Photosynthesis and Cellular Respiration

Photosynthesis Photosynthesis is the process by which plants, some bacteria use the energy from sunlight to produce sugar and starches ……which cellular respiration converts into ATP, the "fuel" used by all living things. ATP – a multifunctional nucleotide known as the “molecular currency” of intracellular energy transfer. - An energy source produced through the process of photosynthesis & cellular respiration -Transports chemical energy within cells.

Photosynthesis The conversion of unusable sunlight energy into usable chemical energy, is associated with the actions of the green pigment chlorophyll.

Photosynthesis The process of photosynthesis uses water and releases the oxygen that we absolutely must have to stay alive.

6H2O + 6CO2 ----------> C6H12O6+ 6O2 Photosynthesis We can write the overall reaction of this process as: 6H2O + 6CO2 ----------> C6H12O6+ 6O2 How does this chemical reaction relate to photosynthesis??

Leaves and Leaf Structure Plants are the only photosynthetic organisms to have leaves (and not all plants have leaves).

Leaves and Leaf Structure The raw materials of photosynthesis, water and carbon dioxide, enter the cells of the leaf, and the products of photosynthesis, sugar (C6H12O6) and oxygen, leave the leaf.

Leaves and Leaf Structure Water enters the root and is transported up to the leaves through specialized plant cells known as xylem

Leaves and Leaf Structure Land plants must guard against drying out and so have evolved specialized structures known as stomata to allow gas to enter and leave the leaf. Carbon dioxide cannot pass through the protective waxy layer covering the leaf (cuticle), but it can enter the leaf through an opening (the stoma; plural = stomata; Greek for (hole) flanked by two guard cells.

Leaves and Leaf Structure Likewise, oxygen produced during photosynthesis can only pass out of the leaf through the opened stomata. Carbon dioxide enters single-celled and aquatic autotrophs through no specialized structures.

The Nature of Light White light is separated into the different colors (=wavelengths) of light by passing it through a prism.

The Nature of Light The order of colors is determined by the wavelength of light. Visible light is one small part of the electromagnetic spectrum. The longer the wavelength of visible light, the more red the color. Likewise, the shorter wavelengths are toward the violet side of the spectrum.

Chlorophyll and Accessory Pigments A pigment is any substance that absorbs light. The color of the pigment comes from the wavelengths of light reflected, not absorbed. Chlorophyll, the green pigment common to all photosynthetic cells, absorbs all wavelengths of visible light except green, which it reflects to be detected by our eyes.

Chlorophyll and Accessory Pigments All photosynthetic organisms (plants and bacteria) have chlorophyll a. Accessory pigments absorb energy that chlorophyll a does not. Accessory pigments include chlorophyll b and carotenoids (such as beta-carotene). Both assist chlorophyll a by absorbing energy chlorophyll a does not.

The Structure of the Chloroplast and Photosynthetic Membranes The thylakoid is the structural unit of photosynthesis. Both photosynthetic prokaryotes and eukaryotes have these flattened sacs/vesicles containing photosynthetic chemicals. Only eukaryotes have chloroplasts with a surrounding membrane.

The Structure of the Chloroplast and Photosynthetic Membranes Thylakoids are stacked like pancakes in stacks known collectively as grana. The areas between grana are referred to as stroma.

Photosynthesis/Cellular Respiration Clips http://www.bing.com/videos/search?q=photosynthesis%2c+cellular+respiration+interrelatedness%2c+video&&view=detail&mid=1E8021619E1639B2F9381E8021619E1639B2F938&rvsmid=9C0730665607D9E7914C9C0730665607D9E7914C&fsscr=-1980&FORM=VDFSRV 1 http://www.bing.com/videos/search?q=photosynthesis%2c+cellular+respiration+interrelatedness%2c+video&&view=detail&mid=E54DF2CAFD8310123C84E54DF2CAFD8310123C84&rvsmid=9C0730665607D9E7914C9C0730665607D9E7914C&fsscr=-1980&FORM=VDFSRV 2 http://www.bing.com/videos/search?q=fermentation+video&view=detail&mid=2876BE6665E5F044A8502876BE6665E5F044A850&FORM=VIRE1 3 http://www.bing.com/videos/search?q=aerobic+and+anaerobic+respiration%2c+video&&view=detail&mid=BD00247669FEBECA3749BD00247669FEBECA3749&rvsmid=38D3E2B58A1C7F7119AF38D3E2B58A1C7F7119AF&fsscr=-2970&FORM=VDFSRV 4 http://www.bing.com/videos/search?q=aerobic+and+anaerobic+respiration%2c+video&&view=detail&mid=6688D71D5F491CE64E346688D71D5F491CE64E34&rvsmid=38D3E2B58A1C7F7119AF38D3E2B58A1C7F7119AF&FORM=VDFSRV 5

Cellular Respiration Cellular respiration – the transfer of energy from various molecules to produce ATP. This process occurs in the mitochondria of eukaryotes, the cytoplasm of prokaryotes. In the process, oxygen is consumed and carbon dioxide is generated. C6H12O6 + 6O2 --------> 6CO2 + 6H2O + 38 ATP

Cellular Respiration During Cellular Respiration, sugar is broken down to CO2 and H2O, and in the process, ATP is made that can then be used for cellular work. (Read Pg 13 1introduction) Cellular Respiration includes 2 steps: Glycolysis (anaerobic process) Aerobic respiration

Glycolysis Glycolysis – a biochemical pathway in which glucose is broken down into an acid and ATP to be used to run a cell. Reactions of glycolysis take place in the cytosol

Glycolysis

Glycolysis In glycolysis, if O2 is not available (anaerobic), some cells can convert pyruvic acid into other compounds through a process called fermentation Fermentation – a process that recycles NAD+, an electron carrier so the process of cellular respiration by producing a SMALL amount of ATP and NADPH for a cell to work.

Fermentation 2 Types of Fermentation: Lactic Acid Fermentation – process that helps make dairy products Alcoholic Fermentation – process used to make beer, bread, and wine

Aerobic Respiration Aerobic Respiration – a process in cellular respiration in which pyruvic acid is converted into CO2 and water when in the presence of O2, producing LARGE amounts of ATP to run a cell.

Efficiency of Cellular Respiration Cellular respiration can produce up to 38 ATP molecules from the oxidation of a single molecule of glucose. Most eukaryotic cells produce about 36 ATP molecules per molecule of glucose. Thus, cellular respiration is nearly 20 times more efficient than glycolysis alone.