ch 19
Terms
undefined, object
copy deck
- histone
- a small protein with a high proportion of positively charged amino acids that binds to the negatively charged DNA and plays a key role in its chromatin structure
- nucleosome
- the basic beadlie unit of DNA packaging in eukaryotes consisting of a segment of DNA wound around a protein core composed of 2 copies of each of 4 types of histone
- heterochromatin
- nontranscribed eukaryotic chromatin that is so highly compacted that it is visible with a light microscope during interphase
- euchromatin
- the more open, unraved form of eukaroytic chromatin that is available for transcription
- repetitive DNA
- nucleotide sequences usually noncoding that are present in many copies in a eukaryotic genome. the repeated present in may be short and arranged tandemly (in series) or long and dispersed in the genome
- satellite DNA
- original name for repetive DNA isolated by cutting genomic DNA before centrifuging
- Alu elements
- a family of similar sequences about 300 nucleotides long
- multigene factor
- a collection of identical or very similar genes
- pseudogenes
- DNA segments very similar to real genes but which do not yield functional products
- gene amplification
- the selective synthesis of DNA which results in multiple copies of a single gene thereby enhancing expression
- retransposons
- transposable elements that move with in a genome by means of a RNA intermediate, a transcript of the retransposonon DNA
- immunoglobulions
- 1 of the class of proteins comprising antibodies
- cellular differentiation
- the structural and functional divergence of cells as tehy become specialized during a multicellular org's development; dependent on the control of gene expression
- DNA methylation
- the addition of methyl groups (-CH3) to bases of DNA after DNA synthesis; may serve as long term control of gene expression
- histone acetylation
- the attchment of acetyl groups to certain amino acids of histone proteins
- genomic imprinting
- th parental effect on gene expression whereby identical alleles have different effects on offspring depending on whether they arrive in the zygote via the ovum or the sperm
- control elements
- segments of noncoding DNA that help regulate transcription of a gene by binding proteins calle dtranscription factors
- enhancers
- DNA sequence that recognizes certain transcription factors that can stimulate transcription of nereby genes
- activator
- a transcription factor that binds to an enhancer and stimulates transcription of a gene
- DNA binding domain
- a part of the 3 dimensional structure of a transcription factor that binds to DNA
- alternative RNA splicing
- type of regulation at RNA processing level where different mRNA molecules are produced from the same primary transcrip depending on which RNA segments are treated as exons or introns
- proteasomes
- griant protein complex that recognizes and destorys proteins tagged for elimination by the small protein ubiquitin
- oncogenes
- a gene found in viruses or as part of a normal genome that is involved in triggering cancerous characteristics
- proto oncogenes
- a normal cellular gene corresponding to an onocogene; gene with a potential to cause cancer but requires some alternation to become oncogene
- tumor suppressor gene
- gene whose protein proudcts inhibit cell divions there by preventing uncontrolled cell growth (cancer)
- ras gene
- gene codes for ras protein, a G protein that relays growth signals from a growth factor receptor on the plasma membrane to a cascade of protein kinases that results in stimulation of cell cycle; most have point mutation that leads to hyperacterive version of Ras protein that results in excessive cell division
- p53 gene
- guardian angel of genome that is expressed when cell's DNA is damaged, product functions as transcription factor for several genes