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Carbohydrates. Honors Biology. Objectives. Use a model to illustrate how photosynthesis transforms light energy into stored chemical energy.
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Carbohydrates Honors Biology
Objectives • Use a model to illustrate how photosynthesis transforms light energy into stored chemical energy. • Construct and revise an explanation based on evidence for how carbon, hydrogen, and oxygen from sugar molecules may combine with other elements to form amino acids and/or other large carbon-based molecules. • Use a model to illustrate that cellular respiration is a chemical process whereby the bonds of food molecules and oxygen molecules are broken and the bonds in new compounds are formed resulting in a net transfer of energy.
Recall: Macromolecules • BIG biological molecules • Made of smaller parts • Monomers • Carbon-based (organic) • Carbohydrates • Nucleic acids • Proteins • Lipids
Carbohydrates • Monomer: monosaccharide • Used for: • Short term energy • Structural support • Cell tags (antennae) • Examples: • Fun fact: many carbohydrates have names that end in -ose
Monosaccharides • Simple (one sugar) carbohydrates • Example: glucose
Disaccharides • Simple (two sugars bonded) carbohydrates • Example: lactose
Polysaccharides • Complex (many sugars bonded) carbohydrates • Example: starch, glycogen, chitin
How do we get carbohydrates? • Photosynthesis • Creates glucose (C6H12O6) from CO2, H2O and sunlight Reactants Products
Why does life depend on photosynthesis? • Autotrophs are the basis of all Earth’s ecosystems • Provide food for all organisms (directly and indirectly) • Provide O2 and remove CO2 from atmosphere
How does photosynthesis happen? • The Details: • Series of 2 reactions: • Light Dependent Reactions • Location: chloroplast • Purpose: harvest solar energy to prepare to make sugars • Events: chlorophyll absorbs light, H2O is split, O2 is released • Calvin Cycle • Location: chloroplast • Purpose: make sugars • Events: CO2 is incorporated into C6H12O6 with H from H2O
How do we get energy? • From eating….unless you are a plant, right? • Not so fast… • Glucose (and other macromolecules) is not usable energy for cells • Glucose must be converted to usable energy (ATP)
ATP • Adenosine triphosphate • Molecule that is usable energy for cells • Energy is found in bonds between phosphate groups
ATP = Life’s Battery • ATP is a rechargeable molecule • Energy releasing reaction: • ATP loses a P • Adenosine diphosphate is left (ADP) • Energy is released for cellular use • Energy storing reaction: • P is reattached to ADP using energy from food • ATP is made again • Energy is stored for next time cell needs it
How do we make ATP? • Cellular respiration • Converts energy from glucose into ATP • Now cells can do work!
Why does life depend on cellular respiration? • Cells can’t use glucose as it is, must have ATP to function • This includes plant cells! • ALL cells must go through cellular respiration
How does cellular respiration happen? • The Details: • Series of 3 reactions: • Glycolysis • Location: cytoplasm • Purpose: begin breakdown of C6H12O6 • Events: C6H12O6is split, 2 ATP made • (glyco = sugar; -lysis = break) • Krebs Cycle • Location: mitochondria • Purpose: continue breakdown of C6H12O6 • Events: CO2 is released, 2 ATP made • Electron Transport Chain • Location: mitochondria • Purpose: complete breakdown of , C6H12O6 make ATP • Events: O2 is used, H2O is formed, 32-34 ATP is made
Aerobic Respiration • Cellular respiration with oxygen • Produces 36-38 ATP per glucose
Anaerobic Respiration • Cellular respiration without oxygen • Much less efficient at converting glucose to ATP • Occurs in 2 steps: 1. Glycolysis 2. Lactic Acid Fermentation (animals) OR Alcoholic Fermentation (plants)
Lactic Acid Fermentation • Animals • Some bacteria, some fungus • Lactic acid is produced • Why muscles are sore after a hard workout
Alcohol Fermentation • Plants • Some bacteria, some fungus • Ethanol, CO2 produced • How yeast makes bread rise • How alcoholic beverages are produced