Lecture 17: Signal Transduction, ECM, Mitochondria Flashcards
Extracellular matrix (ECM) components..
Proteins, glycoproteins, proteoglycans - proteins with chains of polysaccharides
Functions of the ECM (4)
- Cell adherence
- communication between cells
- cell shape, mechanical support, structural integrity
- serves as barrier, filter out some particles
Anchor proteins role
- interacting with components of ECM
- helps with tissue formation and cell function
- communication between cells
Example of ECM
Skin, cell walls (plants)
What is signal transduction
Allows cells to rapidly respond to events happening in their environment, membrane proteins playa. Role in ST by converting extracellular signal to intracellular signals
Signal transduction allows cells to: (5)
- grow
- divide
- survive (or not)
- move
- differentiate
Ligand binding
Ligand binds to receptor on extracellular side, changes conformation of receptor protein in intracellular side of the cell which causes other proteins to be activated, doesn’t enter cell
Signal transduction steps:
- Binding of ligand to receptor
- Signal transduction via second messengers like cAMP, calcium or G-protein
- Cellular response: cellular growth, division, store glucose molecules
Glycogenolysis
Enzyme that acts as primer to polymerize first glucose molecules
Adrenaline (example of signal transduction)
Adrenaline activates conversion of glycogen stored in liver to glucose
Main function of mitochondria (2)
- ATP synth
- apoptosis
Main function of chloroplasts (2)
- photosynthesis
- ATP synth
Endosymbiotic theory
Organelles from eukaryotic cells with two membranes, represent formerly free living prokaryotes (mitochondria and chloroplast) into the cell to create an ancestral eukaryote
Supporting evidence of endosymbiosis theory
- Binary fission
- Circular DNA
Energy supplies
- Aerobic resp.: converts in the presence of oxygen energy stored in food molecules into chemical energy stored in ATP, produces CO2 and waste
- Photosynthesis: building carbohydrates using energy from sunlight and CO2
Mitochondria structure
- Outer Mitochondrial membrane (OMM)
- Inner mitochondrial membrane (IMM)
- aqueous compartments
Mitochondria: OMM
- contains enzymes with diversity
- contains porins - large channels permeable (passive diffusion) to many molecules when opened
Mitochondria: IMM
- 3 protein: 1 lipid
- double-layered folds called Chris yea; increase membrane SA and contain machinery for aerobic resp and ATP formation
- rich in phospholipid called cardiolipin; characteristic of bacterial membranes and needed for optimal function
Mitochondria: Matrix
- high protein content
- gel-like space containing mitochondrial ribosomes and mitochondrial genome (DNA)
What is cellular respiration?
- uses chemical energy stored in molecules such as carbs and lipids to produce ATP
- involves catabolic rxns
- cellular resp in presence of oxygen = aerobic respiration
What is substrate-level phosphorylation
- hydrolysis rxn releases enough energy to drive phosphorylation of ADP to ATP
What is oxidative phosphorylation?
- chemical energy of organic molecules is transferred first to electron carriers that is s used to create an electrochemical gradient that can power ATP synth
Oxidative phosphorylation produces about ____ percent of ATP in animals cells
88
NAD+ is _____ and NADH is ____
Oxidized, reduced
FAD is _____ and FADH2 is ____
Oxidized, reduced
Oxidative phosphorylation steps
- Generate an electrochemical gradient: ET through complexes I-IV and proton (H+) pumping, high-energy electrons pass from coenzymes (NADH and FADH2) in the matrix to electron carriers in IMM, series of intermediate electron carriers is the ETC. energy transfer at each complex used to pump H+ from matrix to inter membrane space. Ultimately, low energy electrons are transferred to terminal electron acceptor (O2) resulting in production of H2O.
- Proton movement down electrochemical gradient to power ATP synthesis
Catabolism
Breaking down molecules
Anabolism
Building up molecules
Substrate-level phosphorylation takes place in the…?
Cytoplasm
