Please take out paper for noted taking today Topics to be covered: Aerobic versus Anaerobic Comparing photosynthesis and respiration Aerobic respiration process Anaerobic respiration process (fermentation)

Cellular Respiration CHAPTER 4.4 AND 4.5

Cell Respiration Chemical energy is released when sugar is broken down to make ATP and oxygen is present. This process is almost a mirror image of photosynthesis. This process also has 2 stages. All this takes place in the mitochondria. But some cells have found a way to make this work even if there is NO oxygen present (that part is coming soon)

The chemical formula for cell respiration is basically the same as photosynthesis, you just reverse the order by swapping the reactants and products! Water

Differences between cell resp and photosynthesis CELL RESPIRATION  Takes place in mitochondria  Makes a lot of ATP  Used to make carbon dioxide and water and energy  Has two stages: Kreb’s cycle and Electron transport chain PHOTOSYNTHESIS  Takes place in chloroplasts  Makes a little ATP  Used to make sugars and oxygen from energy  Has two stages: Light dependent and light independent (Calvin cycle)

Remember this: Aerobic respiration ◦Process that requires oxygen in order to take place Anaerobic respiration ◦Process that requires NO oxygen to take place. Glycolysis ◦Process that splits glucose (6 carbon) into two 3 carbon molecules and makes 2 ATP. (this must take place before respiration can occur)

Stage 1 Known as the Krebs Cycle or the Citric Acid Cycle This is going to produce energy molecules that are used in the 2 nd part of cell respiration. 1.The 3-carbon molecules from glycolysis are broken down. 2.Small amount of ATP is made (for stage 2) 3.Carbon dioxide is given off as a byproduct

AKA: Kreb’s Cycle

Stage 2 Known as the Electron Transport Chain or oxidative phosphorylation 1.Energy is transferred to here from Krebs Cycle. 2.Oxygen is taken in. 3.Lots of ATP are made. 4.Water and heat are given off as byproducts.

Fermentation CHAPTER 4.6

Glycolysis This is where cells break apart 6 carbon sugars into 3 carbon sugars and makes 2 ATP. This does NOT require oxygen ◦Anaerobic This usually stops when oxygen appears. Fermentation allows this to continue so it can make energy for the cells to use. Yeast cells are great examples of organisms that have learned to used fermentation to continue the process of glycolysis

Fermentation Normally you maintain oxygen levels, but when you do hard work, your body can’t keep up the oxygen levels. This means you need a different energy source so you can still function. We use fermentation to continue glycolysis for energy.

Fermentation We’re going to study two different forms: ◦Lactic Acid Fermentation ◦Alcohol Fermentation Both forms use NADPH as it’s energy source. Remember: both of these are Anaerobic – They don’t need oxygen to work. There are actually 100’s of forms of this

Lactic Acid Fermentation 1.Glycolysis makes ATP (used for energy elsewhere) and NADPH 2.Pyruvates (3 carbon molecules) are formed 3.Energy is added and Pyruvates become Lactic Acid. This important byproduct is why your muscles hurt after you work them out.

Alcohol Fermentation 1.Glycolysis makes ATP (used for energy elsewhere) and NADPH 2.Pyruvates (3 carbon molecules) are formed 3.The pyruvates are broken apart and CO2 breaks off. 2 carbon molecule left behind. 4.2 Carbon molecule is alcohol. This is why breads become “fluffy” with time.

Uses Remember: Fermentation doesn’t make energy, it actually spends energy. Glycolysis makes the energy. Fermentation just helps this continue. Lactic acid fermentation – used for your muscles and some bacteria Alcohol fermentation – used for making breads, cheeses or by digestive bacteria.

In Summary You need to know the beginning and end products of cell respiration How are anaerobic and aerobic respiration different from each other? Do you see the differences and similarities between cell respiration and photosynthesis? What are the two systems taking place in aerobic cell respiration? (what’s happening during the Kreb’s cycle and the electron transport chain?) What is glycolysis and how is it used in these processes? How are lactic acid and alcohol fermentation different from each other?

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