BIOL 1543 1st Edition Lecture 5 Outline of Last Lecture I The Art of Looking at Cells II Life began on a young Earth III How did life form IV Other critical steps V Additional critical steps VI PROKARYOTES VII The two kinds of cells prokaryotic and eukaryotic VIII Size of a cell IX PROTISTS the early Eukaryotes X A model of the origin of eukaryotes XI An animal cell contains various membranous organelles XII Plant cells XIII The Endomembrane System XIV The Smooth Endoplasmic reticulum XV The Rough ER XVI The Golgi apparatus finishes sorts ships cell products These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute XVII Lysosomes are digestive compartments within a cell XVIII Vacuoles XIX The endomembrane system XX ENERGY CONVERTING ORGANELLES XXI Cell surfaces protect support and join cells Outline of Current Lecture I Energy is the capacity to perform work II Laws of Thermodynamics III Heat loss during energy transformation IV Chemical reactions either store or release energy V Cellular chemical reactions VI Amazing ATP VII Enzymes VIII Specific enzymes catalyze each cellular reaction IX Membranes X Membrane phospholipids form a bilayer XI Cell Membranes XII Passive tranport XIII Facilitated transport XIV Cells expend energy for active transport XV Exocytosis and endocytosis XVI Cellular respiration XVII Breathing XVIII Cellular respiration banks energy in ATP molecules XIX Stages of Cellular respiration XX Electron transport Current Lecture I Energy is the capacity to perform work a Energy can be used or stored b Energy can be changed from one form to another c Thermodynamics is the study of energy transformations i transmutation transformation II Laws of Thermodynamics a Four laws i zero law 1 in a thermodynamic system if system A B and C B A must C ii The First Law of Thermodynamics 1 Energy cannot be created or destroyed iii The Second Law of Thermodynamics 1 Energy transformations increase entropy disorder and some energy is lost as heat a entropy a measure of energy that is unavailable for useful work iv The Third Law of Thermodynamics 1 You can reach absolute zero 0 degrees Kelvin 2 Not important III Heat loss during energy transformation IV Chemical reactions either store or release energy a Endergonic store i reactions absorb energy and yield products rich in potential energy b Exergonic release i reactions release energy and yield products that contain less potential energy than their reactants V Cellular chemical reactions a Cells carry out thousands of chemical reactions Cellular metabolism is the sum of all these reactions i the sum of endergonic and exergonic reactions b Energy coupling is the process of using energy produced by exergonic reactions to fuel endergonic reactions c Cellular work is sustainable because ATP is a renewable resource that cells regenerate VI Amazing ATP a ATP shuttles chemical energy and powers nearly all forms of cellular work b The energy in an ATP molecule lies in the bonds between its phosphate groups c Phosphorylation transferring a phosphate group to make molecules more reactive is the work done by ATP d go from charged ATP to not charged ADP VII Enzymes a Enzymes types of proteins speed up the cell s chemical reactions by lowering energy barriers b For a chemical reaction to begin reactants must absorb some energy called the energy of activation c An enzyme can act as a catalyst and decrease the energy of activation needed to begin a reaction i if you add an enzyme it lowers the barrier makes it more expedient to get stuff done easier for the process to move forward VIII Specific enzymes catalyze each cellular reaction a Enzymes have unique three dimensional shapes that determine which chemical reactions occur in a cell b every enzyme will not catalyze every reaction i they are unique ii goes from disaccharide polysaccharide poly or di sucrose to monosaccharides monomers isomers through hydrolysis IX Membranes 5 10 15 a A Membrane is a thin pliable layer of tissue covering surfaces or separating areas within a cell b Membranes organize the chemical activities of cells i Membranes provide structural order for metabolism ii The plasma membrane of the cell is selectively permeable controlling the flow of substances into or out of the cell 1 Three primary substance flows a Nutrients flows out in b waste flows in out c Chemical information flows both ways X Membrane phospholipids form a bilayer a Phospholipids i Have a hydrophilic water loving head and two hydrophobic water hating tails ii Are the main structural components of membranes b Phospholipids form a two layer sheet called a phospholipid bilayer with the heads hydrophilic facing outward and the tails hydrophobic facing inward XI Cell Membranes a A membrane is a fluid mosaic with proteins and other molecules embedded in a phospholipid bilayer XII Passive tranport a Passive transport is diffusion across a membrane Substances diffuse through membranes without work by the cell spreading from areas of high concentration to areas of low concentration b Small nonpolar molecules such as O2 and CO2 diffuse easily across the phospholipid bilayer of a membrane i this occurs without work and flows from greatest concentration to least concentration XIII Facilitated transport a Transport proteins facilitate diffusion across membranes acts as a passage way with the flow greater to lesser concentration b Many kinds of molecules do not diffuse freely across membranes For these molecules transport proteins provide passage across membranes through a process called facilitated diffusion i done without expending work XIV Cells expend energy for active transport a Transport proteins can move solutes against a concentration gradient through active transport which requires ATP energy i energy is required to move against the flow XV Exocytosis typeA and endocytosis typeB a Exocytosis expelled moves molecules outside of cell and endocytosis out to in brings molecules into the cell transport large molecules or particles through a membrane b A vesicle may fuse with the membrane and expel its contents exocytosis c Membranes may fold inward enclosing material from the outside endocytosis d Cool Fires Attract Mates and Meals i Fireflies use light to send signals to potential mates instead of using chemical signals like most other insects chemical energy to light energy ii The light comes from a set of chemical