Photosynthesis Cellular Respiration The opposite of photosynthesis Photosynthesis

Photosynthesis & Cellular Respiration

The opposite of photosynthesis!! Photosynthesis is making glucose n Cellular Respiration is breaking down glucose n

Cellular Respiration takes place in the mitchondria

Cellular Respiration n Recall…Energy stored in glucose cannot be used by the cell n Cellular Respiration converts sugar into ATP

3 steps for Cellular Respiration 1) Glycolysis 2) Krebs Cycle (Citric Acid Cycle) 3) Electron Transport Chain (ETC)

1) Glycolysis n n Occurs in the cytoplasm Glucose is split in half into 2 pyruvic acids & ENERGY is released. n NADH is produced (Goes to Electron Transport Chain) n 4 ATP are produced, but need 2 to get process started = 2 NET ATP

Turn to a Partner n Using the diagram, walk your partner through the steps of glycolysis What are the products of glycolysis? (3)

Where Pyruvic Acid goes depends on whether or not oxygen is present Stays in cytoplasm: Anaerobic Respiration Travels to mitochondria: Aerobic Respiration

In the presence on oxygen, pyruvic acid travels to the mitochondria The 2 NADH produced in glycolysis are shuttled directly over to the Electron Transport Chain

2) Krebs Cycle n (AKA Citric Acid Cycle) n Oxygen MUST be present n Occurs in the mitochondrial matrix (interior space of mitochondria).

2) Krebs Cycle 1. Pyruvic acid enters the mitochondria and is converted to citric acid

2) Krebs Cycle 2. Energy molecules (NADH and FADH 2) are produced to carry electrons to the electron transport chain.

2) Krebs Cycle. 3. CO 2 is released as waste; breathed out when you exhale 2 ATPs are produced

Turn to a Partner Using the diagram, walk your partner through the steps of the Krebs cycle What are the products of the Krebs Cycle? (4) n Which continue to the electron transport chain? n # of ATPs produced? n

NADH & FADH 2 Continue to the Electron Transport Chain

3) Electron Transport Chain (ETC) § Occurs in the cristae (inner membrane of the mitochondria) • (For prokaryotes it occurs in the cell membrane. )

3) Electron Transport Chain (ETC) 1. NADH & FADH 2 enter the cristae.

3) Electron Transport Chain (ETC) 2. They lose their hydrogens (H+) and electrons (e) to be shuttled through the ETC.

3) Electron Transport Chain (ETC) 3. Electrons are accepted by oxygen and combines with H+, forming water that is released into the cell

3) Electron Transport Chain (ETC) 4. H+ builds up inside the cristae and is passed through transport protein (ATP synthase) adding ADP and P to form ATP.

ETC continued… n ETC Produce 32 - 34 ATP n NOTE: 2 ATP are used by transport proteins to move NADH from glycolysis into the ETC. n This results in a Net Gain of 32 ATP from the ETC.

Turn to a Partner n What are the products of the ETC? (2)

Cellular Respiration Recap

What is the total # ATP from 1 molecule of glucose during cellular respiration? 36 ATP from Aerobic Respiration (=with Oxygen) 38% of total energy in glucose is held in the bonds of ATP produced 62% released as heat

Reactant? Product ? Reactant ? Word Bank: H 2 O Mitochondri a NADH & FADH 2 Krebs Cycle 2 Product ? Glucose Pyruvic Acid 2 O 2 ETC Cristae Glycolysis

What happens if cells do not receive enough oxygen?

Cornell Summary