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Food and energy

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  1. Food and energy

  2. Photosynthesis&Resipiration • Probably two most complex biological processes we do. • Deprived a living org of matter or energy or both and we eventually die • w/o photosynth – everything dies. Single most important process in the world.

  3. What is phtotsynth • Green stuff converts inorganic to organic. It’s pretty much that simple. • Then that matter gets passed through the food chains to other orgs

  4. Cellular resp • Occurs in both plants and animal cells. Breaking down organic compounds into smaller units with energy trapped in chemical bonds being released for use by cells or body tissues

  5. Energy storage and use - ATP • If ALL the energy in a sugar molecule was released it would generally be too much for most cell actions. • therefore, cells require smaller packets of energy to use effectively. • Cells use adenosine triphosphate (ATP) to store and then use for energy

  6. Decomp reaction breaks ATP down into ADP + P+ ENERGY • (what does that “D” stand for?) • ATP <> ADP + P + Energy

  7. photosynth • All processes involving sythesis or breakdown of matter fall under the heading metabolism • Anabolism – write that down – is the creation of organic matter • Canabolism – same thing – is the breaking down of organic matter to release stored energy

  8. Don’t eat for 10+ hours? Your body begins to canabolize muscle tissue. • Think starving yourself is a good way to ‘get toned’ – think again, your body will store foods as FAT and canabolize muscle tissue because it thinks you’re going to starve it again. And fat contains more calories, so it would be better to have stored fat in a starved situation than lots of muscle.

  9. The innitial organic items then become the building blocks/ sources of energy for other living tissue. Not just plants, but EVERYTHING • Green plants, make their own energy- autotrophs • Other orgs – heterotrophs –don’t

  10. Light & Photosynthesis • Little to no starch produces in plants that had zero, or low, light conditions. • You care, because starch indicates sugars • And sugars are the energy plants make

  11. example • What happens when you cover up the grass with a doghouse? • That green fuzzy stuff dies quickly!

  12. Light also promotes chlorophyl development, although we are not exactly sure how. • Stems leaves etc loose colour when they are stripped of light exposure. And, it does not come back. Why do you care? These plants will stop producing energy from sunlight

  13. Only ~ 1-3% of light hitting plants is converted into chem energy. • The rest bounces off or travels right through the surfaces doing nothing. • Artificial light DOES work (plants absorb mainly visible spectrum)

  14. 5 kinds of chlorophyll • A-e • A is most common • B is in algae and higher orders • Cde in other algae’s

  15. chlorophylls • Act in same way as a catalyst in a reaction • Do you know what a catalyst does? • They initiate and control rates of reactions • C02 & water are generally considered the “raw materials” for photosynth

  16. See “light dependent rx “ handout

  17. Conditions affecting phtosynth • External temps. Extreme heat or cold can stop it. • Lengths of light and dark periods. • If these are synched photosynth happens effectively. If not, it may slow down

  18. FYI • Speculation says that early earth plant conditions were prob oxygen deprived. Much of the 20% of atmosphere that is O2 now was created through photosynth

  19. chemosynthesis • Disect that word. What does it mean?

  20. That’s right Tyson – chemo (chemical) and synthesis (build) • These things can make energy from chemicals (such as sulfides/oxides) • Mainly bacteria near soil surfaces • These things are called chemotrophs

  21. Chemosynth is terribly inefficient and difficult and bacteria are just small dudes so this produces very little org matter

  22. Respiration: • Process involving the release of energy for cell activities • Catabolic part of metabolism

  23. In all living cells • Some in cytoplasm, most in mitochondria • Most common fuel is glucose, some starches or amino acids, or lipids

  24. Three parts: • Part 1: • Glycolosis: in cytoplasm • Glucose first broken down.

  25. Part 2: • Krebs citric acid cycle: • Few steps, glucose is completely dismantled

  26. Part 3: • Electron transport • H atoms & electrons moved along a series of carrier molecules. • Energy released • At this stage, Oxygen available has significant impact

  27. Stages: • Glycolosis is anerobic. no Oxy ~5% of overall energy • Process stops @ final stage if no Oxy present.

  28. Krebs: needs some Oxy. • About 10 steps • Lots of energy forms heat during this phase

  29. Electron transport • Oxygen most important here

  30. Anaerobic respiration • No/low oxygen • Limited number of orgs can do this • Bacteria mainly • Example: that food you left sealed in a container that stanks like crazy when you open it… probanearobic

  31. Results: • Lactic acid in animals • Alcohol in plants

  32. fermentation • Does not produce or release more energy • Lactic acid fermentation more common to aniumals (especially muscle cells) • Leads to muscle soreness and fatigue • Inability of body to supply oxygen fast enough.

  33. Resting allows oxygen to break down lactic acid • Ever gone running and legs hurt like nuts the next day? Probably contributed to both being out of shape/lazy and lactic acid pooling in your muscles. • Ex: sportcenter Ottawa Cenators riding bike after game always

  34. Both alcohol and lactic acid can be deadly in high Cn • Remember that on Friday night

  35. Release of energy also releases heat on most orgs. • Ex: you’re a warm blooded thing • In cold blooded animals & plants this is quickly lost to enviro • Lots of it goes to synthesis of cell parts/substances • Also motion

  36. summary • PS: • Green cells of plants • Begins w light • Requires water and carbon dioxide • Releases oxy • Radiant E converted to chem E • Organic matter produced

  37. Respriation: • All living cells • Takes place all the time • Required org matter and oxygen • Releases water and carbon dioxide • Chem E changed to heat or smaller units of E (ATP) • Org matter broken down