MCB Module 3 Assignment

Microbes that grow readily on the bench top or in a temperature-controlled incubator that is not sealed from the atmosphere in the room are ______.

aerobes

Microorganisms that have complicated nutritional requirements are

fastidious.

It is sometimes difficult to obtain pure cultures of microbes that grow naturally in mixed communities.

True

From which of the following would you be most likely to obtain a pure culture?

A single colony on a streak plate.

Differentiate between direct microscopic counts and direct counts using the flow cytometer in the image shown.

A. Direct Microscopic Count

B. Flow Cytometer

C. Manual

D. Automated

Thioglycolate medium is used to determine the oxygen requirements of a microorganism. You inoculate a tube of this medium with a bacterium and observe dense growth at the bottom of the tube. From this you can conclude that

the organism is an obligate anaerobe

Identify each plating method and the resulting patterns of growth in the image

this one

A candle jar is typically used to grow ______.

capnophiles

When studying microbes, why is it important to separate mixed communities into individual pure cultures of the different species?

So we can understand the biochemical characteristics of one species without confusing it with another species.

Identify the type of bacterial formation being shown in this image.

this one

During which phase of growth do researchers measure the generation time of a culture of bacteria?

Log phase

Please match the optimum temperature categories with the appropriate environment.

this one

Production of extracellular polymeric substances (EPS) enables bacteria to

form biofilms.

A species of bacteria that is fastidious is least likely to be able to grow on which of the following media?

Glucose-salts agar

From which of the following are you most likely to isolate an acidophile?

A hot vent at pH 1.5

Match each type of bacteria with the appropriate incubation setup.

this one

An enclosed compartment filled with an inert gas such as nitrogen would be most appropriate for growing ______.

obligate anaerobes

During which stage of growth does cell division equal the rate of cell death?

Stationary phase

You use the streak-plate method to obtain a pure culture and observe individual colonies following incubation. Consider a single bacterial colony. All of the following statements about the colony are true EXCEPT

All cells in the colony are expressing the same set of genes and are performing the same metabolic functions.

Match each image of growth on an agar plate to the correct broth dilution to complete the serial dilution series shown.

this one

You use the streak-plate method to obtain a pure culture and observe individual colonies following incubation. Consider a single bacterial colony. All of the following statements about the colony are true EXCEPT:

All cells in the colony are expressing the same set of genes and are performing the same metabolic functions.

Which of the following are considered the major elements that primarily make up components of cells in microorganisms and all living things?

• Nitrogen

• Zinc

• Phosphorus

• Sulfur

• Carbon

• Oxygen

• Hydrogen

• Cobalt

• Copper

• Molybdenum

• Manganese

You observe bacteria growing on the surface of a Petri dish of nutrient agar you left on the counter in your lab. You can be confident that your bacteria are NOT which of the following?

Obligate anaerobes

Anabaena is a genus of filamentous cyanobacteria commonly found in aquatic environments, where it harvests energy from sunlight and fixes both carbon dioxide and nitrogen. Knowing this, how would you classify Anabaena?

Photoautotroph

Identify the types of microorganisms based on their optimal growth temperatures. Not all labels are used.

this one

You are given a Gram-positive, motile, anaerobic streptococcus to study. Which of the following best describes this organism?

Chains of round cells with a thick peptidoglycan cell wall, flagella and no oxygen requirement.

Choose the statement that best describes the concept behind the enrichment culture method.

this one

During a one hour time period in a population of approximately a billion cells, ten cells divide, and a hundred thousand cells die. This pattern suggests the population is experiencing which phase of a growth curve?

Phase of prolonged decline

Please select three examples of growth factors from the list.

• Starch

• Amino acids

• Phospholipids

• Cholesterol

• Vitamins

• Nucleotides

• Polysaccharides

• Water

Place the labels to explain the concepts behind how spectrophotometry works. Not all labels are used.

this one