Cellular Respiration

Cellular Respiration

Definition: the creation of energy in the form of ATP from organic (usually glucose) molecules

Simplified, cellular respiration is

C6H12O6 (aq) + 6 O2 (g) → 6 CO2 (g) + 6 H2O (l) + 36 ATP (eukaryotic cells)

ΔG = -2880 kJ per mole of C6H12O6

Steps in Cellular Respiration

Three steps make up the process of cellular respiration:

1.Glycolysis, which occurs in the cytosol2.Kreb’s Cycle (or citric acid cycle) in the

mitochondria3.Oxidative Phosphorylation (electron transport

chain), also in the mitochondria

Glycolysis

AnimationWhat you need to know:1. Occurs in the Cytosol (cytoplasm)2. Breaks up glucose into pyruvate3. Yields 2 ATP molecules4. This would be fermentation

(anaerobic respiration)5. Forms NADH to move to next step

Kreb’s (or citric acid) Cycle

AnimationWhat you need to know:1. Occurs in the mitochondria2. CoEnzyme A facilitates

beginning of this cycle3. Releases CO2

4. Yields 2 ATP Molecules5. Yields NADH and FADH2

5. Breaking and formation of bonds releases energy

Oxidative Phosphorylation

AnimationWhat you need to know:1. Occurs in the cristae of the

mitochondria2. NADH carries the electrons

to start the chain, NAD+ goesback to the citric acid cycle

3. ATP Synthase transports H+ to form ATP from ADP

4. Releases H2O5. Yields 34 ATP Molecules

How to get Energy?????

• Anaerobic Respiration: when only glycolysis phase is completed and 2 ATP are released. This will happen when there is a lack of oxygen (process of making alcohol)

• Aerobic Respiration: complete respiration in the presence of oxygen, yielding 36 ATP (some of the energy is used in the cycle) in eukaryotic cells and 38 ATP in prokaryotic cells

(Bonus: Why is that??????)

Fermentation in Yeast

Yeast, yes the stuff used in bread to make it rise, often undergoes fermentation reactions.

How can you design an experiment to see if the amount of sugar will effect the rate of anaerobic respiration? Observe the materials in front of you and think about the products of cellular respiration to help you do this.

You will need to create a graph that represents your data, but collect data as a class! You may use excel to create your graph in the formal write up this time.