Lesson 1.2 - Physiology of Bacteria

Psychrophiles

Bacteria that prefer cold, thriving at temperatures between 0 degrees celsius and 25 degrees celsius.

Mesophiles

Bacteria that prefer moderate temperatures and grow best at high temperatures, between 40 degrees celsius and 70 degrees celsius (104-158 F)

Hypotonic Solution

Freshwater. A red blood cell will swell and burst because water molecules are moving into the cell.

Strict Saprophytes

Organisms that only survive on dead or decaying organic matter. Completely dependent on their living host for the nutrients they need to survive.

Hypertonic Solution

Seawater. A red blood cell will shrink and wrinkle up because water molecules are moving out of the cell.

Symbiosis

When two or more different species of organisms live together in close association. Distinguished by the degree to which the host organism is harmed.

Five classifications of bacteria based on their oxygen requirements

1. Obligate (strict) aerobes 2. Obligate (strict) anaerobes 3. Microaerophilic organisms 4. Facultative organisms 5. Aerotolerant organisms

Three categories of Heterotrophic Bacteria

1. Strict (obligate) saprophytes 2. Strict (obligate) parasites 3. Facultative Bacteria

What amount of oxygen would a facultative aerobe require for best growth oxygen in air or absence of oxygen

Absence of oxygen

Facultative Bacteria

Adapt to differing sources of nutrition. As food sources in the environment change, this bacteria simply feed on the new food sources or produce their own nutritional sources.

Autotrophic Bacteria

Bacteria are self-nourishing bacteria capable of growing in the absence of organic compounds. Capable of obtaining nutritional value from the carbon in carbon dioxide. One of the largest groups - cyanobacteria. Receive their name from their appearance as blue-green algae; however, they are not algae, and they may be red or pink as well as blue-green. Red color of the Red Seas is due to cyanobacteria. Produce about 20 percent of the Earth's oxygen and are capable of converting inorganic carbon dioxide into the nutrients they need through photosynthesis. Use light and carbon dioxide to produce their own food.

What term is used to describe a visible mass of bacterial cells growing on a solid surface?

Colony

What effect does light (specifically ultraviolet sunlight) have on pathogenic bacteria?

Detrimental to growth

Commensalism

Exists when one organism gains some benefit, such as protection or nourishment, and the host is not harmed. Differs from mutualism in that both organisms gain a benefit in mutualistic relationships, but only one organism gains a benefit during commensalism.

Describe the life of facultative parasite which is only given non-living organic matter: (grows well), (survives minimally), or (dies)

Grows well

Isotonic Solution

Human Blood Serum. A red blood cell remains unchanged because the movement of water molecules into and out of the cell are the same.

Mutualism

In a symbiotic relationship, two different species live in close association to the mutual benefit of each other.

Antagonism

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

Synergism

Occurs when the harmonious action of two microorganisms produces an effect that neither could produce alone.

Osmotic Pressure

Pressure required to prevent the net flow of water across a semipermeable membrane, such as the cell membrane found in bacteria. When the fluids outside of the bacterial cell contain high concentrations of salt, the water inside the bacterium is drawn into the external fluid.

Heterotrophic Bacteria

Require complex organic food from a carbon source to grow and develop. The cause of numerous diseases in humans. Some are able to survive on a wide variety of organic compounds. Pseudomonas is a genus of bacteria that is commonly associated with secondary infections in burn patients. Can survive on over 90 different organic compounds, including napthalene, which is the active ingredient in moth balls and is also a solvent used in refinishing furniture to remove paint, stain, varnish, lacquer, and other finishing compounds.

Microaerophilic microorganisms

Require little free oxygen (about 2 percent to 10 percent) and facultative bacteria are capable of adjusting to changes in oxygen levels in their environment.

pH

Scale ranges from 0-14, with 0 being extremely acidic and 14 being extremely alkaline (basic). Substance is neutral with a pH of 7. Human body is slightly alkaline with a pH of 7.4. Bacteria that cause disease in humans thrive at this neutral pH, although many can survive as long as the pH level of their cytoplasm does not change.

Describe the life of a facultative anaerobe which is given no oxygen from air: (grows well), (survives minimally), or (dies)

Survives Minimally

Parasitism

The host is harmed, while the parasite receives some benefit. All living organisms, including humans can act as hosts for parasites.