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| 193492 | histones | proteins called ____ are responsible for the first level of DNA packing in chromoatin | |
| 193493 | nucleosome | each "bead" is a _________, the basic unit of DNA packing | |
| 193494 | heterochromatin | non-transcribed eukaryotic chromatin that is so highly compacted that it's visible with a light microscope | |
| 193495 | euchromatin | the more open, unraveled form of eukaryotic chromatin that is available for transcription | |
| 193496 | cell differentiation | during development of a multicellular organism, its cells undergo a process of specialization in form and function called _____ _________, resulting in several or many differentiated cell types | |
| 193497 | histone acetylateion | in __________ _________, acetyl groups (--COCH3) are attached to positively charged lysines in histone tails | |
| 193498 | histone deacetylation | the removal of acetyl groups | |
| 193499 | genomic imprinting | a phenomenon in which expression of an allele in offspring depends on whether the allele is inherited from the male or female parent | |
| 193500 | epigenetic inheritance | inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence is called __________ _________ | |
| 193501 | control elements | segments of non-coding DNA that help regulate transcription by binding to certain proteins | |
| 193502 | transcription factors | to initiate transcription, eukaryotic RNA polymerase requires the assistance of proteins called _________ _________ | |
| 193503 | enhancers | the more distance distal control elements, groups of which are called ________, may be thousands of nucleotides upstream or downstream of a gene or even within an intron | |
| 193504 | activator | an __________ is a protein that binds to an enhancer and stimulates transcription of a gene | |
| 193505 | repressors | some specific transcription factors function as _________ to inhibit expression of a particular gene | |
| 193506 | micro RNAs | researchers have found small single-stranded RNA molecules, called ______ ______ (miRNAs), that can bind to complementary sequences in mRNA molecules | |
| 193507 | RNA interference | (RNAi)a technique to silence the expression of selected genes in non-mammalian organisims | |
| 193508 | small interfering RNAs | (siRNAs) Rna of similar size and function as miRNAs | |
| 193509 | proteasomes | giant protein complexes called _________ can recognize the ubiquitin-tagged protein molecules and degrade them | |
| 193510 | oncogenes | research on tumor viruses led to the discovery of cancer-causing genes called ___________ in certain retroviruses | |
| 193511 | proto-oncogenes | the normal cellular genes, _______-__________, code for proteins that stimulatae normal cell growth and division | |
| 193512 | tumor-suppressor gene | a gene whose protein products inhibit cell division, thereby preventing uncontrolled cell growth (cancer) | |
| 193513 | repetitive DNA | most intergenic DNA is ________ ______, sequences that are present in multiple copies in the genome | |
| 193514 | transposons; retrotransposons | eukaryotic transposable elemetsn are of two types: ________, which move within a genome by means of a DNA intermediate, and _______________, which move by means of an RNA intermediate | |
| 193515 | multigene families | collections of identical or very similar genes | |
| 193516 | pseudogenes | non-functional nucleotide sequences quite similar to the functional genes |
