Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
BIO 1113 Ch 17
Transcription, RNA processing, and Translation
| Term | Definition |
|---|---|
| Initation | RNA polymerase binds to the promoter region of DNA |
| Promoter region | a short sequence of DNA (TATAAA); located 25 nucleotides upstream of where transcription begins |
| During Transcription Initiation, what is RNA polymerase responsible for doing? | binds to the promoter region of DNA; causes two DNA strands to separate |
| During transcription elongation, what is RNA polymerase responsible for doing? | Add nucleotides to the growing mRNA strand; synthesises mRNA starting from 5'-3'. |
| What direction does the RNA polymerase read the DNA strand in? | 3'-5' direction |
| Template strand (antisense strand) | Used to synthesize mRNA |
| Nontemplate strand (sense strand, coding strand) | Sequence matches up with RNA, but is not used for mRNA synthesis |
| During transcription Termination, what is RNA polymerase responsible for doing? | mRNA and polymerase will separate from the DNA template strand; caps the three end of the 3' end of the mRNA strand |
| Poly-A-Tail | the 3' end of the mRNA that is capped so that it can be protected from being degraded by certain enzymes. |
| What is the result you get at the end of transcription? | a pre-mRNA strand |
| Introns | Longer sequences of nucleotides that do not code for anything; are removed in process called RNA splicing |
| Exons | shorter sequences of nucleotides that are used to synthesize proteins |
| What happens immediately after the mRNA is synthesized | It leaves the nucleus and enters cytosol to interact with free ribosome or one attached to rough er |
| tRNA (transfer) molecule | Transfer molecule that uses mRNA for further translation |
| Sigma | binds to the enzyme that transcribes genes (core enzyme) to recognize where transcription should begin |
| NTP | Have hydroxyl group on the 2' carbon sugar; makes sugar in a NTP a ribose |
| Downstream | DNA located in direction RNA polymerase moves suring transcription |
| Upstream | DNA located in direction opposite of where RNA polymerase moves. |
| What initiates transcription? | sigma binds to the -35 to 10 boxes in the DNA; the upstream sequence is recognized by part of the RNA polymerase core enzyme |
| are reactions in the initiation process of transcription endergonic or exergonic? | Exergonic |
| What prompts the start of the elongation phase of transcription? | Once RNA polymerase leaves the promoter region as it synthesizes RNA |
| What happens during the elongation phase of transciption? | Enzymes read the DNA template as it catalyzes the addition of nucleotides to the 3' end of growing RNA; double stranded DNA goes into and out of one groove, NTPs enter another, and growing RNA exits at the rear. |
| What prompts transcription to stop? | When RNA polymerase transcribes a DNA sequence called transcription-termination signal. |
| What are the two mechanisms for termination of transcription in bacteria? | Bases in bacterial DNA that make up termination signal are transcribed into RNA and then folds back on itself to form short double helix. |
| If a stretch of U nucleotides follows after the construction of a 'hair-pin' in transcription, what happens? | It immediately separates from the DNA template strand. |
| Holoenzyme | Sigma+ RNA polymerase |
| Spliceosomes | snRNAs+proteins = snRNPs; recognize specific sequences at the end of introns. |
| Alternative RNA splicing | Some exons can be left out of final transcript |
| Why do we have introns? | Play a role in regulating gene expression, and allows a single gene to code for more than one polypeptide. |
| Large subunit of ribosome | where peptide bonds are formed in translatiom |
| small subunit | holds the mRNA in translation |
| A site | the site in ribosome where tRNA is held |
| rRNA | molecules that aid in translation in the ribosome (subunit of ribosome) |
| P-site | holds the growing chain and occupies the P (peptidyl) site inside the ribosome. |
| E-site | When tRNA no longer has an amino acid attached and is about to leave the ribosome. |
| What is the first step in the three-step-translational sequence? | An aminoacyl tRNA diffuses into the A site; if its anitcodon matches a codon in mRNA, it stays in the ribosome |
| What is the second step in the three-step-translational sequence? | A peptide bond forms between amino acid (held by the aminoacyl tRNA) in A site and growing polypeptide, which was held by a tRNA in the p-site. |
| What is the third step in the three-step-translational sequence? | Ribosomes moves by one codon, all three tRNAs are shifted one position within the ribosome; tRNA in E site exits and everything shifts down one. |
| What catalyzes the formation of peptide bonds? | tRNA |
| What is the current definition of a gene? | A region of DNA that can be expressed to produce a final functional product that is either a polypeptide or an RNA molecule. |
| Translational initiation | ribosomal binding site (small subunits of ribosomes) binds to complementary sequence on mRNA( interactions are mediated by initiation factors); initiator tRNA bearing f-met binds to start codon; large subunit binds. |
| Intiation factors | aid in preparing the ribosome for translation and in binding the first aminoacyl tRNA to the ribosome. |
| What molecule binds to start codon in translation? | initiation tRNA |
| Translational elongation | aminoacyl binds to start codon in A site( via base pairing anticodon-codon); binding site is full; translocation occurs |
| What molecule catalyzes protein sythesis? | RNA |
| Translocation | ribosome one codon down the mRNA once new peptide is formed; requires an elongation factors |
| Elongation factor | gains energy for translocation as one of the factors binds to ribosome and breaks down GTP molecule. |
| Release Factor in translation termination | Recognizes the stop codon and fills the A site; are found in the 3' region of an mRNA, but never at very end of mRNA. |
Created by:
CarmTay
Popular Biology sets