CAMPBELL BIOLOGY CHAPTER EXAM 17 QUESTIONS AND ANSWERS

CAMPBELL BIOLOGY CHAPTER EXAM 17 QUESTIONS AND ANSWERS gene expression - answer- The process by which DNA directs the synthesis of proteins or, in some cases, just RNAs. Includes 2 stages - transcription and translation Garrod - answer- scientist who was the first to say in 1909 that genes determine phenotype through the production of enzymes that catalyze chemical reactions; diseases caused by missing enzymes are "inborn errors of metabolism" Beadle and Tatum - answer- Exposed bread mold to X-rays, creating mutants. Showed that each gene encodes a particular substance ("one gene, one enzyme" concept, later restated "one gene one polypeptide"). transcription - answer- process by which a DNA template is used to produce a single-stranded RNA molecule messenger RNA - answer- RNA molecule that carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell translation - answer- Decoding of a mRNA message into a polypeptide chain ribosomes - answer- sites of translation primary transcript - answer- the initial RNA transcript from any gene, including those specifying RNA that is not translated into protein triplet code - answer- the normal version of the genetic code in which a sequence of three nucleotides codes for the synthesis of a specific amino acid central dogma - answer- Crick, 1956, theory that states that, in cells, information only flows from DNA to RNA to proteins template strand - answer- the strand of DNA that the RNA polymerase uses as a guide to build complementary mRNA codon - answer- a specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid (64 were deciphered by mid 1960s, 61 code for amino acids, 3 are stop signals) reading frame - answer- the way a cell's mRNA-translating machinery groups the mRNA nucleotides into codons AUG - answer- codon that initaties ("start" signal) and also codes amino acid Methionine redundant - answer- more than 1 codon may specify a particular amino acid ambiguous - answer- no codon specifies more than one amino acid reading frame - answer- the division of a sequence of DNA or RNA into a particular series of three-nucleotide codons. There are three possible reading frames for any sequence RNA polymerase - answer- enzyme similar to DNA polymerase that binds to DNA and separates the DNA strands during transcription, they can start a chain without a primer. promoter - answer- A specific nucleotide sequence in DNA that binds RNA polymerase and indicates where to start transcribing RNA. terminator - answer- In bacteria, a sequence of nucleotides in DNA that marks the end of a gene and signals RNA polymerase to release the newly made RNA molecule and detach from the DNA. transcription unit - answer- the stretch of DNA that is transcribed into an RNA molecule 3 stages of transcription - answer- initiation, elongation, termination initiation - answer- the first phase of transcription; RNA polymerase binds to DNA @ the promoter, and unwinds the double helix elongation - answer- RNA polymerase slides along DNA in an open complex to synthesize RNA termination - answer- RNA polymerase falls off at the terminator (Bacteria) or falls off after the new RNA strand is removed start point - answer- In transcription, the nucleotide position on the promoter where RNA polymerase begins synthesis of RNA. transcription factors - answer- collection of proteins that mediate the binding of RNA polymerase and the initiation of transcription transcription initiation complex - answer- the whole complex of transcription factors and RNA polymerase II bound to the promoter TATA box - answer- A promoter DNA sequence crucial in forming the transcription initiation complex. RNA processing - answer- Modification of RNA transcripts, including splicing out of introns, joining together of exons, and alteration of the 5' and 3' ends before it is released into the cytoplasm. 5' cap - answer- The 5' end of a pre-mRNA molecule modified by the addition of a cap of guanine nucleotide. poly-A tail - answer- Modified end of the 3' end of an mRNA molecule consisting of the addition of some 50 to 250 adenine nucleotides. RNA splicing - answer- The removal of noncoding portions (introns) of the RNA molecule after initial synthesis. introns - answer- a non-coding, intervening sequence within a eukaryotic gene exons - answer- expressed sequence of DNA; codes for a protein snRNPs - answer- (small nuclear ribonucleoproteins) composed of RNA and protein molecules, recognize the splice sites, join with additional proteins to form a spliceosome spliceosome - answer- A complex assembly that interacts with the ends of an RNA intron in splicing RNA, releasing the intron and joining the two adjacent exons. ribozymes - answer- An RNA molecule that functions as an enzyme, catalyzing reactions during RNA splicing alternative RNA splicing - answer- A type of eukaryotic gene regulation at the RNA-processing level in which different mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns domain - answer- an independently folding part of a protein exon shuffling - answer- The variation in the patterns by which RNA may produce diverse sets of exons from a single gene.`` transfer RNA - answer- An RNA molecule that functions as an interpreter between nucleic acid and protein language by picking up specific amino acids and recognizing the appropriate codons in the mRNA - tRNA. anticodon - answer- A sequence of three bases of a tRNA molecule that pairs with the complementary three-nucleotide codon of an mRNA molecule during protein synthesis. aminoacyl-tRNA synthetases - answer- family of enzymes that matches the correct amino acid to the correct tRNA wobble - answer- flexibility in the base-pairing rules in which the nucleotide at the 5' end of a tRNA anticodon can form hydrogen bonds with more than one kind of base in the third position (3' end) of a codon ribosomal RNAs - answer- RNA molecules that, together with proteins, make up ribosomes; the most abundant type of RNA. P site - answer- one of a ribosome's three binding sites for tRNA, holds the tRNA