MOD- Chapter 1 Flashcards
What do promoter regions and enhancer regions do within DNA?
Promoter regions- initiate gene transcription
Enhancer regions- modulate gene expression
What do non-coding regions of DNA do?
Regulate gene expression
What are “jumping genes” called and what is their function?
Transposons are jumping genes that regulate gene expression and chromatin organization
What are chromosomal ends called?
What are the central tethers that hold chromatids together?
Telomeres are chromosomal ends
Centromeres are central tethers
What are SNPs and CNVs?
SNP- single nucleotide polymorphism that is a single nucleotide change resulting in biallelic genes
CNV- copy number variations are genetic variations that span large stretches of DNA
Explain the organization of DNA with regards to euchromatin, heterochromatin, nucleosomes, histones, and DNA
DNA is wrapped around histone octomers (H2a/b, H3, H4) forming a nucleosome which is connected to other nucleosomes by linker DNA and a linker histone (H1); strings of nucleosomes form chromatin which can either be dense and transcriptionally inactive (heterochromatin) or loose and transcriptionally active (euchromatin); chromatin is wound up to form chromatid which is linked at a centromere to form a chromosome
What is the basic definition of epigenetics?
Epigenetics are heritable changes in gene expression that are NOT caused by alterations of DNA sequences
What are chromatin remodeling complexes?
What are chromatin writer complexes?
What are chromatin eraser?
What are chromatin readers?
Chromatin remodeling complexes will reposition nucleosomes to expose or occlude gene regulatory elements
Chromatin writer complexes add “marks”/histone modifications that can make DNA more or less accessible
Chromatin erasers reverse histone modifications
Chromatin readers bind histone modifications to regulate gene expression
Explain the following epigenetic modifications: Histone methylation Histone acetylation Histone phosphorylation DNA methylation Chromatin organizing factors
Histone methylation- occurs at arginine and lysine residues; can promote or inhibit gene expression
Histone acetylation- occurs at lysine via HAT in order to open chromatin/inc transcription; HDAC reverses actions of HAT
Histone phosphorylation- occurs at serine residues; can promote or inhibit gene expression
DNA methylation- silences transcription
Chromatin organizing factors- bind non-coding regions of DNA to regulate spacial relationships between promoter and enhancer regions to regulate gene expression
Explain the production and role of miRNA
Transcribe primary-miRNA, process into pre-miRNA, transport out of nucleus, bind DICER which creates mature ds miRNA, mature miRNA unwinds to form ss miRNA, ss miRNA binds RISC, RISC:miRNA complex binds transcribed mRNA and prevents translation
POST-TRANSCRIPTIONAL GENE SILENCING
Explain the purpose and functions and lncRNA and give a specific example
LncRNA modulates gene expression in many ways
Can complex with TF to induce or inhibit gene transcription, it can promote histone modification, and can aid as a scaffold for multi-protein complexes
XIST- involved in x chromosome inactivation
Explain location and function of:
- phosphatidylinositol
- phosphatidylserine
- glycolipids
Phosphatidylinositol- inner leaflet lipid that can be phosphorylated to act as IC scaffold or can be hydrolyzed to generate second messengers
Phosphatidylserine- inner leaflet lipid that can be flipped to outer leaflet to attract phagocytes to initiate apoptosis
Glycolipids- outer leaflets involved in cell-cell and cell-ECM interactions
Explain passive diffusion, what can passively diffuse, what drives passive diffusion
Small polar and nonpolar molecules along with hydrophobic molecules (vitamins and steroids) can readily cross the plasma membrane; passive diffusion is driven by concentration gradients
Explain the functions of carriers and channels and give an example of a specific carrier that is present in many cancer cells
Carriers are for large macromolecules which bind their receptors, trigger conformational change, and allow for slow transport
Channels create pores that when opened allow rapid diffusion of ions
MDR Protein channel- pumps drugs out against its concentration gradient and plays a role in drug resistance and cancer cells not responding to drug treatment
Caveolae mediated endocytosis is for what molecules?
Uptake of small molecules
