Cells and Energy

1. Cells Lecture III Cells andEnergy Photosynthesis & Cellular Respiration

2. Biology Standards Covered • 1f ~ students know usable energy is captured from sunlight by chloroplasts and is stored from the synthesis of sugar from carbon dioxide • 1g ~ students know the role of the mitochondria in making stored chemical-bond energy available to cells by completing the breakdown of glucose to carbon dioxide • *1i ~ students know how chemiosmotic gradients in the mitochondria and chloroplasts store energy for ATP production

3. Photosynthesis • There are only two types of organisms on this planet • Producers – living things that make their own food as well as food for other living things • Consumers – living things that rely upon consuming another organism for food (energy) • What are you?

4. Photosynthesis • Producers • An example of a producer would be a plant and how it “makes” food could be through a process known as photosynthesis • This takes place in the chloroplast organelle inside of a plant cell

5. Photosynthesis • Photosynthesis– is the process of using energy from the sun to convert CO2and H2O into chemical energy in the form of sugars • Sunlight radiates the Earth as visible light that we see and is made up of many different colors (ROYGBIV) • Red, Orange, Yellow, Green, Blue, Indigo, and Violet

6. Photosynthesis • Chlorophyll is a molecule in plants that absorbs visible light from the sun • There are two types (Chlorophyll a and Chlorophyll b ) • Together they absorb mostly red and blue wavelengths of light while “reflecting” some yellow and much of the green • This is why you see plant leaves as “green” because of the ‘reflected’ color

7. Photosynthesis • Inside of the chloroplast are two structures important to photosynthesis • Grana– are stacks of membranes that look like a stack of pennies surrounded by compartments called thylakoids • Stroma – is the fluid surrounding the grana inside of the chloroplast

8. Photosynthesis • There are two stages to Photosynthesis • Light-dependent reactions (First) • Chlorophyll absorbs energy from sunlight and energy is transferred along thylakoids, Water is broken down and Oxygen is produced • Energy that is carried along thylakoids is transferred in molecules of ATP • Light-independent reactions (Second) • Carbon Dioxide is added to a cycle of chemical reactions building larger molecules of sugars • Energy, ATP, from the light-dependent reaction is used to form these simple sugars

9. Photosynthesis in a Chloroplast C6H12O6is Glucose, a simple sugar that feeds all living things CO2 (gas) is used to make the sugar Glucose

10. Photosynthesis in Chloroplasts

11. Cellular Respiration The mitochondrion and its role in providing plants and animals with energy

12. Chemical Energy for Organisms • ATP – Adenosine triphosphate • An energy rich molecule that provides all living things with energy for growth, repair, and maintenance • ADP – Adenosine diphosphate • Energy comes from the release of the 3rd phosphate of ATP • This creates ADP

13. What is ATP? • ATP is molecule that acts like a chemical form of electricity for all living things! • Without ATP, you could not move, think, breathe, or grow!

14. What is Cellular Respiration? • Cellular respiration is when chemical energy is released from sugars and other carbon based molecules to make ATP ~ when oxygen is present • This means that cellular respiration is aerobicin that it needs oxygen to take place

15. Energy Production’s 2 StagesGlycolysis & Cellular Respiration

16. How does it work? • Cellular Respiration (stage 2) takes place in a mitochondrion • Some cells have several • IMPORTANT! ~ Before cellular respiration can take place ~ • Food molecules MUST be broken down into simpler molecules • The break down of glucose into (2) 3~Carbon Sugars is called Glycolysis • Glycolysis occurs in thecytoplasm

17. Glycolysis 2 ATP are used to “start” Glycolysis and 4 ATP are made in the second stage. That means Glycolysis yields a “net” of +2 ATP 2 Pyruvic acid Glucose To the electron transport chain * Glycolysis is anaerobic because it does NOT require oxygen to take place! This happens in the cytoplasm

18. Cellular Respiration happens in the Mitochondrion 2 Pyruvate molecules from glycolysis go into Stage 1

19. The Kreb’s Cycle aka. Citric Acid Cycle • STAGE 1: The Krebs Cycle • During stage 1 the (2) 3~Carbon pyruvate molecules from Glycolysis enter the mitochondria • These molecules undergo a series of chemical reactions and a small amount of ATP is produced (2 ATP Molecules) • The waste product of the Kreb’s Cycle is 6 CO2 (Carbon dioxide) molecules • Energy is transferred to “power” Stage 2 of Cellular Respiration

20. The Kreb’s Cycle generates NADH and FADH2 that are fed into stage 2 ~ Electron Transfer Phosphorylation

21. Stage 2 of Cellular Respiration • Stage 2: Electron Transfer Phosphorylation • Energy from Glycolysis and the Krebs Cycle enter Stage 2 to “power” the reactions • NADH and FADH2 are “spent” to create a H+ ion gradient inside of a mitochondrion • When these protons, H+ ions, “rush back in” to the mitochondrion, it generates ATP! • Stage 2 makes 32 ATP molecules! • Glycolysis and the Kreb’s Cycle each only made 2

22. Cellular Respiration & Glycolysis

23. H+ Proton Gradient Formation The inner and outer compartments of the mitochondrion are where the H+ ions are “pumped” and allowed back in for ATP generation

24. H+ Proton Gradient Formation

25. ATP Generation through ATP Synthase