1. Photosynthesis and Respiration Two processes that are necessary for all life to exist on this planet Ultimately all energy comes from the sun and in must be converted into a usable form for living organisms

3. Photosynthesis and Respiration Plants depend on photosynthesis to derive their energy sources. Through evolution, plant cells have acquired chlorophylls to help carry out the photosynthetic reaction. Photosynthesis is carried out in two steps the photo stage (light dependant reaction) and the synthesis stage (light independent stage)

4. Photosynthesis Occurs in specialized organelles called chloroplasts These contain pigments which are specialized molecules that absorb specific colors of light. Main pigments are chlorophyll (green), xanthophylls (red) and carotene (yellow/orange)

5. Chloroplasts It is within the chloroplast that photosynthesis occurs The pigments absorb the light energy but it requires many enzymes to carry out the process of photosynthesis

7. Photo Stage The main purpose of this stage is to convert the sun’s energy into a form that can be used in the synthesis stage of photosynthesis Chlorophyll molecules arranged within the thylakoid membranes in clusters called photosystems Each photosystem is composed of a few hundred pigment molecules that act together Their combined function is to concentrate the sun’s energy so it can be converted to a form that the plant can use

8. (cont’d) When the energy reaches the reaction centre it us used to break water into 2 hydrogen and an oxygen molecule Enzymes in the thylakoid break the hydrogen atoms into protons and electrons This released energy is used to covert ADP and P into ATP ATP is required for the next stage of photosynthesis

9. Synthesis stage The main purpose of this stage is to make simple sugars by using energy from the photo stage and carbon dioxide The synthesis stage of photosynthesis takes place in the stroma (the fluid portion of the chloroplast) Energy from the photo stage is necessary to drive the synthesis of simple sugars

10. (cont’d) There are many separate reactions that make up the synthesis stage of photosynthesis and they are collectively called the Calvin cycle

12. Photosynthesis Through this process, the plant is able to convert sunlight, water, and CO 2 into glucose and ATP. As a byproduct of this process, O 2 is released. The plant's ability to convert water and CO 2 into glucose and O 2 also provides great benefit for animal species that depend on glucose for energy. The photosynthetic reaction can be summarized as follows: 6CO 2 + 12H 2 O + sunlight -> C 6 H 12 O 6 + 6H 2 O + 6O 2

13. Respiration Cells, like all things, need energy to operate. MP3 players use batteries for energy, cells use adenosine triphosphate (ATP) for energy. Unlike MP3 players, cells can produce their own energy. People don't eat ATP, though. Their food consists mostly of proteins, lipids, and polysaccharides (sugars) which need to be broken down into ATP.

15. Respiration Respiration can be either aerobic (in the presence of oxygen) or anaerobic (in the absence of oxygen). Anaerobic respiration may also be called fermentation. In both cases the process begins with the initial breakdown of glucose through the process of glycolysis.

16. Cellular Respiration The four basic phases of respiration are : –Glycolysis –Transition Reaction –Krebs Cycle –Electron Transport chain Each phase is a series of complex reactions that results in the production of ATP (chemical energy for the cell)

17. Aerobic Respiration The end products of glycolysis undergoes further breakdown through a process called aerobic respiration in most organisms. This process requires oxygen and yields much more energy than glycolysis.

18. Aerobic Respiration The end result of ATP would be the production of 36 ATP The energy conversion is as follows: C 6 H 12 O 6 + 6O 2 -> 6CO 2 + 6H 2 O + energy (ATP)

19. Anaerobic Respiration Occurs in aerobic organisms when there is a lack of oxygen This type of respiration is very inefficient – only 2 ATP are produced The product of this type of respiration is lactic acid and 2 ATP When we exercise strenuously our muscles perform this type of respiration It is the lactic acid that build up in the muscle that causes pain after this type of exercise

21. Global Importance Read pages 86 – 91 Answer questions 2,3,4,5