22499967
Description
Flashcards by Evian Chai, updated more than 1 year ago
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Created by Evian Chai
about 4 years ago
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| Question | Answer |
| What is the order of events to get DNA to protein? | DNA-->RNA via transcription RNA--.Protein via translation |
| What are codons? How many codons? | Sets of 3 bases that code for individual amino acids 64 codons |
| How many ORFs per DNA sequence/strand? | 3 per strand, 6 per DNA sequence |
| What type of RNA is the structural component of ribosomes and the largest in size? | rRNA |
| What type of RNA carries genetic information from DNA to the ribosome? | mRNA |
| What type of RNA has a cloverleaf structure and transfers Amino acids from cytoplasm to the ribosome? | tRNA |
| What is the structure of a tRNA? | A cloverleaf structure 3'end with ACC 5' end Anticodon on bottom |
| What is the process of transcription? | 1. DNA unwinds, a strand becomes template 2. RNA elongated one nucelotide at a time 3. DNA closes behind strand |
| What is the difference betwene transcription in eukaryotes and prokaryotes? | Eukaryotes: RNA transcribed in the nucleus, transcription initiation complex needed, post translational modifications, RNAs processed, more complex proteins formed Prokaryotes: Uses RNA polymerase, 3 steps (initiation, elongation, termination), produces polycistronic RNA w many genes on same strand, transcription/translation can occur together |
| What is the Methyl Cap? What is it for? | A post-transcriptional modification at the 5' end 1. It serves to protect RNA from exonuclease 2. Transports RNA from the nucleus to cytoplasm 3. Attaches mRNA to rRNA |
| What is polyadenylation? What is it for? | Post-transcriptional modification on the 3' end of the RNA 1. Stabilises mRNA/aids transport |
| What is spliced out during splicing? By what? | ALL introns and select exons (diffrential splicing) Spliceosome |
| What is translation? | Synthesis of proteins from mRNA to amino acids |
| What is on the small subunit of the ribosome? What about the large subunit? How does the size differ between eukaryote and prokaryote? | 1. mRNA binding site 2. EPA binding sites EU: 40S, 60S, 80S total PRO: 30S, 50S, 70S |
| What are polyribosomes? | Several ribosomes translating one mRNA at the same time |
| How are tRNAs activated? What occurs after this? | Enzymes charge tRNA with amino acid using hydrolysis of ATP as energy Anticodon pairs w/ codon on mRNA |
| What is the process of initiation? | 1. Ribosome complex forms w/ small and large unit 2. Ribosomes bound to start site of mRNA 3. Initiator tRNA annealed to initiated codon (MET) at A site |
| What occurs during elongation? | 1. mRNA moved down complex by one codon 2. tRNA brings relevant AA to "A" site 3. AA from P site linked to AA on A site via peptide bond 4. Same steps repeat, with tRNAs at E site being discharged |
| What occurs during termination? | Termination codon gives signal, newly made peptide released from ribosome |
| How to antibiotics exploite the difference in prokaryote/eukaryote ribosomes to treat disease? | Steptomycin: Binds to 30s subunit, distorts and blocks initiation Tetracyclines: interact w/ 30s subunit to block access of tRNA to A site Chloramphenicol: Blocks peptidyltransferase from creating peptide bond Puromycin: Structurally similar to tRNA, added to peptide chain Others block translocation |
| What in humans has 70s ribosome? | Mitochondria |
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