Eukaryotic Cell Structure and Functions Structure Function Structural Elements Structural Elements Structural Elements Plasma and Endomembrane Plasma and Endomembrane Plasma and Endomembrane Plasma and Endomembrane Plasma and Endomembrane Plasma and Endomembrane Systems Systems Systems Systems Systems Systems Energy Energy Gene Expression Gene Expression Gene Expression Cell Wall Cytoskeleton Flagella Plasma Membrane Endoplasmic Reticulum Nucleus Gogli Complex Lysosomes Peroxisomes Mitochondria Chloroplasts Chromosomes Nucleolus Ribosomes Protection and support Structural support and movement Moving uids over surfaces Regulates what goes in and out cell to cell communication Vesicles protein and lipid synthesis Directs protein synthesis and cell reproduction Packages proteins for exporting vesicles Apoptosis digesting debris and worn out organelles Isolates chemical activities from the cell ATP oxidative metabolism Photosynthesis Hereditary information Assembles ribosomes Protein synthesis Macromolecules and their Functions Name Carbohydrates Proteins Lipids Nucleic Acid Composition Monosaccharides Amino acids H C O C O H N P Blocks C H O Glycerol Nucelotide Examples Function Glucose Energy storage Tissue structure building Enzymes Energy structure Steroids Guanine Stores Genetic Info Terms and De nitions Term Hydrophobic Hydrophilic De nition Tending to repel or fail to mix with water Tending to mix with dissolve in water Gene Expression Transcription and Translation 1 Transcription mRNA copies gene sequence replaces uracil with thymine 2 Translation Ribosomes read mRNA sequence and translate it into amino acid sequences AUG is the starting protein Central Dogma of Molecular Biology The coded genetic information hard wired into DNA is transcribed into individual transportable cassettes composed of RNA mRNA each mRNA cassette contains the program for synthesis of a particular protein or small number of proteins Biology 151 Stem Cells Embryonic Stem Cells Embryonic stem cells are derived from embryos mostly from eggs fertilizes in vitro not in a woman s body Cells whose job is to divide and create more cells and differentiate into cells with specialized functions Differentiated cells cannot divide How they are Grown in a Lab Cell culture 1 Transferring cells to a lab culture dish medium 2 Cells divide and spread 3 The inner layer of the dish is coated with mouse embryo skin cells Feeder layer 4 Novel methods eliminate the use of mouse embryos 5 If cells survive they are removes and put in a new culture dish Subculturing Identifying Embryonic Stem Cells Characterization 1 Growing and subculturing for months and remaining undifferentiated 2 Determining transcription factors Nanog and Oct 4 3 Determining particular cell surface markers 4 Examining chromosomes to asses damage 5 Determining whether cells can be regrown or subcultured 6 Testing whether the cells are pluripotent by a Allowing them to differentiate in cell culture b Manipulating the cells to differentiate to 3 germ layers c Injecting the cells into a mouse for teratoma How are Embryonic Stem Cells Stimulated to Differentiate If cells are grown appropriately they remain unspecialized If cells are allowed to clump they differentiate embryoid bodies To Generate Speci c Differentiated Cells Change the chemical composition of the medium Alter the surface of the culture dish Modify the cells by inserting genes Hematopoietic Stem Cells Derived from mesoderm red bone marrow and give rise to all other types of blood cells Stem Cell Classi cation Differentiate into all cell types Differentiate into almost all types Differentiate into closely related Totipotent Fertilized egg Pluripotent Embryonic stem Multipoint types of cells Difference Between Stem Cells Differentiated Cells Stem Cells Can undergo cell division Can become different types of cells Terminally Differentiated Cells Cannot undergo cell division Cannot differentiate further Perform speci c bodily functions Similar DNA but different gene expression Stem Cell Development Oocyte Morula Blastocyst Inner Cell Mass Sperm Totipotent Unipotent Pluripotent Medically Relevant Types of Stem Cells 1 Embryonic Stem Cells ESC 2 Induced Pluripotent Stem Cells iPS Cells Come from Inner Mass of Blastocyst Pluripotent Adult cells that have been genetically reprogrammed to a stem cell like state by being forced to express genes that de ne properties of stem cells Needed for tissue repair i e Bone Marrow 3 Adult Stem Cells Properties of Quiescent Stem Cells Not dividing Not differentiating Expressing self renewal receptors and transducers but no signal of self renewal yet Fertilized Eggs Newly fertilized eggs are ultimate stem cells because they can become almost any other cell in the human body Some people may have ethical issue with this because the egg eventually develops into a fetus After 5 days of fertilization the egg becomes a blastocyst and they are no longer totipotent a Outer layer Can only become extra embryonic stem cells b Inner layer Can only become cells within the body phosphorylate each other at multiple sites proteins bind and become active Cell Signaling Signal Transduction and Differential Gene Expression 1 Cells receive signals that tell them what to do how to behave and where to go 2 One signal can be received by several receptors 3 Signals may cause different outcomes from different cell types Cell Signaling and Signal Transduction Process Receptor Kinases 1 Receptor receives signal molecule binds to extracellular portion of the receptor which causes the receptor to partner up with another RK Dimerization 2 Dimerization activates kinase domains of paired receptors causing them to 3 Adding the phosphate groups provides places on the receptor where other 4 Transcription factors are activated which affects gene expression 5 The response is terminated so the cell can receive new signals Signal Ampli cation Any time there are enzymes and multiple steps involved in the transduction cascade the signal can be ampli ed What Does Phosphorylation Do to Proteins Turns proteins on and off Causes molecule s chemicals to change Protein structure function How Receptors Work Receptor activation occurs after a signaling molecule binds to the binding site of the receptor a kinase adds a phosphate group to another molecule in a process called phosphorylation usually this causes a protein to be active and on Protein Binding When two proteins bind to form a functional unit