Ch.6 Microbial Nutrition and growth

McGraw -Hill Assignment

Carbon, nitrogen, oxygen, and hydrogen are considered ________ nutrients because they are required in relatively large quantities and cannot be manufactured by microbes themselves.

Essential

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

Photoautotroph

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

Chemoautotroph

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

Photoheterotroph

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

chemoheterotroph

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

saprobe

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

parasite

Move the terms to their correct category to test your understanding of transport processes in cells.

passive transport: simple diffusion, facilitated diffusion, osmosis

Active transport: carrier- mediated transport, phagocytosis, pinocytosis

Move the terms into the correct empty boxes to complete this concept map describing cellular transport.

Left --> right line 1
simple diffusion, facilitated diffusion, OSMOSIS, active transport, bulk transport

Line 2
cell in 20% NaCl, Cell in saline, Cell in pure H2O

Line 3: Phagocytosis

Line 4:
net flow of water out of cell, no net flow of water in or out, net flow of water into cell

Line 5: pinocytosis

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

obligate aerobe

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

facultative anaerobe

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

Microaerophile

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

Obligate anaerobe

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

Aerotolerant Anaerobe

With respect to oxygen requirements, an _________ can use gaseous oxygen and possesses enzymes to process toxic oxygen products. (1)

aerobe

Expanding on this classification, an ______ aerobe cannot grow without oxygen. (2)

obligate

______________ do not grow at normal atmospheric oxygen concentrations, but they do require very minute concentrations of oxygen for metabolism. (3)

Microaerophiles

Still other organisms, called__________, can grow with or without oxygen, but grow faster when oxygen is present. (4)

facultative anaerobes

_______ represent a final group of organisms, whose members lack the required enzymes needed for using oxygen in respiration and may not be able to tolerate any free oxygen in their environment ___________.

-Anaerobes
- Obligate anaerobes

hypotonic condition

net diffusion of water into cell

isotonic condition

rates of diffusion are equal in both directions

hypertonic condition

net diffusion of water is OUT of the cell

Move the terms into the correct empty boxes to complete the concept map.

Left
- plasmolysis --> out of the cell

Right
- swelling --> into the cell

Label the image to test your understanding of temperature adaptations exhibited by various bacteria.

left --> right
- psychrophile (-15-15)
- psychrotolerant (5-35)
- Mesophile (10-50)
- Thermophile (45-80)
- Extreme Thermophile (65.5- >130)

Most of the microbiota in the human body are classified as ______.

mesophiles

Refrigeration will _____ the doubling time of most pathogens.

increase

What type of bacteria will grow in the refrigerator, and why is this usually not a concern?

Psychrophiles; very few are pathogenic to humans

You leave your potato salad out on the table at the company picnic. When you made it, you unknowingly introduced 100 cells of Salmonella. How much time will it take for the population of Salmonella to reach at least one million if its doubling time is 20 minutes at picnic conditions?

over 4 hr

explanation: It would take 14 generations for the numbers to rise above one million. At twenty minutes per generation, this would take about 4 hours and 40 minutes. You can calculate this using the equation: Nf = (Ni)2^n and then multiply the number you get for n by 20 minutes.

Most bacteria increase their numbers by _______.

binary fission

During binary fission, one bacterial cell becomes _______ cells.

two genetically identical

What factors can affect the doubling time of a bacterial cell?

All of these factors can affect growth rates.
( temp, moisture, pH, Oxygen lvl)

Pathogens usually have _____ doubling times.

short

You ingest 20 cells of Salmonella. This bacterium has a doubling time of 30 minutes. After 4 hours, how many of these bacteria would be present in the body (assuming no immune system responses or other biological activities affect its growth)?

5,120

Label the image to test your understanding of bacterial growth curves.

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

Drag and drop the labels into the correct empty boxes to complete the concept map.

left to right Line 1:
symbiosis, nonsymbiosis

line 2(purple boxes)
mutualism, commensalism, parasitism

line 3:
normal biota(blue), pathogens (yellow)

Line 4:
protection (blue), disease(yellow)

Label the chart to review the major types of microbial associations.

Green boxes
- symbiotic
- mutualism, Commensalism, Parasitism

Blue boxes
- Nonsymbiotic
- synergism, Antagonism

In a viable count, each _______ represents a _______ from the sample population.

colony; CFU

A _________ derives its nutrients and energy from the organic matter of dead organisms, whereas a _________ lives in or on another living organism and derives its nutrients and energy from that living organism.

saprobe; parasite

Diffusion of water through a selectively permeable membrane is _________.

osmosis

Diffusion is a general term referring to the net movement of atoms and molecules along a concentration gradient, from an area of ________ concentration to an area of _______ concentration.

high; low

Select the physical factors below that can affect microbial growth. SATA

- temperature
- radiation( visible light, UV, gamma)
- Barometric Pressure

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

Mutualism

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

commensalism

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

parasitism

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

Synergism

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

Antagonism

The Hawaiian bobtail squid and the Vibrio fischeri bacteria have established a symbiosis.

The bacteria live in a special organ of the squid and the squid uses the bacteria bioluminescence to camouflage itself.

V. fischeri produces light only when quorum sensing indicates that the bacteria have reached a threshold concentration in the squid

Chose all correct statments about quorum sensing

- Is a chemical system of communication used by bacteria
- can only be intraspecific
- Requires bacteria to be connected via a pilus

For a physician, treating a biofilm infection in a patient poses a significant challenge compared to treating an infection with planktonic bacteria. This is due to the fact that ________.

the biofilm likely contains several different species of bacteria living in a thick, extracellular matrix that cannot be treated by routine antibiotic therapy

The time required for one complete cycle of binary fission is known as the ________ time or generation time.

doubling

Consider the following hypothetical conditions: A population of 10,000 bacteria has a doubling time of 20 minutes, under a given set of growth conditions. The culture is allowed to grow for 2 hours. Select the number of bacteria that best predicts the population size at the end of the 2 hours incubation. Assume there is no lag phase.

640,000

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

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

Exponential growth phase

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

Lag phase

Death phase

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

Choose the phase of the bacterial growth curve during which a bacterial population has the briefest doubling time.

Exponential growth phase

Most bacteria reproduce by ________.

binary 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 grow in oxygenated environments are referred to as ________.

alkainophiles

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°F

The patient asks the RN to describe the disease process of a urinary tract infection. The RN describes bacterial urea digestion and ammonium release. How does the RN most accurately describe the resultant pH following bacterial urine decomposition, facilitating pathogen growth?

Alkaline pH

The RN may anticipate all of the following to be ordered for treatment of the urinary tract infection, except ________.

vaccination

The RN educates the patient about managing the urinary tract infection at home. She recommends increasing fluid intake and consuming cranberry juice. Which of the following is the rationale for the consumption of cranberry juice?

Cranberry juice increases urine acidity.

his patient's wound was likely caused by ________.

poor circulation from diabetes

Clostridium perfringens is the causative agent of ________.

gas gangrene

Which of the following statements describes Clostridium perfringens?

It's a gram-positive organism

C. perfringens causes tissue damage by release of ________.

alpha toxin

Clinical findings not associated with clostridial gas gangrene

- gram staining of cultures reveals gram-negative cocci
- optimal culture growth occurs under aerobic conditions
- endotoxins from organism causes direct muscle tissue damage

Why was hyperbaric oxygen therapy an effective treatment in this case?

The causative agent is an anaerobe

What does it mean to say that C. perfringens can be found as normal biota in the intestine?

It can live in a commensal/mutualistic relationship with the human host

Why were antibiotics prescribed for Mr. Jones?

The causative agent was a bacterium