All questions of Energy and Respiration for A Level Exam

Citric acid is ist compound of TCA cycle ...

Fermentation normally occurs in an anaerobic environment. In the presence of O2, NADH and pyruvate are used to generate ATP in respiration. Some fermentation processes involve obligate anaerobes, which cannot tolerate oxygen.

Option a is correct. Because, in Anaerobic Respiration, respiration takes place on the absence of oxygen. Iteans, the oxidation of pyruvate takes place in the absence of oxygen to release CO2, Ethanol along with the release of Energy. Here, in Anaerobic Respiration, Water is not yet released due to the absence of oxygen. So, there will be incomplete oxidation of glucose takes place.

Matrix of mitochondrial

*Tricarboxylic acid (TCA) cycle is a series of enzyme-catalyzed chemical reactions used by all aerobic organisms to release the stored energy........ *It is a part of cellular respiration........ *It is also called as citric acid cycle or Krebs cycles which is named after it's discoverer Hans Krebs..... Thus, the correct answer is option 'D'.

Glycolysis ( process of break down of glucose into pyruvic acid ) is the process common to both aerobic and anaerobic respiration. 

RQ value is less than 1 in case of ground nut

Aerobic respiration is a process in which organisms break down glucose to produce energy in the presence of oxygen. This process is common in higher organisms, which include animals and plants.

Reasons why aerobic respiration is common in higher organisms:

1. Energy production: Higher organisms require a lot of energy to carry out their daily activities, such as movement, reproduction, and growth. Aerobic respiration provides a large amount of energy in the form of ATP, which is used for these activities.

2. Efficiency: Aerobic respiration is a highly efficient process, producing a large amount of energy from each glucose molecule. This makes it an ideal process for higher organisms, which require a lot of energy to survive.

3. Oxygen availability: Higher organisms have complex respiratory systems that allow them to take in oxygen and distribute it throughout their bodies. This makes it possible for them to carry out aerobic respiration, which requires oxygen.

4. Evolution: Higher organisms have evolved to carry out aerobic respiration as a means of producing energy. This process has been refined over millions of years of evolution, making it an integral part of their biology.

In summary, aerobic respiration is common in higher organisms because it provides a large amount of energy, is highly efficient, requires oxygen, and has evolved as a means of energy production.

Mitochondrial matrix.
In the mitochondrion, the matrix is the space within the inner membrane. ... The enzymes in the matrix facilitate reactions responsible for the production of ATP, such as the citric acid cycle, oxidative phosphorylation, oxidation of pyruvate and the beta oxidation of fatty acids.

Correct answer should be "D"...But here the answer is (C),which is wrong because Citric acid cycle and tricarboxylic cycle are other names of Krebs cycle

Anaerobic Respiration in Muscles

- Anaerobic respiration is a type of respiration that occurs in the absence of oxygen.
- It is also called fermentation and is an inefficient process that produces very little ATP (energy) compared to aerobic respiration.
- Anaerobic respiration in muscles occurs when there is not enough oxygen available to meet the energy demands of the muscles.
- As a result, the muscles switch to anaerobic respiration to produce ATP.
- The end product of anaerobic respiration in muscles is lactic acid (C3H6O3).

Lactic Acid

- Lactic acid is a three-carbon molecule that is produced by the anaerobic breakdown of glucose.
- It is a byproduct of anaerobic respiration in muscles and is responsible for muscle fatigue and soreness.
- Lactic acid can accumulate in the muscles during intense exercise and can cause a burning sensation.
- It is eventually transported to the liver where it is converted back into glucose through a process called gluconeogenesis.

Conclusion

- Anaerobic respiration in muscles produces lactic acid as the end product.
- Lactic acid is responsible for muscle fatigue and soreness.
- It is eventually converted back into glucose in the liver.

Glucose + 6O2 -> 6CO2 + 6H2O + energy ( 686 Kcal.)

The energy obtained by a cell from catabolic reactions is stored immediately in the form of ATP, as it is the energy currency of the cell.
Hence, option 'C' is correct.

Explanation:
The interconnection between glycolysis and the Krebs cycle occurs through the conversion of pyruvate to Acetyl-CoA.

Glycolysis:
Glycolysis is the process of breaking down glucose into pyruvate. It occurs in the cytoplasm of the cell and yields two molecules of ATP along with two molecules of NADH.

Krebs Cycle:
The Krebs cycle, also known as the citric acid cycle, occurs in the mitochondria of the cell. It involves the oxidation of Acetyl-CoA to produce energy in the form of ATP, NADH, and FADH2.

Interconnection:
The interconnection between glycolysis and the Krebs cycle occurs through the conversion of pyruvate to Acetyl-CoA. Pyruvate is transported from the cytoplasm to the mitochondria, where it is converted to Acetyl-CoA by the enzyme pyruvate dehydrogenase.

Acetyl-CoA is then used in the Krebs cycle to produce energy in the form of ATP, NADH, and FADH2. The Krebs cycle produces NADH, which is used in the electron transport chain to produce more ATP.

Therefore, Acetyl-CoA is the enzyme that interconnects glycolysis and the Krebs cycle.

Aerobic respiration is the complete oxidation of sugars in presence of oxygen.
The carbohydrates are broken down into CO₂ and H₂O and this releases energy. This energy is stored in the form of ATP and later used in the body.
So, the correct option is 'Carbon dioxide, water, and energy'

The correct answer is option 'C' - Tricarboxylic acid cycle and citric acid cycle.



Tricarboxylic Acid Cycle:
- The tricarboxylic acid cycle, also known as the TCA cycle or the Krebs cycle, is a series of chemical reactions that take place in the mitochondria of eukaryotic cells.
- It is an important part of aerobic respiration, which generates energy in the form of ATP (adenosine triphosphate) by breaking down carbohydrates, fats, and proteins.
- The cycle involves a series of enzymatic reactions that ultimately produce carbon dioxide, ATP, and electron carriers (NADH and FADH2).

Citric Acid Cycle:
- The citric acid cycle, also known as the Krebs cycle or the tricarboxylic acid cycle, is a part of the metabolic pathway that occurs in the mitochondria of all aerobic organisms.
- It is named after the first intermediate compound formed during the cycle, which is citric acid.
- The citric acid cycle is an essential component of cellular respiration as it plays a crucial role in the oxidation of carbohydrates, fats, and proteins to produce ATP.



Tricarboxylic Acid Cycle and Citric Acid Cycle refer to the same metabolic pathway. The only difference lies in their names and the nomenclature used in different scientific texts or contexts. The terms "tricarboxylic acid cycle" and "citric acid cycle" are used interchangeably to describe the same set of reactions occurring in the mitochondria.

Therefore, the correct answer is option 'C' - Tricarboxylic acid cycle and citric acid cycle, as they both refer to the same metabolic pathway involved in cellular respiration.

Explanation:

When dough is kept overnight in a warm place, it undergoes a process called fermentation, which is responsible for the soft and spongy texture of the dough. Fermentation is a biological process in which yeast or bacteria convert sugars present in the dough into alcohol and carbon dioxide gas.

Importance of Fermentation:

Fermentation is an important step in the preparation of various food products like bread, beer, yogurt, cheese, and many others. It helps in improving the texture, flavor, and nutritional value of the food products.

How Fermentation Works in Dough:

When yeast is added to the dough, it starts feeding on the sugars present in the dough, and in the process, it produces carbon dioxide gas as a byproduct. This gas gets trapped in the dough and causes it to rise, making it soft and spongy.

Factors Affecting Fermentation:

The rate of fermentation is affected by several factors like temperature, pH, moisture content, and the type of yeast or bacteria used.

Conclusion:

In conclusion, the soft and spongy texture of dough kept overnight in a warm place is due to the process of fermentation that occurs in the dough. Fermentation is an important process in the preparation of various food products and is influenced by several factors.

Phosphofructokinase-1 (PFK-1) is one of the most important regulatory enzymes (EC 2.7.1.11) of glycolysis. It is an allosteric enzyme made of 4 subunits and controlled by many activators and inhibitors. For example, a high ratio of ATP to ADP will inhibit PFK and glycolysis.

Pyruvate dehydrogenase complex is used in converting pyruvate to acetyl coA..this reaction is called link reaction

• Total ATP during aerobic glycolysis = 8ATP
• In pyruvic acid oxidation ATP produced = 6 ATP
• In Krebs cycle ATP produced =24 ATP
therefore total ATP produced is 38 ATP

Pyruvate, the product obtained through glycolysis, gets oxidised with the loss of its carboxy group as CO2, to give acetyl Co-A, under aerobic condition. This acetyl Co-A is further oxidised completely to CO2 + H2O in citric acid cycle. Other options are incorrect as Lactic acid is formed in muscles under anaerobic conditions. Ethanol and CO2 are products of anaerobic respiration in yeast cells. CO2 and H2O are final and complete reaction products released at the end of cellular respiration.   

NADH through electron trnasport system gives 3 ATP

Glycolysis, Krebs cycle and electron transport system are the three major metabolic pathways involved in the production of ATP, the primary energy currency of the cell. The overall goal of these pathways is to convert the energy stored in glucose into ATP, which can be used for various cellular processes. The correct option is (b) ATP in small stepwise units.

Glycolysis
Glycolysis is the breakdown of glucose into pyruvate, which occurs in the cytoplasm of the cell. It involves a series of ten enzymatic reactions, which convert one molecule of glucose into two molecules of pyruvate. Glycolysis is an anaerobic process, which means it does not require oxygen.

Krebs cycle
The Krebs cycle, also known as the citric acid cycle, occurs in the mitochondria of the cell. It is a series of eight enzymatic reactions that oxidize acetyl-CoA, a product of pyruvate oxidation, into carbon dioxide. The Krebs cycle produces ATP, NADH, and FADH2 molecules, which are used in the electron transport system.

Electron transport system
The electron transport system occurs in the inner membrane of the mitochondria. It is a series of enzymatic reactions that use the NADH and FADH2 molecules produced in the Krebs cycle to generate a proton gradient across the membrane. The energy released from this gradient is used to produce ATP through the process of oxidative phosphorylation.

Formation of ATP
The overall goal of these three metabolic pathways is the production of ATP, which occurs through the process of oxidative phosphorylation in the electron transport system. The energy released from the oxidation of glucose is stored in the form of ATP, which can be used by the cell for various processes.

However, ATP is not formed in one large oxidation reaction, but rather in small stepwise units. The energy released in each step is used to produce ATP, which ensures that the energy is not wasted and is efficiently used by the cell.

In summary, the overall goal of glycolysis, Krebs cycle, and electron transport system is to produce ATP in small stepwise units, which can be used by the cell for various processes.

The universal hydrogen acceptor is NAD (Nicotinamide adenine dinucleotide). It is knows as universal hydrogen acceptor because it gets easily reduced by combining with a hydrogen bond.

Opt a is correct because in option A the process included to convert pyruvic acid to carbondioxide and water includes link rxn. + krebcycle in which maximum energy is formed or released.

Aerobic respiration is a metabolic process that occurs in the presence of oxygen and involves the breakdown of glucose to produce energy. This process takes place in the mitochondria of cells and is the most efficient way to produce energy in the form of adenosine triphosphate (ATP). The overall equation for aerobic respiration is:

Glucose + Oxygen → Carbon Dioxide + Water + Energy (ATP)

The process of aerobic respiration involves several steps, including glycolysis, the Krebs cycle, and the electron transport chain.

1. Glycolysis:
Glycolysis is the initial step of aerobic respiration that takes place in the cytoplasm of the cell. In this step, glucose molecules are broken down into two molecules of pyruvate, producing a small amount of ATP and reducing equivalents in the form of NADH.

2. Krebs cycle:
After glycolysis, the pyruvate molecules enter the mitochondria, where they are further broken down in a series of reactions called the Krebs cycle. During this cycle, the carbon atoms from pyruvate are released as carbon dioxide, and reducing equivalents in the form of NADH and FADH2 are produced.

3. Electron transport chain:
The NADH and FADH2 molecules generated in glycolysis and the Krebs cycle enter the electron transport chain, which is located in the inner mitochondrial membrane. This chain consists of a series of protein complexes that transfer electrons from NADH and FADH2 to oxygen. As the electrons are transferred, energy is released and used to pump protons across the membrane, creating a proton gradient. This gradient is then used by ATP synthase to produce ATP.

The total energy produced during aerobic respiration can be calculated by considering the number of ATP molecules generated from each NADH and FADH2 molecule. On average, each NADH molecule yields around 2.5 ATP, while each FADH2 molecule yields around 1.5 ATP. Since glycolysis produces 2 NADH molecules and the Krebs cycle produces 8 NADH molecules and 2 FADH2 molecules per glucose molecule, we can calculate the total energy produced as follows:

(2 NADH x 2.5 ATP) + (8 NADH x 2.5 ATP) + (2 FADH2 x 1.5 ATP) = 5 ATP + 20 ATP + 3 ATP = 28 ATP

Since each ATP molecule carries around 7.6 K.Cal of energy, the total energy produced can be calculated as:

28 ATP x 7.6 K.Cal/ATP = 212.8 K.Cal

However, this calculation only accounts for the ATP produced through oxidative phosphorylation in the mitochondria. Additional ATP is also generated during glycolysis, resulting in a total energy production of around 686 K.Cal per glucose molecule.

Hence, option C is the correct answer.

Respiration is a catabolic process, which oxidises reduced substrates, thus, resulting in the energy stored in reduced substrates. The reduced substrates are produced by the process of photosynthesis occurring in green plants and the reduced substrates are oxidised through respiration releasing CO2​, water vapour and energy in the form of ATP.