Glycolysis Life needs energy to survive and function efficiently.

Cells need to harvest energy Energy needed to grow and function Unicellular organisms Ex. Yeast, bacteria Multicellular organisms Human body has 3 trillion cells

Chemical Energy: ATP “Energy currency” Adenine, ribose, and 3 phosphate groups Transfers energy from one source to another 3 rd phosphate group acts as energy ATP “active”: can donate extra phosphate group ADP 2 phosphate groups “non-active”: must go try to recruit a phosphate group

Metabolism All chemical activities in a cell or organism Two types Synthesis −Building large, more complex molecules −“uses” free energy Decomposition −“breaking down” rxn to smaller, simpler things −“releases” free and heat energy

Cell Respiration A type of decomposition Reaction A pathway Made up of several steps Generate energy by breaking down molecules Sugar first choice Also breaks down starch, fats, proteins

Sources of energy Carbohydrates Simple Sugars Broken down very fast Ex. Sucrose, glucose, fructose Starches Sugar units strung together Broken down into glucose first for energy Protein Lipids Glucose

Steps of Cellular Respiration Pathway made up of 3 major steps 1. Glycolysis 2. Kreb’s Cycle 3. Electron transport system

First stage in Respiration:Glycolysis Happens in cell cytoplasm a.k.a. “cytosol” Fluid filling cell Breaks down glucose into pyruvate

Starting Material: Glucose Common raw material C 6 H 12 O 6 Complex sugars get broken down by enzymes to make glucose CCCCCC

Step 1: Adding phosphates Enzyme converts glucose to glucose-6- phosphate 2 ATP needed for this step 1 ATP gives energy 1 ATP donates a phosphate group CCCCCCPP

Step 2: Breaks in Half Glucose-6-biphosphate unstable breaks down into two 3-carbon sugar- phosphates CCCP CCCP

Step 3:Form Pyruvate Enzymes rearrange and oxidize(remove electrons) to form 2 pyruvate A.k.a “pyruvic acid” Electrons add to NAD+ to make 2 NADH 4 ATP are produced(overview)overview CCC CCC pyruvate

Next step depends on O 2 After glycolysis, next step depends on oxygen Growing Yams in Australia Oxygen= normal aerobic respiration Creates more energy(ATP) No oxgyen=anaerobic respiration

Anaerobic respiration NO OXYGEN!!!! Produces less energy Starts with glycolysis Glucose breaks down into 2 pyruvate Does not continue on til Kreb’s cycle A.k.a “fermentation” Lactic acid fermentation Ethanol fermentation

PYRUVATE Lactate Ethanol Carbon dioxide

Anaerobic:Lactic acid fermentation Animal cells and some bacteria will reverse the rxn that produced pyruvate NADH and pyruvate become NAD+ and lactate(3-carbon acid) Yogurt: sour taste Sore muscles

:Anaerobic: Ethanol Fermentation Done by yeast and some bacteria “waste” products Ethanol Carbon dioxide Alcohol Bread

Bread: Ethanol Fermentation Add baker’s yeast Yeast perform anaerobic fermentation Produce carbon dioxide and ethanol Carbon dioxide gets trapped in gluten(protein in wheat) Air bubbles in bread Ethanol evaporates during baking Gives it that wonderful smell when baking

Aerobic Respiration There is oxygen!!! Pyruvate is transported to second step of respiration: The Kreb’s Cycle

Making Homemade Ginger Ale Ethanol fermentation Produces carbon dioxide and a unalcoholic form of ethanol Organism: yeast Dry baker’s yeast Used by bakers for making dough Add water to revive yeast Feed it sugar

Add 1 cup of sugar Add ¼ cup of dry yeast Mix by shaking Add 2 tbspoons of ginger to a cup Juice a whole lemon Stir lemon and ginger together

Add slurry of lemon and ginger to bottle Rinse cup with water and add to bottle Cap bottle and shake Fill bottle with clean, cool water Leave only an inch of air at the top Cap bottle and invert to dissolve sugar.