Term
| This is the DNA protein complex in Eukaryotes. |
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Definition
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Term
| Both Prokaryotes and Eukaryotes must alter their gene expression in response to what? |
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Definition
| Changes in environmental conditions. |
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Term
| These proteins are responsible for the first level of DNA packing in Chromatin. |
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Definition
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Term
| These proteins have a high proportion of positively charged amino acids (lysine and arginine) and they bind tightly to the negatively charged DNA. |
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Definition
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Term
| In electron micrographs, unfolded chromatin has the appearance of beads on a string. These "beads" are called what? |
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Definition
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Term
| The string between each nucleosome is called? |
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Definition
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Term
| This consists of DNA wound around a protein core composed of molecules each of four types of histone: H2A, H2B, H3, and H4. |
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Definition
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Term
| This occurs during development of a multicellular organism. It is a process of specialization that results in several or many differentiated cell types. |
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Definition
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Term
| Differences between cell types are due to what? |
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Definition
| differential gene expression |
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Term
| What side of the histone molecule in a nucleosome protrudes outward and is accessible to various modifying enzymes? |
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Definition
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Term
| What do the various modifying enzymes that modify the N-terminus end of a nuclesome do? |
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Definition
| They catalyze the addition or removal of specific chemical groups. |
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Term
| Acetyl groups are attached to positively charged lysines in histone tails in this type of modification. |
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Definition
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Term
| What happens when the histone tail of a nucleosome are acetylated? |
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Definition
| Their positive charges are neutralized and they no longer bind to neighboring nucleosomes. |
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Term
| What is the end result of histone acetylation? |
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Definition
| Transcription proteins have easier access to genes in an acetylated region. |
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Term
| According to this model, specific combinations of modifications, rather than the overall level of histone acetylation, help determine the chromatin configuration, which in turn influences transcription. |
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Definition
| The histone code hypothesis. |
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Term
| a typical human cell expresses how much of its genes at any given time? |
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Definition
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Term
| What does the methylation of certain bases in DNA account for? |
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Definition
| DNA methylation seems to be essential for long-term inactivation of certain genes. |
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Term
| What permanently regulates the expression of either the maternal or paternal allele of certain genes? |
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Definition
| Methylation and the pattern maintained by it. |
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Term
| What is the maintained methylation pattern of either paternal or maternal genes known as? |
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Definition
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Term
| Inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence is called ________ _________. |
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Definition
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Term
| Once a gene is optimally modified for expression, the initiation of what is the most important and universally used stage at which gene expression is regulated? |
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Definition
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Term
| Segments of noncoding DNA that help regulate transcription by binding certain proteins. |
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Definition
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Term
| To initiate transcription, eukaryotic RNA polymerase requires the assistance of proteins called _____ ________. |
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Definition
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Term
| These are distal control elements can be grouped together as _________. They are used in RNA transcription. |
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Definition
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Term
| A protein that binds to an enhancer and stimulates transcription of a gene. |
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Definition
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Term
| What are 2 common structural elements that have been found in activator proteins? |
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Definition
1. A DNA binding domain
2. one or more activation domains |
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Term
| transcription factors that inhibit expression of a particular gene. |
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Definition
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Term
| Some repressors recruit proteins that deacetylate histones, leading to reduced transcription. This is known as _______. |
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Definition
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Term
| This is one example of gene regulation at the RNA processing level. Different RNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns. |
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Definition
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Term
| small, single stranded RNA molecules that bind to complementary sequences in mRNA molecule. They block expression of certain mRNA molecules. |
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Definition
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Term
| Inhibition of gene expression by RNA molecules is called what? |
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Definition
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Term
| What is responsible for RNA interference? |
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Definition
| small interfering RNAs (siRNAs) |
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Term
| The inititiation of translation of select mRNA molecules can be blocked by what? |
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Definition
| Regulatory proteins that bind to specific sequences or structures within the untranslated region at the 5' end of the mRNA, preventing the attachment of ribosomes. |
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Term
| What are the major stages of gene expression that can be regulated in eukaryotic cells? |
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Definition
1.Chromatin modification
2.transcription
3.RNA processing
4.transport to cytoplasm
5.degradation of mRNA
6.translation
7.cleavage chemical modification
8.degradation of protein |
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Term
| True or false; regulation might occur at any of the steps involved in modifying or transporting a protein. |
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Definition
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Term
| The length of time each protein functions in a cell is strictly regulated by means of what? |
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Definition
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Term
| Giant protein complexes that recognize ubiquitin-tagged protein molecules and degrade them. |
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Definition
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Term
| How do tumor viruses transform cells into cancer cells? |
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Definition
| Through the integration of viral nucleic acid into the host cell DNA. |
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Term
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Definition
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Term
| Normal cellular genes that code for proteins that stimulate normal cell growth and division. |
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Definition
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Term
| What are the 3 main reasons proto-oncogenes become oncogenes? |
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Definition
1.movement of DNA within the genome
2.amplification of a proto-oncogene
3.point-mutations in a control element or in the proto-oncogene itself. |
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Term
| genes whose normal products inhibit cell division. The proteins they encode help prevent uncontrolled cell growth. |
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Definition
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Term
| What gene codes for the Ras protein?(A G-protein that relays a signal to stimulate the cell cycle.) |
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Definition
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Term
| This gene has been called the "guardian angel" of the genome because it helps guard cells from becoming cancerous in many ways. |
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Definition
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Term
| What are some of the ways the p53 gene protects cells from becoming cancerous? |
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Definition
1.it activates a gene that halts the cell cycle by binding cyclin-dependent kinases.
2. turns on genes directly involved in DNA repair
3. activates "suicide" genes that can cause cells to go into apoptosis.(cell death) |
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Term
| viruses seem to play a role in about how many human cancer cases worldwide? |
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Definition
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Term
| Intergenic DNA with sequences present in multiple copies in the genome. |
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Definition
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Term
| What are the two types of eukaryotic transposable elements? |
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Definition
1.transposons
2.retrotransposons |
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Term
| This transposable element moves within a genome by means of a DNA intermediate. |
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Definition
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Term
| This transposable element moves by means of an RNA intermediate, a transcript of retrotransposon DNA. |
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Definition
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Term
| What are the 2 ways transposons can move? |
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Definition
1. "cut and paste"
2. "copy and paste" |
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Term
| These always leave a copy at the original site of transposition. |
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Definition
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Term
| most transposable elements in eukaryotic genomes are ___________. |
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Definition
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Term
| Why are transposable elements often described as "noncoding" DNA even though many do encode for proteins? |
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Definition
| Because the proteins they make do not carry out normal cellular functions. |
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Term
| this DNA contains many copies of tandemly repeated short sequences. |
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Definition
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Term
| Much of a genes simple sequence DNA is located at chromosomal telomeres and centromeres, suggesting what? |
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Definition
| That it plays a structural role for chromosomes. |
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Term
| Collections of identical or very similar genes. |
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Definition
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Term
| Nonfunctional nucleotide sequences quite similar to the functional genes. |
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Definition
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Term
| What are some examples of evolution of genes with related functions? |
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Definition
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Term
| The mixing and matching of different exons either within a gene or between to nonallelic genes owing to errors in meiotic recombination. |
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Definition
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Term
| Why is exon shuffling possibly a large part of evolution? |
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Definition
| Because it could lead to new proteins with novel combinations of functions. |
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Term
| the functioning of enhancers is an example of what? |
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Definition
| transcriptional control of gene expression. |
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Term
| One of the characteristics of retrotransposons is what? |
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Definition
| They code for an enzyme that synthesizes DNA using an RNA template. |
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Term
| Within a cell, the amount of protein made using a given mRNA molecule depends partly on what? |
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Definition
| The rate at which the mRNA is degraded. |
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Term
| identical or similar genes that have evolved by gene duplication. |
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Definition
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Term
| 2 eukaryotic proteins have one domain in common but are otherwise very different. What most likely contributed to this? |
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Definition
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