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AP Biology Gene Expression Flashcards

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5760162915Transformationa change in genotype and phenotype due to assimilation of foreign DNA0
5760162916bacteriophagesviruses that infect bacteria. Bacteriophages consist only of proteins and DNA.1
5760162917DNA 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
5760162918nucleotidesa nitrogenous base, a sugar, and a phosphate group3
5760162919PurineA/G, 2 organic rings, 2X the size, 2 hydrogen bonds4
5760162920PyrimidineC/T, single ring, X size, 3 hydrogen bonds5
5760162921Why do purine and pyrimidines bases always pair together?because of the number of *hydrogen bonds* they are able to form6
5760162922Semiconservative model7
5760162923origins of replicationThe site where replication occurs where the two DNA strands are separated, opening up a replication "bubble".8
5760162924DNA 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
5760162925RNA PrimaseIn DNA replication, RNA primase adds temporary RNA nucleotides for DNA polymerase to work from and add nucleotides to10
5760162926replication forka Y-shaped region where new DNA strands are elongating that is located at the end of the replication bubble.11
5760162927Single-strand binding proteinsbind to and stabilize single-stranded DNA12
5760162928Helicasesenzymes that untwist the double helix at the replication forks.13
5760162929Topoisomerasecorrects "overwinding" ahead of replication forks by breaking, swiveling, and rejoining DNA strands14
5760162930leading strandthe template strand of DNA where replication happens continuously toward the replication fork because it is aligned properly15
5760162931lagging strandthe template strand of DNA where DNA polymerase must work in the direction away from the replication fork16
5760162932Other functions of DNA polymerasesproof reading by replacing any incorrect nucleotides17
5760162933Okazaki 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
5760162934mismatch repairrepair enzymes that correct errors in base pairing19
5760162935nucleotide excision repaira *nuclease* cuts out and replaces damaged stretches of DNA20
5760162936Telomeresnon-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
5760162937bacterial chromosomedouble-stranded, circular, few22
5760162938eukaryotic chromosomelinear, large amount of protein23
5760162939Chromatina complex of DNA and protein, is found in the nucleus of eukaryotic cells24
5760162940euchromatinLoosely packed chromatin25
5760162941heterochromatindensely pack chromatin26
5760162942What is a gene?protein27
5760162943How is a gene transcribed?RNA polymerase28
5760162944How is transcript processed?RNA splicing29
5760162945What is the language of DNA/RNA?genetic code30
5760162946How is RNA read?tRNA31
5760162947How is protein produced?ribosomes32
5760162948Transcriptionthe synthesis of RNA using information in DNA Transcription produces messenger RNA (mRNA)33
5760162949Translationthe synthesis of a polypeptide, using information in the mRNA34
5760162950Codon/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
5760162951Reading 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
5760162952Ribosomesthe sites of translation (in eukaryotes, the nuclear envelop separates transcription)37
5760162953primary transcriptinitial RNA transcript from any gene prior to processing38
5760162954central dogmahe concept that cells are governed by a cellular chain of command: DNA to RNA to protein39
5760162955RNA polymeraseThe Starter of RNA synthesis. It pries the DNA strands apart and hooks together the RNA nucleotides40
5760162956terminatorin bacteria, the sequence signaling the end of transcription41
5760162957promoterThe DNA sequence where RNA polymerase attaches to start transcription.42
5760162958transcription unitThe stretch of DNA that is transcribed43
5760162959The three stages of transcriptionInitiation, Elongation, Termination44
5760162960transcription initiation complexThe completed assembly of transcription factors and RNA polymerase II bound to a promoter45
5760162961Transcription factorsmediate the binding of RNA polymerase and the initiation of transcription Transcription factors guide the blind polymerase46
5760162962TATA boxThe promotor that crews the initial complex in eukaryotes47
5760162963intronsThese noncoding regions are called intervening sequences48
5760162964Initiation 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
5760162965Elongation 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
5760162966Termination of translationA release favor comes in (the stop codon) and the chain stops building on the polypeptide. The protein is then released.51
5760162967exonsthey are eventually expressed, usually translated into amino acid sequences52
5760162968RNA splicingremoves introns and joins exons, creating an mRNA molecule with a continuous coding sequence53
5760162969domainsProteins often have a modular architecture consisting of discrete regions54
5760162970Ribozymescatalytic RNA molecules that function as enzymes and can splice RNA55
5760162971RNAIt 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
5760162972How 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
5760162973tRNAstransfer amino acids to the growing polypeptide in a ribosome58
5760162974anticodonthe anticodon base-pairs with a complementary codon on mRNA59
5760162975wobbleFlexible pairing at the third base of a codon that allows some tRNAs to bind to more than one codon60
5760162976RibosomesRibosomes facilitate specific coupling of tRNA anticodons with mRNA codons in protein synthesis61
5760162977P siteholds the tRNA that carries the growing polypeptide chain62
5760162978POINT MUTATIONSsingle base changed63
5760162979FRAMESHIFTS:any insertion or deletion NOT divisible by 3 will shift the reading frame... causing extense missense (wrong amino acid coding)64
5760162980Silent mutationshave no effect65
5760162981missensehave the wrong amino acid66
5760162982nonsensehave an early stop!67
5760162983operatorAclusteroffunctionallyrelatedgenescanbeundercoordinated control by a single "on-off switch"68
5760162984repressorcan switch the operon off/on by preventing gene transcription by binding to the operator and blocking RNA polymerase69
5760162985operonthe 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
5760162986corepressora molecule that cooperates with a repressor protein to switch an operon off (tryp)71
5760162987REPRESSIBLE 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
5760162988INDUCIBLE 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
5760162989eukaryotic gene regulationhappens through many steps74
5760162990DNA PACKING: regulation of eukaryotesRegulate condensation of DNA regions into inactive heterochromatin or decondensation into transcriptionally active euchromatin75
5760162991TRANSCRIPTION: regulation of eukaryotesRegulate individual genes using transcription factors (TFs) and activators76
5760162992RNA PROCESSING: regulation of eukaryotesRegulate alternative splicing possibilities with proteins that block splice sites77
5760162993RNA OR PROTEIN DEGRADATION: regulation of eukaryotesRegulate lifespan of each using exonucleases and proteasomes78
5760162994Result of heterochromatinGenes within highly packed heterochromatin are usually not expressed79
5760162995NUCLEOSOMEDNA makes 1.75 turns around the histone octamer80
5760162996HISTONESDNA is wrapped around a set of eight proteins Histones are small, proteins that binds tightly to negatively charged DNA to make chromatin.81
5760162997ChromatinDNA packaged with proteins82
5760162998histone acetylationacetyl groups are attached to positively charged lysines in histone tails83
5760162999control elementssegments of noncoding DNA that serve as binding sites for transcription factors that help regulate transcription84
5760163000DNA 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
5760163001Control elements and the transcription factorsthey bind and are critical to the precise regulation of gene expression in different cell types86
5760163002transcription 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
5760163003alternative RNA splicingdifferent mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns88
5760163004Proteasomesgiant protein complexes that bind protein molecules and degrade them89
5760163005RNA interference (RNAi)The phenomenon of inhibition of gene expression by RNA molecules90
5760163006Cell differentiationthe process by which cells become specialized in structure and function91
5760163007Cytoplasmic determinantsmaternal substances in the egg that influence early development92
5760163008inductionsignal molecules from embryonic cells cause transcriptional changes in nearby target cells93
5760163009Determinationcommits a cell to its final fate94

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