Chapter 11:DNA Transcription and Translation Flashcards
Where is a segment of DNA transcribed?
In the nucleus
Where is mRNA translated?
cytoplasm
As more mutations occur in DNA what risk increases?
cancer
Does translation always have to be perfect?
NO but transcription within the nucleus does
List characteristics of DNA!
DNA:
- T= A
- double stranded
- 250 000 000nt
- DNA poly
- Primer
- 1 in 10^7 nt errors
List haracteristics of RNA!
- U= A
- single stranded
- 1000 nt
- RNA Poly
- no primer
- 1 in 10^4 nt errors
Does RNA poly have more errors than DNA poly?
- YES
- it does not require a poly like DNA but it has many more errors but that is okay because it is not a fixed representation of the DNA
What does it mean that RNA is a mobile nucleic acid?
- permits cell to separate information storage in the nucleus ( or not if you’re a prokaryote) into information utilization which is the RNA
How can you amplify the amount of protein in a cell?
- by transcribing/transcription many times
DNA Transcription:
- Double stranded DNA must be ___ to expose a single stranded DNA template.
- unwound
DNA Transcription:
- Ribonucleotide addition is to the ___ DNA strand.
- non coding DNA strand
DNA Transcription:
- there is a temporary __/__ hybrid?
- DNA/RNA hybrid
~9nt
DNA Transcription:
- With your DNA it is double stranded and there are certain sequences within your DNA that tell the RNA poly ?
- which strand needs to be used as the template and which is not
DNA Transcription:
- What is the template used for?
- mRNA transcription (well RNA)
DNA Transcription:
Which of these strands of DNA is the coding strand and which is the non coding strand?
5’AATTGGC3’
3’TTAACCG5’
- AATTGGC = coding strand
- TTAACCG = non coding strand
DNA Transcription:
After transcription what will the following coding strand’s mRNA strand be?
3’TTAACCG5’
- AAUUGGC
DNA Transcription:
What is a protein?
- amino acid chain (polypeptide)
DNA Transcription:
Protein is coded into ___ via ____ which are a pile of nucleic acids which are arranged via complementary strands which make up genes.
- DNA via chormosmes
DNA Transcription:
- Genes CODE for proteins. Code??
- a certain arrangement of nucleotides give you nucleic acids so the gene is telling you that particular sequence of aa that will give you the resulting protein
DNA Transcription:
- Gene?
- a sequence of nucleotides that tell us the sequence of aa’s for a protein
DNA Transcription:
- why is the sequence of nucleotides in the gene extremely important?
- because if you take the wrong genes you are not getting the correct sequence of aa’s
DNA Transcription:
- coding strand?
- it’s sequence in the gene codes for the correct sequence of amino acids
DNA Transcription:
- non-coding strand?
- the complementary strand to the coding strand..
DNA Transcription:
-RNA is synthesized on?
- a complementary DNA strand ..it needs to choose the correct one so it will be read during translating giving us the right aa’s
DNA Transcription:
- What is the RNA sequence and what is it coming from?
- It needs to be the exact same as the coding strand this is ensured by using the non coding DNA strand as a template! So you are not actually touching the sequence of DNA that codes for the genes that give us the protein
What are the three Eukaryotic RNA polymerases that we discussed in class?
- RNA Poly I
- RNA Poly II
- RNA Poly III
Eukaryotic RNA Polymerases:
- RNA Poly I?
- rRNA - structural (ribosomal RNA which are not translated so they stay in an RNA state and are used along with ribosomes to make proteins.
Eukaryotic RNA Polymerases:
- RNA Poly II?
- mRNAs- informational
Eukaryotic RNA Polymerases:
- RNA Poly III?
- tRNA’s (transfer RNA’s…transfer aa’s), snRNA’s (splicing …getting rid of introns) and ribosomal 5s RNA
Eukaryotic Nuclear RNA Polymerases.
Enzymes? (5)
- RNA Poly I - synthesizes larger rRNAs (28S, 18S and 5.8S)
- RNA Poly II- synthesizes mRNAs, most small nuclear RNAs( snRNAs and snoRNAs) most micro RNAs and telomerase RNA
- RNA Poly III - small RNAs, including tRNAs, 5S rRNA and U6 snRNA
- RNA Poly IV and V (plants only)- siRNAs
Eukaryotic RNA Polymerases:
-rDNA?
- rRNA genes in 100’s of copeies (nucleolus region)
Eukaryotic RNA Polymerases:
- nucleolus region?
- makes subunits and transcribing rRNA so in us when you see those granular regions…RNA genes are in clusters …there are certain regions on each of our chromosomes that look like that and are called this .
Initiation of RNA Synthesis in Bacteria:
- core enzyme?
-RNA poly with no roman numerals
Initiation of RNA Synthesis in Bacteria:
- Sigma factor?
- associates with the core enzyme helping it join to the dsDNA
Describe the Initiation of RNA Synthesis in Bacteria!
- Loose association between DNA and core enzyme. RNA chains that are begun are not initiated at proper sites.
- Complete enzyme (holoenzyme) = Sigma factor + core enzyme)
- Association of complete enzyme with DNA (in promoter region) at proper site and opening of the double helix.
L> proper site= -35 and -10 site that is specific for them to sit on and associate with DNA
Initiation of RNA Synthesis in Bacteria:
- where is the start of synthesis?
+1
Initiation of RNA Synthesis in Bacteria:
- upstream?
- downstream?
- to the left (-35 and -10)
- to the right (+1?)
What are the steps to RNA synthesis in Bacteria?(4)
- Recognition: sigma factor permits the RNA poly to recognize promoter regions in DNA at that time when it comes in once it associates with DNA it will actually unwind DNA at that point aka exposed template after recognition has occurred
- Initiation: warm up occurs… needs to get started…RNA poly… 10-12 nt are synthesized and then released…now RNA poly is ready to go.
- Elongation: RNA poly synthesizes 50nt per second…a hybrid of RNA and DNA is created (ant long)…so 50nt per second are added to the molecule which occurs until termination…once elongation occurs sigma is let go
- Termination: RNA poly will stop and dissociate