module 9 Flashcards
What are restriction endonucleases?
Enzymes that cut DNA at specific sequences, often used in genetic research and biotechnology.
What is the role of ligases in molecular biology?
Ligases are enzymes that glue or join DNA fragments together by catalyzing the formation of phosphodiester bonds.
Which enzymes are responsible for synthesizing DNA and RNA?
Polymerases are the enzymes that synthesize DNA (DNA polymerase) and RNA (RNA polymerase).
What is the function of polymerases in DNA and RNA synthesis?
Polymerases add nucleotides to a growing DNA or RNA strand, using a template strand to guide the sequence.
What is reverse transcriptase and how does it differ from other polymerases?
An enzyme that makes DNA from RNA.
How do restriction endonucleases cut DNA?
They recognize specific short DNA sequences (often palindromes) and cut both strands of DNA at these sites.
Can reverse transcriptase be used to synthesize RNA from a DNA template? Why or why not?
No, it makes DNA from RNA.
How are restriction endonucleases and ligases used together?
Endonucleases cut DNA, and ligases join it into vectors during cloning.
What is a restriction digest?
A process where restriction enzymes cut DNA into smaller fragments.
What is electrophoresis used for?
Separates DNA fragments by size using an electric field.
What is molecular cloning?
A technique to insert a gene into a plasmid vector and introduce it into a host cell.
What is PCR (Polymerase Chain Reaction)
A method to amplify specific DNA sequences rapidly.
What is DNA sequencing?
Determining the exact order of nucleotides in a DNA molecule.
What is hybridization in molecular biology?
The process of binding complementary DNA or RNA strands together.
What are microarrays used for?
Analyzing gene expression by detecting hybridization of labeled DNA/RNA to a grid of probes.
What is the natural source of restriction endonucleases?
They are naturally found in bacteria, where they protect against viral DNA.
What is the main function of restriction endonucleases?
They cut double-stranded DNA without damaging the nitrogenous bases.
How does the length of a restriction enzyme’s recognition sequence affect fragment size
Longer recognition sequences produce longer DNA fragments.
Is restriction digestion time-dependent?
Yes, the efficiency of digestion can depend on the incubation time.
Why isn’t bacterial DNA digested by its own restriction enzymes?
Bacterial DNA is protected by methylation, which prevents recognition by the enzymes
whats a sticky 5 prime end
results from staggered cutes leaving single stranded dna. These sticky ends can easily pair with complementary sticky ends from other DNA fragments, making them useful for molecular cloning and recombination
whats ecorI and what does it do
it is a restriction enzyme known as Escherichia coli.EcoRI recognizes and cuts the DNA sequence GAATTC. it does a sticky cut.
sticky cuts are _____
staggered
whta is HindIII and what does it cut.
HindIII recognizes the palindromic sequence AAGCTT,. it is a restriction enzyme called haemophilus influenzae