Chapter 15 Energy Flow

1. 04 Organisms obtain energy in a variety of ways 04.1 Explain the importance of photosynthesis in the conversion of light energy to chemical energy as illustrated by the following equation: Chapter 15 Energy Flow

2. Some organisms use the radiant sun’s energy to synthesise large molecules- photosynthesis • Autotrophs or more correctly photo-autotrophs • Some can obtain energy form inorganic chemical reactions- chemo-autotrophs • Photosynthesis largest most important manufacturing process • 160 billion tonnes per year produced-organic matter • 1/3 rd in the ocean • ¼ tropical rain forests • Chlorophyll is the pigment in green plants that is responsible for photosynthesis-chloroplasts • Some prokaryotes can photosynthesis- no chloroplasts- chlorophyll attached to the plasma membrane • While chlorophyll is the most prevalent- other pigments are photosynthetic • Rhodophyll –red • Chrysophyl –gold • (seaweeds) • -Photosynthesis is complex- many reactions • -some need light/not all do • -all reactions collectively – THE CALVIN CYCLE ( details not required) • MOST GREEN PLANTS ARE GREEN BECAUSE THEY REFLECT GREEN LIGHT • THEREFORE THEY ABSORB RED AND BLUE ENDS OF THE SPECTRUM

3. Photosynthesis • Production of simple sugars from simple molecules and sunlight • Transported in plants as SAP • Converted to polysaccharides- mostly starch which can be stored for later use • A few vegies store starch in the leaves- spinach • Carrots in the roots • Celery in the stems • Apples store starch and sugars in the fruit • RATE OF PHOTOSYNTHEIS: • Influenced by • Volume of carbon dioxide available • Temperature • Light- intensity/wavelength • 04 .2 Understand that heterotrophs rely on existing organic molecules for their nutrition • Heterotrophs: • Rely on other organisms for food source • Three groups: • Predators, bacteria &fungi,-decomposers, parasites

4. Need to process the nutrients form what they eat Digestion- already covered 04.3 Explain how most autotrophs and heterotrophs transform chemical energy for use through aerobic respiration as illustrated by the following equation: Heterotrophs….

5. Stored in chemical bonds that hold atoms together • Bigger molecules-more stored energy • When broken- energy released in a more useful form by the cell • SIMPLY: • Food eaten-reacts with air we breathe-smaller molecules produced-energy needed for life • Glucose the chemical which reacts to produce energy in the presence of oxygen- cellular respiration • Quite efficient • Results in quite harmless waste products- CO 2 AND WATER Energy cannot be created or destroyed: only transformed

6. Process of respiration in several steps Process is glycolysis Six carbon glucose broken down in half –forms two pyruvate Further breakdown then occurs (citric acid cycle) more carbon bonds broken waste product CO2 is formed Each steps involves energy released and transferred to ATP New products with less energy are made/formed Glycolysis occurs in the cytoplasm Glycolysis:

7. Occurs in the mitochondria Most active cells have the most amount of mitochondria- i.e. muscle cells/sperm cells Mitochondria have folded membranes to increase surface area and facilitate rapid processing Produces 38 molecules of ATP- for every 1 glucose molecule About 40% of energy is extracted- quite efficient compared to cars (only 10-20%) of energy in petrol is converted to efficient motion Remaining steps-Cellular respiration

8. aerobic resp always needs oxygen • when no oxygen available- respiration can still occur- less energy produced- FERMENTATION • TWO TYPES: • Alcohol fermentation- plants/yeast/bacteria + energy 04.4 Explain that fermentation is an anaerobic alternative to aerobic respiration

9. Does not occur when oxygen present • Ethanol is poisonous- accumulation will kill organism • Brewers need to maintain suitable levels • In baking- yeast converts sugar to alcohol and carbon dioxide- causes the bread dough etc. to rise- (alcohol is burnt off/evaporates in the baking process) • Brewing- the alcohol and carbon dioxide are dissolved- important parts of the drink- beer and wine • Distillation- increases the concentration of ethanol- whiskey • LACTIC ACID AND FERMENTATION: • In animals fermentation can also occur • Less efficient- lactic acid produced-poisonous to cells • C6H1206 -> 2C3H603 + ENERGY

10. No carbon dioxide is produced • Lactic acid accumulates • Converted to lactate- can be dissolved in blood-carried to liver converted to pyruvate and respired aerobically • Fermentation important for animals that with a poor supply of oxygen • Seals, dolphins, whales • Humans can make good use of fermentation- sprint activities • Bacteria produce lactic acid- yoghurt/cheese • http://www.youtube.com/watch?v=00jbG_cfGuQ&ytsession=r_DYbCW3CXEC4FVH8u5SeLcOp-OX7Ms8Lwk2mz44uNoaWpAdO6SU_g26lvIgUTgdnE6ux8qWLUgQbNtPKdF0h5MJ2-zQZp5eoL9AB6kCg_7YUxMNhCRGPt1co8dLWYEDgOem2AXJJIlkaM_jWp4NiDA8y8o-t2vTIDuQ04pvo-KYwifbW_3GoUxkKfe_gS22cNM04DBZeZdCTGfkJNtbJBENwysxehUJwxoeVL9eu7uygUkFpTEzuXxXKwQHae0VtkbcKwk3uomyRX3YmSmex5o5o5PBRezATt8Ml3v4-cM

11. See page 147 (large book) Pretty well covered in previous video-can dot point by self if need. 04.4 know that much more energy is released through aerobic respiration than through fermentation Comparing aerobic respiration and fermentation.

12. 05.1 Understand that energy is required for growth, movement, repair and reproduction • Growth: requires uptake of materials by active processes into the cell and cell division • Energy required to join small molecules to larger ones • Synthesis or anabolic reactions • Enable elongation/differentiation 05 energy is required to maintain life

13. Occurs at different levels Proteins need to change their shapes- enzymes- and be actively transported across membranes Cytoskeleton needs to move chromosomes in cell division Membranes moves in exo and endocytosis Sperm and protists need to move/swim in watery environmentslarge organisms need to expend energy to move Movement:

14. Cells and tissues wear out- need replacing Skin cells replace every week or so Energy needed for repairs of broken bones/formation of scar tissue REPRODUCTION: Lots of energy required see fig 325 “cellular processes requiring energy” Repair: