Ch 6: Microbial Nutrition and Growth

Which type of nutrition:

__ - any substance that must be provided to an organism

Essential nutrient

Macronutrients are required in relatively large quantities and play principal roles in __ and __.

Ex. carbon, hydrogen, and oxygen

cell structure, metabolism

Which type of nutrition:

__ - also known as trace elements.

Ex. manganese, zinc, nickel

Micronutrients

Which type of nutrition:

__ - an atom or simple molecule that contains a combination of atoms other than carbon and hydrogen.

Found in the crust of the earth, bodies of water, and the atmosphere.

Inorganic nutrients

Which type of nutrition:

__ - contain carbon and hydrogen atoms are the products of living things. Simple organic molecules such as methane.

Ex. large polymers (carbohydrates, lipids, proteins, nucleic acids)

Organic nutrients

What are the essential elements of microbial cytoplasm that take up 96% of dry cell weight?

carbon, hydrogen, oxygen, nitrogen, phosphate, sulfur

What Microbes Eat:

A __ is an organism that must obtain its carbon in an organic form.

heterotroph

What Microbes Eat:

An __ (“self-feed”) is an organism that uses inorganic CO₂ as its carbon source.

autotroph

What Microbes Eat:

The __ are microbes that photosynthesize.

phototroph

What Microbes Eat:

The __ are microbes that gain energy from chemical compounds.

chemotroph

Chemoheterotrophs have the following characteristics EXCEPT:

All choices are characteristics

Saprobes perform the following functions EXCEPT:

All choices are functions

What derive nutrients from the cells or tissues of a living host, and range from viruses to helminths?

Parasites

__ are parasites that cause damage to tissues or even death.

Pathogens

Which type of parasite:

__ - live on the body.

Ectoparasites

Which type of parasite:

__ - live within cells such as the leprosy bacillus and the syphilis spirochete.

Intracellular parasites

Which type of parasite:

__ - unable to grow outside of a living host.

Obligate parasites

Transport of necessary nutrients occurs across the cell membrane, …

… even in organisms with cell walls.

Diffusion is molecular movement going from __ to __.

higher concentration, lower concentration.

Which type of diffusion:

• Movement of water through a selectively, or differentially, permeable membrane.

Osmosis

Which type of transport is against the diffusion gradient?

Active Transport

Endocytosis is when __ encloses the substance in its membrane, and simultaneously forms a __ that engulfs the substance.

cell, vacuole

Which type of endocytosis:

__ - accomplished by amoebas and white blood cells, and ingest whole cells or large solid matter.

Phagocytosis

Which type of endocytosis:

__ - ingestion of liquids such as oils or molecules in solution.

Pinocytosis

Which of the following terms describes an organism that derives its energy and carbon from organic molecules?

Chemoheterotroph

What is the lowest temperature that permits a microbe’s continued growth and metabolism?

Minimum Temperature

What is the highest temperature at which growth and metabolism can proceed before proteins are denatured?

Maximum Temperature

What is an intermediate between the minimum and the maximum that promotes the fasted rate of growth and metabolism?

Optimum Temperature

Which of the following is FALSE regarding Mesophiles temperature conditions:

All choices are TRUE about Mesophiles

Thermoduric microbes can survive __ exposure to __ temperatures but are normally mesophiles.

short, high

O₂ has the __ impact on microbial growth, and is an important __ gas and a powerful oxidizing agent.

greatest, respiratory

Microbes fall into one of three categories EXCEPT:

Those that use oxygen but cannot detoxify it.

Singlet oxygen (O) is a(n) __ reactive molecule that can damage and destroy a cell by the __ of membrane lipids.

extremely, oxidation

Which microbe oxygen process:

__ - highly reactive.

Superoxide ion (O₂^-)

Which microbe oxygen process:

__ - toxic to cells and used as a disinfectant.

Hydrogen peroxide (H₂O₂)

Which microbe oxygen process:

__ - also highly reactive like superoxide ion.

Hydroxyl radicals (OH^-)

Superoxide ion is converted into hydrogen peroxide by __. Hydrogen peroxide is converted into harmless water and oxygen by __.

superoxide dismutase, catalase.

Catalase + or - is another major test performed by microbiologist in determining types of __.

Ex. generally, staphylococci + streptococci - (there are many other examples of Catalase +/- bact.)

bacteria

Aerobes can use gaseous oxygen in their __ and possess the __ needed to process toxic oxygen products.

metabolism, enzymes

Which aerotolerance:

__ - organisms that require oxygen for energy production.

Ex. many bacteria such as Bacillus species and Mycobacterium tuberculosis

obligate aerobe.

What are microorganisms harmed by normal atmospheric concentrations of oxygen, but require a small amount of it for metabolism?

Microaerophiles

Which aerotolerance:

__ - do not require oxygen for metabolism but use it when it is present.

Ex. many gram-negative intestinal bacteria, staphylococci

Facultative anaerobes

Anaerobes lack the metabolic __ systems for using __ in respiration.

enzyme, oxygen

Which aerotolerance:

__ - cannot have any oxygen in their environment. Also lack the enzymes for processing toxic oxygen and die in its presence.

Ex. many oral bacteria, intestinal bacteria

Obligate anaerobes

Which aerotolerance:

__ - do not utilize oxygen but can survive and grow to a limited extent in its presence.

Ex. certain lactobacilli and streptococci, clostridial species

Aerotolerant anaerobes

What is a general term to denote a situation in which two organisms live together in a close partner ship?

Symbiosis

Which type of symbiosis:

__ - organisms live in an obligatory but mutually beneficial relationship.

Mutualism

Which type of symbiosis:

__ - the partner called the commensal receives benefits, while its partner is neither harmed nor benefitted.

Commensalism

Which type of symbiosis:

__ - a relationship in which the host organism provides the parasitic microbe with nutrients and a habitat; parasite usually harms the host to some extent.

Parasitism

Antagonism is an __ between free-living species that arises when members of a community __ .

association, compete.

__ - members of a symbiosis.

Symbionts

Antibiosis is the production of inhibitory compounds such as __ into surrounding environment that inhibit or destroy another __ in the same habitat.

antibiotics, microbe

Synergism have the following characteristics EXCEPT:

An interrelationship between two organism that compete for survival

The following is true regarding formation of a biofilm EXCEPT:

All choices are true

Bacteria can use __ to interact with other members of the same members of the same species, as well as members of other species that are close by.

quorum sensing

Bacteria in biofilms behave and respond very differently than __ bacteria.

planktonic (free-living)

Which of the following describes an association between microbes in which one organism is benefitted and one is harmed in some way?

Parasitism

What are the phases of growth curve in order?

lag phase, exponential growth phase, stationary phase, death phase

The __ is a predictable pattern of a bacterial population growth in a closed system can be measured.

Growth Curve

Which phase of the growth curve:

__ - is a flat period of growth due to:

• Newly inoculated cells that require a period of adjustment, enlargement, and synthesis

• Cells are not yet multiplying at their maximum rate

• Population of cells is so sparse or dilute that sampling misses them

lag phase

Which phase of the growth curve:

• Growth increases geometrically

• Will continue as long as cells have adequate nutrients and the environment is favorable

exponential growth phase

Which phase of the growth curve:

• Cell birth and cell death rates are equal

• Cell division rate is slowing down

• Caused by depleted nutrients and oxygen

stationary growth phase

Which phase of the growth curve:

• Cells begin to die at an exponential rate due to the buildup of wastes

• Speed with which death occurs depends on the resistance of the species and how toxic the conditions are

death phase

Microbes in the __ phase are more vulnerable to antimicrobial agents and heat.

exponential growth

A clear nutrient solution becomes __ or cloudy as microbes grow in it.

turbid