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Bio Quiz 3.2
| Question | Answer |
|---|---|
| what is a polypeptide? | chain of amino acids |
| what is a protein? | 1 or more polypeptides that have folded into a specific shape and obtained a specific function. |
| what is folding of protein affected by? | amino acids interacting with each other and environment. |
| levels of protein structures | primary, secondary, tertiary, quaternary |
| what are between amino acids? | peptide bonds |
| how do peptide bonds form? | through a special covalent bond, between carboxyl and NH2 of amino acid |
| what determines a protein's 3D shape & function? | the order and type of amino acids |
| what levels of structure (1-4) are polypeptides involved in? | 1&2 |
| what levels of structure are proteins involved in? (1-4) | 3&4 |
| what do we call primary structure and what is it? | chain of amino acid - not called a protein yet, call it a polypeptide |
| what are the levels of structure? | primary, secondary, tertiary, quaternary |
| what happens to the chain in secondary structure? what is its shape? | chain starts folding & shapes include alpha helix & beta pleated sheet |
| what happens in tertiary structure? | the protein keeps folding (upon secondary structure). more complex interactions between R groups on amino acids in the chain. may become finalized into a functional protein at this level (depends on the specific protein) the protein is ready to do its job |
| what kind bond is a peptide bond? | covalent! |
| what happens in quaternary structure? | multiple polypeptides with tertiary structure that make functional proteins (similar between R groups as tertiary structure) |
| BIG picture of protein synthesis (3 steps) & when the processes are involved | central dogma - sequences of nucleotides in DNA determines (process 1&2) sequences of nucleotides in mRNA determines (process 3) sequences of amino acid in polypeptide |
| what are the 3 processes involved in protein synthesis/gene expression? | 1) transcription 2) RNA Processing (Editing) 3) Translation |
| what is the function of RNA? | involved in process of making proteins from instructions in DNA. |
| why is RNA needed? | because DNA can't leave the nucleus |
| what are the 3 types of RNA? | 1) mRNA (messenger RNA), 2) tRNA (transfer RNA), 3) rRNA (ribosomal RNA) |
| what is transcription? | process that makes ALL types of RNA using info from DNA |
| which 2 of 3 RNAs can be reused? | tRNA and rRNA |
| which 1 RNA can NOT be reused? | mRNA has to be made new each time cell needs to make protein. |
| WHERE - transcription | nucleus |
| WHEN - transcription | g1+ g2 of interphase |
| HOW - transcription | 1) unwinding and unzipping part of DNA that will be transcribed. 2) new complementary RNA nucleotides are added to one strand according to base pairing between DNA and RNA. 3) newly made molecule of RNA separates from DNA and DNA strands go back together. |
| base pairings for RNA!! | A-U, T-A, C-G, G-C |
| what is a template strand? what other names does it have? | strand of DNA that is read to know which RNA nucleotides to add based on base pairing. (noncoding, antisense strand) |
| what is the opposite strand of DNA called? | the nontemplate, CODING, SENSE strand because it matches the mRNA (except it has Ts instead of Us) |
| what is the result of transcription? | ONE new piece of RNA and original DNA (not used/affected) - pre mRNA |
| what are the enzymes that are in transcription? | topoisomerase and helicase, RNA polymerase (NO DNA POLYMERASE OR LIGASE) |
| what is topoisomerase? | relaxes supercoiling in front of replication fork (where strands are separating) |
| what is helicase? | unzips and separates 2 strands of DNA by breaking H bonds between bases |
| what is RNA polymerase? (3) | adds the new RNA nucleotides in transcription. Used in DNA replication to add RNA primers. READ FROM 3, ADD FROM 5! |
| what is a promoter? | area on DNA where RNA polymerase starts transcription. |
| what are the 3 stages of transcription? | initiation, elongation, and termination |
| what is initiation in transcription? | RNA polymerase binds to the promoter on TEMPLATE strand |
| what is elongation in transcription? | creation of RNA molecule (most often RNA) |
| what is termination in transcription? | RNA polymerase reaches a stop. sequence on the DNA which causes DNA, RNA, and RNA polymerase to separate (DNA goes back to normal). |
| where does RNA processing happen? | in nucleus |
| does DNA have introns and extrons intermingled? | yes |
| what are introns? | segments that don't code for the protein (inter-between) |
| what are extrons? | segments that DO code for the protein "expressed" |
| how do introns and extrons work? | introns are cut out of pre-mRNA and exons put together to make final mRNA (introns spliced out) |
| what is a GTP cap? | modified guanine molecule |
| where is the cap added to mRNA? | 5' end of mRNA "HAT" |
| where is the tail added to mRNA? | 3' end of mRNA |
| what does the poly-A-tail contain? | 150-200 adenine nucleotides |
| what does the poly-A tail help do? (3) | helps mRNA leave nucleus, help initiate translation, keeps mRNA stable (keeps it from falling apart) |
| WHAT - translation | putting together amino acids to make a polypeptide that will become a protein |
| WHY - translation | to make proteins |
| WHEN - translation | G1 and G2 of Interphase |
| WHERE - translation | on ribosomes in cytoplasm |
| HOW - translation | rRNA, mRNA, and tRNA work together to do translation. |
| what are the 3 types of RNA? | mRNA, tRNA, rRna |
| what does mRNA do? and full name? | messenger RNA, carry out code for protein synthesis because DNA can not leave the nucleus. |
| what is code? | code is the instructions from the DNA. |
| what does tRNA do? and full name? | transfer RNA, brings amino acids to ribosome in a certain order according to info in mRNA. |
| what does rRNA do? and full name? | ribosomal RNA, component of ribosomes (along with protein) |
| what is a codon? | 3 nucleotides on mRNA |
| what is an anticodon? what does it do? | 3 nucleotides on tRNA 'private driver', bonded with amino acid. |
| what is the relationship between anti-codons and codons? | anticodon in complementary to codon, which allows correct tRNA to bring correct amino acid. (each tRNA brings a certain amino acid) |
| what are the 3 steps of translation? | 1) initiation, elongation and termination |
| what is initiation in translation? | mRNA, ribosome and first tRNA with first amino acid come together |
| what is elongation in translation? | building polypeptide, tRNA bring amino acids, amino acids get connected by peptide bonds (type of covalent bond), previous tRNA leave ribosome and everything shifts to expose a new codon. |
| what is termination in translation? | whole process ends when stop codon is reached. mRNA, tRNA, and ribosome polypeptide all separate. |
| what is genetic code? | allows us to translate between nucleotides in mRNA and amino acids in polypeptide. |
| what descriptors do we use for the code? | degenerate (redundant), unambiguous |
| what does it mean for code to be degenerate? | more than one codon for amino acids |
| what does it mean for code to be unambiguous? | each codon only gives a certain thing (amino acid or stop codon) |
| is code mostly universal? | yes |
| what is the amino acid and pair that starts it all for coding? | AUG -> MET amino acid |
| how many start and stop codons are there? | 1 start codon, 3 stop codons (do NOT code an amino acid) |
| do some polypeptides get cut off before folding from MET amino acid? | yes. |
| what is synthesized during translation? | polypeptides |
Created by:
studying11