Cellular Respiration

Question 1

When an electron is transferred from one molecule to another, what happened to the potential energy of the molecules?

Answer 1

Loss in the potential energy of the first molecule and gain in the potential energy of the second molecules.

Question 2

What are the electron carriers in living systems ?

Answer 2

NAD FAD and NADP
Oxidized form of NAD= NAD+
Reduced form of NAD= NADH

Oxidized form of FAD= FAD+
Reduced form of FAD= FADH2

OxidizedformofNADP=NADP+
Reduced form of NADP= NADPH

These electron carrier molecules can easily be oxidized of
reduced

Question 3

How are photosynthesis and cellular respiration interdependent?

Answer 3

The photosynthesis and cellular respiration are interdependent.
The products of photosynthesis, carbohydrates and oxygen are used in cellular respiration. Likewise, the byproducts of cellular respiration, carbon dioxide is used during photosynthesis.

Question 4

Where does glycolysis occur in prokaryotes and eukaryotes?

Answer 4

Glycolysis occurs in the cytoplasm of both prokaryotes and eukaryotes

Question 5

Does glycolysis use oxygen?

Answer 5

No. Glycolysis does not use ATP and it is anaerobic.

Question 6

What is the only source of energy in RBCs?

Answer 6

Glycolysis is the only source of ATP in RBCs. Bcuz they are not capable of aerobic respiration. When glycolysis is interrupted, these cells cannot maintain sodium potassium pump and eventually, they die.

Question 7

What gas does cellular respiration use and what gas does it produce ?

Answer 7

It uses oxygen and produces carbon dioxide.

Question 8

How does glucose enter into the cell ?

Answer 8

By secondary active transport or glucose transporter GLUT.

Question 9

What are the by products of glycolysis?

Answer 9

Pyruvate , 4 ATP ( 2 ATP net) and 2 NADH

Question 10

What is the purpose of 1st step of glycolysis, phosphorylating glucose molecules?

Answer 10

To prevent the glucose from leaving the cell via GLUT transporters. The negatively charged phosphate group does not interact with the hydrophobic interior of the cell membrane.

Question 11

where does CAC occur?

Answer 11

Occurs in cytoplasm in prokaryotes but occur in the mitochondria matrix in eukaryotes.

Question 12

What are the by products of CAC?

Answer 12

One ATP or GTP, three NADH and one FADH2

Question 13

Where does the enzymes that catalyzes the reduction of FAD to FADH2 present?

Answer 13

In the inner membrane of the mitochondria so they can transfer the electrons from FADH2 into electron transport chain directly.

Question 14

What is the oxidation of pyruvate and where does it occur?

Answer 14

Prior to the CAC, pyruvate from glycolysis are oxidized into acetyl CoA by reducing the NAD+ to NADH It occurs in the mitochondria matrix in eukaryotes and cytoplasm in the prokaryotes.

Question 15

Why is CAC a closed loop cycle?

Answer 15

The end product of CAC,malate is used to reform oxaloacetate after reaction.

Question 16

Where does oxidative phosphorylation take place?

Answer 16

It takes place in the inner mitochondria membrane or cristae.

Question 17

How many complexes are there in the electron transport chain?

Answer 17

4 complexes- 1, 2 , 3 and 4.

Question 18

Where is electron transport chain located in prokaryotes?

Answer 18

Located in the plasma membrane

Question 19

What is complex 1 made of?

Answer 19

FMN ( flavin mono nucleotide) and FeS containing protein.

FMN is the prosthetic groups of the complex 1.

Question 20

Where does complex 2 accept electrons and where does it transfer its electrons to?

Answer 20

It accepts electrons from FADH2 and it sends its electrons to the ubiquinone (Q).

Question 21

From which complexes does uniquinone accept electrons from?

Answer 21

From complex 1 and 2.

Question 22

What is the difference between ubiquinone and cytochrome c?

Answer 22

Uniquinone can accept pairs of electrons at a time but cytochrome c can only accept an electron at a time.

Question 23

What is complex 3 made of?

Answer 23

cytochrome b, FeS containing protein and cytochrome c.

cytochromes contain heme groups as their prosthetic group which can carry electrons instead of oxygen as in haemoglobin.

Question 24

What is complex 4 made of?

Answer 24

Cytochrome c , cytochrome a, cytochrome a3.

Cytochrome a, a3 contains heme groups and cytochrome a3 have a pair of CuA and one CuB molecules.

They hold the atmospheric oxygen very tightly between heme and Cu molecules until it becomes fully reduced.

Question 25

How many ATP does one molecule of NADH and FADH2 produce?

Answer 25

1 NADH molecule pumps 3 H+ ions and hence can produce 3 ATP. One molecule of H+ can produce one ATP.

1 FADH2 molecule can pump 2 H+ ions and hence can produce 2 ATP.

Question 26

How many ATP molecules are produced from glycolysis and cellular respiration?

Answer 26

Glycolysis=2 NADH+2 ATP Oxidation of pyruvate=2NADH
CAC= 6 NADH for one glucose
2 ATP for one glucose
2 FADH2 for one glucose.

Total=38 ATP but variances present and only 30-32 ATP are high end expected.

Question 27

Why can’t RBC perform aerobic respiration and what kind of fermentation do they perform?

Answer 27

RBCs do not have mitochondria so they cannot perform aerobic respiration. They perform lactic acid fermentation and.

Question 28

What is the anaerobic respiration of archae called mathanogens?

Answer 28

Methanogens reduces CO2 to CH4.

Question 29

Which fermentation does not produce gas ?

Answer 29

Lactic acid fermentation

Question 30

What is alcoholic tolerance for yeast?

Answer 30

Alcoholic tolerance for yeast ranges from 5-21 percent.