NCERT Solutions for Class 11 Science Biology Chapter 14 - Respiration In Plants

Answer:

The ultimate electron acceptor of respiration in an aerobic organism is oxygen. It is located in the terminal stage of the ETS.
Here, oxygen acts as a final hydrogen acceptor.
Hence, the correct answer is option B.

Answer:

Glycolysis is the partial oxidation of glucose to produce pyruvic acid. It is a 10 steps reaction. Here, glucose and fructose are phosphorylated to give rise to glucose-6-phosphate by the enzyme hexokinase.
Hence, the correct answer is option C.

Answer:

Pyruvic acid is the key product of glycolysis. It has different fates based on the presence and absence of oxygen in the cell. Under aerobic conditions, that is, in the presence of oxygen, pyruvic acid forms CO₂ and H₂O. Ethanol, lactic acid and CO₂ are produced under anaerobic conditions.
Hence, the correct answer is option B.

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During aerobic respiration, electrons are passed from one carrier to another through a metabolic pathway called electron transport system (ETS). It is located in the inner membrane of mitochondria.
Hence, the correct answer is option C.

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Rate of respiration in a particular tissue depends upon the type of metabolic activity performed by that tissue. Germinating seeds show highest rate of respiration because they consume lots of oxygen to breakdown chemical compounds and obtain energy for growth.
Hence, the correct answer is option B.

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Mitochondria are found in almost all eukaryotic cells. These cell organelles are involved in the production of ATP, which acts as energy currency of the cell. Thus, mitochondria are called powerhouses of the cell.
Hence, the correct answer is option A.

Answer:

Oxidative phosphorylation takes place in the mitochondria. During the last stages of oxidative phosphorylation the complex IV uses oxygen as final electron acceptor and produces a water molecule. Complex V or ATP synthase use the proton gradient and synthesizes ATP.
Hence, the correct answer is option D.

Answer:

Molecular oxygen acts as the final hydrogen acceptor in the electron transport system (ETS). Cytochrome acts as a electron acceptor in the ETS. Pyruvate dehydrogenase is involved in oxidative decarboxylation and forms acetyl CoA from the pyruvic acid. α-ketoglutaric acid undergoes decarboxylation during the citric acid cycle to form succinic acid.
Hence, the correct answer is option A.

Answer:

During respiration ATP is produced in the mitochondria. ATP or adenosine triphosphate is a high energy compound that shares its energy in the chemical bonds. When required, our body utilizes these ATPs to perform cellular works.

Answer:

Like normal currency is used to buy anything, our body uses 'energy currency' to perform various cellular works. ATP or adenosine triphosphate acts as energy currency in plants and animals.

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By measuring the value of RQ, one can determine the type of the substrate used for respiration.
$RQ=\frac{A}{B}$

Here, A stands for volume of CO₂ evolved and B stands for volume of O₂ consumed.
Carbohydrates have a R.Q of 1, fat or proteins have R.Q. less than 1 and organic acids like malic acids have RQ greater than 1.

Answer:

F₁ particles are present in the inner membrane of mitochondria. They take part in ATP synthesis.
F₁ particles participate in the synthesis of ATP.

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Anaerobic respiration occurs in the absence of oxygen. In humans, anaerobic respiration takes place in the muscle, during vigorous exercise producing lactic acid. In yeast it occurs in the absence of oxygen producing ethanol.

Answer:

The amount of energy released on oxidation of unit amount of food.
The calorific value of 1 gm of fat is 9.45 kcal/gm
The calorific value of 1 gm of protein is 5.65 kcal/gm
The calorific value of 1 gm of carbohydrate (glucose) is 4.1 kcal/gm
The calorific value of 0.5 g of protein + 0.5 g glucose


The ascending order will be : c < d < b < a.

Answer:

Glycolysis occurs in every living cell and does not depend on the presence of oxygen. The product of glycolysis is pyruvic acid which converts into lactic acid under hypoxia and in ethanol in yeast during anaerobic respiration. The product of glycolysis (under hypoxia) in skeletal muscle and anaerobic fermentation in yeast are respectively lactic acid and ethanol.

Answer:

Glucose or fruit juice (containing glucose) is readily mixed with the blood and being simple in structure breaks easily and provides instant energy. On the other hand, cheese sandwich is a complex food and needs more time to break and produce energy. Thus, a person who is feeling dizzy is offered glucose or fruit juice but not cheese sandwich.

Answer:

In aerobic respiration total 38 ATPs are produced per glucose molecule. While in anaerobic respiration, only 2 ATPs are produced per glucose molecule. Efficiency is measured on the basis of number of ATP produced per glucose molecule. Thus, it is stated that "aerobic respiration is more efficient".

Answer:

Answer:

Aerobic respiration is more efficient than anaerobic respiration, as more amount of energy is produced. Although, anaerobic respiration occurs in organisms that live in aerobic condition due to deficiency of oxygen. Like in human beings, muscle cells undergo anaerobic respiration during vigorous exercise. At this point there is shortage of both oxygen and energy in the muscle and it produces lactic acid through anaerobic respiration to fulfill the energy needs. Similarly, yeast cells undergo anaerobic respiration when oxygen is deficient and produces ethanol and CO₂.

Answer:

Oxygen is an essential requirement for aerobic respiration but it enters the respiratory process at the end because it is most electronegative in the electron transport chain (ETC). In the electron transport chain each member than the previous one is more electronegative. Thus, movement of electrons down the ETC is energetically downhill, that is energy is released at each step. 

Answer:

1. Cellular respiration is not a single step process. During aerobic respiration glucose is broken down in three major steps,
(i) glycolysis,
(ii) TCA cycle and
(iii) electron transport chain, to release energy.
2. Living cells use organic substances such as carbohydrate, protein or fat as respiratory substrates. These compounds are get oxidized
to release energy. If glucose and fat are used as respiratory substrates then it is called floating respiration. If protein and amino acids are
used then it is called protoplasmic respiration.

Answer:

During aerobic respiration of one molecule of glucose 2 ATPs are utilized in the glycolysis preparatory phase. But 4 ATPs are also generated during the pay off phase of glycolysis. So, net 2 ATPs are produced. Similarly, in other steps of respiration ATP is generated. So, overall 
respiration is an energy producing process although ATP is being used in some steps of the process.

Answer:

At step E, energy is being used up.

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Earlier it was thought that respiration is a catabolic process which involves break down of substrates to release energy. But sometimes compounds are withdrawn from the respiratory pathway to synthesize substrates. For example, acetyl CoA is used in the respiratory process. But if fat is needed, acetyl CoA is withdrawn from the respiratory pathway to synthesize fat. As, the respiratory pathway is involved in both catabolism and anabolism, it is considered as an amphibolic pathway.

Answer:

The energy currency is a organic molecule that provides energy to various biochemical reactions. ATP acts as an energy currency. Along with that GTP (guanosine triphosphate) and NADH (nicotinamide adenine dinucleotide phosphate) are some other energy carriers present in a cell.

Answer:

When a high energy compound acts as a donor and donates a phosphoryl group to the ADP or GDP to form ATP or GTP, it is called substrate level phosphorylation. In glycolysis, there are two steps where ATP produced as a result of substrate level phosphorylation.
1. 1, 3 - bisphosphoglycerate is converted into 3-phosphoglycerate.

2. Phosphoenol pyruvate is converted into pyruvate.

Answer:

During substrate level phosphorylation a high energy compound acts as a phosphoryl group donor to the ADP or GDP and forms ATP or GTP. In TCA cycle during the conversion of succinyl CoA into succinic acid, one molecule of GTP is synthesized which is an example of substrate level phosphorylation.

Answer:

a. The process is aerobic respiration.
b. It is a catabolic process as it involves breakdown of glucose.
c. The raw materials for this process are glucose and oxygen.

Answer:

When a substrate is being metabolized energy is released in multiple steps. The advantages of step wise release of energy are-
1) Not all energy is used up at a single time.
2) Energy is also stored for later use.
3) Some energy is utilized to make intermediates of a reaction.
4) Energy is also used up in anabolic processes.

Answer:

The first cells on earth were anaerobic. They use inorganic compounds like H₂S to carry out anaerobic respiration and produces energy. 
Thus, the first cells on the earth manage to survive in an atmosphere that lacked O₂.

Answer:

Red muscle fibres in animals can work for longer periods of time continuously because -
i) It contains an oxygen storing pigment called myoglobin that supplies oxygen during vigorous muscle contraction.
ii) Red muscle fibres contain numerous number of mitochondria that help in production of huge amount of ATP.

Answer:

In aerobic respiration ATP is produced in multiple steps, viz., glycolysis, TCA cycle and electron transport chain. The total amount of ATP produced per glucose molecule is 38 ATPs. Whereas, only 2 ATPs are produced per glucose molecule during anaerobic respiration. Thus, energy yield in terms of ATP is higher in aerobic respiration than during anaerobic respiration. 

Answer:

a. Photosynthesis - RUBP carboxylase, PEP carboxylase
b. Respiration - Pyruvate dehydrogenase, ATPase, cytochrome oxidase, hexokinase, lactate dehydrogenase
c. Both in photosynthesis and respiration - ATPase

Answer:

Each plant part takes care of its own gaseous exchange. Stomata are present on the plant leaves. Tree trunk lacks stomata but has small openings called lenticels through which the tree trunk exchange gases with the environment.

Answer:

Energy is produced through substrate level phosphorylation in glycolysis. Two energy yielding steps in glycolysis are -
1. Conversion of 1, 3-bisphosphoglyceric acid into 3-phosphoglyceric acid.

2. Conversion of phosphoenol pyruvic acid into pyruvic acid.

Answer:

Pyruvate is synthesized in the cytoplasm through glycolysis.
Decarboxylation of pyruvate is catalyzed by pyruvic acid dehydrogenase to form acetyl CoA.

$\mathrm{Pyruvic} \mathrm{acid} + \mathrm{CoA} + \mathrm{NA}{\mathrm{D}}^{+}\underset{\mathrm{Pyruvate} \mathrm{dehydrogenase}}{\overset{{\mathrm{Mg}}^{2+}}{\to }}\mathrm{Acetyl} \mathrm{CoA}+{\mathrm{CO}}_2+\mathrm{NADH}+{\mathrm{H}}^{+}.$

Answer:

1. The events of aerobic respiration that occur in the matrix of mitochondrion are tricarboxylic acid cycle (TCA cycle). One molecule of acetyl CoA enters into the cycle liberating 3 molecules o carbon dioxide.
2. The important series of events of aerobic respiration that occur in the inner membrane of the mitochondrion is electron transport chain (ETC). It is involved in ATP production by using the proton gradient.

Answer:

TCA or tricarboxylic acid cycle is considered as an amphibolic pathway because it functions in both catabolism and anabolism. Catabolism occurs when two carbon atoms of acetyl CoA is oxidized into carbon dioxide. Anabolism occurs when reducing factors like NADH, FADH₂ are generated. Along with that TCA cycle intermediates also take part in synthesis of various compounds.

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Aerobic respiration takes place only in the presence of oxygen. Although it is located at the terminal stage of the electron transport chain (ETC). Oxygen acts as a final hydrogen acceptor and removes hydrogen from the system. In the ETC electrons are transferred through a sequence of electron carriers and finally reach the oxygen molecule. Oxygen being most electronegative creates a gradient through which electrons are transferred and energy is liberated. This process of energy harnessing through a series of protein complexes embedded in the inner membrane of mitochondria is called oxidative phosphorylation.

Answer:

The assumptions that we undertake in making the respiratory balance sheet are - 
1. There is a sequential, orderly pathway functioning, with one substrate forming the next and with glycolysis, TCA cycle
and ETS pathway following one after another.
2. The NADH synthesized in glycolysis is transferred into the mitochondria and undergoes oxidative phosphorylation.
3. None of the intermediates in the pathway are utilized to synthesize any other compound.
4. Only glucose is being respired-no other alternative substrates are entering in the pathway at any 
of the intermediary stages.
The above assumptions are invalid for a living organism. Because 1. All the biochemical pathways do not occur one
after another but occur simultaneously. 2. Many of the intermediates are used in synthesis of other products. 3. Substrates other than
glucose are also respired.

Answer:

Glycolysis is often referred to as the EMP pathway based on its discovers Gustav Embden, Otto Meyerhof and J. Parnas. In anaerobic organisms, it is the only process in respiration. Glycolysis occurs in the cell cytoplasm and observed in all living organisms. During this reaction complete oxidation of glucose occurs to produce two molecules of pyruvic acid.

Pyruvic acid enters into the aerobic respiration (TCA cycle and electron transport chain) and produces 38 molecules of 
ATP along with CO₂ and H₂O. During anaerobic respiration, pyruvic acid is broken down into lactic acid or ethanol and CO₂.
Along with that 2 ATPs are produced.