3.4 Cell Respiration

POINT > Define cell respiration POINT > Describe the two stages of respiration POINT > Show the equation for respiration POINT > Compare respiration with photosynthesis POINT > Describe two types of fermentation

POINT > Define cell respiration In respiration cells use oxygen (O2) to get energy from carbohydrates (like glucose) The energy contained in glucose is released in a form the cell can use for many functions (ATP) Remember that the energy in glucose came from the sun during photosynthesis

POINT > Describe the two stages of respiration The first stage of respiration is called glycolysis Glycolysis happens in the cytoplasm and does not require oxygen

POINT > Describe the two stages of respiration During glycolysis, glucose is split into two smaller molecules, releasing some energy as ATP The cell can use ATP for many functions

CHECK: What is respiration? What is the first stage of respiration? Where in the cell does glycolysis happen? What happens during glycolysis? What is chlorophyll? What part of the cell is where photosynthesis happens? Does glycolysis require oxygen?

POINT > Describe the two stages of respiration The second stage of respiration takes place in the mitochondria and requires oxygen This is where most energy from glucose is released

POINT > Describe the two stages of respiration The molecules from glycolysis diffuse into the mitochondria and enter the Krebs cycle:

POINT > Describe the two stages of respiration The Krebs cycle produces more ATP and releases carbon dioxide (CO2)

POINT > Describe the two stages of respiration Molecules produced in the Krebs cycle enter more reactions that produce lots of ATP This is why the mitochondria are the “powerhouse” of the cell

CHECK: Where does the second part of respiration happen? What is produced during the second part of respiration? Which produces more ATP, the first part or the second part of respiration? What types of organisms use photosynthesis? What types of cells have a cell wall? What is a prokaryote?

POINT > Show the equation for respiration C6H12O6 + 6O2  6CO2 + 6H2O + energy Glucose + oxygen  carbon dioxide + water + energy (ATP) Does this equation look familiar?

 ATP POINT > Compare respiration with photosynthesis The equation for photosynthesis: light energy + 6CO2 + 6H2O  C6H12O6 + 6O2 The equation for respiration: C6H12O6 + 6O2  6CO2 + 6H2O + ATP energy The energy from the sun is changed into ATP for the cell!  ATP

CHECK: What are the products of respiration? What are the reactants for respiration? What is ATP? What is a heterotroph? What are stomata?

POINT > Compare respiration with photosynthesis The products of photosynthesis C6H12O6 + 6O2 are the reactants for respiration: C6H12O6 + 6O2  6CO2 + 6H2O + ATP (energy)

POINT > Describe two types of fermentation If there is no oxygen, the second part of respiration can not happen Without oxygen, most of the energy in glucose cannot be used by the cell Some cells can get a little energy from glucose using fermentation There are two types of fermentation...

POINT > Describe two types of fermentation 1. Alcoholic fermentation: yeast and/or bacteria use glucose to produce alcohol and CO2 This is used for making bread, beer and wine. The holes in bread and bubbles in beer are caused by carbon dioxide release

CHECK: What organisms use alcoholic fermentation? What is produced by alcoholic fermentation? What causes the holes in bread and the bubbles in beer?

POINT > Describe two types of fermentation 2. Lactic acid fermentation: Bacteria and muscle cells produce lactic acid through fermentation This is used to make cheese and yogurt

CHECK: What organisms use lactic acid fermentation? What is produced by lactic acid fermentation? Does fermentation require oxygen? What cell structure performs cell respiration? What is something you can eat that is made by fermentation?

Homework: Read pages 91-94 S.A. page 94 #1-2 GRAS pages 47-49