8 Aerobic Cellular Respiration and Fermentation

Cellular Respiration

process where sugar molecules are broken down inside the cells. It releases energy that can be harnessed to make ATP.

What are the coenzymes that are electrons carriers during cellular respiration?

NAD+ and FAD

How does the electron transport chain work?

• It is found in the cristae of the mitochondrion (I-IV)

• NAD+ gives e- to complex I and FAD to II

• complexes accept e- and pass them on as they release energy to surroundings 

• as they release energy, it causes complexes to pump H+ across the membrane against concentration gradient

• at complex IV, e- pass to O2 and combine with H+ to form H2O. 

• Oxygen is final e- acceptor

What are the three stages of cellular respiration? 

1. Glycolysis 

2. Citric Acid Cycle 

3. Oxidative Phosphorylation

Glycolysis

• oxidizes glucose (6C) into pyruvate 2(3C) & ATP

• occurs in cytosol 

• 2 ATP, 2 NADH, 0 FADH2, 0 CO2

• substrate level phosphorylation

What is the molecule in glycolysis that will move to the next phase? 

Pyruvate

Oxidation of Pyruvate 

• pyruvate is converted into Acetyl-CoA

• First: since pyruvate loses a C and turns into acetyl, 2 CO2 is released

• Second: To get lost electrons, 2 NADH are made

• Third: Coenzyme A attaches to Acetyl

What is the overall job of the Citric Acid Cycle?

• to oxidize glucose in the matrix of mitochondria

• creates 2 ATP, 6 NADH, 2 FADH2, 4 CO2

• substrate level phosphorylation

Which molecules actually enter the CAC cycle?

Acetyl, NAD+, FAD, Oxaloacetate, Citric Acid

Explain oxidative phosphorylation

• After NADH and FADH2 transport e- to complexes I and II, it gets left at complex IV at the O2 to make H2O.

• The energy from e- causes H+ transportation

• after H+ is transported to the intermembrane space, it comes to complex V

• Chemiosmosis : H+ activates the ATP synthase (channel protein)

• H+ flows through by facilitated diffusion

• exergonic flow of H+ drives the formation of ATP synthesis (phosphorylation)

Name 2 types of fermentation and describe them

Alcohol fermentation: end result is ethanol

Lactic Acid fermentation: end result is lactate

What type of organism perform each type of fermentation?

alcohol: yeast

lactic: bacteria

What happens to NADH during fermentation? Why is this important? 

the electron carrier is involved with 2 chemical reactions. It is responsible for picking up lost electrons from glycolysis and then they give those electrons to reduce pyruvate into lactic acid. Without it, glycolysis cannot happen.

Where does lactic acid occur in the human body? What is the purpose of it?

It occurs in the human muscles. The purpose is to get larger amount of energy when O2 is running low.

Is the full oxidation of glucose—anabolism or catabolism? —ender or exergonic—-negative or positive?

catabolism, exergonic, negative triangle G

Synthesis of proteins—anabolism or catabolism? —ender or exergonic—-negative or positive?

anabolism, endergonic, positive

Breakdown of glycogen—anabolism or catabolism? —ender or exergonic—-negative or positive?

catabolism, exergonic, negative

Synthesis of ATP via substrate level phosphorylation—anabolism or catabolism? —ender or exergonic—-negative or positive?

anabolism, endergonic, positive