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All questions of Respiration in Plants for ACT Exam

The net gain of ATP in glycolysis is__________.
  • a)
    4
  • b)
    8
  • c)
    2
  • d)
    6
Correct answer is option 'B'. Can you explain this answer?

Lalit Yadav answered
Glycolysis is the first stage of the breakdown of glucose in the cell. 
During glycolysis 2 ATP molecules are used up and four ATP molecules are generated. In the entire process of glycolysis, two NADH₂ molecules are also generated. When these molecules undergo ETS they will form 3 ATP per NADH₂  which means 6 ATP.
Therefore the total ATP that are forming are 10 and as 2 ATP is used up the net gain will be 8.
So, the correct option is '8'

Respiration is
a)Amphibolic process
b)Catabolic process
c)Anabolic process
d)Both anabolic and catabolic
Correct answer is option 'A'. Can you explain this answer?

Geetika Shah answered
Because the respiratory pathway is involved in both anabolism and catabolism, it would hence be better to consider the respiratory pathway as an amphibolic pathway rather than as a catabolic one.

In plants, the gaseous exchange take place in
a) Stomata
b) Roots
c) Stems
d) Lenticles
  • a)
    a and b
  • b)
    a and d
  • c)
    b and d
  • d)
    b and c
Correct answer is option 'B'. Can you explain this answer?

Geetika Shah answered
Plants unlike animals have no special systems for breathing or gaseous exchange. Stomata and lenticels allow gaseous exchange by diffusion.

Which of the following is not correct about the Krebs cycle?
  • a)
    It starts with a six-carbon compound.
  • b)
    It occurs in mitochondria.
  • c)
    It is also called the citric acid cycle.
  • d)
    The intermediate compound which links glycolysis with the Krebs cycle is malic acid.
Correct answer is option 'D'. Can you explain this answer?

Om Desai answered
  1. Krebs cycle is also known as the citric acid cycle because this reaction starts with the six-carbon compound which is citric acid. It occurs in the mitochondrial matrix.
  2. Krebs cycle is a closed-loop cycle. And each loop of the cycle generates a molecule of ATP. This cycle consists of eight steps which include redox, dehydration, hydration, and decarboxylation reactions. It is an aerobic pathway because NADH is produced and the electrons released are used up in the next cycle which uses oxygen.
  3. The process of the cycle starts with the condensation of acetyl- CoA with oxaloacetate.
  4. This reaction is controlled by the amount of ATP present.
  5. If the ATP level increases then the rate of the reaction decreases and vice versa. After glycolysis, the pyruvate is then converted into acetyl CoA which enters the citric acid cycle.
  6. The Krebs cycle is the pathway that all organisms use to generate energy. The intermediate compound that links pyruvate to the Krebs cycle is Acetyl CoA.
  7. So, the answer is option (B) ‘the intermediate compound which links glycolysis with the Krebs cycle is malic acid’.

The site of glycolysis is
  • a)
    Chloroplast
  • b)
    Cytoplasm
  • c)
    Mitochondrial inner membrane
  • d)
    Mitochondrial matrix
Correct answer is option 'B'. Can you explain this answer?

Geetika Shah answered
Glycolysis takes place in the cytoplasm of a cell as the first step in cellular respiration of the Kreb’s cycle. When glycolysis occurs, it breaks down glucose into pyruvic acids in the cytoplasm.

Fermentation is
  • a)
    Excretory process
  • b)
    Aerobic respiration
  • c)
    Incomplete oxidation
  • d)
    Anaerobic respiration
Correct answer is option 'D'. Can you explain this answer?

Vijay Bansal answered
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.

During anaerobic respiration less energy is produced than aerobic respiration because
  • a)
    Incomplete oxidation of glucose takes place
  • b)
    It takes place is micrograms
  • c)
    It takes place in inert medium
  • d)
    Glucose is not available
Correct answer is option 'A'. Can you explain this answer?

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.

The TCA cycle is named after
  • a)
    Robert Emerson
  • b)
    Melvin Calvin
  • c)
    Embden
  • d)
    Hans Krebs
Correct answer is option 'D'. Can you explain this answer?

Hitakshi Tamta answered
*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'.

F0−F1 particles participate in the synthesis of
  • a)
    NADPH
  • b)
    FADH2
  • c)
    ADP
  • d)
    ATP
Correct answer is option 'D'. Can you explain this answer?

Lalit Yadav answered
  • Oxysomes refer to small round structures present within the folds of the cristae of the inner mitochondrial membrane. It is also known as F0-F1 particles.
  • F0 and F1 particles are found in the inner mitochondrial region and are attached to the cristae and help in ATP production and oxidation.

The process common to both aerobic and anaerobic organisms is
  • a)
    TCA cycle
  • b)
    Krebs cycle
  • c)
    Glycolysis
  • d)
    Glyoxylate cycle
Correct answer is option 'C'. Can you explain this answer?

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

Most of the enzymes of the TCA cycle are present in
  • a)
    Intermembrane space of mitochondria
  • b)
    Mitochondrial matrix
  • c)
    Inner membrane of mitochondria
  • d)
    Cytoplasm
Correct answer is option 'B'. Can you explain this answer?

Anjali Iyer answered
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.

Aerobic respiration is common in
  • a)
    Yeast
  • b)
    Higher organisms
  • c)
    Prokaryotes
  • d)
    Unicellular eukaryotes
Correct answer is option 'B'. Can you explain this answer?

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.

Mitochondria are called the powerhouses of the cell. Which of the following observations support this statement?
  • a)
    Mitochondria are found in almost all plant and animal cells.
  • b)
    The enzymes of the Krebs cycle and the cytochromes are found in mitochondria.
  • c)
    Mitochondria synthesise ATP.
  • d)
    Mitochondria have a double membrane.
Correct answer is option 'C'. Can you explain this answer?

Riya Banerjee answered
Mitochondria (singular - Mitochondrion) are known as the powerhouse of the cell because they are responsible for the release of energy from food ,i.e, cellular respiration. This energy is released in the form of ATP (adenosine triphosphate), the energy currency of the cell.
While the cells release 2 ATP, mitochondria releases 34 ATP which adds up to 36 ATP. Since a major portion of the ATP is released by mitochondria, they are called the powerhouse of the cell.

When fats are the respiratory substrate, the value of RQ would be​
  • a)
    Approx. 0.7
  • b)
    Approx. 1.0
  • c)
    More than 1.0
  • d)
    None of the above
Correct answer is option 'A'. Can you explain this answer?

Surbhi Mishra answered
Ans.

The respiratory quotient (or RQ or respiratory coefficient), is a dimensionless number used in calculations of basal metabolic rate (BMR) when estimated from carbon dioxide production. ... If metabolism consists solely of lipids, the Respiratory Quotient is 0.7, for proteins it is 0.8, and for carbohydrates it is 1.0.

Energy obtained by a cell from catabolic reaction is stored immediately in the form of
  • a)
    Pyruvic acid
  • b)
    Glucose
  • c)
    ATP
  • d)
    DNA
Correct answer is option 'C'. Can you explain this answer?

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.

The enzyme that interconnects the glycolysis and kreb cycle is
  • a)
    Oxalo acetic acid
  • b)
    NADH
  • c)
    Acetyl-CoA
  • d)
    NADP
Correct answer is option 'C'. Can you explain this answer?

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.

End-products of aerobic respiration are
  • a)
    Carbon dioxide and energy
  • b)
    Sugar and oxygen
  • c)
    Carbon dioxide, water and energy
  • d)
    Water and energy
Correct answer is option 'C'. Can you explain this answer?

Vartika Shukla answered
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'

In which of the following do the two names refer to one and the same thing?
  • a)
    Krebs cycle and Calvin cycle
  • b)
    Citric acid cycle and Calvin cycle
  • c)
    Tricarboxylic acid cycle and citric acid cycle
  • d)
    Tricarboxylic acid cycle and urea cycle
Correct answer is option 'C'. Can you explain this answer?

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

Explanation:


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.

Comparison:


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.

Krebs cycle is both catabolic and anabolic because it provides
  • a)
    A number of intermediates
  • b)
    Produce energy as well as use energy
  • c)
    ATP is released as well as utilised
  • d)
    A number of final products
Correct answer is option 'A'. Can you explain this answer?

Anand Jain answered
During breakdown and synthesis of protein too, respiratory intermediates form the link. Breaking down processes within the living organism is catabolism, and synthesis is anabolism. Because the respiratory pathway (Kreb’s cycle) is involved in both anabolismand catabolism, it would hence be better to consider the respiratory pathway.

Dough kept overnight in warm place becomes soft and spongy due to
  • a)
    Absorption of CO2
  • b)
    Osmosis
  • c)
    Fermentation
  • d)
    Cohesion
Correct answer is option 'C'. Can you explain this answer?

Nitya Joshi answered
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.

Oxidation of one molecule of glucose in aerobic respiration results in the production of
  • a)
    36 ATP molecules
  • b)
    38 ATP molecules
  • c)
    3 ATP molecules
  • d)
    15 ATP molecules
Correct answer is option 'B'. Can you explain this answer?

User4284711 answered
• 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

Excess of ATP inhibits the enzyme –
  • a)
    Phosphofructokinase
  • b)
    Hexokinase
  • c)
    Aldolase (Lyases)
  • d)
    Pyruvate decarboxylase
Correct answer is option 'A'. Can you explain this answer?

Rajat Kapoor answered
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.

Pyruvic acid, the key product of glycolysis, can have many metabolic fates. Under aerobic conditions, it forms​
  • a)
    CO2
  • b)
    CO2+ H2O
  • c)
    Lactic acid
  • d)
    Acetyl CoA + CO2
Correct answer is option 'D'. Can you explain this answer?

Rohit Shah answered
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.   

Choose the correct statement.
  • a)
    There is a complete breakdown of glucose during fermentation.
  • b)
    Pyruvate is formed in the mitochondrial matrix.
  • c)
    During the conversion of succinyl CoA to succinic acid, a molecule of ATP is synthesised.
  • d)
    Oxygen is vital in respiration for the removal of hydrogen.
Correct answer is option 'D'. Can you explain this answer?

Hansa Sharma answered
  • Oxygen sits at the end of the electron transport chain, where it accepts electrons, hydrogen and picks up protons to form water.
  • Pyruvate is formed in the cytoplasm.
  • During fermentation glucose is partially broken down by glycolysis.
  • During the conversion of succinyl CoA to succinic acid a molecule of GTP is synthesized.
So, the correct option is 'Oxygen is vital in respiration for removal of hydrogen'.

Which of the following is coenzyme - II ?
  • a)
    NAD
  • b)
    NADP
  • c)
    FAD
  • d)
    None of the above
Correct answer is option 'B'. Can you explain this answer?

Moumita Khanna answered
Ans.

Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed)

(Synonyms:
coenzyme II
NADP
NADP(+)
triphosphopyridine nucleotide
beta-NADP+)


The TCA cycle starts with
  • a)
    Condensation
  • b)
    Dehydrogenation
  • c)
    Phosphorylation
  • d)
    Decarboxylation
Correct answer is option 'A'. Can you explain this answer?

Anand Jain answered
The TCA cycle starts with the condensation of acetyl group with oxaloacetic acid (OAA) and water to yield citric acid.

The overall goal of glycolysis, Krebs cycle and electron transport system is the formation of
  • a)
    Nucleic acids
  • b)
    ATP in small stepwise units
  • c)
    ATP in one large oxidation reaction
  • d)
    Sugars
Correct answer is option 'B'. Can you explain this answer?

Ciel Knowledge answered
The overall goal of glycolysis, Krebs cycle and electron transport system is the formation of ATP step-wise. The three processes are involved in cellular respiration of food to produce energy, which will be used for various cellular activities. 

 The universal hydrogen acceptor is
  • a)
    NAD
  • b)
    ATP
  • c)
    Co-A
  • d)
    FMN
Correct answer is option 'A'. Can you explain this answer?

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.

In respiration pyruvic acid is
  • a)
    Formed only when oxygen is available
  • b)
    One of product of Krebs cycle
  • c)
    Broken down into Acetyl Co-A and CO2
  • d)
    a result of protein break down
Correct answer is option 'C'. Can you explain this answer?

Pooja Shah answered
Respiration occurs in two stages. In the first stage called as glycolysis, which occurs in the absence of oxygen, one molecule of hexose glucose is broken down into two molecules of three carbon atom containing pyruvic acid. Each molecule of pyruvic acid is then oxidatively decarboxylated by the enzyme pyruvate dehydrogenase. The pyruvate dehydrogenase releases one molecule of carbon dioxide from each molecule of pyruvic acid during its conversion to Acetyl CoA. The Acetyl CoA is subsequently metabolised in Krebs cycle generating reduced coenzymes.

Aerobic respiration of glucose produces energy
  • a)
    637 K.Cal
  • b)
    640 K.cal
  • c)
    686 K.cal
  • d)
    693 K.cal
Correct answer is option 'C'. Can you explain this answer?

Prerna Basu answered
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.

What is the importance of respiration in organisms?
  • a)
    It provides oxygen to plant
  • b)
    It liberates CO2
  • c)
    It liberates energy
  • d)
    All the above
Correct answer is option 'B'. Can you explain this answer?

Raza Great answered
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.

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