Unit 1: DNA Enzymes Flashcards
what is the genome?
The compete complement of genetic information of an organism
what are exons?
unique sequence of DNA that actually codes for proteins
what are introns?
remaining DNA used as spaced DNA between genes and within genes. they make genes larger to be able to code them
what are introns necessary for?
regulate gene expression and generate new protein molecules during evolution
what are the three approaches to sequencing the genome
genetic mapping
physical mapping
DNA sequencing
what is polymerase?
catalyses the condensation of DNA and RNA nucleic acid polymers, formation of phosphodiester bonds between a nucleotide in a newly synthesised strand
what is a primer?
a short sequence of polymer complementary to the start of the template strand that initiates polymerisation
what is Taq polymerase?
a thermostable DNA polymerase for PCR and DNA sequencing that withstands temps to 95°C.
what is DNA ligase?
catalyses the condensation of phosphodiester bonds between two strands of nucleic acid polymer. join sugar-phosphate backbone between DNA fragments
what is endonuclease?
catalyses the hydrolytic cleavage degradation of phosphodiester bonds
why is restriction endonuclease different from endonuclease?
they are restricted to make the cut only between specific sequences of nucleotide bases
how are blunt ends produced?
when restriction enzyme cuts straight across the DNA strand breaking the two phosphodiester bonds opposite one another
how are sticky ends produced?
restriction enzyme makes a staggered cut in DNA hydrolysing a phosphodiester bond on each strand several base pairs apart
what is an advantage of a blunt end?
they can be joined to any other blunt edge fragment
what are the advantages of sticky ends?
DNA fragments with sticky ends will hybridise with other DNA fragments produced by the same restriction enzyme but not with fragments produced by different restriction enzyme
what are plasmids?
small loops of DNA
why are plasmids useful?
as vectors for the movement of genes between cells in lab or to manufacture recombinant DNA
to transform prokaryotic cells to produce useful proteins - insulin, growth hormone
store as a library of DNA fragments
what is a Ti plasmid?
vector to transform eukaryotic plant cells
why if cut with same restriction enzyme can two fragments be sealed?
same sticky ends with complementary ends are produced
