Results for "lipid bilayer"

Cell Membrane Parts

Lecture 3-1: The Lipid Bilayer

endomembrane system Semi-autonomous organelles Protein sorting to organelles Systems biology of cells Cell Biology & Cell Theory Cell biology: The study of individual cells and their interactions. Cell Theory (Schleiden & Schwann, with contributions from Virchow): All living organisms are composed of one or more cells. Cells are the smallest units of life. New cells arise only from pre-existing cells through division (e.g., binary fission). Origins of Life: Four Overlapping Stages Stage 1: Formation of Organic Molecules Primitive Earth conditions favored spontaneous organic molecule formation. Hypotheses on the origin of organic molecules: Reducing Atmosphere Hypothesis: Earth's early atmosphere (rich in water vapor) facilitated molecule formation. Stanley Miller’s experiment simulated early conditions, producing amino acids and sugars. Extraterrestrial Hypothesis: Organic carbon (amino acids, nucleic acid bases) may have come from meteorites. Debate exists over survival after intense heating. Deep-Sea Vent Hypothesis: Molecules formed in the temperature gradient between hot vent water & cold ocean water. Supported by experimental evidence. Alkaline hydrothermal vents may have created pH gradients that allowed organic molecule formation. Stage 2: Formation of Polymers Early belief: Prebiotic synthesis of polymers was unlikely in aqueous solutions (water competes with polymerization). Experimental evidence: Clay surfaces facilitated the formation of nucleic acid polymers and polysaccharides. Stage 3: Formation of Boundaries Protobionts: Aggregates of prebiotically produced molecules enclosed by membranes. Characteristics of a protobiont: Boundary separating the internal & external environments. Polymers with information (e.g., genetic material, metabolic instructions). Catalytic functions (enzymatic activities). Self-replication. Liposomes: Vesicles surrounded by lipid bilayers. Can enclose RNA and divide. Stage 4: RNA World Hypothesis RNA was likely the first macromolecule in protobionts due to its ability to: Store information. Self-replicate. Catalyze reactions (ribozymes). Chemical Selection & Evolution: RNA mutations allowed faster replication & self-sufficient nucleotide synthesis. Eventually, RNA world was replaced by the DNA-RNA-protein world due to: DNA providing more stable information storage. Proteins offering greater catalytic efficiency and specialized functions. Microscopy Microscopy Parameters Resolution: Ability to distinguish two adjacent objects. Contrast: Difference between structures (enhanced by special dyes). Magnification: Ratio of image size to actual size. Types of Microscopes Light Microscope: Uses light; resolution = 0.2 micrometers. Electron Microscope: Uses electron beams; resolution = 2 nanometers (100x better than light microscopes). Light Microscopy Subtypes Bright Field: Standard; light passes directly through. Phase Contrast: Amplifies differences in light phase shifts. Differential Interference Contrast (DIC): Enhances contrast for internal structures. Electron Microscopy Subtypes Transmission Electron Microscopy (TEM): Thin slices stained with heavy metals. Some electrons scatter while others pass through to create an image. Scanning Electron Microscopy (SEM): Heavy metal-coated sample. Electron beam scans the surface, producing 3D images. Cell Structure & Function Determined by matter, energy, organization, and information. Genome: The complete set of genetic material. Prokaryotic vs. Eukaryotic Cells Feature Prokaryotic Cells Eukaryotic Cells Nucleus ❌ Absent ✅ Present Membrane-bound organelles ❌ None ✅ Yes Size Small (1-10 µm) Large (10-100 µm) Examples Bacteria, Archaea Plants, Animals, Fungi, Protists Prokaryotic Cell Structure Plasma Membrane: Lipid bilayer barrier. Cytoplasm: Internal fluid. Nucleoid Region: DNA storage (no nucleus). Ribosomes: Protein synthesis. Cell Wall: (Some) Provides structure & protection. Glycocalyx: Protection & hydration. Flagella: Movement. Pili: Attachment. Eukaryotic Cell Structure Nucleus: Contains DNA & controls cell functions. Organelles: Rough ER: Protein synthesis & sorting. Smooth ER: Lipid synthesis, detoxification. Golgi Apparatus: Protein modification & sorting. Mitochondria: ATP production (Powerhouse of the Cell™). Lysosomes: Digestive enzymes for breakdown & recycling. Peroxisomes: Breakdown of harmful substances. Cytoskeleton: Provides structure (microtubules, actin filaments, intermediate filaments). Plasma Membrane: Regulates transport & signaling. Endomembrane System Includes: Nucleus, ER, Golgi apparatus, lysosomes, vacuoles, and plasma membrane. Nuclear Envelope: Double membrane structure. Nuclear pores allow molecule transport. Golgi Apparatus: Modifies & sorts proteins/lipids. Packages proteins into vesicles for secretion (exocytosis). Lysosomes: Contain acid hydrolases for macromolecule breakdown. Perform autophagy (organelle recycling). Semi-Autonomous Organelles Mitochondria Function: ATP production (cellular respiration). Structure: Outer & inner membrane (inner folds = cristae for increased surface area). Mitochondrial matrix houses metabolic enzymes. Chloroplasts (Plants & Algae) Function: Photosynthesis (light energy → chemical energy). Structure: Outer & inner membrane. Thylakoid membrane (site of photosynthesis). Contains chlorophyll. Endosymbiosis Theory Mitochondria & chloroplasts evolved from free-living bacteria that were engulfed by an ancestral eukaryotic cell. Protein Sorting & Cell Organization Co-translational sorting: Proteins destined for ER, Golgi, lysosomes, vacuoles, or secretion. Post-translational sorting: Proteins sent to nucleus, mitochondria, chloroplasts, peroxisomes. Systems Biology Studies how cellular components interact to form a functional system

Chapter 10, Biomembrane Structure: Lipid Bilayer, Membranelyco Proteins, Phospholipids, Sphinglolipids, Cholesterol

section 1: part 2 - lipid bilayers

Section 1: Lipid Bilayers

Section 1 Part B Lipid Bilayers

Chapter 3 bio lipid bilayer chart

Chapter 11 Lipid Bilayer

Membrane lipid bilayers consist primarily of ____. a. phospholipids b. cholesterol c. proteins d. saturated fatty acid

Ch 10 learning objectives Lipid bilayer & Membrane proteins

CSF CH 10A: Lipid Bilayer

Unit 2 Lectures 2, 3 & 4 - The Lipid Bilayer

Kartlar: Lipid Bilayer and Membrane Proteins | Quizlet

Dependant/ independent variables Independent- The variable being manipulated Dependant- The observed result of the independent variable being manipulated 3 Domains Prokaryotes, Eukaryotes, Archae 3 Types of Relationships Commensalism Parasitism Mutualism Scientific Hypothesis an idea that proposes a tentative explanation about a phenomenon or a narrow set of phenomena observed in the natural world. Difference between Archea/ Bacteria Archaea consists of three RNA whereas bacteria consists of single RNA. Quantitative/ Qualitative data Quantitative data is numbers-based, countable, or measurable Qualitative data is interpretation-based, descriptive, and related to language. Homeostasis Balance of the body Controlled Experiment In a controlled experiment, all extraneous variables are held constant so that they can't influence the results. Difference between Hydrophobic/ Hydrophilic Any substance that repels water Any substance that has an affinity for water Protons/ electrons/ neutron Protons- a subatomic particle with a positive electric charge Electrons- a negatively charged subatomic particle that can be either bound to an atom or free (not bound). Neutron- an uncharged atomic particle that has a mass nearly equal to that of the proton and is present in all known atomic nuclei except the hydrogen nucleus What a cation/ Anion Cations are ions that are positively charged. Anions are ions that are negatively charged. Isomers Chemical compounds that have identical chemical formulae but differ in properties and the arrangement of atoms in the molecule Picture of elements/ what's on valence electrons Valence electrons have negatively charged particles How many valence electrons are in shells 8 electrons What are examples of trace elements? zinc (Zn), copper (Cu), selenium (Se), chromium (Cr), cobalt (Co), iodine (I), manganese (Mn), and molybdenum (Mo). Different types of Bonds Covalent Bonds- one or more electrons shared between atoms Non-polar covalent: electrons are shared equally between nuclei Polar covalent- electrons shared equally between the nuclei Ionic Bonds- one or more electrons transformed from one to another Hydrogen Bonds- a weak bond between a partially positive hydrogen atom and a partially negative oxygen atom Cohesion/ Adhesion Cohesion- the attraction of molecules for other molecules of the same kind Adhesion- the sticking of molecules or surfaces to each other Radioactive Isotopes, Why are they used Radioisotopes are an essential part of medical diagnostic procedures. In combination with imaging devices that register the gamma rays emitted from within, they can be used for imaging to study the dynamic processes taking place in various parts of the body. Why is Water Important Water's role as a solvent helps cells transport and use substances like oxygen or nutrients. Properties of Water Water is polar Water is a solvent Water is less dense as a solid than a liquid What are reactions a process that converts one or more substances to another substance. .Why are trace elements important? function primarily as catalysts in enzyme systems What are Buffers Substances in the cells that help maintain a relatively stable pH What is the pH scale? a measure of how acidic/basic water is Find the molecular mass of something Atomic weight on the periodic table is equal to moles #/1m = x/ desired # moles Functional groups The shape of molecules directly affects their function Types of atoms, bonds A specific arrangement of atoms Difference between Hydraullisis/ Dehydration Dehydration- removes a water molecule from a new bond Hydrolysis- add a water molecule, breaking a bond Differentiate between Polymers/ Monomers A monomer is a molecule with low molecular weight that can combine with others of the same kind to form a chemical compound known as a polymer Different types of Proteins/ enzymes antibodies, contractile proteins, enzymes, hormonal proteins, structural proteins, storage proteins, and transport proteins Difference between plants and animals Plants are not mobile and animals are Cell membrane components Phospholipids, cholesterol, glycolipids, lipid bilayer, membrane proteins

ABI 103 Lipid Bilayer and Components

Chapter 10: Membrane Structure