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Bio Exam 2
Foundations of Biology Exam 2 UIOWA
| Term | Definition |
|---|---|
| Inducible Operons | Substrate (inducer) for a catabolic enzyme binds to repressor and changes it so it cannot bind to the operator, turns transcription on. |
| Repressible Operons | End product of the anabolic pathway acts as co-repressor to allow repressor to bind Operator and repress transcription, turns transcription off. |
| transcription factors | Regulatory proteins that must assemble on the chromosome before RNA polymerase is recruited to the promoter |
| Recognition sequence | A part of DNA that is recognized by RNA polymerase |
| TATA box | where DNA begins to unwind and expose the template strand |
| Enhancers | positive regulators that increase transcription above normal levels |
| Silencers | negative regulators that reduce transcription |
| the combination of ____________ determines the rate of transcription | regulatory factors |
| Genes can be regulated during _____ steps of protein synthesis | all |
| Acetylation of histones | Opens the chromatin to allow access to DNA for transcription (epigenetic modification) |
| Methylation of DNA bases | Prevents transcription from occuring (epigenetic modification) |
| Epigenetic changes can be passed on to daughter cells, but they are __________. | reversible |
| Alternative splicing | as introns and exons are spliced differently, distinct proteins can be made; can generate many different proteins from a single gene |
| introns | transcribed regions that are removed from pre-mRNA prior to nuclear export |
| Exons | Proteins coding regions that can remain in mRNA and is exported from the nucleus |
| microRNA | combines with proteins to form an RNA-induced silencing complex to inhibit translation or causes degradation of complementary RNAs |
| phosphorylation | posttranslational modification of adding a phosphate group to alter the shape of a protein |
| glycosylation | posttranslational modification of adding sugars for targeting and recognition |
| proteolysis | cleaving the polypeptide allows the fragments to fold into different shapes |
| transcriptional control | regulates access and recruitment of RNA polymerase to the promoter in nucleus |
| processing control | regulates splicing capping and tailing of pre-mRNA in nucleus |
| mRNA transport and stability | regulates nuclear export and localization in cytoplasm and half-life of mRNA |
| Translational control | regulates mRNA assembly with ribosome and polypeptide synthesis |
| posttranslational processing | regulates protein activity through processing, folding, and making chemical modifications |
| phenotypic variation | the action of multiples different genes, as well as environmental influence on on a single phenotype i.e. height, weight, skin pigmentation etc. |
| general purpose genes | needed by all cells like those involved in DNA replication byt not expressed at all times of cell cycle |
| specialty function genes | needed for response to specific environmental changes or for specialized call function |
| regulatory proteins | control expression of other genes, most are under the control of multiple regulatory proteins |
| negative regulation | binding of a repressor protein of DNA prevents transcription |
| positive regulation | binding of an activator protein of DNA to stimulate transcription |
| promoter | the region of DNA where RNA polymerase binds and initiates transcription |
| operator | the region of DNA between the promoter and structural genes that is bound by the repressor |
| ribosome | holds mRNA and charged tRNAs in the correct positions to allow assembly of polypeptide chain |
| C terminus | the end of a peptide strand or last amino acid with a free carboxyl group |
| N terminus | the start of a peptide strand or first amino acid with a free amino group |
| genetic code | specifies which amino acids will be used to build a polypeptide |
| codon | a sequences of three bases that encodes a particular amino acid |
| start codon | AUG - initiation signal for translation near 5' end of mRNA |
| stop codon | UAA, UAG,UGA, - stop translation and polypeptide is released |
| the genetic code is nearly _____________. | universal |
| tRNA (transfer) | the adapter molecule, associates information in the mRNA codons with specific amino acids |
| anticodon | the base pairing on the tRNA molecules and the site of pairing with mRNA |
| wobble | specificity for the base at the 3'end of the codon is not always observed, meaning codons that are different can be recognized by the same tRNA |
| somatic mutations | occur in body cell - passed on by mitosis but not to gametes so is not genetic |
| germ line mutations | occur in germ line cells which for gametes and is genetical |
| silent mutations | do not change polypeptide sequences so there is not change in protein function or outwardly affect |
| loss of function mutations | affect protein function and may lead to structural proteins or enzymes that no longer work |
| gain of function mutations | lead to a protein with altered function |
| conditional mutations | cause phenotypes under restrictive conditions but are not detectable under permissive conditions |
| point mutations | results from the grain loss or substitution of a single base pair of DNA |
| missense point mutation | a nonsynonymous site changes a single amino acid |
| nonsense point mutations | shortens polypeptide by causing premature termination of translation |
| loss of stop mutations | causes read-through translation to new stop codon |
| frame-shift point mutation | changes the reading frame |
| one gene to __________ relationship | one polypeptide |
| Beadle & Tatum experiment | each mutation caused a defect to only one enzyme (proved one gene, one enzyme relationship) |
| transcription | copies information from a DNA sequence to a complementary RNA sequence |
| Translation | converts RNA sequences to amino acid sequence to a polypeptide |
| mRNA (messenger) | carries a copy of DNA sequence to site of protein synthesis |
| rRNA | catalyzes peptide bonds and provides structure |
| RNA polymerase | catalyzes synthesis of RNA from a DNA template, does not need primers, and lacks a proofreading function |
| DNA template | one of the two strands of DNA used to make RNA |
| nucleoside triphosphates | ATP, GTP, CTP, UTP as substrates |
| promoter | a special sequence of DNA required for initiation of transcription that tells RNA polymerase where to start and which direction to transcribe |
| RNA polymerase makes a reads ______ so it produces a _______ strand | 3' to 5' : 5' to 3' |
| spliceosome | cuts pre-mRNA, releases introns, and splices exons together to produce mature mRNA |
| RNA splicing | removes introns and splices exons together |
| snRNPs | small nuclear ribonucleoprotein particles that form the spliceosome |
| G cap goes on the | 5' end of mature mRNA to facilitate binding to the ribosome and protection from degradation |
| Poly A tail goes on the | 3' end of mature mRNA to assist in export from nucleus and mRNA stability |
| mutation | the changes of the nucleotide sequence of the genome of an organism |
| Proofreading | DNA polymerase II recognizes a mismatch, backs up, removes the mismatched nucleotide and recommences synthesis |
| mismatch repair mechanism | recognizes old and new strand by modifications and removes mismatched fragments after replication due to abnormal hydrogen bonding |
| excision repair | enzymes constantly scan DNA for damaged bases which are removed and re-added by DNA polymerase |
| spontaneous mutations | caused by polymerase errors or spontaneous chemical changes (tautomeric shift and deamination) |
| Tautomeric shift | when a base switch to a rare isomer and pairs with a different base, leading to a mismatch |
| deamination | loss of an NH2 group in cytosine forming uracil |
| mutagens | cause induced mutations from chemicals, radiation, or even cigarette smoke. |
| conditional mutations | affect the phenotype only under certain environmental conditions |
| chromosomal mutations | extensive changes in genetic material involving long DNA sequences; often deleterious |
| deletions | loss of chromosome segment; has severe or fatal consequences |
| duplications | a portion of chromosome is replicated, resulting in multiple copies |
| inversions | result from breaking and rejoining but the segment is flipped (homologous) |
| translocations | segment of DNA breaks off and is inserted into another chromosome (non-homologous) |
| semiconservative DNA model | each parental strand is a template for a new strand |
| conservative | the two parental strands remain together in one daughter molecules, while as a template for another molecule |
| dispersive | parent molecule is dispersed among both strands in the daughter molecules |
| Meselson & Stahl experiment | proved that DNA replication is semiconservative because the 1st generations had an intermediate weight |
| ingredients to PCR | DNA template, primers, dNTPS, DNA polymerase, salts, and a buffer |
| DNA helicase | "unzips" and separates the two strands of DNA |
| topoisomerase | protects the rest of the DNA molecule from being wound tighter |
| SSBs (single stranded binding proteins) | keep the single strands of unwound DNA seperated |
| primase | enzyme that synthesizes a short RNA primer to initiate a new DNA strand for DNA polymerase to bind to |
| DNA polymerase I | removes RNA primers from Okazaki fragments and replaces them with DNA nucleotides |
| DNA ligase | seals the nick between the two lagging strand fragment s |
| replication fork | the site where DNA unwinds to expose bases |
| DNA polymerase III | adds new nucleotide bases in the 5' to 3' direction |
| leading strand | grows continuously at its 3' end as the fork opens (continuous) |
| lagging strand | synthesized in small fragments in the 5' to 3' direction (discontinuous) |
| Okazaki fragments | small synthesized fragments on the lagging strand |
| DNA polymerase II | repairs mismatches and proofreads, mainly in the lagging strand |
| telomeres | repetitive sequences at the ends of eukaryotic chromosomes that do not encode proteins and prevents coding regions of DNA from being cut off |
| telomerase | adds telomeres back on to the end of the chromosome |
| apoptosis | programmed cell death |
| Griffith experiment | concluded that chemicals from dead S strains transformed live R cells into virulent S cells |
| Avery et al. experiment | concluded R stain was still transformed when S-RNA or S-protein was destroyed but was not transformed if the S-DNA was destroyed (suggested DNA was carrying information's and not proteins) |
| Hershey and Chase experiment | concluded that DNA contained information because the bacteriophages contained the P isotope which was more abundant in DNA than the S in proteins |
| Chargaff's experiment | determined that a DNA molecules has equal amounts of purines and pyrimidines |
| Franklin's experiment | determined that DNA had a helical structure through X-ray crystallography |
| Watson & Crick's experiment | determined the full structure of DNA through modeling |
| antiparallel strands | polarity of the strand is determined by the sugar-phosphate bonds |
| 5' end has a free _______ group | phosphate |
| 3' end has a free _______ group | hydroxyl |
| DNA is ____ handed | right |
| DNA has major and minor groves because of the _________ bonds in base paring | hydrogen |
| hemizygous | only have one copy of the genes on the X chromosome |
| X-linked recessive phenotypes | appear much more often in males than females who can serves a carriers, tend to skip generations |
| sex-linked inheritance | traits that are influence by genes carried on the sex chromosomes |
| complete dominance | heterozygous individuals appear similar to one of the homozygotes; purple + white = purple |
| incomplete dominance | heterozygous individuals appear as an intermediate of homozygotes; purple + white = pink |
| co-dominance | phenotypes of both alleles appear in the heterozygote: purple + white = spotted |
| epistasis | phenotypic expression of one gene is influenced by genotype of another gene |
| for independently assorting loci you can ______ the probabilities of each phenotype to determine the outcomes in a dihybrid cross | multiply |
| if there are more parental types than recombinant types the genes exhibit ___________. | linkage |
| recombinant frequency | # of recombs divided by total offspring; proportional to map units |
| maximum recombinant frequency is ______. | 0.5 |
| greater recombinant frequencies mean the loci are _________. | farther apart |
| crossing over | exchange between non-sister chromatids produces recombination between DNA molecules |
| independent assortment | haploid sets of chromosomes inherited from parents mixed by segregation of homologs during meiosis I |
| 2^n | number of possible genotypic combinations, n = number of homologous pairs |
| law of segregation | two alleles of a gene separated and are transmitted individually and equally to gametes |
| law of independent assortment | alleles of different genes assort independently during gamete formation |
| Morgan experiments | established drosophila melanogaster as the model for genetic studies and discovered the phenomenon of linkage |
| meiosis | sexual, creates 4 haploid gametes through 2 nuclear divisions and generates genetic diversity |
| meiosis I | segregation of homologs forming haploid nuclei |
| meiosis II | separation of sister chromatids to form 4 daughter cells |
| nondisjunction | homologous pairs fail to separate at Anaphase I or sister chromatids fail to separate at Anaphase II |
| aneuploidy | chromosomes are missing or present in excess |
| Cdks (cyclin-dependent kinases) | activated when bound to cyclin and active Cdk catalyzes transfer of phosphate from ATP to another protein that signals a cell cycle event |
| If RB is active it _____________ the cell cycle. If RB is phosphorylated by cyclin-Cdk making it inactive, the cell cycle is not ___________. | inhibits : restricted |
| binary fission | asexual, prokaryotes, identical daughter cells |
| mitosis | asexual, eukaryotes, identical daughter cells |
| diploids are __n and haploids are __n. | 2 : 1 |
| interphase | when normal cell functions occur, not dividing but may be preparing for division |
| m phase | when mitosis occurs |
| S phase of interphase | when DNA replicates forming 2 identical sister chromatids for each chromosomes |
| phases of mitosis | PMAT (prophase, metaphase, anaphase, telophase, and cytokinesis) |
| MTOC (microtubule organizing center) | high concentration of tubulin dimers that form and orient mitotic spindles to attach and move chromosomes |
| centrosome is the MTOC of animal cells | consists of two centrioles formed of microtubules which move to opposite ends of nuclear envelope and determine the spindle orientation and plane of cell division |
Created by:
emmajean
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