Lecture 10

Question 1

Nucleic Acid Palindromes

Answer 1

• sequences of double-stranded nucleic acids with two fold symmetry.
• Form either hairpins(single strand) or cruciform structures(double stranded).

Question 2

How do bacteria protect themselves from bacteriophage infection

Answer 2

restriction endonuclease (restriction enzymes)

Question 3

Denaturation of DNA

Answer 3

• strand separation by heating or pH extremes

- Process called melting when heating is used

Question 4

Renaturation of DNA

Answer 4

• Rapid spontaneous annealing or renaturation when returned to physiologic range so long as some residues are in double helix
• if strands completely separated annealing is a slower 2 step process.

Question 5

Melting temp of DNA depends on

Answer 5

• pH
• ionic strength
• base composition

Question 6

Melting temperature of DNA is determined

Answer 6

by the GC content in the DNA segment.

-the higher the GC the higher the Temp.

Question 7

Part of DNA that denatures first

Answer 7

AT rich regions