Chapter 8 & 9 Photosynthesis & Cellular Respiration

8-1 Energy – ability to do work Energy – ability to do work W/out the ability to obtain & use energy, life would cease to exist W/out the ability to obtain & use energy, life would cease to exist Almost all energy comes from the sun directly or indirectly (*fill this into your notes*) Almost all energy comes from the sun directly or indirectly (*fill this into your notes*) Living things get energy from food Living things get energy from food

Autotrophs – organisms that obtain energy from sunlight or inorganic substances Autotrophs – organisms that obtain energy from sunlight or inorganic substances 1. most are photosynthetic 2. ex: plants, algae & certain bacteria Heterotrophs – obtain energy from food thru cellular respiration Heterotrophs – obtain energy from food thru cellular respiration Ex. Humans, animals, fungi Ex. Humans, animals, fungi

ATP Facts 1. Structure – nucleotide w/ 2 extra energy – storing phosphate 2. Energy is released when bonds holding phosphate groups together are broken 3. Energy is required for breaking the bond; more is released than used 4. ATP → ADP + P + Energy 5. Is the basic energy source of all cells 6. Most cells only have a small amount of ATP that lasts a few seconds 7. ATP is portable energy – delivered wherever needed in cell

Photosynthesis Photosynthesis- process by which light energy is converted to chemical energy Equation: 6CO 2 + 6H 2 O light C 6 H 12 O 6 + 6O 2 Carbon Dioxide + Water light Glucose + Oxygen Occurs in chloroplasts of plants & algae; cell membrane of certain bacteria Has 3 stages Requires carbon dioxide & water Some form starch which is stored in stems & roots

Light - radiation wavelengths Besides water & carbon dioxide, photosynthesis needs light & chlorophyll Sunlight contains all wavelengths of visible light Pigments – light absorbing substances found in plants & algae 1. absorb only certain wavelengths 2. reflects all others 3. types of pigment a. chlorophyll – primary pigment of photosynthesis *absorbs mostly blue & red light *reflects green & yellow light *two types – a & b b. carotenoids – pigments that absorb other wavelengths 4. Found in chloroplasts that absorb light = energy

The orange ring surrounding Grand Prismatic Spring is due to carotenoid molecules, produced by huge mats of algae and bacteria. Caretnoids absorb mostly green & blue reflects yellow & red Chlorophyll is found in high concentrations in chloroplasts of plant cells.

Factors that affect Photosynthesis Light intensity ; rate to a maximum value CO 2 concentration rate to a maximum point Temperature – enzymes that help the process work best in a temperature range. Any  or  of temperature will slow or stop the process Amount of water: shortage of water will slow or stop the process.

Cellular respiration- releases energy by breaking down food molecules Equation: Equation: C 6 H 12 O 6 + 6O 2 enzymes 6CO 2 + 6H 2 O + ATP Glucose + Oxygen enzymes Carbon Dioxide + Water + Energy Most foods contain usable energy stored in protein, carbohydrates and fats Most foods contain usable energy stored in protein, carbohydrates and fats Before this energy can be used, it must be transferred to ATP to release a little energy at a time Before this energy can be used, it must be transferred to ATP to release a little energy at a time Used by All Organisms Used by All Organisms Requires glucose & oxygen Requires glucose & oxygen Has two stages Has two stages

**Primary fuel a. is glucose – C 6 H 12 O 6 b. comes from starch & sucrose c. if necessary, can use fats, proteins & nucleic acids 2 Stages of Cellular Respiration Stage one – Glycolysis – breaking down glucose   Occurs in the cytoplasm   Produces carbon dioxide, water & energy   Glycolysis continues to produce ATP until all of the glucose is gone.  Produces 2 ATP

2 versions of Stage Two Aerobic –used when O 2 is present Anaerobic – (not in air) w/out O 2 Stage Two Aerobic respiration  Occurs in the mitochondria  Produces: CO 2 + H 2 O + 36 ATP Anaerobic respiration Fermentation – releases energy from food producing ATP in the absence of O 2

Lactic acid fermentation 1. Occurs in animals 2. With vigorous exercise, muscle cells use this process causing lactic acid to build up Lactic acid makes muscles have burning pain 3. Blood removes lactic acid with time 4. Prokaryotes uses this process to make cheese, yogurt, sour cream, pickles & sauerkraut.

Alcoholic fermentation 1. Done by plants & fungi (yeast) 2. Products are ethyl alcohol & CO 2 3. Example: bread

Photosynthesis-Cellular Respiration Comparison Summary PhotosynthesisCellular Respiration FunctionCaptures energyReleases Energy LocationChloroplastsMitochondria ReactantsCO 2 H 2 0 C 6 H 12 O 6 O 2 ProductsC 6 H 12 O 6 O 2 CO 2 H ATP