Energy In A Cell

1. Energy In A Cell Cellular Respiration Photosynthesis

2. The Need for Energy • All cells use energy for life processes. • Potential energy is stored energy. Ex: compressed spring. • Kinetic energy is energy in motion. Ex: moving parts in an engine. • Chemical energy- energy contained in chemical bonds and released by chemical reactions; Ex: energy from food, gas, batteries, any combustible fuel

3. Where do cells get energy? Food (chemical energy) • What is the original energy source for most organisms? Sunlight (electromagnetic energy) • Autotrophs- (producers) make their own food from the sun’s energy. Ex: Plants • Heterotrophs- (consumers) organisms unable to make their own food; they depend on other organisms for a source of food. Ex: animals, fungi

4. Autotroph Sun Heterotroph

5. II. Thermodynamics A. The study of energy (heat dynamics). B. There are two thermodynamic laws that govern all the activities of our universe. One applies to this unit. 1. First law of thermodynamics: a. energy cannot be created or destroyed b. It can change forms or move through a system, which organisms rely on c. Generally, biological energy is lost to the biospherein the form of heat, which decreases the amount of energy at each step

6. Reactants- the substance that changes during a chemical reaction; what the reaction starts with • Products- the substance resulting from a chemical reaction; what is produced at the end of a reaction • In photosynthesis and cellular respirations, these arrows/reactions only travel in one direction, so: • Left of the arrow is reactants • Right of the arrow is products

7. Energy for Life Processes • There are 2 stages in the passage of energy from the sun to the cells: • Stage 1: Photosynthesis • The process of plants taking CO2 from the atmosphere along with water from the soil to produce O2 gas and glucose • This process converts sunlight into chemical energy.

8. Energy for Life Process Cont. • Stage 2 Cellular Respiration • The process of taking oxygen gas from the atmosphere and glucose from food molecules to produce CO2, H2O, and energy in the form ATP. • **This process occurs in the mitochondria and the cytoplasm of cells.** • This process does not occur in prokaryotes, since they do not have mitochondria. Cellular Respiration takes in food to give us energy!! This player really needed ENERGY!

9. State Test Question • Many cell processes cannot directly use the energy from food. Which organelles covert food energy to a form that can be used by the cell? • Endoplasmic reticulum • Golgi body • Ribosomes • Mitochondria

10. Energy For Life Processes Cont. • Most organisms depend on cellular respiration and photosynthesis to provide energy directly or indirectly. • The alternation of photosynthesis and cellular respiration results in the continuous recycling of CO2 and O2.( carbon & oxygen cycles)

11. Metabolism: • set of chemical reactions that takes place in cells to maintain life • Conversion of energy within a cell ATP: • Main form of energy used by cells of living organisms • Stores and releases SHORT TERM energy • Made when organisms break down food (chemical energy) like glucose, starch, and other sugars/carbohydrates

12. ATP (Adenosine Triphosphate)- Stores/ & ReleasesEnergy • ATP is found in all living things, and it is able to absorb energy and release it when needed by a cell. • There are 3 parts of the ATP molecule: 1. Adenine-a nitrogen containing molecule 2. Ribose-a 5-carbon sugar 3. 3 phosphate groups *The adenine combines with ribose to form adenosine.*

13. State Test Question Energy from food sources drives the production of ATP. Why is this molecule essential in all living cells? • It is the main energy source for most cellular processes. • It is the basis of DNA. • It is a structural component found in cell walls. • It is required for osmosis and diffusion.

14. Some related terms: • AMP (Adenosine Monophosphate)- identical to ATP except it has 1 phosphate group. • ADP (Adenosine Diphosphate)- identical to ATP except it has 2 phosphate groups. Cells have more ADP molecules than ATP because of constant energy transformations. • ATP (Adenosine Triphosphate)- The bond holding together the last 2 phosphates is a high-energy bond. When the bond is broken, a tremendous amount of energy is released for use by the cell. After the bond is broken, the remaining molecule holds only two phosphate groups. It is now called ADP. ADP can absorb energy from carbohydrates in food, use this energy to add another phosphate, and become ATP again. ATP allows the cell to use its energy a little at a time.

15. Some uses of ATP (energy) • Active transport (endocytosis, exocytosis, sodium-potassium pump) • Move organelles inside cells • Transmit nerve impulses & contract muscles • Photosynthesis (plants) to make glucose

16. BOOM! A – P ~ P~P A – P ~ P ~ P A – P ~ + Energy ATP ADP + Energy Note: When a bond is broken, energy is released. When cells break down food molecules, some of the energy in the molecules is released as heat. Much of the remaining energy is stored temporarily in molecules of ATP. High Energy Bond *Energy is stored in high energy bonds

17. State Test Question ATP is continuously regenerated from ADP when energy released by cellular respiration is used in an endergonic reaction. Energy stored in food is released when— • chemical bonds are broken. • atomic nuclei are split. • elements combine. • electrons are produced.

18. State Test Question ATP is called the energy currency for cells because it— • is a constantly renewing source of energy. • is the ultimate source of energy on Earth. • is the exchange molecule for energy transfers. • provides energy for exergonic reactions.

19. State Test Question The process of breaking down ATP to ADP is termed— • fermentation. • an exergonic reaction. • an endergonic reaction. • a synthesis reaction.

20. State Test Question Energy for most cellular processes is obtained by breaking a bond between which two components of ATP? • Phosphate and nitrogen • Phosphate and carbon • Phosphate and adenosine • Phosphate and phosphate

21. State Test Question Which of the following is needed to transfer and release energy? • Calcium • Phosphate • Nitrate • Potassium

22. State Test Question Energy stored in food is released when— • chemical bonds are broken. • atomic nuclei are split. • elements combine. • electrons are produced.

23. Photosynthesis: Photosynthesis provides energy for almost all life. • Chemical Equation: • 6CO2 + 6H2O+ sunlight C6H12O6 + 6O2 • Word Equation: • Carbon dioxide plus water plus light energy yields glucose sugar and oxygen • Photosynthesis Occurs in 2 Phases: • Phase 1 is the light reaction • Phase 2 is the dark reaction (The Calvin Cycle)

24. Chloroplasts: • the site of photosynthesis • Chlorophyll: green, photosynthetic pigment that converts light energy into chemical energy (glucose) for later use producing oxygen as a byproduct • Thylakoids: stacks of flattened sacs containing photosynthetic membranes that contain clusters of chlorophyll, protein, and other pigments; where light reactions take place • Granum: stack of thylakoids

25. Photosystems: energy capturing elements of thylakoids in chloroplasts • Stroma: watery fluid surrounding thylakoids in chloroplasts; where Calvin cycle takes place • Not all photosynthetic organisms are green. Red and brown algae (protists) rely on other pigments for photosynthesis • Some bacteria like cyanobacteria are also photosynthetic

27. Phase 1. The light reactionor light-dependent reaction • Occurs in thylakoids • Stage 1: Sunlight energy excites electrons in photosystems (chlorophyll, protein, & accessory pigments) • Stage 2: Light energy is converted to chemical energy • Once electrons are energized in the photosystems, water is split (photolysis) • Photolysis releases oxygen into the atmosphere as a byproduct • The rest of the hydrogen ions and electrons attach to the carrier molecule NADP+ (making it NADPH+) in the electron transport chains (ETC) • ETCs convert ADP into ATP (storing chemical energy in the bonds between phosphate groups)

29. State Test Question The light-dependent reactions of photosynthesis use the Sun’s energy to produce— • glucose. • chemical energy. • carbon dioxide. • water.

30. The light reaction (Stage 1 and 2) produces the O2 gas and the energy ATP+NADPH for the Dark reaction-Calvin cycle.

31. State Test Question In the light-dependent phase of photosynthesis, energy from the Sun is used to drive the production of which of the following molecules? • Proteins • Carbohydrates • ATP • ADP

32. State Test Question The process of photosynthesis produces sugar, water and— • hydrogen gas. • nitrogen dioxide gas. • carbon dioxide gas. • oxygen gas.

33. State Test Question The glucose produced during photosynthesis is an example of a— • lipid. • monosaccharide. • protein. • nucleic acid.

34. State Test Quesiton When excess sugar is produced in a plant, the plant will— • release the sugar into the soil. • convert the sugar into minerals. • store the sugar by forming larger molecules. • burn the leaves of the plant as it releases energy.

35. State Test Question Because most plants are able to undergo photosynthesis, they do NOT— • require carbon dioxide. • store energy for later use. • undergo cellular respiration. • depend on other organisms for energy.

36. State Test Question Photosynthesis begins when sunlight causes chlorophyll molecules to— • produce sugars. • absorb carbon dioxide. • emit oxygen. • emit electrons.

37. State Test Question In photosynthesis, light energy from the Sun is stored in the bonds of— • lipids. • carbohydrates. • proteins. • enzymes.

38. State Test Qustion What are the raw materials for photosynthesis? • CO2 and H2O • H2O and O2 • C6H12O6 and O2 • C6H12O6 and H2O

39. Phase 2: The Dark Reaction: Calvin Cycle or light independent reaction • CO2 enters the leaf through hundreds of small porescalled stomata • CO2 combines with ATP, NADPH+, and hydrogen ions to form C6H12O6-glucose (stores chemical energy long term) • carbohydrates can be combined to make complex carbohydrates like sucrose (disaccharide) & starch (polysaccharide) in which energy is stored for later use. So, this excess sugar is stored for use later. • Plants can use excess sugar for growth & development • ***The dark reaction-Calvin cycle produces the organic compound C6H12O6-glucose

41. The Calvin cycle takes place in the stroma of the chloroplast • Remember the Calvin cycle deals with Carbon (turning CO2 into C6H12O6) • Carbon fixation is when inorganic carbon is turned into organic carbon, which occurs in photosynthesis in the Calvin cycle

42. State Test Question What are the main products of photosynthesis? • Glucose and oxygen • Glucose and water • Carbon dioxide and water • Water and ATP

43. State Test Question During photosynthesis, energy from the sun is trapped in— • chemical bonds. • the nuclei of atoms. • enzymes. • Golgi bodies.

44. Cellular Respiration • All living cells require energy and undergo cellular respiration • The process of taking O2 gas from the atmosphere and glucose from food molecules to produce CO2, H2O and energy in the form of ATP. Cellular Respiration produces ATP. Food molecule are broken down to release the energy in their bonds. Glucose is the energy source for cellular respiration. Respiration occurs in the cytoplasm; glycolysis) in the mitochondria (Citric Acid Cycle/ Krebs’ Cycle.)

45. Gives off Carbon Dioxide Takes in Oxygen Gives off water Takes in Glucose from food molecules Releases energy in the from of ATP Cellular Respiration

46. Metabolic process that require oxygen are called aerobic. (Krebs cycle, ETC) • Metabolic process that do NOT require oxygen are called anaerobic meaning “without air”. (glycolysis & fermentation) • Chemical Equation: • C6H12O6 + 6O2 6CO2 + 6H2O + ATP Cellular Respiration Aerobic respiration = oxygen Sore muscles = anaerobic respiration

47. State Test Question Most organisms exhibit aerobic respiration which requires— • oxygen. • carbon. • nitrogen. • hydrogen.

48. State Test Question In which of the following places would you most likely find anaerobic organisms? • Freshwater streams or rivers • The intestinal tract of animals • Warm, humid habitats • Cold, dry habitats

49. Word equation: • Glucose plus oxygen yields carbon dioxide, water, and energy • Cellular Respiration (Aerobic Respiration with Oxygen) Occurs in 3 phases: • Phase 1 is Glycolysis (Anaerobic) • Phase 2 is the Citric Acid Cyle/Kreb’s Cycle (Aerobic) • Phase 3: Election Transport Chain (Aerobic)