Topic 8- Cell Respiration

Question 1

Describe environmental energy cycling.

Answer 1

The idea that light energy captured by photosynthesis builds organic molecules, some of which go into cell respiration and are turned into ATP.

Question 2

What are redox reactions?

Answer 2

When one component gains electrons while other components lose electrons. usually uneven sharing of electrons

OIL RIG

Oxidation is Loss

Reduction is Gain

Question 3

Where does Cellular Respiration happen?

Answer 3

The Mitochondria

Question 4

NAD+ vs NADH

Answer 4

2 electrons and a hydrogen attach to NAD+ to make NADH

Question 5

What are the steps to Cellular Respiration?

Answer 5

1. Glycolysis
   Happens outside the cytoplasm and breaks Glucose down into 2 pyruvates and H2O.
   Also releases 2 NADH and 2 ATP.
2. Citric Acid/TCA Cycle-
   Happens in the mitochondrial membrane
   a. turns each pyruvate into 1 acetyl CoA and 1 CO2
   then enters the Citric acid cycle where the acetyl CoA is turned into 2 ATP, and 8 NADH, 2 FADH2, and 6 CO2
3. Oxidative Phosphorylation/Electron Transport Chain
   Happens in the inner mitochondrial membrane
   a. The NADH goes to protein complex 1 and FADH2 goes to protein complex 2 to drop off its electrons.
   b. Proteins are then passed from protein to protein where it slowly loses energy. As the electrons pass proteins 1,3, and, 4 it powers the proton pumps which builds a electrochemical gradient by pumping out hydrogen ions.
   c. Electrons have very little energy and are collected by oxygen which is the terminal electron acceptor.

Question 6

How do electrons move through the electron transport cycle?

Answer 6

As the energy of the electrons decreases the electronegativity of the proteins increases to pull the depleted electrons

Question 7

Why is oxygen a good terminal electron conductor?

Answer 7

Depleted electrons bond with o2 because it is very electronegative. The added electrons causes it to split into two oxygens which then bonds with hydrogen to make it stable. This produces H2O

Question 8

What is ATP synthase?

Answer 8

Enzyme that uses hydrogen ions flowing back into the cell as power to force as phosphate back onto ADP to make ATP. Produces around 28 ATP

Question 9

What are the ways Cell Respiration can happen without oxygen?

Answer 9

Fermentation:
When you produce ATP using just glycolysis. Because you only have a limited amount of NAD+, you need to get rid of the electron.
Lactic acid fermentation- when NADH gives electrons to pyruvates to create lactic acid
Alcohol Fermentation: when NADH gives electrons to pyruvates to create ethanol. Yeast does this

Anerobic Respiration:
Uses another terminal electron receptor.
Creates less ATP because the receptor isn’t as electronegative as oxygen so you have to leave more energy on the electron for it to stick.
Thus the electron transport chain is shorter which means fewer proton pumps are powered and the electrochemical gradient is weaker.