MCB 2010 Exam 4 Study Guide ed Verified Latest Update

Exam 4 Study Guide for MCB 2010 | Certified A+ Answers Cell membrane - answer - Phospholipid bilayer separating the internal and external environments of the cell Fluid mosaic model - answer - Model stating membranes are fluid phospholipid bilayers with mobile proteins Phospholipid - answer - Membrane lipid with hydrophilic head and hydrophobic tails Hydrophilic - answer - Water-attracting property Hydrophobic - answer - Water-repelling property Integral membrane protein - answer - Protein embedded in the membrane Peripheral membrane protein - answer - Protein loosely attached to membrane surface Lipid rafts - answer - Cholesterol and sphingolipid-rich semisolid membrane regions Membrane fluidity - answer - Depends on temperature, cholesterol, and fatty acid saturation Unsaturated fatty acids - answer - Increase membrane fluidity Cholesterol - answer - Regulates membrane fluidity and stability Selective permeability - answer - Membranes allow only certain molecules to pass Simple diffusion - answer - Movement of molecules down concentration gradient without proteins or ATP Molecules using simple diffusion - answer - O2, CO2, small hydrophobic molecules Facilitated diffusion - answer - Movement down concentration gradient through membrane proteins Carrier proteins - answer - Transport proteins that change conformation to move molecules Channel proteins - answer - Transport proteins forming pores through membranes Ion channels - answer - Selective channels allowing ion movement across membranes Aquaporins - answer - Water channel proteins Voltage-gated channels - answer - Channels opened by changes in membrane potential Ligand-gated channels - answer - Channels opened by ligand binding Facilitated diffusion ATP requirement - answer - Does not require ATP Active transport - answer - Movement against concentration gradient using energy Primary active transport - answer - Uses ATP directly Secondary active transport - answer - Uses ion gradients generated by ATP pumps Ion pumps - answer - Membrane proteins moving ions against gradients using ATP Na+/K+ pump - answer - Pumps 3 Na+ out and 2 K+ into the cell using ATP Function of Na+/K+ pump - answer - Maintains membrane potential and osmotic balance Symport - answer - Transport of two molecules in the same direction Uniport - answer - Transport of one molecule Antiport - answer - Transport of molecules in opposite directions CFTR - answer - Chloride channel mutated in cystic fibrosis Cystic fibrosis - answer - Caused by defective CFTR leading to thick mucus Cell signaling - answer - Process by which cells communicate and respond to stimuli Signal transduction - answer - Series of events between receptor activation and cellular response Autocrine signaling - answer - Cell signals itself Paracrine signaling - answer - Local signaling to nearby cells Endocrine signaling - answer - Long-distance hormone signaling Juxtacrine signaling - answer - Direct cell-cell contact signaling GPCR - answer - G protein-coupled receptor with 7 transmembrane domains Adenylyl cyclase - answer - Enzyme converting ATP into cAMP cAMP - answer - Second messenger activating PKA PKA - answer - Protein kinase activated by cAMP CREB - answer - Transcription factor activated by PKA Receptor tyrosine kinase - answer - Single-pass receptor activated by dimerization and autophosphorylation Autophosphorylation - answer - Process where RTKs phosphorylate themselves SH2 domain - answer - Protein domain binding phosphotyrosines JAK/STAT pathway - answer - Pathway where STAT proteins activate transcription directly Ras - answer - Small GTPase activated downstream of RTKs MAPK pathway - answer - Ras → Raf → MEK → ERK signaling cascade ERK - answer - MAP kinase entering nucleus to regulate transcription PI3K - answer - Enzyme converting PIP2 to PIP3 Akt - answer - Kinas