Honors Bio - Unit 3, Concept 5

Cellular Respiraton

What is the goal of cellular respiration?

To convert the chemical energy in food (glucose) to chemical energy stored in ATP.

What is the chemical equation for cellular respiration?

C6H12O6  + 6O2  🡪  6H2O  + 6CO2 + Energy (ATP)

What are the reactants for cellular respiration?

Glucose and Oxygen

What are the products of cellular respiration?

CO2 and water as waste products, and the main product is Energy (or ATP)

What is the difference between aerobic and anaerobic respiration?

Aerobic respiration has oxygen to use.
Anaerobic respiration doesn't have oxygen to use.

How much ATP does Anaerobic and Aerobic respiration make each?

Anaerobic: 2-4 ATP
Aerobic: 36-38 ATP

What is the first stage in cellular respiration?

Glycolysis

What is Glycolysis?

A stage where glucose breaks down.

What happens during Glycolysis?

It's a 10 step process where the 6-C molecule of glucose is split in half, making 2 3-C molecules called pyruvate.

Where does glycolysis take place?

This stage takes place in the cytoplasm.

Does glycolysis need oxygen?

This first stage doesn't need oxygen. It is anaerobic.

How much ATP does glycolysis make?

It produces a net 2 ATP and 2 NADH molecules total.

* Tip: 1 glucose creates 2 NADH, 2 pyruvate molecules, and 4 ATP, but it uses 2 of that ATP to work at all. This means there's a net of 2 ATP.

What are the reactants and products of glycolysis?

Reactants: Glucose

Products: 2 ATP, 2 NADH, and 2 pyruvate molecules

What will move on from glycolysis and be released onto the next stage?

ATP, NADH, pyruvate will move on from this stage.

What happens after glycolysis?

The cell must make a decision on what type of respiration to continue to after it completes this stage.

• If there is O2 present, the cell will go through a 2-step process called aerobic respiration to gain energy.

• If there isn't O2 present, the cell will go through anaerobic respiration, aka fermentation, to gain energy.

What cycle goes on during aerobic respiration?

The Krebs/Citric Acid Cycle.

What is the purpose of Krebs Cycle?

This stage’s purpose is to make electron carriers (NADH and FADH2) to move on to ETC.

Where does the Krebs Cycle take place?

This stage takes place in the Mitochondrial Matrix.

What happens during the Krebs/Citric Acid Cycle?

8-steps of chemical reactions where 2 pyruvate molecules from glycolysis chemically convert to make 2 ATP (and some CO2, NADH, and FADH2) in this cycle.

Pyruvate from glycolysis has converted into acetyl-CoA during the Krebs Cycle. It has now entered the Citric Acid cycle.

* NAD+ and FAD act as electron carriers and become NADH and FADH2, and they carry electrons into the final step.

What is released as waste during the Krebs Cycle?

CO2 is released as a waste product.

How many times does the Krebs/Citric Acid Cycle happen?

This cycle happens 2 times - once per pyruvate.

What are the products of Citric Acid/Krebs Cycle?

8 NADH, 2 ATP, 2 FADH2, and 6 CO2 are the products of this cycle.

\*Note: The cycle happened twice. Each time it happens, half of these overall products are made. For example, that means 1 ATP and 3 CO2 are made each time.

What stage happens after the Krebs Cycle?

Electron Transport Chain (ETC) happens after this cycle.

Where does the ETC take place?

This takes place in the Inner Membrane of the Mitochondria (called cristae).

What happens during ETC?

A series of reactions using electrons & hydrogens carried by NADH & FADH2 - which were both made in the Krebs cycle - happen.

• Oxygen combines with electrons and H+ to make water.

• the enzyme ATP Synthase creates the ATP

What is made during ETC?

34 ATP and water is made during this stage

Why is the ETC so important?

This stage is so important b/c it makes the most ATP.

What reactants are in ETC (what does it use)?

NADH, FADH2, oxygen are used as reactants for this stage.

What are products of ETC?

Water and 34 ATP are products of this stage.

What are the 2 types of anaerobic respiration?

Lactic acid and Alcohol Fermentation are the 2 types of this.

Where does lactic acid fermentation occur?

This fermentation occurs in some bacteria and animal cells (like our muscles).

What happens during Lactic Acid fermentation?

Pyruvate from glycolysis converts into lactic acid and 2 ATP.

Where does Alcohol fermentation occur?

This fermentation occurs in yeast when there’s no oxygen.

What happens during Alcohol fermentation?

Pyruvate from glycolysis breaks down into alcohol, CO2, and 2 ATP.

What are examples of organisms that go through lactic acid fermentation?

Bacteria and animals (like humans!) are examples of organisms that go through this fermentation.

What are examples of organisms that go through alcohol fermentation?

Yeast is an organism (is it? It’s a thing that does, at least) that goes through alcohol fermentation.