Vacuoles and Microbodies Questions in English

(C) Microbodies are membrane-bound,minute vesicles found in both plant and animal cells. They contain various enzymes,such as oxidases and catalases,which are involved in metabolic processes like photorespiration and the breakdown of fatty acids. Lysosomes are primarily associated with hydrolytic enzymes,while mitochondria are the sites of cellular respiration.

(D) In plant cells,the vacuole is a membrane-bound space found in the cytoplasm. It is bound by a single membrane called the $tonoplast$. The vacuole contains water,sap,excretory products,and other materials not useful for the cell. It acts as a storage organelle for various substances,including water,ions,and nutrients,and helps in maintaining turgor pressure. Therefore,it is a membrane-bound structure that stores various substances.

(D) Organelles can be classified based on the number of membranes surrounding them:
$1$. Double membrane-bound organelles include the $Nucleus$,$Mitochondria$,and $Chloroplast$.
$2$. Single membrane-bound organelles include the $Lysosome$,$Vacuole$,$Golgi$ $apparatus$,$Endoplasmic$ $reticulum$,and $Sphaerosome$.
$3$. Non-membrane-bound organelles include $Ribosomes$ and $Centrosomes$.
Therefore,the $Sphaerosome$ is a single membrane-bound organelle.

(C) The membrane-bound space found in the cytoplasm is called a $Vacuole$.
Vacuoles are storage sacs for solid or liquid contents.
They are bound by a single membrane called the $tonoplast$.

(D) The provided figure represents a plant cell.
In the diagram,label $a$ points to a small vesicle-like structure,which is a small vacuole.
Label $b$ points to the membrane surrounding the large central vacuole,which is known as the tonoplast or vacuolar membrane.
Therefore,the correct identification is $a -$ small vacuole and $b -$ vacuolar membrane.

(A) In many protists,such as $Amoeba$,the contractile vacuole is a specialized organelle responsible for osmoregulation and excretion. It collects excess water from the cytoplasm and expels it out of the cell to maintain the internal osmotic pressure,preventing the cell from bursting.

(B) is the correct answer because a large central vacuole is a characteristic feature of plant cells. Animal cells typically contain many small,scattered vacuoles or lack them entirely.

(B) The correct answer is $B$.
Vacuoles are membrane-bound organelles found in the cytoplasm of plant cells,separated from the cytoplasm by a single membrane called the tonoplast.
In mature plant cells,a large central vacuole occupies a significant portion of the cell volume.
These vacuoles store water,ions,and solutes,which create turgor pressure against the cell wall.
This turgor pressure is responsible for the osmotic expansion and maintenance of the cell's shape and rigidity.

(D) The correct answer is $D$. Glyoxysomes are specialized peroxisomes found in the cells of germinating fatty seeds. They contain enzymes of the glyoxylate cycle,which allows the conversion of stored fatty acids into carbohydrates (gluconeogenesis) to provide energy and carbon skeletons for the growing embryo.

(D) : In a plant cell,a vacuole is a membrane-bound organelle. The membrane surrounding the vacuole is called the tonoplast,which is selectively permeable. The vacuole contains cell sap,which is a solution of water,minerals,sugars,amino acids,and various excretory substances or metabolic waste products.

(A) Vacuoles are membrane-bound spaces found in the cytoplasm. They contain water, sap, excretory products, and other materials not useful for the cell.
In many plant cells, the vacuole can occupy up to $90\%$ of the volume of the cell.
The membrane surrounding the vacuole is called the tonoplast.
The tonoplast facilitates the transport of a number of ions and other materials against concentration gradients into the vacuole, thereby maintaining a higher concentration in the vacuole than in the cytoplasm.
Thus, vacuoles play a significant role in the storage of waste products and their subsequent removal from the cell, which is a form of excretion.

(B) The $Tonoplast$ is the cytoplasmic membrane that surrounds the vacuole in plant cells.
It is a $single$ membrane that separates the vacuolar contents from the cytoplasm.
This membrane is selectively permeable and plays a crucial role in maintaining the turgor pressure of the cell by controlling the transport of ions and other materials between the vacuole and the cytoplasm.

(D) In plant cells,the vacuole is a large,membrane-bound organelle that stores water,nutrients,and waste products.
Due to its large size,it pushes the nucleus and other organelles to the periphery of the cell.
According to the $NCERT$ textbook,in plant cells,the vacuoles can occupy up to $90\%$ of the volume of the cell.

(B) $1$. Mitochondria are double-membrane bound organelles.
$2$. Vacuoles are bound by a single membrane called the tonoplast.
$3$. Lysosomes are single-membrane bound organelles containing hydrolytic enzymes.
$4$. Golgi bodies were discovered by Camillo Golgi,not Leuvan Hawk.
Therefore,the correct pair is Vacuole - single layer.

(C) In $Amoeba$,excretion and osmoregulation are primarily carried out by the contractile vacuole.
When the contractile vacuole reaches its maximum size,it moves to the plasma membrane and discharges its contents (waste products and excess water) to the outside environment through a process called exocytosis.
Therefore,the vacuole is the organelle responsible for excretion in $Amoeba$.

(C) Protein synthesis is primarily carried out by ribosomes.
$RER$ (Rough Endoplasmic Reticulum) is studded with ribosomes and is involved in the synthesis and transport of proteins.
Vacuoles are membrane-bound organelles primarily involved in storage,waste disposal,and maintaining turgor pressure in plant cells; they are not involved in protein synthesis.
Therefore,the correct answer is Vacuole.

(A) The vacuole is a membrane-bound space found in the cytoplasm of plant and fungal cells,as well as some protist,animal,and bacterial cells.
It contains water,sap,excretory products,and other materials not useful for the cell.
The vacuole is bound by a single membrane called the $Tonoplast$.
Therefore,the correct option is $A$.

(A) The endomembrane system includes organelles that work together to modify,package,and transport lipids and proteins.
These include the endoplasmic reticulum,Golgi complex,lysosomes,and vacuoles.
Peroxisomes are not part of the endomembrane system because their functions (such as lipid metabolism and detoxification) are independent of the coordinated membrane flow between the other organelles.

(D) Glyoxysomes are specialized peroxisomes found in plants,particularly in the germinating seeds of oil-rich plants.
They contain enzymes for the glyoxylate cycle,which allows the conversion of stored fatty acids into carbohydrates (sugars) through gluconeogenesis.
This process provides the necessary energy and carbon skeletons for the growth of the embryo before it becomes photosynthetically active.

(B) In germinating seeds,fatty acids are converted into carbohydrates through a process called the glyoxylate cycle. This cycle takes place in specialized organelles known as $Glyoxysomes$. These organelles are a type of microbody found in the endosperm of germinating seeds,which allow the plant to utilize stored fats as an energy source for growth before photosynthesis begins.

(B) In plant cells,the vacuole is a membrane-bound space found in the cytoplasm. It contains water,sap,excretory products,and other materials not useful for the cell. The vacuole is bound by a single membrane called the tonoplast. Therefore,it is a membrane-bound structure that contains water and excretory products.

(B) When a plant cell is placed in water,water enters the cell due to osmosis. The vacuole,which contains cell sap,plays a crucial role in maintaining the turgor pressure of the cell. The tonoplast (membrane of the vacuole) facilitates the transport of ions and other materials against concentration gradients into the vacuole,thereby regulating the water potential and the expansion of the cell volume.

(D) The correct answer is $D$.
$A$. Protists are eukaryotic organisms,which is correct.
$B$. Methanogens are archaebacteria,which are prokaryotic,which is correct.
$C$. Gas vacuoles are found in blue-green,purple,and green photosynthetic bacteria,which is correct.
$D$. Large central vacuoles are characteristic of plant cells,not animal cells. Animal cells typically have small,temporary vacuoles or lack them entirely. Therefore,this is the incorrect match.

(C) In plant cells,the vacuole is a membrane-bound organelle that stores various substances. Water-soluble pigments,such as anthocyanins,are dissolved in the cell sap within the vacuole. These pigments are responsible for the red,purple,or blue colors in many flowers and fruits. Chlorophyll,carotenoids,and xanthophylls are typically found in plastids (like chloroplasts) and are generally fat-soluble,not water-soluble.

(A) In many freshwater protozoans like $Amoeba$ and $Paramecium$,the contractile vacuole is the specialized organelle responsible for osmoregulation and excretion.
It collects excess water from the cytoplasm and expels it out of the cell to maintain the internal osmotic balance.
Therefore,the correct option is $A$.

(N/A) Lysosomes are membrane-bound vesicular structures containing a variety of hydrolytic enzymes such as lipases,proteases,and carbohydrases. Their primary function is the digestion of worn-out cell organelles and foreign materials,earning them the name 'suicidal bags' or 'waste disposal systems' of the cell.
In contrast,vacuoles are membrane-bound storage sacs. In plant cells,they occupy a large volume and store water,sap,and excretory products. In unicellular organisms like Amoeba,food vacuoles are involved in the digestion of food,while contractile vacuoles play a role in osmoregulation and the excretion of excess water and waste.

(A) $\Rightarrow$ The structure is called the $Vacuole$.
$\Rightarrow$ The vacuole is a membrane-bound space found in the cytoplasm. It contains water, sap, excretory products, and other materials not useful for the cell.
$\Rightarrow$ The vacuole is bound by a single membrane called the $Tonoplast$.
$\Rightarrow$ In plant cells, the vacuoles can occupy up to $90\%$ of the volume of the cell.
$\Rightarrow$ In plants, the $Tonoplast$ facilitates the transport of a number of ions and other materials against concentration gradients into the vacuole; hence, their concentration is significantly higher in the vacuole than in the cytoplasm.
$\Rightarrow$ In $Amoeba$, the contractile vacuole is important for excretion. In many cells, such as in protists, food vacuoles are formed by engulfing food particles.

(N/A) $\Rightarrow$ The vacuole is the membrane-bound space found in the cytoplasm. It contains water,sap,excretory products,and other materials not useful for the cell.
$\Rightarrow$ The vacuole is bound by a single membrane called the tonoplast.
$\Rightarrow$ In plant cells,the vacuoles can occupy up to $90\%$ of the volume of the cell. In plants,the tonoplast facilitates the transport of a number of ions and other materials against concentration gradients into the vacuole; hence,their concentration is significantly higher in the vacuole than in the cytoplasm.
$\Rightarrow$ In $Amoeba$,the contractile vacuole is important for excretion. In many cells,such as in protists,food vacuoles are formed by engulfing food particles.

(B) Microbodies are small,membrane-bound organelles found in the cytoplasm of plant and animal cells.
They contain various enzymes,such as oxidases and catalases,which are involved in metabolic reactions like photorespiration and the breakdown of hydrogen peroxide.
Therefore,the correct answer is that they contain various enzymes.

(A) Fresh water organisms live in a hypotonic environment,meaning the concentration of solutes inside their cells is higher than that of the surrounding water. Due to osmosis,water constantly enters their bodies. The contractile vacuole acts as a pump to expel this excess water,preventing the cell from bursting. In contrast,marine organisms live in a hypertonic or isotonic environment where the osmotic pressure is balanced,so they do not face the problem of excess water influx and thus do not require contractile vacuoles.

(N/A) $(1)$ Vacuole:
Location: Found in plant cells,occupying a large portion of the cytoplasm.
Function: Maintains turgor pressure and regulates osmosis.
$(2)$ Plasmodesmata:
Location: Microscopic channels traversing the cell walls of plant cells.
Function: Acts as a pathway for the transport of water,nutrients,and signaling molecules between neighboring cells.
$(3)$ Stomata:
Location: Small pores located primarily on the epidermis of leaves.
Function: Facilitates the exchange of respiratory gases ($CO_2$ and $O_2$) and regulates the rate of transpiration.

(B) The tonoplast is the vacuolar membrane that surrounds the central vacuole of a plant cell.
It is biologically classified as a selectively permeable membrane $(SL)$ because it actively regulates the transport of ions and other materials into and out of the vacuole to maintain cellular homeostasis.
Therefore,the correct classification for the tonoplast is Selectively Permeable $(SL)$.

(C) In mature plant cells,the vacuoles are large and can occupy up to $90$ percent of the volume of the cell.
These vacuoles store water,sap,excretory products,and other materials not useful for the cell.
The vacuole is bound by a single membrane called the tonoplast.

(C) Cell sap is a non-living fluid found within the vacuole of a plant cell.
It is produced by the cytoplasm and consists of water,minerals,sugars,amino acids,and various metabolic waste products.
Since it is a fluid mixture of solutes and water,it is considered a non-living component of the vacuole.
It plays a crucial role in maintaining the turgor pressure and osmotic potential of the cell.

(C) The vacuole is a membrane-bound organelle found in plant cells,bounded by a selectively permeable membrane called the $tonoplast$.
It contains a highly concentrated fluid known as cell sap or vacuolar sap.
Due to the active transport of ions and other solutes into the vacuole against the concentration gradient,the cell sap is typically $hypertonic$ compared to the surrounding cytoplasm.
Furthermore,the accumulation of various organic acids and protons ($H^+$ ions) within the vacuole results in an $acidic$ $pH$ for the cell sap.

(B) The vacuole is a membrane-bound organelle found in both animal and plant cells,although they are significantly larger in plant cells.
Vacuoles are essentially enclosed compartments filled with water containing inorganic and organic molecules,including enzymes in solution.
They store food or various nutrients that a cell needs to survive.
They can also store waste products,protecting the rest of the cell from contamination.

(C) Statement $(i)$ is correct: In many organisms like Amoeba,contractile vacuoles are involved in osmoregulation and excretion.
Statement $(ii)$ is correct: Food vacuoles are formed in many protists by engulfing food particles through phagocytosis.
Statement $(iii)$ is incorrect: The vacuole is bound by a single membrane called the tonoplast,not a double membrane.
Statement $(iv)$ is correct: In plant cells,the vacuole can occupy up to $90$ percent of the volume of the cell.
Therefore,statements $(i), (ii),$ and $(iv)$ are correct.

(D) The given characters describe the vacuole.
$(i)$ Vacuoles are membrane-bound spaces found in the cytoplasm.
$(ii)$ They are bounded by a single membrane known as the tonoplast.
$(iii)$ The vacuole contains water,sap,excretory products,and other materials not useful for the cell.
$(iv)$ In plant cells,the concentration of ions and other materials is significantly higher in the vacuole than in the cytoplasm,which helps in maintaining turgor pressure.

(C) Gas vacuoles $\rightarrow$ Provide buoyancy to bacteria and help in floating.
Sap vacuoles $\rightarrow$ Found in plant cells.
Contractile vacuoles $\rightarrow$ Involved in osmoregulation.
Food vacuoles $\rightarrow$ Involved in digestion.

(C) Contractile vacuoles are specialized organelles found in freshwater protozoans like $Amoeba$.
They function in osmoregulation by collecting excess water from the cytoplasm and expelling it out of the cell to maintain internal water balance.
Therefore,the correct option is $C$.

(D) Food vacuoles are specialized organelles formed by the fusion of lysosomes with phagosomes. They help in the digestion of food particles engulfed by protists through the action of digestive enzymes.

(A) Microbodies are small,membrane-bound,vesicular organelles found in both plant and animal cells. They contain various enzymes,such as peroxidases and catalases,which are involved in metabolic reactions like photorespiration and the breakdown of hydrogen peroxide.

(A) In plant cells,the tonoplast is the membrane surrounding the vacuole.
It facilitates the transport of a number of ions and other materials against the concentration gradient into the vacuole.
Because this transport occurs against the concentration gradient,it requires energy.
Plant cells do not contain gas vacuoles or contractile vacuoles.

(B) Glyoxysomes are specialized peroxisomes found in germinating seeds that convert stored fats into sugars. They are abundant in the endosperm of oil-rich seeds like castor,peanuts,and sunflower,not in wheat (which is a starchy endosperm). Therefore,the statement in option $B$ is incorrect.

(B) The glyoxylate cycle occurs in specialized peroxisomes known as glyoxysomes. These organelles are primarily found in the endosperm of germinating fatty seeds, such as castor seeds $(Ricinus communis)$, where they facilitate the conversion of stored fats into carbohydrates to provide energy for the developing embryo. While some studies suggest their presence in other oil-bearing seeds, castor seeds are the classic textbook example for the occurrence of the glyoxylate cycle.

(D) Catalase and urate oxidase are marker enzymes of peroxisomes. Peroxisomes are involved in photorespiration and the oxidation of glycolate. Since both photorespiration and glycolate oxidation are correct,the correct answer is option $D$.

(C) $\Rightarrow$ The vacuole is a membrane-bound organelle found in the cytoplasm of plant cells.
$\Rightarrow$ It contains water,cell sap,excretory products,and other materials that are not useful for the cell.
$\Rightarrow$ In plant cells,the vacuole can occupy up to $90\%$ of the volume of the cell.
$\Rightarrow$ It plays a crucial role in maintaining the turgor pressure (turgidity) and structural shape of the plant cell.

(N/A) Gas vacuoles,also known as pseudo-vacuoles or air vacuoles,are specialized structures found in certain prokaryotes,such as cyanobacteria,purple and green photosynthetic bacteria.
Each gas vacuole is composed of numerous sub-microscopic,hollow,cylindrical,or hexagonal vesicles.
These vesicles are enclosed by a thin,rigid protein membrane that is permeable to gases but impermeable to water.
Their primary function is to regulate buoyancy,allowing the organism to float at an optimal depth for photosynthesis or nutrient acquisition.

(N/A) The osmotic concentration of fresh water organisms like $Amoeba$ and $Paramoecium$ is hypertonic to the surrounding water,causing water to enter their bodies via endosmosis. This excess water must be expelled to prevent the cell from bursting,which is achieved by contractile vacuoles; thus,they play a crucial role in osmoregulation. In contrast,marine protozoans are isotonic to sea water,meaning there is no net movement of water into the cell,and therefore,they do not require contractile vacuoles.

(C) In plant cells,the vacuole is a membrane-bound space found in the cytoplasm. It contains water,sap,excretory products,and other materials not useful for the cell. The vacuole is bound by a single membrane called the tonoplast. In plant cells,the vacuoles can occupy up to $90 \%$ of the volume of the cell.