Temperature

Microbial cells are ______ to control their own temperature and therefore take on the ambient. temperature of their natural habitats

unable

The range of temperatures for the growth of a given microbial species is described as three _________ ________

Cardinal temperatures

The ______ _______ is the lowest temperature that permits a microbe’s continued growth and metabolism

minimum temperature

Below the minimum temperature, its activities ______

stop

The _____ ______ is the highest temperature at which growth and metabolism can proceed

maximum temperature

If the temperature rises slightly above maximum, growth will ________ stop, but if it continues to rise beyond that point, the enzymes and nucleic acids will eventually become _______ _______ (otherwise known as _______) and the cell will _____

Temporarily

Permanently Inactivated

denatured

die

The ______ _______ covers a small range, somewhere between the minimum and maximum, which promotes the FASTEST RATE OF GROWTH AND METABOLISM. This is a narrow range.

optimum temperature

A _______ is a microorganism that is capable of growing at LOW TEMPERATURES

psychotrophile

________ have an optimum temperature below 15 celcius and is capable of growth at 0 celcius.

psychotrophiles

_________ bacteria are less extreme than psychrophiles and much more common. They grow slowly in cold but have an optimum temperature between 15C and 30C

psychotolerant

Examples of psychotolerant bacteria are _______ _______ and ______ _________ they can cause foodborne illness

Staphylococcus aureus and Listeria monocytogenes

The majority of medically significant microorganisms are ________. That grow at intermediate temperatures

Mesophiles

The optimum growth temperatures for ______ fall into the range of 20C and 40C

mesophiles

Most human pathogens grow optimally somewhere between _____C and _____C

30

40

Human body temperature is ______C

37

Mesophiles have adapted to in ….

animals (human body), plants, soil, and water

Some mesophilic bacteria such as Staphylococcus aureus, grow optimally at body temperature but are also _______ _______ meaning they can survive and multiply slowly at refrigerator temperatures causing concern for food storage.

Facultatively psychrotolerant

_____ is a term used in biology that designates an organism as capable of growing under differing sets of conditions

facultative

______ _______ is a human pathogen that is truly psychrotolerant, meaning its optimum growth is between 30C and 40C. But it will grow slowly at temperatures as low as 1C, and often grows in ice cream and refrigerated meat.

Listeria

________ microbes which can survive short exposure to high temperatures, but are normally mesophiles, are common contaminants of heated or pasturized foods

Thermoduric

Examples of thermoduric microbes in clude heat-resistnant _______ formers such as Bacillus and Clostridium

endospore

A ________ is a microbe that grows optimally at temps greater than 45C

Thermophile

Thermophile vary in heat requirements with a general optimum range of growth of ___C and _____C

45

80

Most eukaryotic forms cannot survive above ______

60C

One group of bacteria which is now a separate domain ______ includes organisms that grow in ________ conditions.

archaea

extreme

Archaea are called _________ ________

extreme thermophiles

Extreme theromphiles grow between ________. Researches sometimes use autoclave to isolate them as most other bacteria are KILLED AT THESE TEMPS

80 and 121

Why do some strict parasitic bacteria like typhus and viruses like rhinovirus have a narrow cardinal temperature range?

only survive a few degrees below or above the host’s body temperature

Some thermophiles cannot grow below a temperature of about

60