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Prokaryotes & Viruses Free Response

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1 Compare and contrast the lac and trp operons by responding to the following prompts:

A Identify the lac operon and the trp operon as either an

inducible operon or a repressible operon.

B Identify which type of operon is typically on (inducible or

repressible).

C Identify which type of operon is usually off (inducible or

repressible).

D

Explain the steps that occur with a repressible operon (identify the factors or molecules that alter the typical state

• f a repressible operon as well as the following

terminology: co-repressor and operator)

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2 The illustration below represents how antibiotic resistant can develop within a bacterial

• population. All of the circles represent a bacterial

colony with varying level of antibiotic resistance. Explain this process by responding to the prompts below:

A

Explain what occurs within the first circle, “Before antibiotics” that leads to the results in the second circle, “After antibiotics”.

B

Explain what happens within the second circle, “After antibiotics”, that leads to the third circle, “Final population”.

C Describe the final population of bacteria.

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3 The illustration below shows a type of virus that infects bacterial cells.

A What is the name for this type of virus? B Label the parts of the virus shown on the illustration. C

Describe the sequence of events that occur within the lytic cycle from attachment of the virus to a bacterial cell through the release of new viruses.

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4 There are four phases to bacterial growth, as shown in the graph below.

A the activities of the bacterial cells B the state of the resources available to the bacteria

http://www.smccd.edu/accounts/case/biol230/growth

For each of the four phases labeled on the graph above, describe the following:

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5 An experiment was performed to determine the effectiveness of various antibiotics on a particular species of bacteria. The plating results are shown below.

A Two disks, C and E, have zones of inhibition. Explain what

this result indicates and why these circles are clear.

B

The bacteria cells surrounding disk A grew at a rapid rate

• nce they were plated onto the agar. This area of the plate

began with 100 bacterial cells. This species of bacteria has a generation time of 60 minutes. The plates were placed into a 37oC incubator for 48 hours. When the plates were removed and viewed, approximately how many bacterial cells had grown around disk A?

Use the results shown on the image above in responding to the prompts below:

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