Topic 7 Done Flashcards
What is the genome
All the genetic material in an organism
What are coding vs non coding regions called
Exons are coding and introns are non coding
PCR process
Denature DNA at 95 degrees, breaks apart strands
Anneal primers at 50-65 degrees, attach primers just upstream
Extension at 72 degrees, taq polymerase or similar extend primers
How we sequence our own DNA
Do PCR, use terminator bases that halt the chain and colour tag them. Then do gel electrophoresis.
How are strands of DNA cut for a profile
Restriction endonuclease. Example of restriction enzyme
What is a transcription factor
Protein that binds to the DNA in the nucleus and affect the process of transcribing genetic material
What is the promotor sequence
Found just upstream, what the transcription factor binds to
What is an enhancer sequence
Regulates the activity by regulating the structure of the chromatin ( structure of histones)
How mRNA changes before arriving at ribosome
Spliceosomes remove introns and combine exons to produce mature RNA from pre - mRNA
What are exons
coding regions of DNA
What are introns
non-coding regions of DNA
What is PCR
Polymerase Chain Reaction; used to amplify DNA
Conditions & Steps of PCR
Conditions:
Good supply of nucleotide bases, suitable buffer, primers, thermocycler, Taq DNA polymerase,
- Denaturation:
- DNA sample heated to ~90-95 degrees to seperate DNA strands by breaking HBonds - Annealing
- Sample is cooled to ~50-55 degrees so that primers can bind/anneal to the single DNA strand - Extension
- Sample in then heated to ~72 degrees, optimum for Taq DNA polymerase (Thermus aquaticus) to build complementary strands of DNA
What are primers
Short, single stranded pieces of DNA that are complementary to the bases at the start of the fragment you want to replicate
Gel Electrophoresis Steps
Everything is the same for protiens, but use pH or protease enzymes to split them:
- Cut DNA into fragements using restriction endonucleases at specific base sequences called recognition sites
- Make the gel with suitable pH (Buffer), and dye (e.g. EtBr, ethidium bromide, that binds to DNA fragments which will florescent in UV light)
- Set up gel apparatus
- Load DNA sample into gel wells
- Hook up electric current/Potential difference and run gel
- Stain gel/UV light and analyze results
What is the process of DNA sequencing?
- DNA strands are chopped into smaller fragments and double strands are separated into single strands
- PCR is used to replicate DNA fragments to produce large quantities of DNA
- terminator base is added to the single strands of DNA, halts the chain so no more bases are added and replication is terminated
- Each terminator base has a fluorescent tag in a specific colour to allow the sequence of bases to be read quickly by an automated system
What is DNA profiling?
the analysis of DNA fragments to determine whether they come from the same individual
What is southern blotting?
a procedure for identifying specific sequences of DNA, in which fragments separated on a gel are transferred directly to a second medium, nylon filter, on which detection by hybridization may be carried out using gene probes
What is a polysome?
Several ribosomes using a mRNA molecule to synthesize protein at the same time
What are promoter regions?
DNA sequences that tell the enzyme RNA polymerase where to start producing mRNA during transcription through the bind of transcriptional factors
RNA splicing?
Process by which the introns are removed from RNA transcripts (Pre-mRNA) and the remaining exons are joined together by spliceosomes into mature mRNA
What are enhancer regions?
Specific regions of DNA which transcriptional factors can bind too and regulate gene expression by changing the structure of chromatig, making it more or less available for RNA polymerase
How does RNA splicing result in variation?
A single gene may results in many forms of mature mRNA through a variety of ways and combinations the exons can be joined together
What is DNA methylation?
DNA methylation is the addition of methyl group to the DNA’s cytosine base
It may affect gene transcription through several different mechanisms (usually repression of transcription)
The methylation pattern is heritable after cell division; therefore, DNA methylation plays an important role cell differentiation during development
