chapters 7 and 11 (week 4) learning objectives

What are bio elements

basic requirements for life (carbon, hydrogen, oxygen, phosphorus, potassium, nitrogen, sulfur, calcium, iron, sodium, chlorine, magnesium)

What are essential nutrients

substance (element or compound) an organism must get from a source outside its cells

What are macronutrients

required in large quantities; play principal roles in cell structure and metabolism (proteins, carbohydrates)

What are micronutrients

required in small amounts; involved in enzyme function and maintenance o f protein structure (manganese, zinc, nickel)

What are organic nutrients?

contain carbon and hydrogen atoms and are usually the products of living things

What are inorganic nutrients

atom or molecule that contains a combination of atoms other than carbon and hydrogen

Environmental factors in microbial growth

Temperature

Oxygen requirements

pH

Osmotic pressure

Barometric pressure

What are the three adaptations of temperature for microbial growth

Minimum temperature

Maximum temperature

Optimum temperature

What is minimum temperature

lowest temperature that permits a microbe’s growth and metabolism

What is maximum temperature

highest temperature that permits a microbe’s growth and metabolism

What is optimum temperature

promotes the fastest rate of growth and metabolism

What is the threshold for the psychrophiles adaptation group

optimum temperature below 15°C; capable of growth at 0°C

What is the threshold for the mesophiles adaptation group

optimum temperature 20°-40°C; most human pathogens

What is the threshold for the thermophiles adaptation group

optimum temperature greater than 45°C

What aerobe microbes

Microbe that can grow in the presence of oxygen, and may even require it.

What are Obligate aerobe microbes

Microbes that require oxygen to grow.

What are facultative microbes

Microbes that can grow with or without oxygen.

What are anaerobe microbes

Microbes that do not use oxygen to grow.

What are acidophiles

grow in extremely acidic environments like the human stomachs

What are alkalinophiles

grow in extremely basic environments

What is binary fission

A simple, asexual reproduction method where a single parent cell duplicates its genetic material and then divides, resulting in two identical daughter cells

What are the four stages in population growth

Lag phase

Exponential growth phase

Stationary phase

Death phase

What occurs in the lag phase of population growth

Less than exponential growth rate; period of adjustment, enlargement

What occurs in the exponential growth phase of population growth

a period of maximum growth when cells have adequate nutrients and a favorable environment

What occurs in the stationary phase of population growth

rate of cell growth equals rate of cell death caused by depleted nutrients and O2, excretion of organic acids and pollutants

What occurs in the death phase of population growth

as limiting factors intensify, cells die rapidly

What is the name of number 3

Stationary phase

What is the name of number 4

Death phase

What is the name of number 2

Exponential growth phase

What is the name of number 1

Lag phase

What is sterilization

process to destroy all viable microbes

What is disinfection

Use of a physical process or a chemical agent (disinfectant) to destroy vegetative pathogens but not bacterial endospores

What is antisepsis

application of chemical agents directly to exposed body surfaces, wounds, and surgical incisions to destroy or inhibit vegetative pathogens

What is decontamination

physical, chemical, and mechanical methods that destroy or reduce undesirable microbes in a given area.

Factors that affect microbial death

Number of microbes

Nature of microbes in the population

Temperature and pH of environment

Concentration or dosage of agent

Mode of action of the agent

Presence of solvents, organic matter, or inhibitors

What are the 4 modes of action for chemical agents

Cell walls

Cell membranes

Protein and nucleic acid synthesis

Protein structure and function

 

 

____kills microbes at lower temperatures and over a shorter period of time than dry heat

Moist heat

What happens when the cell wall is targeted

becomes fragile and cell lyses

What happens when the cell membrane is targeted

It loses integrity

What happens when protein and nucleic acid synthesis is targeted

prevention of replication, transcription, translation, peptide bond formation, protein Synthesis

What happens when protein function is targeted

It disrupts and denatures proteins

What are the 3 importantphysical methods of control

-temp

-radiation

-filtration

What is filtration

Physical removal of microbes by passing a gas or liquid through filter