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56 Cards in this Set
- Front
- Back
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what is the first step in protein synthesis?
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transcription
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what is the second step in protein synthesis?
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translation
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where does translation occur?
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cytoplasm
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what is the genetic code?
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used to translate the “language” of nucleic acids into the “language” of proteins
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what is the number of nucleotides that code for an amino acid?
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3
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why is the genetic code said to be degenerate?
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because most of the amino acids are represented by more than one DNA coding sequence
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how many possible codons are there?
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64
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what do stop codons do and how many are there?
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they signal the end of translation
3 |
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what amino acid is always the first to be incorporated in proteins?
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methionine (met)
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the genetic code (differs/is universal) among all living organisms
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universal
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codons are read sequentially on mRNA starting at the ... prime end beginning with the ... codon which has the sequence ...
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5
start AUG |
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codons are read ... prime to ... prime and end at the ... codon
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5
3 stop |
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the three stop codons are ...
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UGA
UAG UAA |
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a change in a single nucleotide in the DNA results in a ... in the mRNA sequence, possibly changing a codon
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single change
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reading frame mutations are caused by ...
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insertions, deletions, frameshift mutations
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how many possible reading frames are there in mRNA?
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3
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translation occurs in the ... in association with ...
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cytoplasm
ribosomes |
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in translation, ... contains the genetic code, ... transports the appropriate amino acid and ... brings the nucleotide language and amino acid language together to form a protein
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mRNA
tRNA ribosome |
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what do ribosomes consist of?
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consist of protein and rRNA
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what are the prokaryotic ribosomal subunits? and they come together to form ...s
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30s and 50s
70 |
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what are the subunits of eukaryotic ribosomes? and what do they come together to form?
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40s and 60s
80s |
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what is Nmd3p?
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the G protein-dependent transporter that transports the 60s subunit out of the nucleus
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transfers a specific amino acid to a growing polypeptide chain within a ribosome
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tRNA (transfer RNA)
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specific amino acid
3'end 5'end anticodon codon |
identify the labeled structures:
a. b. c. d. e. |
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on the tRNA, what nucleotide is usually on the 5'end?
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G
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on the tRNA, what nucleotide sequence is usually at the 3' end?
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CCA-3'
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to what side does the amino acid attach to on the tRNA?
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3'
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d loop
t loop anticodon loop |
name the labeled loops?
a. b. c. |
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what is non-standard base pairing in the 3rd position of the codon in mRNA (some anti-codons can bind to more than one codon)
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Wobble Phenomenon
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in addition to binding to cytosine, guanosine can pair with ...
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uracil
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one of the many modified bases in tRNA that is especially promiscuous in base pairing
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inosine
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a tRNA is said to be “charged”
when it has ... attached |
amino acid
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aminoacyl-tRNA synthetase does what?
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attaches amino acid to tRNA
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how does aminoacyl-tRNA synthetase know what amino acid to attach?
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uses anticodon as recognition
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the attaching of an amino acid to tRNA (requires/does not require) ATP
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requires
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step 1. of formation of aminoacyl-tRNA:
amino acid's ... group reacts with ... forming ... complex |
carboxyl
ATP enzyme-aminoacyl-AMP |
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what is an aminoacyl-tRNA?
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tRNA that has an amino acid covalently attached to its 3’-end
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the second step in the formation of aminoacyl-tRNA involves the activated amino acid being transferred to 2’ or 3’ hydroxyl group on the ribose sugar of the ... prime end of the tRNA forming an aminoacyl-tRNA ... bond
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3
ester |
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translation of protein involves 3 steps:
a. b. c. |
initiation
elongation termination |
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first step in eukaryotic initiation involves formation of ...
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initiation complex
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eukaryotic pre-initiation complex consists of ...
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Methionyl-tRNAiMet
eukaryotic initiation factor 2 (eIF2) small (40S) ribosomal subunit |
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what is an aminoacyl-tRNA?
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tRNA that has an amino acid covalently attached to its 3’-end
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the second step in the formation of aminoacyl-tRNA involves the activated amino acid being transferred to 2’ or 3’ hydroxyl group on the ribose sugar of the ... prime end of the tRNA forming an aminoacyl-tRNA ... bond
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3
ester |
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translation of protein involves 3 steps:
a. b. c. |
initiation
elongation termination |
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first step in eukaryotic initiation (preparing the tRNA) involves formation of ...
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pre-initiation complex
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eukaryotic pre-initiation complex consists of ...
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Methionyl-tRNA(met)
eukaryotic initiation factor 2 (eIF2) small (40S) ribosomal subunit |
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mRNA initiation factors are ...?
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cap binding protein (CBP) or eIF4E
poly-A binding protein (PABP) |
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what does the poly-A binding protein (PABP) do?
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circularize some mRNAs which stimulates or inhibits translation
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at what point does the small ribosomal subunit bind to large ribosomal subunit?
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after start codon is found and initiation factors are released
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what is the funciton of the cap recognition complex?
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targets mRNA to the pre-initiation complex
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3 binding sites available in the complete ribosome are:
a. b. c. |
P site (peptidyl)
A site (aminoacyl) E site (exit) |
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put the following in order:
a. initiation factors dissociate b. initiation factor associate c. large ribosomal unit binds d. initiator tRNA moves along mRNA searching for start codon e. mRNA binding fo tRNA |
b, e, d, a, c
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eIF2 major regulator of initiation step is is (inactivated/activated) by phosphorylation and phosphorylation of eIF2 can be induced by ...
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inactivated
starvation, heat shock, or viral infection |
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what is the role of insulin in regards to eIF4E (mRNA cap binding protein)?
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stimulates protein synthesis
phosphorylation and activation |
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eIF2 (is/is not) a rate limiting step?
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is
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Leukoencephalopathy with Vanishing White Matter (VWM) is a degenerative brain disease that involves rapid deterioration of white matter (myelin) following febrile infections or minor head trauma. it is caused by mutations within two subunits of ...
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eIF2B
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