CHAPTER 5 BACTERIAL TRANSFORMATION & POLYMERASE CHAIN REACTION

What is the clinical significance of Bacterial transformation in biotechnology?

Explains antibiotic resistance spread, enable genetic engineering, and underlies gene therapy vectors.

When did Griffith discover transformation?

1928

How did the mouse die in station 1?

From pneumonia

What did the s-strain contain?

Polysaccharide capsule

How was the R-strain different from the s-strain?

Lacks capsule and appears rough and uncapsulated

What happened in station-3 of griffith’s experiment?

Heat-killed S strain injected into mouse and it survives

What happened in station 4?

Heat-killed S strain and live R strain injected into mouse and it dies

How did the bacteria demonstrate genetic variation?

Has some chromosomal DNA injected as well.

What happens during DNA release and uptake in the transformation process?

The S chromosome released from heat-killed bacteria contains capsule synthesis gene

What happens during DNA integration?

New DNA is added into existing DNA.

What happens during Bacterial division in the transformation process?

The bacteria copies and passes on the new DNA it absorbed

What is the clinical significance of Bacterial conjugation?

Helps bacteria share genes, especially genes that make them resistant to antibiotics.

What are the different bacterial mating types?

What is the Fertility factor?

F⁺ (donor) and F⁻ (recipient)

What is the conjugation bridge?

Tiny connection that forms between two bacteria so they can transfer DNA.

How are genes transferred during conjugation?

DNA passes from one bacteria to another through a conjugation bridge formed by a pilus

What is high frequency Recombination?

Occurs when an Hfr bacteria transfers a large number of chromosomal genes to another bacteria during conjugation

What is Bacterial Transduction?

When a virus transfers DNA from one bacteria to another.

What happens during Bacteriophage attachment?

The virus binds to specific receptors on the bacterial cell so it can begin infection.

What happens during phage DNA replication?

The virus uses the host cell’s machinery to make many copies of its own DNA.

What happens during packaging and phage release?

During packaging, new phage DNA is enclosed in protein coats, and during release the bacterium lyses, freeing the newly formed viruses.

What are the steps of generalized transduction?

When a virus accidentally transfers random bacterial DNA from one bacterium to another.

What happens during prophage integration and excision?

During integration, viral DNA inserts into the bacterial chromosome as a prophage; during excision, the prophage is cut out and becomes active again.

What is hybrid DNA formation?

When DNA from two different sources combines into one DNA molecule.

How is DNA transferred to recipient?

DNA is transferred to the recipient when genetic material moves into the cell by conjugation, transformation, or transduction.

What is the pre-integration state?

When new DNA has entered a cell but has NOT yet joined with the cell’s own DNA.

What is the post-integration state?

When new DNA has successfully joined with the cell’s original DNA.

What is the clinical significance of Bacterial Transduction?

Allows the spread of antibiotic resistance and disease-causing genes, making infections harder to treat.

How did genetic engineering revolutionize medicine?

Enable bacteria to produce insulin, growth hormone, and blood clot

What is the donor plasmid

Small, circular DNA molecule

What are Restriction enzyme?

Precise DNA fragment insertion

What are DNA ligase

Glue

Where do foreign DNA come from

Animal tissues or human cells

What is a chimera

Recombinant plasmid created when foreign DNA combines with the donor plasmid at the restriction point.

What does CaCl2 solution do to cells?

Opens cell walls and membranes

How does the host bacteria reproduce quickly?

Binary fission

How can recombinant proteins be used?

Harvested for medical use.

How did PCR revolutionize medicine?

Enable Covid-19 testing

What are primers?

Short sequences to bind

What are dNTPs?

Building blocks for new DNA synthesis

What is Taq DNA polymerase?

Synthesizes new DNA strands

What are the three steps of PCR?

Denaturation, Annealing, Elongation

What temperature does denaturation occur at?

95 celsius

What happens during the denaturation phase?

DNA separates into two strands.

What temp does annealing happen?

55 celsius

What happens during annealing phase

Glue pieces of DNA together

What temp does elongation happen at?

What occurs during elongation stage?

DNA synthesis creates long stands.

How does PCR multiply?

2^n

How many cycles of PCR are typical?

30 cycles