) time exposed to disinfectant