Lab 7, 8, & 9

What is important about Potato Dextrose Agar?

Potato starch and dextrose support the luxuriant growth of fungi. Lowering the pH of the medium to approximately 3.5 with sterile tartaric acid inhibits bacterial growth.

What are bacteriophages?

• Types of viruses that infect bacteria

  • “Eat bacteria”

What is the lytic cycle?

The normal process of viral reproduction involving penetration of the cell membrane, nucleic acid synthesis, and lysis of the host cell

What is the lysogenic cycle?

• Latency: the ability of a pathogenic virus to lie dormant within a cell

• A form of viral reproduction involving the fusion of the nucleic acid of a bacteriophage with that of a host, followed by proliferation of the resulting prophage

What are the typical units used to represent concentration for bacteriophages?

Plaque forming units (PFU)

What are the steps in PCR?

1. Denaturation - Heat melts double-stranded DNA into two single strands

2. Annealing - Primers bind to their complementary target sequences

3. Elongation - DNA polymerase extends from the primers to synthesize new complementary strands.

At what temperature does denaturation occur in PCR?

94-96℃

At what temperature does annealing occur in PCR?

~68℃

At what temperature does elongation occur in PCR?

72℃

What ingredients are in a Master Mix in PCR?

GoTaq buffer, MgCl₂, dNTPs (nucleotide mix), water, forward primer, reverse primer, GoTaq DNA polymerase.

How are PCR results observed?

• Loading and running on agarose gel to check the presence and the size of the PCR products

• DNA fragments are negatively charged, so they move towards the positive electrode