BIO151 1nd Edition Lecture 8 Outline of Last Lecture - Cytoskeletono Filament typeso Polarityo Cellular motility- Structural Reinforcemento Intermediate Filamentso Cell wallsOutline of Current Lecture - Energy flow- Enzymes- Metabolic pathwayso Feedback inhibition- ATP- Mitochondria- Cellular Respirationo OverviewCurrent Lecture- Where does Energy come from?o Before life evolved, energy from sun would hit earth and radiate back as heato Now, once life evolved, energy gets borrowed and then leaves as heat energybetween this time period, life exists.o Autotrophs: “self feeding;” photosynthetic organisms; includes plants, algae, photosynthetic bacteria Primary producers Net accumulators of organic moleculesThese 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.o Heterotroph: “other feeding”; ultimately rely on primary producers for nutrients;cut into cycle - Enzymes: biological catalyst; most often protein, but sometimes RNAo Catalyst: helps reactions proceed, but neither created nor destroyed during the process How named: Prefix= substrate (reactants); what it’s working on- Suffix= always –ase; ei ATPase Can also be named by their action- Add phosphate groups: kinase- Takes off phosphate group: phosphorylateo Many pathways possible, varying size Final product  feedback inhibition  interacts with enzyme 1 to make process slow down Overall rate determined by enzyme 1o Enzymes function in metabolic pathways Regulation is important Ei. feedback inhibition form of – regulation where end product binds toturn off enzyme number oneAllostene: “other site” regulationo Long-Term Energy storage done by organic molecules: carbohydrates (mostly), fats, oils, sugar, starcheso Short-term energy storage: ATP (Adenosine triphosphate): a nucleotide because has phosphate, adenine, and ribose; takes a lot of energy to bond the phosphate groups (negative charge all close together); unstable; high energy bonds Another way of writing ATP: ADP ~ P (denotes high energy phosphate ATP used for cellular work ATP is the form of energy that’s most readily available to cells (ei. ATP used in muscle movement; can only last 1 minute if take away ATP regenerationregeneration is important)o Concept of Energy Charge ATP/ADP=Energy charge of a cell When ATP/ADP is low, the cell increases the rate of energy-releasing reactions, breaking down energy-rich long term storage forms (sugars, fats, oils) When ATP/ADP is high, cell decreases the rate of energy releasing reactions ATP: ADP ration regulates rate of regenerationo 2 Mechanisms or making ATP: Substrate-Level Phosphorylation: more ancient- X~P + ADP X+ADP~P (X=some organic molecule; ~=high energy bond)- Chemical bond energy on organic molecule  chemical bond energy on ADP- Direct transfer from high energy phosphate group Chemiosmosis: requires membrane gradient- ADP+P1ADP~P (P1=inorganic phosphate)- Enzyme: ATP synthase- Energy from membrane gradient  chemical bond energy occurs in: Prokaryotes (evolved in)- mitochondria and chloroplasts in eukaryotes (inherited it)- Evolutionary Historyo Mitochondrial features Many copies of small DNA 70S (smaller, as in bacteria [prokaryotic genes]) ribosome genes encoded in DNA are most closely related to bacterial genes (prokaryotic genes) unusual lipids in membrane (not just phospholipids) divide by spitting in halfo Features of Mitochondria support prokaryotic origino Formally expressed as the Endosymbiosis Hypothesis (inside interaction between 2 organisms)- Cellular Respiration (Eukaryotes) o Most efficient in the presence of O2 o Requires mitochondriao Overall reaction C6H12O6 (glucose-sugar) +6O2  6CO2 + 6H2O +ATP (lots)- Waste product is carbon dioxide and