CHAPTER 7 MICROBIOLOGY

Nutrition

Process of obtaining nutrients needed for growth and metabolism

Nutrients

Substances required by cells

Macronutrients

Nutrients needed in relatively large amounts

CHONPS

Carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur

Micronutrients

Nutrients needed in smaller amounts

Organic nutrients

Carbon

Inorganic nutrients

Examples include water, minerals, salts, and carbon dioxide

CO2

Inorganic

Autotroph

Gets carbon from CO2

Heterotroph

Gets carbon from organic compounds

Phototroph

Gets energy from light

Chemotroph

Gets energy from chemicals

Photoautotroph

Gets carbon from CO2 and energy from light

Photoheterotroph

Gets carbon from organic compounds and energy from light

Chemoautotroph

Gets carbon from CO2 and energy from chemicals

Chemoheterotroph

Gets carbon from organic compounds and energy from chemicals

Passive transport

Transport that does not require ATP

Active transport

Transport that requires energy, usually ATP

Diffusion

Movement from high concentration to low concentration without energy

Facilitated diffusion

Passive movement using membrane proteins

Permease

A membrane transport protein

Osmosis

Net movement of water across a selectively permeable membrane

Osmosis energy requirement

Does not require ATP

Isotonic

Solute concentration is equal; no net water movement

Hypotonic

Lower solute concentration outside; water moves into the cell

Hypertonic

Higher solute concentration outside; water moves out of the cell

Active transport direction

Can move substances against their concentration gradient

Sodium

potassium pump

Endocytosis

Movement of material into a cell

Exocytosis

Movement of material out of a cell

Phagocytosis

Endocytosis of solids; cell eating

Pinocytosis

Endocytosis of liquids; cell drinking

Minimum growth temperature

Lowest temperature at which growth occurs

Maximum growth temperature

Highest temperature at which growth occurs

Optimum growth temperature

Temperature at which growth is maximized

Human body temperature

Approximately 37°C

Psychrophile

Cold

Psychrotroph

Organism that grows in cold temperatures but can grow at warmer temperatures than psychrophiles

Mesophile

Organism preferring moderate temperatures

Thermophile

Heat

Hyperthermophile

Organism preferring extremely high temperatures

Obligate aerobe

Requires oxygen

Obligate anaerobe

Oxygen is harmful

Facultative anaerobe

Can grow with or without oxygen and generally grows better with oxygen

Microaerophile

Requires oxygen at lower

Superoxide dismutase

Enzyme that helps detoxify reactive oxygen products

Catalase

Enzyme that helps detoxify hydrogen peroxide

Acidic pH

Less than 7

Neutral pH

7

Basic/alkaline pH

Greater than 7

pH

Related to hydrogen ion concentration

Neutrophile

Prefers near

Acidophile

Prefers acidic conditions

Alkalinophile

Prefers alkaline conditions

Halotolerant

Can tolerate salt

Halophile

Requires high salt

Osmophile

Prefers environments with high osmotic pressure, often high sugar

Synergism

Two organisms work together and produce a greater effect than either alone

Antagonism

One organism inhibits or harms another

Binary fission

Bacterial reproduction in which one cell divides into two cells

Generation time

Time required for a population/cell to double

Growth equation

Nf = Ni × 2^n

Nf

Final number of cells

Ni

Initial number of cells

n

Number of generations

Four growth phases

Lag, log/exponential, stationary, death

Lag phase

Cells adapt and prepare for growth/division

Log phase

Rapid exponential cell division

Stationary phase

Cell division and cell death are approximately balanced

Death phase

Number of viable cells decreases