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AP Biology Gene Expression Flashcards

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6051573410Transformationa change in genotype and phenotype due to assimilation of foreign DNA0
6051573411bacteriophagesviruses that infect bacteria. Bacteriophages consist only of proteins and DNA.1
6051573412DNA is the genetic materialpolymer of nucleotides, DNA composition varies from one species to the next, A and T bases are equal and the number of G and C bases are equal2
6051573413nucleotidesa nitrogenous base, a sugar, and a phosphate group3
6051573414PurineA/G, 2 organic rings, 2X the size, 2 hydrogen bonds4
6051573415PyrimidineC/T, single ring, X size, 3 hydrogen bonds5
6051573416Why do purine and pyrimidines bases always pair together?because of the number of *hydrogen bonds* they are able to form6
6051573417Semiconservative model7
6051573418origins of replicationThe site where replication occurs where the two DNA strands are separated, opening up a replication "bubble".8
6051573419DNA polymeraseadds nucleotides to the 3' end of the growing DNA sequence. It needs a primer. It can only go in one direction and extend on an existing DNA molecule is gets it's energy from dATP9
6051573420RNA PrimaseIn DNA replication, RNA primase adds temporary RNA nucleotides for DNA polymerase to work from and add nucleotides to10
6051573421replication forka Y-shaped region where new DNA strands are elongating that is located at the end of the replication bubble.11
6051573422Single-strand binding proteinsbind to and stabilize single-stranded DNA12
6051573423Helicasesenzymes that untwist the double helix at the replication forks.13
6051573424Topoisomerasecorrects "overwinding" ahead of replication forks by breaking, swiveling, and rejoining DNA strands14
6051573425leading strandthe template strand of DNA where replication happens continuously toward the replication fork because it is aligned properly15
6051573426lagging strandthe template strand of DNA where DNA polymerase must work in the direction away from the replication fork16
6051573427Other functions of DNA polymerasesproof reading by replacing any incorrect nucleotides17
6051573428Okazaki fragmentsThe fragments that are going by DNA ligase to compose the lagging strand. They are short replicated fragments on the lagging strand that are formed 5-3. The spaces between the fragments are filled via DNA ligase to make a continuous DNA strand.18
6051573429mismatch repairrepair enzymes that correct errors in base pairing19
6051573430nucleotide excision repaira *nuclease* cuts out and replaces damaged stretches of DNA20
6051573431Telomeresnon-coding DNA at the ends of chromosomes. Telomerase adds "junk" repeats to leading strands... Polymerase is able to copy lagging strand... Now the unreplicated lagging overhang is unimportant "junk" (BUT telomerase can only be found in cancerous tissues)21
6051573432bacterial chromosomedouble-stranded, circular, few22
6051573433eukaryotic chromosomelinear, large amount of protein23
6051573434Chromatina complex of DNA and protein, is found in the nucleus of eukaryotic cells24
6051573435euchromatinLoosely packed chromatin25
6051573436heterochromatindensely pack chromatin26
6051573437What is a gene?protein27
6051573438How is a gene transcribed?RNA polymerase28
6051573439How is transcript processed?RNA splicing29
6051573440What is the language of DNA/RNA?genetic code30
6051573441How is RNA read?tRNA31
6051573442How is protein produced?ribosomes32
6051573443Transcriptionthe synthesis of RNA using information in DNA Transcription produces messenger RNA (mRNA)33
6051573444Translationthe synthesis of a polypeptide, using information in the mRNA34
6051573445Codon/triplet nucleotidesThe genetic code must be written in triplets because they are the smallest unit of uniform length that can code for all the amino acids. There are 20 amino acids. This will allow for 64 possible codes, with repetition. Gentic code in universal35
6051573446Reading framethe sequence of the DNA that is between the start codon and the end codon (with triplet sequences in between). They can be altered/changes when there are insertions and deletions.36
6051573447Ribosomesthe sites of translation (in eukaryotes, the nuclear envelop separates transcription)37
6051573448primary transcriptinitial RNA transcript from any gene prior to processing38
6051573449central dogmahe concept that cells are governed by a cellular chain of command: DNA to RNA to protein39
6051573450RNA polymeraseThe Starter of RNA synthesis. It pries the DNA strands apart and hooks together the RNA nucleotides40
6051573451terminatorin bacteria, the sequence signaling the end of transcription41
6051573452promoterThe DNA sequence where RNA polymerase attaches to start transcription.42
6051573453transcription unitThe stretch of DNA that is transcribed43
6051573454The three stages of transcriptionInitiation, Elongation, Termination44
6051573455transcription initiation complexThe completed assembly of transcription factors and RNA polymerase II bound to a promoter45
6051573456Transcription factorsmediate the binding of RNA polymerase and the initiation of transcription Transcription factors guide the blind polymerase46
6051573457TATA boxThe promotor that crews the initial complex in eukaryotes47
6051573458intronsThese noncoding regions are called intervening sequences48
6051573459Initiation of translationSmall subunit of the ribosome attaches to the cap and moves to the translation initial site. TrNA anticodons attach to the codon that had MET (the amino acid for the start codon). The large subs unit attaches to make the P and the A site.49
6051573460Elongation of translationMET is transferred to the A site amino acid and the tRNA moves along to the next site. The amino acids attach on the tRNA in the a site. The ribosome moves along the mRNA.50
6051573461Termination of translationA release favor comes in (the stop codon) and the chain stops building on the polypeptide. The protein is then released.51
6051573462exonsthey are eventually expressed, usually translated into amino acid sequences52
6051573463RNA splicingremoves introns and joins exons, creating an mRNA molecule with a continuous coding sequence53
6051573464domainsProteins often have a modular architecture consisting of discrete regions54
6051573465Ribozymescatalytic RNA molecules that function as enzymes and can splice RNA55
6051573466RNAIt can form a three-dimensional structure because of its ability to base-pair with itself Some bases in RNA contain functional groups that may participate in catalysis RNA may hydrogen-bond with other nucleic acid molecules56
6051573467How is protein synthesized?Requires all three major types of RNA... • mRNA - "Recipe" the coding sequence of the gene • aminoacyl tRNAs - "Cook" read codon, carry appropriate amino acid (translation!) • rRNA - "Cookware" forms the core of the ribosome which forms peptide bonds between amino acids57
6051573468tRNAstransfer amino acids to the growing polypeptide in a ribosome58
6051573469anticodonthe anticodon base-pairs with a complementary codon on mRNA59
6051573470wobbleFlexible pairing at the third base of a codon that allows some tRNAs to bind to more than one codon60
6051573471RibosomesRibosomes facilitate specific coupling of tRNA anticodons with mRNA codons in protein synthesis61
6051573472P siteholds the tRNA that carries the growing polypeptide chain62
6051573473POINT MUTATIONSsingle base changed63
6051573474FRAMESHIFTS:any insertion or deletion NOT divisible by 3 will shift the reading frame... causing extense missense (wrong amino acid coding)64
6051573475Silent mutationshave no effect65
6051573476missensehave the wrong amino acid66
6051573477nonsensehave an early stop!67
6051573478operatorAclusteroffunctionallyrelatedgenescanbeundercoordinated control by a single "on-off switch"68
6051573479repressorcan switch the operon off/on by preventing gene transcription by binding to the operator and blocking RNA polymerase69
6051573480operonthe entire stretch of DNA that includes the operator, the promoter, and the genes that they control How gene expression is controlled in bacteria they are only in prokaryotes70
6051573481corepressora molecule that cooperates with a repressor protein to switch an operon off (tryp)71
6051573482REPRESSIBLE OPERON:repressor is NOT bound; operon is usually on • for enzymes that ARE normally needed • can be turned OFF if not needed (repressor is made active by excess product of the pathway) tryp ***anabolic pathways; their synthesis is repressed by high levels of the end product ***negative control72
6051573483INDUCIBLE OPERON:repressor IS bound; operon is usually off • for enzymes that are usually NOT needed • can be turned ON when necessary (repressor is inhibitted by the pathway's substrate) lac ***catabolic pathways; their synthesis is induced by a chemical signal ***negative control73
6051573484eukaryotic gene regulationhappens through many steps74
6051573485DNA PACKING: regulation of eukaryotesRegulate condensation of DNA regions into inactive heterochromatin or decondensation into transcriptionally active euchromatin75
6051573486TRANSCRIPTION: regulation of eukaryotesRegulate individual genes using transcription factors (TFs) and activators76
6051573487RNA PROCESSING: regulation of eukaryotesRegulate alternative splicing possibilities with proteins that block splice sites77
6051573488RNA OR PROTEIN DEGRADATION: regulation of eukaryotesRegulate lifespan of each using exonucleases and proteasomes78
6051573489Result of heterochromatinGenes within highly packed heterochromatin are usually not expressed79
6051573490NUCLEOSOMEDNA makes 1.75 turns around the histone octamer80
6051573491HISTONESDNA is wrapped around a set of eight proteins Histones are small, proteins that binds tightly to negatively charged DNA to make chromatin.81
6051573492ChromatinDNA packaged with proteins82
6051573493histone acetylationacetyl groups are attached to positively charged lysines in histone tails83
6051573494control elementssegments of noncoding DNA that serve as binding sites for transcription factors that help regulate transcription84
6051573495DNA methylationthe addition of methyl groups to certain bases in DNA, is associated with reduced transcription in some species. DNA methylation can cause long-term inactivation of genes in cellular differentiation. Methylation regulates expression of either the maternal or paternal alleles of certain genes at the start of development basically, it loosens or tightens the chromatin to allow or inhibition transcription by making DNA available or not.85
6051573496Control elements and the transcription factorsthey bind and are critical to the precise regulation of gene expression in different cell types86
6051573497transcription factorsTo initiate transcription, eukaryotic RNA polymerase requires the assistance of proteins called transcription factors*** are essential for the transcription of all protein-coding genes. Some transcription factors function as repressors, inhibiting expression of a particular gene by a variety of methods87
6051573498alternative RNA splicingdifferent mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns88
6051573499Proteasomesgiant protein complexes that bind protein molecules and degrade them89
6051573500RNA interference (RNAi)The phenomenon of inhibition of gene expression by RNA molecules90
6051573501Cell differentiationthe process by which cells become specialized in structure and function91
6051573502Cytoplasmic determinantsmaternal substances in the egg that influence early development92
6051573503inductionsignal molecules from embryonic cells cause transcriptional changes in nearby target cells93
6051573504Determinationcommits a cell to its final fate94

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