Photosynthesis Biology Chapter 8.1 & 8.2 PDF

PHOTOSYNTHESIS  ENERGY & LIFE  Energy = the ability to do work  WHERE do organisms get the energy from?  Food  Are all organisms able to make their own food?  NO AUTOTROPHS EXAMPLES Organisms able to synthesize their own food using the raw mate...

PHOTOSYNTHESIS  ENERGY & LIFE  Energy = the ability to do work  WHERE do organisms get the energy from?  Food  Are all organisms able to make their own food?  NO AUTOTROPHS EXAMPLES Organisms able to synthesize their own food using the raw materials in their environment E.g.-plants, some protists, some bacteria These are the producers  AUTOTROPHS, CON’T. PHOTOAUTROPHS- use the energy of the sun to help make food CHEMOAUTOTROP HS-use chemicals in their environment, not the sun, to help make food  HETEROTROPHS Organisms NOT able to synthesize their own food using the raw materials in their environment E.g.-animals, some protists, some bacteria, fungi These are the consumers Autotrophs & Heterotrophs, con’t. Autotrophs & Heterotrophs, con’t.  ENERGY  You may think of light, heat or electricity  The energy that is useful for us is stored in the chemical bonds of the food we eat  When these bonds are broken, molecules of ATP are produced  ATP = the energy storage molecule of the cell  ATP  ATP = adenosine triphosphate  This molecule is very efficient at transferring energy, but not at storing it; so cells don’t have a large supply of it.  Is this a problem?  NO. The cell is quite able to produce ATP as needed.  ATP, CON’T. Composed of a N- containing adenine, a ribose sugar and 3-phosphate groups  ATP, ADP & AMP  The ATP molecule has 2 high-energy bonds associated with its phosphate groups  When one of these bonds is broken and the phosphate group is transferred to another molecule, energy is released  This process is called phosphorylation (the transfer of a phosphate group from one molecule to another)  ATP, ADP & AMP, CON’T. When ATP loses a phosphate group, it becomes ADP. ADP = adenosine diphosphate This is represented as ATP  ADP + P ADP has one high-energy bond associated with its phosphate groups. When ADP loses a phosphate group, it becomes AMP. AMP = adenosine monophosphate This is represented as ADP  AMP + P AMP has NO high-energy bonds.  ATP, ADP & AMP, CON’T.  The phosphate groups can be removed from or added to these molecules as needed by the cell.  This is a very efficient way of transferring energy around the cell.  IMPORTANT NOTE: phosphate groups can be added to or removed from molecules other than the ones just discussed. SCIENTISTS & PHOTOSYNTHESIS  Photosynthesis – the process whereby organisms use the energy from the sun to convert carbon dioxide and water into glucose and oxygen.  OVERALL EQUATION: 6 CO2 + 6 H2O  C6H12O6 + 6 O2 carbon water glucose oxygen dioxide  Jan van Helmont (1643) Question: As a tree grows, does its increase in mass come from the soil, the water or the air? CONCLUSION: Trees gain most of their mass from water.  Joseph Priestley (1771) CONCLUSION: Plants release a substance needed to keep the candle burning – that substance is oxygen.  Jan Ingenhousz (1779) CONCLUSION: Aquatic plants produced oxygen bubbles in the light, not the dark; therefore, plants need sunlight to produce oxygen. THE CHLOROPLAST  CHLOROPHYLL This is the photosynthetic pigment of green plants. (We’ll be focusing on green plants for our discussion of photosynthesis.) It is found in the thylakoid membranes of the chloroplast. There are 5 types of chlorophyll: chlorophyll a most common forms chlorophyll b chlorophyll c chlorophyll d bacteriochlorophyll CHLOROPHYLL, CON’T.  Each type of chlorophyll can capture a different wavelength of light.  Chlorophyll is an example of a PIGMENT: a molecule able to absorb a particular wavelength of light.  Chlorophylls a and b absorb wavelengths of light that are blue and red the best; green is reflected, hence plants look green. CHLOROPHYLL, CON’T.  WHAT happens to all of the other colors of the rainbow?  CAN plants absorb any of these?  YES, because plants have accessory pigments. These pigments absorb wavelengths of light that chlorophyll can’t.  LIGHT  Sunlight travels through space in the form of waves.  The portion we “see” makes up the visible spectrum (the colors of the rainbow; white light).  REMEMBER: light is a form of energy, so when a plant absorbs light, it is absorbing energy. LIGHT, CON’T.  LIGHT, CON’T. Wavelength ( λ ): distance between the midpoint of one crest (or trough) and the next Frequency: the number of crests that pass a given point per second RELATIONSHIPS: a short λ = high frequency a long λ = a low frequency  ACCESSORY PIGMENTS Carotene = orange Xanthophyll = yellow