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level: Level 1

Questions and Answers List

level questions: Level 1

QuestionAnswer
What is DNA combined from two different organisms called?Recombinant DNA
What is meant by "Universal DNA?"Every living organism uses the same genetic code with the system involving DNA to RNA to Protein.
What enzyme used by retroviruses such as the coronavirus Sars-COV-2 enables RNA to be converted to single-stranded cDNA?Reverse Transcriptase
What enzymes produced naturally as a protection mechanism by bacteria can be used to cut DNA into fragments?Restriction endonucleases enzymes, or just restriction enzymes.
What is a restriction site?A specific base sequence targeted by a specific restriction enzyme due its complementary active site
The restriction enzyme HindIII "recognises" the DNA restriction site AAGCTT and cuts to produce overhanging bases. These are are called?"Sticky ends"
What enzyme synthesises messenger RNA - mRNA - from a DNA sense strand?RNA polymerase
What are the names for the DNA regions where transcription of mRNA starts and finishes?Promotor region and terminator region
What are plasmids and what is their role in genetic engineering?Small circular lengths of DNA that contain antibiotic resistance genes. They are used as vectors for a transport recombinant DNA "gene" into another organism.
Genes used in plasmids to identify gene take-up include antibiotic-resistance genes, lactase synthesising genes, as well as GFP, or Green fluorescent Protein genes are examples of what type of gene?Marker Genes
What is PCR?Polymerase Chain Reaction
What does PCR do and why is this described as "In vitro" gene cloning.PCR is used to amplify small quantities of DNA. It takes place "In vitro" which literally means "In glass" or more precisely outside the living body (In vivo)
What is the role of the enzyme DNA polymerase in PCR?Joins DNA nucleotides in correct sequence according to single DNA template strand.
In PCR, how are double DNA strands separated?By heating to 95 degrees C - this is know as "melting"
Why is taq polymerase used?It is thermostable (heat tolerant) at the higher than normal body temperatures used in the melting stage.
In PCR, what is the short, single-stranded DNA that provides the starting sequences for DNA polymerase to begin DNA copying called?Primers
What is the name for the process that allows primers to bind to a complementary DNA base sequence? and what must happen to the temperature for this to happen?Annealing, that happens when the high melting temperature is lowered - 55 degrees C.
What does the technique of DNA fragment analysis by Gel electrophoresis achieve?Separates DNA fragments according to their molecular size
In genetic fingerprinting, what are VNTR's and STR's?Variable Number Tandem Repeats and Short Tandem Repeats. These repetitive non-coding sequences can be digested with restriction enzymes to provide different-sized fragments that can identify individuals.
How does Gel electrophoresis separate the different-sized fragments that are digested by the restriction enzymes?Resisted by the gel, negatively-charged DNA fragments are pulled towards the positive end of electrophoresis tank. The smaller fragments travel at a faster rate and form bands in "bar-code" pattern that determines the size of the fragments.
What role does DNA hybridisation play in the genetic fingerprinting process?Single-stranded DNA, radioactive or fluorescent probes bind to complementary sequences on VNTR's/STR's to enable visualisation.
What is meant by "55 Kbp" with reference to digested DNA strandsThe strands are 55 thousand base pairs long, with base pairs forming a constant length measurement to provide the unit of DNA fragment measurement.