1. List three differences between gram + and gram - bacteria.

Gram + bacteria have a thicker peptidoglycan layer and no outer membrane. Gram – have an outer membrane.

Gram + require antibiotics that break down their peptidoglycan layer (penicillin) whereas Gram - bacteria require antibiotics disrupt protein synthesis (ciproflaxin – a “broad spectrum” antibiotic)

Gram + bacteria stain violet because their thicker peptidoglycan layer retains the Gram stain whereas Gram – bacteria stain pink because their thinner peptidoglycan layer retain less Gram stain.

B. Bacilli A. Cocci

D. Spirilla C. Vibrio

3. If the spirilla bacteria above are stained pink, this indicates that

4. If the cocci bacteria above are stained purple, this indicates that

5. When a bacterium is in a stressful or unfavorable environment it enters a state. It forms a structure called the endospore, which encloses its ____ and part of its .

the bacteria are Gram negative.

the bacteria are Gram positive.

dormantDNA

cytoplasm

6. A person is infected with a virus. Create a graph of body temperature over time that shows how a lytic virus

would progress, and then create another graph that shows how a lysogenic virus would progress.

0 5 10 15 20 25949698

100102104106

Body T in a Lytic In-fection

Time after infection (hours)

Body

Tem

pera

ture

(F)

1 day

2 days

10 days

1 5 10 15 20 25 30949698

100102104106

Body T in a Lysogentic In-fection

Time after infection (years)

Body

Tem

peat

ure

(F)

6. Give a short explanation to defend each graph.

In the lytic infection cycle, a person infected with a virus will show symptoms, such as a rapid increase in body temperature, within hours.

In the lysogenic infection cycle, a person infected with a virus may show symptoms of the initial infection (seen in the initial increase in body temperature), but may not show symptoms for years (seen by the constant body temperature). The virus may enter the lytic cycle after many years (seen by the sharp increase in body temperature).

7. Contrast conjugation and binary fission using the table below. How are they different?

CONJUGATION:

1. Increases genetic diversity2. Not true reproduction3. Plasmid is replicated (copied) and sent via sex pilus.

BINARY FISSION:

4. Daughter cell identical to parent cell. 5. Asexual reproduction6. Grows exponentially7. Replication requires the bacterial chromosome

10. Label the type of bacterial cell well and the parts of the cell wall in the diagram below using the following terms: inner membrane, outer membrane, peptidoglycan, membrane protein, inside the cell, and outside the cell.

Inside of cell

Outside of cell

Inner membrane

Outer membrane

Peptidoglycan

Gram negativebacteria

Membrane protein/s

8. Penicillin attacks the in the ________of _______________bacteria.

9. Whereas, ciproflaxin disrupts at the ribosomal level, therefore is typically used against ____________ bacteria.

peptidoglycan cell wallGram +

protein synthesis

Gram -

11. Compare and contrast lytic and lysogenic infections.

• Fast acting• Virus induces

host cell to replicate genetic material and synthesize proteins• Virus lyses

host cell to “spread”

• Virus attaches and inserts

genetic material into host cell• Occur in

many organisms

• Virus remains dormant in host for many years (slow acting)

• Viral genetic material inserted into host genome• Viral genetic material replicates when host cell replicates• Has two phase

(progresses to lytic phase in

stressful conditions)