Question

1. What is the importance of NAD+/NADH to cellular respiration?

2. Be able to write out the biochemical equations for glucose respiration and photosynthesis AND label the oxidizing and reducing agents in each reaction.

3. What are the three stages of cellular respiration and where does each occur in the cell?

4. During cellular respiration, what is the role of each of these molecules: glucose, pyruvate, ATP, NAD+, FAD, NADH, FADH2, acetyl CoA, CO2, H2O, and O2?

5. For each stage of cellular respiration, what are the NET OUTPUTS of ATP per one glucose molecule?

Answer 1

1.CELLULAR RESPIRATION:

A metabolic process where it breaks glucose molecules and produced ATP.

The stages of cellular respiration:

Glycolysis

Pyruvate oxidation

Citric acid or krebs cycle

Oxidative Phosphorylation

NAD AND NADH are the important cofactors involved in many redox reactions .

NADH(Nicotinamide adenine dinucleotide) is the reduced form of NAD.

NAD act as a carrier of H+ and e- in many important metabolic pathways like glycolysis,TCA cycle,fatty acid synthesis and steroid synthesis.

ROLE OF NAD AND NADH IN CELLULAR RESPIRATION:

NAD selects an electron from glucose and it becomes NADH.

The NADH combine with another molecule FADH2(Flavin adenine dinucleotide),it transports the electron to mitochondria.

In mitochondria where the cells can collect energy and stored in the electrons.it plays a main role in energy metabolism by accepting and donating electrons

So the reduced coenzymes of NAD and FAD undergo oxidative phosphorylation and electron transport chain,it become converted to a more energy in the form of ATP ,used for other cellular process.

2.The biochemical equations for Photosynthesis and Respiration:

Photosynthesis and cellular respiration are interconnected.

The product of one system are the reactants of other.

Photosynthesis involved the energy from sunlight,water,carbon-di-oxide and produced energy molecules glucose,oxygen.

So,the cellular respiration used these glucose molecules and oxygen to produce carbon-di-oxide and water.

Oxygen produced by plants during photosynthesis has been inhaled by humans and animals for respiration.

Carbon-di-oxide released from body absorbed by plants,it helps to provide energy for growth and development.

Both process synthesize and used ATP,the energy currency.

The equations are:

Cellular Respiration : C6H12O6 + 6O2 -> 6CO2 + 6H2O

Photosynthesis : 6CO2 + 6H2O -> C6H12O6 + 6O2

Oxidising and Reducing agents in cellular respiration;

NAD is the reducing agent

NADH is the oxidised form of NAD

Oxidising and reducing agents in Photosynthesis:

Water is oxidised in photosynthesis,it losses electrons

Carbon-di-oxide is reduced,it gains electrons

3.Three main stages of Cellular respiration:

Glycolysis in the cytoplasm - Breakdown of glucose into 2 pyruvic acid in the cytoplasm and released two ATP and Hydrogen molecules

The Krebs cycle in the Mitochondria- It takes Citric Acid as a derivative of Pyruvic acid and convert this through 4 cycles into Hydrogen,Carbon-di-oxide and water in the mitchondrial matrix

The Electron transport chain in the Mitochondrial membrane- The chain takes the electron carrying Hydrogens and released the energy as ATP and water in the mitochondrial membrane.

4.The role of moleules:

GLUCOSE:

The body used the respiration process and to convert glucose into ATP and carbon -di- oxide using oxygen.without glucose respiration stops and loss of life happens

PYRUVATE:

Act as a transport molecule and carries carbon atoms in the mitochondria for complete oxidation into carbon di oxide.It reacts with carbon-di-oxide to create large molecules and recycle molecules.

in glycolysis, the glucose breaks down and formed pyruvate with the production of two molecules of ATP.

ATP:

It used as a energy currency of cells.used for the metabolic process

ATP is consumed inthe process of glycolysis for the conversion of glucose into pyruvate and also produced in electron transport chain

NAD,FAD,NADH,FADH2:

Electron carriers in cellular respiration.NADH is oxidised as NAD+ and FADH2 is oxidised again as FAD.This stored energy used to generate ATP molecules

Acetyl CoA:

Used in aerobic respiration.It delivers acetyl group into the citric acid cycle and to be oxidised for energy production.

CO2,H2o,O2 :

These are the main components involved in forming energy molecules.oxidising and reducing agents

5. One glucose molecule produce Four ATP ,two NADH, two pyruvate molecules during glycolysis.

38ATP molecules can be produced per oxidised glucose molecule during celllular respiration.(2 from glycolysis, 2 from krebs cylce,34 from electron transport chain)