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32 Cards in this Set
- Front
- Back
Where are proteins in the cell made? How was this proved?
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At ribosomes. Cells were placed in a solution of radioactive amino acids. The amino acids first appeared at the ribosomes.
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What are the three sites of the ribosome? How many parts is a ribosome divided into?
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The A, P, and E sites. Two.
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What are ribosomes made of? What does each substance do?
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Proteins (stability) and RNA (actual function)
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What are the different types of RNA? What do they do?
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rRNA (site of protein assembly), tRNA (take amino acids to ribosome), mRNA (copied from DNA to code for protein)
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What is transcription? How does it start?
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The copying of mRNA from DNA. It starts when RNA Polymerase binds at a promoter binding site.
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What is translation?
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The construction of a polypeptide from the code sequence on mRNA.
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How many RNA nucleotides code for a single amino acid? What are these groups called?
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Three. Codons or Triplets.
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What is gene expression?
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The entire process of transcription and translation.
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Does the code that determines which codons code for which amino acids differ greatly between organisms?
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No.
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The genetic code for which two organelles is different?
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Mitochodria and Chloroplasts.
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In transcription, what is the strand of DNA that is copied to RNA called?
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The template or antisense strand.
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In transcription, what is the strand of DNA that is not copied to RNA called?
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The coding or sense strand.
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In RNA synthesis, the RNA polymerase adds nucleuotides to which end of the synthesizing strand?
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The 3' end.
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Where does transcription start on the DNA strand?
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On the promoter.
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What stops the gene transcription?
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The GC hairpin.
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What are the three RNA polymerases in eukaryotes and what do they synthesize?
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RNA Polymerase I (rRNA), RNA Polymerase II (mRNA), RNA Polymerase III (tRNA)
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What is an initiation complex?
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A system of protein transcription factors that bind to the promoter region that enhances the rate of transcription.
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How is mRNA modified after transcription in eukaryotes?
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A GTP and methyl group is put on the 5' cap and a poly-adenine tail is put on the 3' end. Also, introns are cut out of the mRNA.
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What activating enzymes attach the amino acids to the tRNA anticodons?
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Aminoacyl-tRNA Synthetases
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What is the start signal codon in translation? What are the three nonsense (stop) codons?
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AUG. UAA, UAG, UGA.
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Does translation have an initiation complex?
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Yes
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What happens in the elongation stage of translation?
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Codons are exposed and bound to anticodons sequentially from the start codon.
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What is the process of the ribosome moving down the mRNA strand called? In what direction does it move?
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Translocation. 5' to 3'.
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What are exons? What are introns?
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Exons are sequences of DNA that code for protein. Introns are sequences of DNA that do not code for protein.
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When small nuclear ribonuclearproteins (snRNPs) associate with other proteins, they form ________.
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Spliceosomes
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What do the spliceosomes do? What is the process called?
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They remove the introns from the mRNA and splice together the exons. Alternative splicing.
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Do prokaryotes tend to have many introns?
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No, mostly eukaryotes have introns.
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Can prokaryotic mRNA have more than one gene in them?
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Yes.
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Does prokaryotic mRNA have to be completely formed before it is translated?
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No.
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How does the beginning of translation differ in prokaryotes from eukaryotes?
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In prokaryotes, translation begins at an AUG codon just after a special nucleotide sequence.
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Which has larger ribosomes, eukaryotic cells or prokaryotic cells?
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Eukaryotic cells.
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Who made these flashcards?
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Robert Fromm
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