Mitochondria Questions in English

(C) The mitochondria consist of an outer membrane and an inner membrane. The inner membrane of the mitochondria forms several infoldings called cristae. On the surface of these cristae,there are numerous stalked particles known as '$F_1$ particles' or oxysomes. These particles are involved in the synthesis of $ATP$.

(B) Mitochondria are known as the powerhouse of the cell because they produce cellular energy in the form of $ATP$ (Adenosine Triphosphate) through the process of aerobic respiration.

(A) The inner membrane of the mitochondria is folded into structures called cristae,which increase the surface area for biochemical reactions. These cristae are studded with $F_1$ particles (also known as oxysomes or $ATP$ synthase complexes). These particles are essential for the synthesis of $ATP$ during oxidative phosphorylation. Therefore,both the assertion and the reason are correct,and the presence of $F_1$ particles on the cristae is the reason why they are the site of oxidative phosphorylation. Thus,$P$ is the correct explanation of $Q$.

(C) The provided image shows the structure of a mitochondrion.
In the diagram,the label '$a$' points to the inward folds of the inner mitochondrial membrane,which are known as cristae.
The label '$b$' points to the fluid-filled space enclosed by the inner membrane,which is known as the matrix.
Therefore,'$a$' represents cristae and '$b$' represents the matrix.

(A) Mitochondria are double-membrane-bound organelles.
Their dimensions typically range from $0.2 - 1.0 \, \mu m$ in diameter and $1.0 - 4.1 \, \mu m$ in length.
They contain inner folds called cristae, which increase the surface area for biochemical reactions.
They are known as the 'powerhouse of the cell' because they produce energy in the form of $ATP$ through aerobic respiration.
They also contain their own circular $DNA$ and ribosomes.
Option $A$ is incorrect because the provided range in the question $(0.02 - 1.0 \, \mu m)$ is inaccurate compared to the standard biological range $(0.2 - 1.0 \, \mu m)$.

(C) Statement $P$ is false because the number of mitochondria per cell is variable and depends on the physiological activity of the cell. Cells with higher energy requirements,such as muscle cells,contain a higher number of mitochondria.
Statement $Q$ is true because mitochondria are semi-autonomous organelles found in almost all eukaryotic cells,including both plants and animals.
Therefore,statement $P$ is false and statement $Q$ is true.

(B) Based on the structure of the mitochondrion:
$A$ represents the Matrix,which is the site of the Krebs cycle and contains enzymes for cellular respiration.
$B$ represents the Inner membrane,which forms infoldings known as cristae to increase surface area.
$C$ represents the Cristae (or the inner space/matrix area depending on the specific pointer,but in this context,it points to the inner membrane folds).
$D$ represents the Outer membrane,which forms the continuous limiting boundary of the organelle.
Therefore,option $B$ correctly identifies that $B$ is the inner membrane which forms infoldings called cristae.

(C) In eukaryotic cells,most of the $DNA$ is located in the nucleus. However,semi-autonomous organelles like chloroplasts and mitochondria contain their own circular $DNA$ molecules,which are similar to prokaryotic $DNA$. This supports the endosymbiotic theory. Therefore,the correct pair is chloroplast and mitochondria.

(A) $1$. Mitochondria are known as the powerhouses of the cell because they produce cellular energy in the form of $ATP$ (Adenosine Triphosphate).
$2$. This energy production occurs through cellular respiration.
$3$. The matrix of the mitochondria is the site for the Krebs cycle ($TCA$ cycle),while the inner mitochondrial membrane is the site for the electron transport system and oxidative phosphorylation.
$4$. Since the energy production ($ATP$ synthesis) is directly dependent on these processes occurring within the mitochondria,$R$ is the correct explanation for $A$.

(B) The provided figure shows a double-membrane-bound organelle with internal foldings called cristae $(A)$ and an inner matrix $(B)$. This structure is characteristic of a mitochondrion,which is known as the powerhouse of the cell. Chloroplasts have thylakoids,while the nucleus has a nuclear envelope and chromatin,and the nucleolus is a dense region within the nucleus. Therefore,the correct option is $B$.

(C) The provided figure shows the structure of a mitochondrion.
In this diagram,the label $A$ points to the folds of the inner mitochondrial membrane,which are known as cristae.
These folds increase the surface area for biochemical reactions.
Therefore,$A$ represents cristae.

(B) The provided figure shows the structure of a mitochondrion.
In this diagram,label $A$ points to the cristae (folds of the inner membrane),and label $B$ points to the inner space of the mitochondrion,which is known as the matrix.
The matrix contains enzymes,ribosomes,and circular $DNA$ required for mitochondrial function.
Therefore,$B$ represents the matrix.

(D) The given figure represents a mitochondrion.
Part $A$ points to the cristae (inner membrane folds), while part $B$ points to the matrix.
The mitochondrial matrix contains a single circular $DNA$ molecule, a few $RNA$ molecules, ribosomes $(70S)$, and the enzymes required for the Krebs cycle (citric acid cycle).
Therefore, all the components mentioned in options $A, B,$ and $C$ are present in the matrix $(B)$.

(B) The figure shows a mitochondrion,which is a double-membrane-bound organelle.
It is commonly known as the 'powerhouse of the cell' because it produces cellular energy in the form of $ATP$ through aerobic respiration.
'Suicidal bag' refers to lysosomes,and 'kitchen of the cell' refers to chloroplasts.
Therefore,the correct name for the structure shown is the powerhouse of the cell.

(C) : Mitochondria are miniature biochemical factories where food substances or respiratory substrates are completely oxidized to carbon dioxide and water.
The energy liberated in this process is initially stored in the form of reduced coenzymes and reduced prosthetic groups.
These subsequently undergo oxidation to form energy-rich $ATP$.
$ATP$ is released from the mitochondria and helps perform various energy-requiring processes of the cell,such as muscle contraction,nerve impulse conduction,biosynthesis,membrane transport,cell division,and movement.
Because of the formation of $ATP$,mitochondria are known as the powerhouses of the cell.

(A) The organelle labeled '$A$' in the diagram is the Mitochondrion.
Mitochondria are miniature biochemical factories where food stuffs or respiratory substrates are completely oxidised to carbon dioxide and water.
The energy liberated in the process is initially stored in the form of reduced coenzymes and reduced prosthetic groups.
The latter soon undergo oxidation and form energy-rich $ATP$.
$ATP$ comes out of mitochondria and helps perform various energy-requiring processes of the cell like muscle contraction,nerve impulse conduction,biosynthesis,membrane transport,cell division,movement,etc.
Because of the formation of $ATP$,the mitochondria are called powerhouses of the cell.

(B) The correct answer is $B$.
Each mitochondrion is a double membrane-bound structure with the outer membrane and the inner membrane dividing its lumen distinctly into two aqueous compartments,$i.e.$,the outer compartment and the inner compartment.
The inner compartment is called the matrix.
The outer membrane forms the continuous limiting boundary of the organelle.
The inner membrane forms a number of infoldings called the cristae towards the matrix.
The cristae increase the surface area.
The two membranes have their own specific enzymes associated with the mitochondrial function.

(A) The correct answer is $A$.
Both mitochondria and chloroplasts are semi-autonomous organelles.
They contain their own circular $DNA$,which is responsible for producing their own $mRNA$,$tRNA$,and $rRNA$.
These organelles also possess their own $70S$ ribosomes,which allow them to synthesize some of their own proteins independently of the nucleus.

(C) : The outer membrane of the mitochondrion is smooth,freely permeable to most small molecules,contains fewer enzymes,and is poor in proteins. It has porin proteins which form channels for the passage of molecules. It allows the uptake of substrates and the release of $ATP$. The inner membrane is semipermeable and regulates the passage of materials into and out of the mitochondrion. It is rich in enzymes and carrier proteins (permeases). It is usually produced into numerous infolds called cristae (singular: crista). It bears minute,regularly spaced,lollipop-shaped particles known as oxysomes. The inner membrane contains the electron carrier molecules of the electron transport chain,not the outer membrane.

(C) The provided figure represents a plant cell.
In the diagram,the label $X$ points to a small,double-membrane-bound organelle typically found in the cytoplasm,which is the mitochondrion.
$A$ Mesosome is a characteristic feature of prokaryotic cells,not eukaryotic plant cells.
$B$ Lysosomes are rare in plant cells,as their function is often performed by the large central vacuole.
$D$ The membrane refers to the plasma membrane or cell wall,which is not what $X$ is pointing to.
Therefore,the correct identification for $X$ is the mitochondrion.

(A) The mitochondria are double-membrane-bound organelles. The inner membrane of the mitochondria forms a number of infoldings called $Cristae$ towards the matrix. These folds increase the surface area for the attachment of enzymes involved in the electron transport chain and $ATP$ synthesis.

(A) $F_1$ particles,also known as $F_1$ subunits or oxysomes,are located on the inner mitochondrial membrane.
These particles are part of the $F_0-F_1$ $ATP$ synthase complex,which is responsible for the synthesis of $ATP$ during oxidative phosphorylation.
Therefore,the correct location for $F_1$ particles is the mitochondria.

(B) The provided figure represents the structure of a mitochondrion.
$S$ points to the outer membrane.
$P$ points to the matrix,which is the inner compartment of the mitochondrion.
$Q$ points to the cristae (folds of the inner membrane).
$R$ points to the inner membrane.
The matrix $(P)$ contains a single circular $DNA$ molecule,a few $RNA$ molecules,ribosomes $(70S)$,and the enzymes required for the synthesis of proteins.
Therefore,the alphabet $P$ indicates the location of the matrix where circular $DNA$ is present.

(C) The provided figure shows the ultrastructure of a mitochondrion.
$1$. $X$ points to the inner fluid-filled compartment,which is the Matrix.
$2$. $Y$ points to the infoldings of the inner membrane,known as Cristae (singular: Crista).
$3$. $Z$ points to the Inner membrane itself,which forms these folds.
Therefore,the correct identification is $X-$ Matrix,$Y-$ Crista,$Z-$ Inner membrane. However,looking at the options provided,option $C$ matches this description best.

(D) Mitochondria are known as the powerhouses of the cell because they are the primary sites of aerobic respiration.
During aerobic respiration,mitochondria utilize oxygen to break down glucose and other nutrients to produce energy in the form of $ATP$ (Adenosine Triphosphate).
This process involves the Krebs cycle and the electron transport chain,which occur within the mitochondrial matrix and inner membrane,respectively.

(C) The $F_0-F_1$ particles,also known as oxysomes or elementary particles,are found on the inner mitochondrial membrane.
These particles are involved in the process of oxidative phosphorylation,where they synthesize $ATP$ using the proton gradient generated across the inner mitochondrial membrane.
The $F_1$ headpiece projects into the mitochondrial matrix,while the $F_0$ base is embedded within the inner membrane.

(D) Mitochondrial cristae are the inner membrane folds of the mitochondria.
These cristae significantly increase the surface area of the inner mitochondrial membrane.
The inner mitochondrial membrane contains the components of the Electron Transport System $(ETS)$ and $ATP$ synthase.
These components facilitate various oxidation-reduction (redox) reactions,which are essential for the process of oxidative phosphorylation to generate $ATP$.
Therefore,the cristae are the specific sites for these oxidation-reduction reactions.

(D) The inner membrane of the mitochondrion forms a number of infoldings called $Cristae$ towards the matrix.
These infoldings increase the surface area of the inner membrane,which is essential for the attachment of enzymes involved in the electron transport chain and $ATP$ synthesis.
Therefore,the correct option is $D$.

(A) Microtubules are cytoskeletal components made of tubulin protein. They are structural components of centrioles,cilia,flagella,and spindle fibers. Mitochondria are double-membrane-bound organelles involved in cellular respiration and do not contain microtubules.

(A) The mitochondrial outer membrane is not permeable to all types of molecules. It contains large protein channels called $porins$ that allow the passage of small molecules like ions,$ATP$,and small proteins,but it is not permeable to all molecules. The electron transport chain enzymes are located in the inner mitochondrial membrane,not the outer membrane. Therefore,statement $A$ is incorrect as the electron transport chain is in the inner membrane,and statement $D$ is incorrect as the outer membrane is selectively permeable.

(A) Mitochondria are semi-autonomous organelles that contain their own circular $DNA$,$RNA$,and $70S$ ribosomes. This allows them to synthesize some of their own proteins independently of the nucleus. Other organelles like lysosomes,dictyosomes (Golgi apparatus),and peroxisomes do not contain their own $DNA$.

(D) Mitochondria are known as the '$powerhouse$ of the cell'.
They are the sites of aerobic respiration,where they perform the oxidation of carbohydrates to release energy in the form of $ATP$ (Adenosine Triphosphate).
Lysosomes are involved in digestion,ribosomes in protein synthesis,and chloroplasts in photosynthesis.

(B) The correct answer is $B$. The enzymes of the electron transport chain $(ETC)$ are embedded in the inner mitochondrial membrane,not the outer membrane. The outer membrane is permeable to small molecules like ions,$ATP$,and nutrients due to the presence of porins. The inner membrane forms infoldings called cristae,which increase the surface area for biochemical reactions. The mitochondrial matrix contains a single circular $DNA$ molecule,a few $RNA$ molecules,and $70S$ ribosomes.

(B) Mitochondria are known as the power house of the cell because they are the sites of aerobic respiration.
They produce a large amount of energy in the form of $ATP$ (Adenosine Triphosphate) through the process of oxidative phosphorylation.
Since the production of $ATP$ is the direct reason why mitochondria are termed the power house,the Reason correctly explains the Assertion.

(C) Mitochondria and chloroplasts are considered semi-autonomous organelles because they contain their own $DNA$ and ribosomes,which allow them to synthesize some of their own proteins.
They are formed by the division of preexisting organelles.
However,the statement that they 'lack protein-synthesizing machinery' is incorrect because they possess $70S$ ribosomes,which are essential for protein synthesis.
Therefore,the Assertion is correct,but the Reason is incorrect.

(D) The Assertion is incorrect because mitochondria are the sites of cellular respiration,not photosynthesis. Photosynthesis occurs in chloroplasts.
The Reason is also incorrect because the enzymes for the dark reaction (Calvin cycle) are located in the stroma of the chloroplast,not in the mitochondria.
Therefore,both the Assertion and the Reason are incorrect.

(A) The mitochondrion is the site of aerobic cellular respiration. During this process,oxygen $(O_2)$ is consumed,and organic substrates are oxidized to release energy. This energy is used to synthesize $ATP$ from $ADP$ and inorganic phosphate $(Pi)$. The byproducts of this process include carbon dioxide $(CO_2)$ and water $(H_2O)$. Therefore,the correct representation is that $O_2$ and $ADP$ + Phosphate enter the mitochondrion,while $ATP$,$CO_2$,and $H_2O$ are produced and released. This corresponds to the process shown in option $A$.

(N/A) $\Rightarrow$ Mitochondria are stained specifically to be observed under a microscope.
$\Rightarrow$ The number of mitochondria per cell is variable,depending on the physiological activity of the cells.
$\Rightarrow$ In terms of shape and size also,a considerable degree of variability is observed.
$\Rightarrow$ Typically,it is sausage-shaped or cylindrical,having a diameter of $0.2-1.0 \mu m$ (average $0.5 \mu m$) and a length of $1.0-4.1 \mu m$.
$\Rightarrow$ Each mitochondrion is a double membrane-bound structure,with the outer membrane and the inner membrane dividing its lumen distinctly into two aqueous compartments,i.e.,the outer compartment and the inner compartment.
$\Rightarrow$ The inner compartment is called the matrix. The inner membrane forms a number of infoldings called cristae towards the matrix. The cristae increase the surface area.
$\Rightarrow$ The two membranes have their own specific enzymes associated with the mitochondrial function.
$\Rightarrow$ Mitochondria are the sites of aerobic respiration. They produce cellular energy in the form of $ATP$,hence they are called the 'powerhouses' of the cell.
$\Rightarrow$ The matrix also possesses a single circular $DNA$ molecule,a few $RNA$ molecules,ribosomes $(70S)$,and the components required for the synthesis of proteins.
$\Rightarrow$ The mitochondria divide by fission.

(D) Mitochondria and chloroplasts contain their own circular $DNA$,which is independent of the nuclear $DNA$.
During mitosis,the process of karyokinesis (nuclear division) specifically involves the replication and segregation of nuclear chromosomes.
The organelles like mitochondria and chloroplasts replicate independently through binary fission and are distributed into the daughter cells during cytokinesis,not through the mitotic spindle mechanism used for nuclear $DNA$.

(N/A) $\Rightarrow$ Mitochondria contain proteins,lipids,enzymes for carbohydrate metabolism,and small amounts of $RNA$ and $DNA$.
$\Rightarrow$ Mitochondria perform three main functions:
$(i)$ Produce cellular energy in the form of $ATP$ and release it as needed.
$(ii)$ Collect,transform,and translocate $ATP$ energy.
$(iii)$ Regulate the active transport of substances across the cell membrane.
$\Rightarrow$ Mitochondria are considered small biochemical factories that generate $ATP$ from food,$ADP$,and oxygen.
$\Rightarrow$ During the chemical process of cellular respiration,glucose molecules are oxidized,yielding $38$ molecules of $ATP$.
$\Rightarrow$ The matrix of the mitochondria contains the necessary enzymes for the Krebs cycle,where $ATP$ is synthesized.
$\Rightarrow$ Therefore,mitochondria are called the powerhouse of the cell.

(N/A) Mitochondria are referred to as the "powerhouses of the cell" because they are the primary sites for cellular respiration.
$1$. They perform aerobic respiration to produce energy in the form of $ATP$ $(Adenosine Triphosphate)$ through the process of oxidative phosphorylation.
$2$. The inner membrane of the mitochondria is folded into structures called cristae, which increase the surface area for the attachment of enzymes involved in the electron transport chain.
$3$. Since $ATP$ is the energy currency used by the cell to perform various metabolic activities, the mitochondria are essential for providing the necessary energy for cellular functions.

(B) $(1)$ Cristae:
Location: Infoldings of the inner mitochondrial membrane.
Function: They significantly increase the surface area of the inner membrane to accommodate more enzymes and complexes required for the Electron Transport System $(ETS)$ and oxidative phosphorylation.
$(2)$ ATPase ($F_0-F_1$ particle):
Location: Embedded in the inner mitochondrial membrane.
Function: It acts as a channel for the facilitated diffusion of protons $(H^+)$ from the intermembrane space into the mitochondrial matrix,providing the energy required for the synthesis of $ATP$ from $ADP$ and inorganic phosphate $(Pi)$.

(A) Chloroplasts and mitochondria are considered semi-autonomous organelles because they possess their own circular genomic $DNA$ and $70S$ ribosomes.
Due to the presence of their own $DNA$,they are capable of self-replication.
Whenever the cell requires more of these organelles,they can duplicate themselves independently of the cell cycle.
However,they are still dependent on the nuclear genome for the synthesis of many of their proteins,which is why they are termed 'semi-autonomous' rather than fully autonomous.

(C) Extranuclear genes are genes located outside the nucleus of a cell.
In eukaryotic cells,extranuclear $DNA$ is primarily found in organelles such as mitochondria and chloroplasts.
These organelles possess their own circular $DNA$,which is independent of the nuclear genome.
Therefore,mitochondria contain extranuclear genes.

(D) Mitochondria are double-membrane-bound organelles. They contain a single circular $DNA$ molecule and a few $70S$ ribosomes in their matrix,not many circular $DNA$ molecules. Therefore,statement $D$ is incorrect.

(C) and $B$ are mitochondria and chloroplast,respectively.
They are called semiautonomous organelles because they possess their own $DNA$ and ribosomes,which allow them to synthesize some of their own proteins.
However,they are not fully independent as they still rely on the nuclear genome and cytoplasmic machinery for many of their functions.

(B) The mitochondrial inner membrane forms infoldings known as cristae,which allow greater surface area for proteins such as cytochromes to function properly and efficiently.
In the given diagram:
$(D)$ represents the outer membrane.
$(B)$ represents the inner membrane,which forms infoldings called cristae.
$(C)$ represents the matrix.
$(A)$ represents the intermembrane space.
Therefore,the correct match is $Part (B)$.

(B) In the figure, $(A)$ shows the cell organelle mitochondria.
The mitochondria are bounded by two membranes, i.e., an outer membrane and an inner membrane.
Mitochondria are referred to as the "powerhouse" of the cell as they produce the majority of cellular $ATP$.
This energy is produced during the breakdown of food molecules, which involves processes like glycolysis, oxidative decarboxylation, and oxidative phosphorylation (Krebs cycle and respiratory chain).

(B) The mitochondrion is a double membrane-bound organelle found in most eukaryotic cells.
It consists of an outer and an inner membrane,both composed of phospholipid bilayers and proteins.
The two membranes possess distinct structural and functional properties.
The outer membrane is smooth and contains porins,making it permeable to small molecules.
The inner membrane is highly folded into structures called cristae,which increase the surface area for biochemical reactions like the electron transport chain and $ATP$ synthesis.
Due to these differences in composition and specialized roles,the membranes are considered structurally as well as functionally different.