Chemistry

Cellular Respiration Stage 1: Glycolysis What?s the point? The point is to make ATP! ATP Glycolysis Breaking down glucose ?glyco ? lysis? (splitting sugar) ancient pathway which harvests energy where energy transfer first evolved transfer energy from organic molecules to ATP still is starting point for ALL cellular respiration but it?s inefficient generate only 2 ATP for every 1 glucose occurs in cytosol glucose ? ? ? ? ? pyruvate 2x 6C 3C In the cytosol? Why does that make evolutionary sense? That?s not enough ATP for me! Evolutionary perspective Prokaryotes first cells had no organelles Anaerobic atmosphere life on Earth first evolved without free oxygen (O2) in atmosphere energy had to be captured from organic molecules in absence of O2

* Chapter 4 Carbon and the Molecular Diversity of Life * Carbon Chemistry Carbon is the Backbone of Biological Molecules (macromolecules) All living organisms Are made up of chemicals based mostly on the element carbon Figure 4.1 * Carbon Chemistry Organic chemistry is the study of carbon compounds Carbon atoms can form diverse molecules by bonding to four other atoms Carbon compounds range from simple molecules to complex ones Carbon has four valence electrons and may form single, double, triple, or quadruple bonds * The bonding versatility of carbon allows it to form many diverse molecules, including carbon skeletons (a) Methane (b) Ethane (c) Ethene (ethylene) Molecular Formula Structural Formula Ball-and-Stick Model Space-Filling Model H H H H H H H H H H H H H H C C C C C

Organic Compounds The Structure and Function of Macromolecules Biological Molecules The study of carbon compounds, organic chemistry, focuses on any compound with carbon (organic compounds) Proteins, DNA, carbohydrates, and other molecules that distinguish living matter from inorganic material are all composed of carbon atoms bonded to each other and to atoms of other elements Carbon Atoms Carbon is building block of molecules Carbon has 4 valence electrons Can form 4 covalent bonds Tetravalence by carbon makes large, complex molecules possible Carbon Skeletons Carbon chains form the skeletons of most organic molecules The skeletons may vary in length and may be straight, branched, or arranged in closed rings. The carbon skeletons may include double bonds.