microbiology - physiology of bacteria

psychrophiles, mesophiles, thermophiles

3 broad categories of bacteria based on their temperature requirements for growth.

Temperature

A factor in growth of microorganisms

the internal structures to produce energy or utilize food sources.

All viruses, viroids, and prions are obligate parasites because they lack:

Autotrophic

An organism capable of synthesizing its own food from inorganic substances, using light or chemical energy. Green plants, algae, and certain bacteria are autotrophs. Capable of obtaining nutritional value from the carbon in carbon dioxide.

Symbiotic relationships

Are distinguished by the degree to which the host organism is harmed.

Photosynthesis

Autotrophic bacteria are capable of converting inorganic carbon dioxide into the nutrients they need throught:

human remains

Autotrophic bacteria participate in the decomposition of ___________________.

Agonal algor

Body temp cooled before death

Mutualism

Both organisms gain a benefit in mutualistic relationships

Facultative bacteria

Can adapt to differing sources of nutrition. They feed on the new food sources or produce their own nutritional sources.

formation of disease in humans and decomposition of human remains

Different types of associations' microorganisms form with other organisms are related to both the:

Yeasts and molds

Do Not contain chlorophyll, so they cannot utilize light to produce energy. They tend to prefer dark areas for maximum growth.

Agonal fever

Fever before death

20%

How much of the earth's oxygen does autotrophic bacteria produce?

Autotrophic micororganisms

One way growth of microorganisms is controlled is through the presence of antagonistic microorganisms.

Commensalism

Only one organism gains a benefit

High concentrations of salt

Retards microbial growth and inhibits decomposition of proteins.

Osmotic Pressure

The pressure required to prevent the net flow of water across a semipermeable membrane, such as the cell membrane found in bacteria.

Yeasts and molds

This grows well in an acidic environment, such as that found in the vagina.

Stomach acids

This is neutralized by the presence of the ammonia in the area of the bacteria, allowing bacteria to survive.

True

True or False: Autotrophic bacteria do cause some human diseases lie swimmer's itch.

True

True or False: Autotrophic bacteria do not cause disease in humans.

True

True or False: Bacteria that cause disease in humans thrive at this neutral pH.

False

True or False: Heterotrophic bacteria are not the cause of numerous diseases in humans.

False

True or False: Not all organisms have oxygen requirements.

pH scale

Used to indicate pH - refers to the concentration of hydrogen ions.

Light

What affects microbial growth?

light and carbon dioxide

What does autotrophic bacteria use to produce their own food?

Reduces bacterial decomposition by retarding the growth of mesophilic bacteria.

What does placing the deceased on refrigeration do?

Osmotic pressure is high in many embalming fluids

What is one of the reasons that osmotic pressure retards microbial decomposition and decreases the spread of infectious disease from the deceased to the public?

7.4 on pH scale

What is the human body on the pH scale (slightly alkaline)?

Normal flora inhibit growth of other microorganisms by competing for nutrients or space, or by producing toxins that kill the microorganisms.

When does antagonism occur?

Symbiosis

When two or more different species live together in close association, the arrangement is known as:

Changes in body temp occur before and after death influencing rate of decomposition of the human remains.

Why are variations in temperature preferences of different bacteria important to the embalmer?

Antagonism

a mutual opposition or contrary action, and in the case of microbial relationships, term refers to inhibition of one microorganism's growth bythe presence of another.

Mesophiles

bacteria taht prefer moderate temps and grow best between 25° C and 40° C

Thermophiles

bacteria that grow best at high temps, between 40° C and 70°C. Some bacteria grow in extremely hot temps (volcanoes) 105°C and 110°C.

Psychrophiles

bacteria that prefer cold, thriving at temps between 0° C and 25° C

Facultative bacteria

capable of adjusting to changes in oxygen levels in their environment.

Cyanobacteria

capable of converting light into a food source and thrive in its presence

Meningococcal meningitis, gonorrhea, stomach ulcers

caused by microaerophilic bacteria... do not gain any benefit from presence of oxygen (indifferent)

Multicellular molds

contain the necessary structures for reproduction

Commensalism

exists when one organism gains some benefit, such as protection or nourishment, host is not harmed.

0 on pH scale

extremely acid (on pH scale)

14 on pH scale

extremely alkaline (on pH scale) (basic)

Parasitism

host is harmed, while parasites receive some benefit

Obligate anaerobes

microbes that can only survive in an environment devoid of oxygen

Norma Flora aka normal microbiota

microorganisms present in the body that usually do not cause disease.

Obligate aerobes

need oxygen to metabolize sugars

Synergism

occurs when harmonious action of tow microorganisms produces an effect that neither could produce alone

Cyanobacteria

one of the largest groups of autotrophic bacteria. The name comes from appearance as blue-green algae. However NOT algae.

Strict saprophytes

organisms that only survive on dead or decaying organic matter

Heterotrophic bacteria

require complex organic food from a carbon source to grow and develop.

Microaerophilic microorganisms

require little free oxygen (2-10%)

Cyanobacteria

responsible for the continuation of the nitrogen cycle - can convert atmospheric nitrogen into its organic form.

7 on pH scale

substance is neutral (on pH scale)

Mutualism

two different species live in close association to the mutual benefit of each other.