Micro 150 Ch.9 HW WIP

Photoautotroph

Uses sunlight as an energy source and carbon dioxide as a carbon source (example:  cyanobacteria)

Chemoautotroph

Uses simple inorganic compounds for energy and carbon dioxide for a carbon source (example:  methanogens)

Photoheterotroph

Uses sunlight as an energy source and an organic carbon source (example:  purple photosynthetic bacteria)

Chemoheterotroph

Converts nutrients from other organisms into energy and uses an organic carbon source (example:  protozoa)

Saprobe

Metabolizes organic matter of dead organisms for energy and uses an organic carbon source (example:  fungi)

Parasite

Utilizes the tissues of a live host and an organic carbon source (example:  pathogens)

What matches for Hypotonic condition

Netdiffusion of water into cell - solute water concentration is greater so water will move into the cell

What matches for Isotonic Condition

Rates of diffusion are equal in both direction - Water will move both direction for same solute concentration

What matches for Hypertonic condition

Net diffusion of water is out of the cell - More solutes outside of cell making water move outside of cell causing shrinkage.

Which method tests for Turbidometry

Spectrophotometer

Which method tests Direct Cell Count

Microscopic Count

Method that tests for Viable Plate Count

Viable plate count method

What tests Coulter Counter

Electronic cell counting

What test Flow cytometry

Method requiring labeling of cells with fluorescent in order to detect bacteria in natural sample

Real-time PCR is

Method that allows for the quantification of microorganisms in environmental or tissue samples without isolating them or culturing them.

Photoheterotroph

An organism which requires light as its energy source and organic compounds as its carbon source

Chemoautotroph

An organism which requires simple inorganic chemicals as its energy source and carbon dioxide as its carbon source

Photoautotroph

An organism which requires light as its energy source and carbon dioxide as its carbon source

Chemoheterotroph

An organism which requires organic compounds as both its energy and carbon source

Hypertonic environment

A cell in this environment will lose water and shrink as water moves out of the cell by osmosis.

Hypotonic Environment

A cell in this environment will swell as water moves in by osmosis and may lyse if it does not have a cell wall.

Isotonic Environment

A cell in this environment will neither shrink nor swell as there is no net movement of water into or out of the cell by osmosis.

Psychrophile

Describes an organism that grows optimally at temperatures ranging from 0°C to 15°C

Psychrotolerant

Describes an organism that has an optimum growth temperature between 15°C and 30°C, but is able to grow slowly at colder temperatures

Mesophile

Describes an organism that grows optimally at temperatures ranging from 20°C to 40°C

Thermophile

Describes an organism that grows optimally at temperatures ranging from 45°C to 80°C

Extreme Thermophile

Describes an organism that grows optimally at temperatures ranging from 80°C to 120°C

Obligate Aerobe

Describes an organism which requires oxygen for growth and has the enzymes to remove toxic by-products of oxygen metabolism

Facultative Anaerobe

Describes an organism that can grow in the presence of oxygen and can detoxify it, but can also grow in the absence of oxygen

Microaerophile

Describes an organism that can’t grow at normal atmospheric oxygen concentrations, but does require a small amount of oxygen for growth

Obligate Anaerobe

Describes an organism that is unable to use oxygen and lacks the enzymes to detoxify oxygen, thus requiring the absence of oxygen for growth

Aerotolerant Anaerobe

Describes an organism that does not use oxygen, but can grow to a limited extent in the presence of oxygen

Mutualism

Two organisms living together in which both partners benefit from the relationship

Commensalism

Two organisms living together in which one organism is benefited and the other is neither benefited nor harmed

Parasitism

Two organisms living together in which one organism is benefited and the other (the host) is harmed

Synergism

A relationship in which free-living organisms cooperate and share nutrients

Antagonism

A competitive relationship between free-living organisms in which one organism secretes substances that  are toxic to the other in order to acquire more space or nutrients for itself

Stationary growth Phase

Phase during which nutrient depletion and accumulation of wastes begin to slow cell growth such that the rate of cell increase equals the rate of cell death

Exponential growth Phase

Phase during which cells are growing very quickly, at their maximum rate of cell division

Lag Phase

Adjustment period during which cells are dividing slowly while they adjust to growth conditions

Death Phase

Nutrient depletion and waste accumulation prevent cell growth and cells die exponentially

Turbidometry

A spectrophotometer is used to measure the light scattering properties of a bacterial culture.  As the number of bacteria increase, more light is scattered and less is transmitted to the detector

Direct Cell Count

Method uses a special (cytometer) and cells are counted by observing through a microscope

Coulter Counter

This is an automated cell counting device that scans a culture as it passes through a tiny pipette

Flow Cytometry

This is an automated cell counting device that requires fluorescent labeling of cells that will be scanned and counted

Like budding, binary fission produces two differently sized cells that contain an equal amount of genetic information. T/F

False

Selenium is a major essential nutrient required by all bacterial cells for survival. T/F

False

Which of the growth curves represents an obligate aerobe grown in the presence of oxygen?

A

Which of the growth curves represents an obligate anaerobe grown in the presence of oxygen?

C

Which of the growth curves represents an aerotolerant anaerobe grown in the presence of oxygen?

B

Which of the growth curves represents a facultative anaerobe grown in the presence of oxygen?

A

Using the equation Nf = Ni (2^n), determine how many Staphylococcus aureus cells are present in a custard tart under these circumstances. During preparation, 15 cells were deposited in the custard, and the tart has sat at room temperature for 5 hours. S. aureus has a generation time of 20 minutes.

4.9 × 10^5

In the United States, the CDC estimates that _________blank people suffer each year from some form of food-borne infection.

Several million

The presence of microbes in food can be

• harmful.

• beneficial.

• neutral.

Individual bacteria (such as Salmonella)

grow best at an optimum temperature and a range above and below it.

The type of food-borne infection known as an intoxication is caused by

toxins produced by microbes as they grow in the food

Most bacteria reproduce by

Fission

After six generations, how many bacteria would have formed from the reproduction of one bacterium?

64

Bacteria that grow in oxygenated environments are referred to as

Aerobes

Bacteria that thrive in environments with a pH of greater than 7 are classified as

alkalinophiles

What is the effect of heat on a population of bacteria?

Cells begin to die at a temperature slightly above the maximum.

What is the effect of cold on a population of bacteria?

Cells survive but do not divide at temperatures below the minimum

What food product is least likely to contain viable vegetative pathogens?

Chicken cooked to 170 degrees F

If conditions are favorable, the generation time of bacteria

can be as short as 30 minutes

The environmental factor that influences bacterial growth the most is

temperature.

The safe temperature ranges for the storage of foods are determined by

the low temperature where microbes stop multiplying and the high temperature where they physically die.