1. The Working Cell: Energy From Food Chapter 7

2. Obtaining Food All organisms need food for energy.
Autotroph- Makes its own food (photosynthesis); producers
Plants, algae
Heterotroph- Cannot make own food; consumers
Animals
Must eat producers or other consumers

4. How do heterotrophs get energy from food?
Through Cellular Respiration
Makes energy for the cell by breaking down glucose
Uses oxygen to do this (why we need to breathe!)
Energy is in the form of ATP

5. Food Stores Energy Energy =The ability to perform work. 2 forms:
Kinetic Energy- energy of motion
Thermal energy- random molecular motion (heat)
Potential Energy- energy that is stored
Chemical Energy- ready to do work; due to arrangement of atoms

7. Calories: Units of Energy
Calorie- amount of energy required to raise the temperature of 1 gram of water by 1 degree Celsius.
Tiny number (too tiny to measure energy in food)
Energy in food is expressed in kilocalories
1 kcal = 1000 cal

8. Measuring the Energy Content of a Peanut
Burning peanut converts its stored chemical energy into thermal energy, releasing heat
Measure increase in water temp– calculate # of calories in a peanut
1 peanut has 5000 calories (5 kcal)
____ °C x ____ mL = ____ cal/ 1000 = ___ kcal

9. Do Cells “Burn” our food?
Use enzymes to break down organic molecules through cellular respiration, thus releasing energy.

10. Online Activities www.phsuccessnet.com
Complete online activities 7.1, 7.2, and ch. 7 prelab questions

11. Lab: Food as Fuel Calorimeter: Measures calorie content in food
We will be burning food to measure their calorie content.
Remember: 1000 cal = 1 kcal
Remember: Calorie- amount of energy required to raise the temperature of 1 gram of water by 1 degree Celsius.
Animation

12. Lab: Food as Fuel
The longer something burns, the more energy (kcal) it has.
Proteins/ carbs 4 kcal/g
Fats 9 kcal/g

13. ATP Adenosine Tri-Phosphate Stores energy
Provides energy for chemical reactions.

15. The ATP Cycle
ATP is continuously converted to ADP as your cells do work.
ATP is “recyclable”
Energy that makes this happen is from food

16. Mighty Mitochondria Mitochondria makes energy!
Site of cellular respiration in a cell
Cristae (folds) & matrix (thick fluid)

17. Cellular Respiration Converts energy in food to energy in ATP
glucose+ oxygen  carbon dioxide + water + energy
C6H12O O2  6CO2 + 6H2O + 38ATP

18. Try This…
The atoms in cellular respiration are merely rearranged by breaking the bonds.
Using the molecular model kits, model the process of cellular respiration.
C6H12O O2  6CO2 + 6H2O + 38ATP

19. Review 6 H2O C6H12O6 + 6O2  6CO2 + 6H2O + 36ATP Subscript: # of atoms
Coefficient: # of molecules
C6H12O O2  6CO2 + 6H2O + 36ATP

20. Lab Review
Lab- we burned food to release energy (different from our bodies… we use enzymes to do this)
The more fat, the longer it burned (what is this telling us?)
What is a calorie? A kilocalorie?

21. CR Review
Cellular Respiration is making energy (in the form of ATP) from glucose.
CR takes place in the mitochondria of cells (“mighty mitochondria”)
Activity with ball-and-stick models shows that atoms are neither created nor destroyed in CR, just rearranged to release energy.

22. glucose+ oxygen  carbon dioxide + water + energy
C6H12O O2  6CO2 + 6H2O + 38ATP

23. Three Stages of CR 1) Glycolysis (in CYTOPLASM of cell)
2) Krebs Cycle (in MITOCHONDRIA CRISTAE)
3) Electron Transport Chain (in MITOCHONDRIA MATRIX)

24. Glycolysis Glucose Pyruvic Acid + 2 ATP 2 ATP used to make this happen
Oxygen is NOT needed (anaerobic)

25. Krebs Cycle Cristae of mitochondria
Pyruvic Acid carbonic acid + CO2 + 2 ATP
Needs Oxygen!

26. Electron Transport Chain
Matrix of mitochondria
Most of the energy is made here!
Carbonic acid + O H2O + 34 ATP
Needs Oxygen!

27. Is it possible to make ATP without oxygen??

28. Fermentation in Human Muscle Cells
Long Distance Running– muscles regenerate ATP through CR
Sprint– lungs/blood can’t supply oxygen fast enough to make enough ATP!
How does this happen?? FERMENTATION- makes ATP without using oxygen

29. Lactic Acid Fermentation
Occurs in muscle cells
But only small amts of ATP made
Glycolysis still occurs
Glucose Pyruvic Acid + 2 ATP
Pyruvic acid CO2 + Lactic acid
Lactic Acid is what makes your muscles sore after a lot of hard exercise!

30. Training Improves ATP production
Weight lifting & sprinting = increase glycogen & lactic acid tolerance
Long-distance running= increase mitochondria & oxygen delivery to cells

31. Alcoholic Fermentation
No oxygen present in yeast cell environment
Ethyl alcohol produced instead of lactic acid
Pyruvic acid CO2 + ethyl alcohol

32. Cellular Respiration Lab
Cell Respiration- converting the chemical energy of organic molecules into a form immediately usable by organisms
What is this chemical energy called?
What is the usable form called?

33. Cellular Respiration Lab
All organisms, including plants and animals break down glucose for energy using oxygen.
Peas undergo CR during germination.

34. Germination of Peas
What does germination mean?

35. Cellular Respiration Lab
Today, you will be using the CO2 gas sensor to measure the rate of CR in germinating and ungerminating peas.

36. Lab Procedure
Do you expect the carbon dioxide levels to increase or decrease?
Will the rates be the same in the germinating and ungerminating peas?

38. 1 ATP
Organisms that make their own food are called ______________.

39. 1 ATP
Organisms that cannot make their own food and must obtain energy from the foods they eat are called _______________.

40. 2 ATPs
Cell respiration uses oxygen to convert the chemical energy stored in organic molecules into _________.

41. 3 ATPs
Energy is released from ATP when a ____________ is released.

42. 4 ATPs What is the chemical equation for cellular respiration? Hint:
Glucose + oxygen = carbon dioxide + water + energy

43. 2 ATPs
How many total ATPs are made as a result of cellular respiration?

44. 3 ATPs
What is the net gain of ATPs as a result of glycolysis?

45. 3 ATPs
List the steps of cellular respiration in order.

46. 3 ATP
The Krebs cycle starts with _____________ and yields carbon dioxide.

47. 2 ATP
What process is used to make bread rise?

48. 1 ATP
Is cellular respiration aerobic or anaerobic?

49. 1 ATP
Is fermentation aerobic or anaerobic?

50. 2 ATP
Where does lactic acid fermentation take place?

51. 2 ATPs
Where in the cell does glycolysis take place?

52. 2 ATPs
Where in the cell does the Krebs cycle take place?

53. 2 ATPs
Where in the cell does the electron transport chain take place?

54. 3 ATPs
Without oxygen, a cell can make only _______ ATPs from each glucose molecule.

55. 3 ATPs
Glysolysis converts glucose into 2 molecules of _____________.

56. 4 ATPs
What is the difference between kinetic and potential energy?

57. 4 ATPs
What is the definition of a calorie?

58. 1 ATP
# 4 is the __________ of the mitochondria.

59. 3 ATPs
The device used to measure the amount of calories in a piece of popcorn is called a __________.

60. 2 ATPs
There are __________ calories in a kilocalorie.

61. 2 ATPs
What is the function of ATP?

62. 4 ATPs
What does ATP stand for?

63. 3 ATPs
Most energy made from cellular respiration comes from this stage.

64. 2 ATPs
What makes your muscles sore after hard exercise?