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.

Atoms

Recall: Macromolecules BIG biological molecules Made of smaller parts Monomers Carbon-based (organic) Carbohydrates Nucleic acids Proteins Lipids

Carbohydrates Monomer: monosaccharide Used for: Examples: 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

Photosynthesis

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 Purpose: make sugars Events: CO2 is incorporated into C6H12O6 with H from H2O

Cellular Respiration

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: C6H12O6 is 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 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 Ethanol, CO2 produced Some bacteria, some fungus Ethanol, CO2 produced How yeast makes bread rise How alcoholic beverages are produced

Fermentation is useful

Carbohydrates: Big Picture

We eat more than carbohydrates…