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Osmotic relations of plant cells - class-XII

Description: osmotic relations of plant cells
Number of Questions: 71
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Tags: biology botany bio-chemistry cell membrane plant physiology transport in plants absorption by roots - the processes involved
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Which of the following statements is not correct?

  1. In plant cells, vacuoles are absent.

  2. Vacuole is bounded by a single membrane.

  3. In Amoeba, contractile vacuole is important for excretion.

  4. Flagellum is important for transport of bacteria.


Correct Option: A

Passage of cell contents out of the cell. Water potential can be calculated as : 

  1. $\pi + WP$

  2. $\Psi + WP $

  3. Osmotic potential + TP

  4. $\pi + TP$


Correct Option: A
Explanation:

  • Water potential is the energy potential of water compared to pure water in a system when both temperature and pressure are same .
  •  When the contents of the the cell moves out then then the wall pressure or turgour pressure will decrease .
So the correct answer is ' B ' . 

$2\%$ NaCl as compared to $18\%$ glucose solution is

  1. Isoomotic

  2. Hypersmotic

  3. Hypoosmotic

  4. None of the above


Correct Option: A

When the cell is placed in water, it takes water this is due to?

  1. Osmotic pressure

  2. Suction pressure

  3. Diffusion

  4. Water potential and TP


Correct Option: A

Red blood cells when placed in a hypotonic solution will ______.This process is known as ______.

  1. Shrink, crenation

  2. Swell up, plasmolysis

  3. Turgid, deplasmolysis

  4. Burst, haemolysis


Correct Option: A
Explanation:

Crenation is defined as the process by which a blood cell shrinks when it is exposed to a hypotonic solution.

The value of $2, 4$-D is $25$ ppm. How many amount of $2, 4$-D should require for making its $5$ litres, $15$ litres and $25$ litres solutions respectively.

  1. $25$gm, $50$gm, $75$gm

  2. $50$gm, $175$gm, $525$gm

  3. $250$gm, $750$gm, $1250$gm

  4. $125$gm, $375$gm, $625$gm


Correct Option: D
Explanation:

1 ppm is equal to 1 gm per litre.

25 ppm is equal to 25 gm per litre.
Therefore, 
for 5 litres, amount needed is 5 times 25= 125 gm
for 15 litres, amount needed is 15 times 25= 375 gm
for 25 litres, amount needed is 25 times 25= 625 gm.
So the correct option is D.

Plant cells do not burst in distilled water, because

  1. Cells wall is rigid and do not get overstretched

  2. Cell wall is living

  3. Cell wall is the outer most layer of plant cell

  4. Cell wall is permeable


Correct Option: A
Explanation:

Cell wall is the outermost, rigid, protective, non living and supportive layer found in all the plant cells. Due to its rigid nature it prevent the cell from bursting. It is not found in animal cells. An animal cell placed in pure water will swell up and burst, because of endosmosis.

When a grape is placed in concentrated sugar solution, then it will show

  1. Endosmosis

  2. Exosmosis

  3. Imbibition

  4. None of the above


Correct Option: B
Explanation:

When a grape is placed in a solution of concentrated sugar solution, it will show the process of exosmosis and lose water. When a cell is kept in hypertonic solution, it readily crosses the cell wall and fills the space between the cell wall and cell membrane. This hypertonic solution in direct contact with the cell membrane causes plasmolysis and extracts water from the cytoplasm of the cell.

So, the correct answer is option B.

A cell is plasmolysed after being kept in a hypertonic solution. What will be present between the cell wall and plasmalemma?

  1. Isotonic solution

  2. Hypertonic solution

  3. Air

  4. Hypotonic solution


Correct Option: B
Explanation:

The cell wall is nonliving and cannot regulate the entry and exit of solute or solvent molecules. When a cell is kept in hypertonic solution, it readily crosses the cell wall and fills the space between the cell wall and cell membrane. This hypertonic solution in direct contact with the cell membrane causes plasmolysis and extracts water from the cytoplasm of the cell.

So, the correct answer is option B.

Which bacterium causes cotton destruction

  1. Clostridzum botulinum

  2. Spirochaeta cytophaga

  3. Mycobacterium

  4. Vibrio


Correct Option: B
Explanation:

Some bacteria damage cellulose of textiles. e.g., Spirochaete cytophage, cellulomonas etc.

Which one of the following is the most suitable medium for culture of Drosophila melanogaster ?

  1. Ripe banana

  2. Cow dung

  3. Moist bread

  4. Agar agar


Correct Option: A
Explanation:

For the culture of Drosophila melanogaster  one of the most suitable medium is ripe banana, rich in carbohydrates.

So, the correct answer is 'Ripe banana'

Osmotic pressure is higher in _______________.

  1. Xerophytes

  2. Lithophytes

  3. Halopyhtes

  4. Mesophytes


Correct Option: C
Explanation:

Because halophytes are the plants of saline habitat.

So the correct option is C.

OP of a solution can be measured by 

  1. Photometer

  2. Osmometer

  3. Calorimeter

  4. Plasmolysis


Correct Option: B
Explanation:

An osmometer is a device for measuring the osmotic strength of a solution.
Photometer is an instrument for measuring the intensity of light.

A calorimeter is an object used in the process of measuring the heat capacity. 
Plasmolysis is the contraction of the protoplast of a plant cell as a result of loss of water from the cell.
Thus, the correct answer is option (B). 

A higher plant cell covered with cutin and suberin is placed in water. After 15 minutes the cell

  1. Will be killed

  2. Size will increase

  3. Size will remain unchanged

  4. Size will decrease


Correct Option: C
Explanation:

Suberin and cutin are complex macromolecules which mainly function as a barrier to movement of water and solutes. Thus if a higher plant cell is covered with cutin and suberin and placed in water then there will not be any change in the size of the cell as cutin and suberin are hard and water repulsive substances. There will not be any exosmosis or endosmosis in such type of cell.

So the correct answer is 'Size will remain unchanged'.

In a plant cell, O.P. is equal to 

  1. T.P. - D.P.D.

  2. D.P.D - T.P.

  3. T.P. - D.P.

  4. D.P.D + T.P.


Correct Option: D
Explanation:

Here O.P. stands for osmotic pressure, D.P.D. stands for diffusion pressure deficit and T.P. stands for turgor pressure. 

Diffusion pressure deficit( DPD) is the reduction in the diffusion pressure of water in a solution over its pure state due to the presence of solutes and consequent development of turgor pressure. It is equal to the osmotic pressure of the system minus wall pressure:
$D.P.D=O.P.-W.P.(=T.P.)$

Thus the osmotic pressure is the sum of DPD and TP.
So the correct answer is 'D.P.D +T.P'.

Movement of water through semipermeable membrane produces 

  1. Wall pressure

  2. Suction pressure

  3. Osmotic pressure

  4. Turgor pressure


Correct Option: C
Explanation:
(A) Wall pressure is the pressure exerted by cell wall against turgor pressure.
(B) Suction pressure is the actual pressure by which cell absorb water.
(C) The movement of water from higher concentration to lower concentration through a semi-permeable membrane is called osmosis. The pressure required to stop osmosis is called osmotic pressure. 
(D) Turgor pressure is pressure applied against the cell wall.
So, the correct answer is 'Osmotic pressure'.

The cell becomes turgid in solution which is

  1. Hypertonic

  2. Isotonic

  3. Hypotonic

  4. None of the above


Correct Option: C
Explanation:
The cell becomes turgid in solution which is hypotonic because a hypotonic solution has more concentration of solvent molecules than the fluid inside the cell. So, the solvent molecules move inside the cell from the region of higher concentration to the lower concentration by the process of endosmosis. The cell swells and increases in size.
So, the correct answer is option C.

Water will enter a cell, if it is placed in solution less concentrated than cell sap due to

  1. Endosmosis

  2. Diffusion

  3. Imbibition

  4. Plasmolysis


Correct Option: A
Explanation:

(A) Endosmosis is the movement of solution from outside of the cell to inside the cell.

(B) Diffusion is the movement of the molecule from higher concentration to the lower concentration.
(C) Imbibition is the special diffusion where water is absorbed by solid colloids to get an increase in the volume.
(D) Plasmolysis is the process of cell getting contracted due to the loss of water from the cell.
So, the correct answer is 'Endosmosis'.

Glucose is not stored in plants due to its ability to 

  1. Decrease osmotic pressure

  2. Increase osmotic pressure

  3. Increase turgor pressure

  4. Decrease turgor pressure


Correct Option: B
Explanation:

  • Osmosis occurs only through the semi-permeable membrane. Osmosis is a gradient dependent process, osmosis is different from diffusion as it is characterized by a semi-permeable membrane.
  • Net direction and rate of osmosis depend on both pressure gradient and concentration gradient.
So, the correct answer is 'Increase osmotic pressure'.

The space between plasma membrane and cell wall of a plasmolysed cell surrounded by a hypertonic solution is occupied by

  1. Isotonic solution

  2. Hypotonic solution

  3. Hypertonic solution

  4. Water


Correct Option: C
Explanation:

The hypertonic solution involves the movement of a solute particle from low concentration to high concentration. The water will move from a higher concentration to a lower concentration. The cell will swell up.

So, the correct option is 'Hypertonic solution'.

2% NaCl as compared to 18% glucose solution is 

  1. Isoosmotic

  2. Hypoosmotic

  3. Hyperosmotic

  4. None of the above


Correct Option: B

Osmotic pressure of pure water is

  1. 0

  2. 1

  3. 10

  4. 100


Correct Option: A
Explanation:

Osmotic pressure is generated when solutes are added to water. It depends on the concentration of a solution.

If pure water is taken, it has 0 osmotic pressure.
So the correct answer is '0'.

Choose the wrong statement.

  1. Cells swell in hypertonic solutions and shrink in hypotonic solutions.

  2. Water potential is the kinetic energy of water which helps in movement of water.

  3. Absorption of water by seeds and dry wood takes place by special type of diffusion called imbibition.

  4. $ \Psi _s $ is always negative.


Correct Option: A
Explanation:

The solute potential is always negative as it reduces osmotic pressure.

Absorption of water by seeds and embryo takes place by imbibition which leads to their growth and swelling respectively.
Water potential is the energy of water that helps it in moving.
Cells absorb water when kept in hypotonic solutions and they swell up while they lose water when kept in hypertonic solutions and shrink.
So the correct answer is 'Cells swell in hypertonic solutions and shrink in hypotonic solutions'.

Osmotic pressure of a cell kept in water is chiefly regulated by

  1. Vacuoles

  2. Plastids

  3. Ribosomes

  4. Mitochondria


Correct Option: A
Explanation:

Vacuoles are the organelles that store all the extra water and salts that are the basis of creating osmotic pressure in the cell. The vacuole takes up a huge central place in the cell. The solution outside the cell is hypertonic, hypotonic or isotonic with respect to the contents inside the vacuole. Plastids are the centres for photosynthesis, Ribosomes are small granule-like structures that help in protein synthesis whereas mitochondria generate energy for the cell by utilising sugars. 

So the correct answer is 'Vacuoles'.

RBC placed in distilled water will

  1. Burst

  2. Shrink

  3. Stick to one another

  4. Divide


Correct Option: A
Explanation:

RBCs placed in distilled water will burst because distilled water is extremely hypotonic to the cytoplasm of the cell. This will involve the intake of enormous amounts of water and the cells will burst.

So the correct answer is 'Burst'.

Flaccid cell means

  1. Cell with turgidity

  2. Plasmolysed cell

  3. The cell in which water flows in and out of cell are in equilibrium

  4. The cell kept in hypotonic solution


Correct Option: C
Explanation:

When a cell is placed in an hypertonic solution water is transported out of the cell and the cell shrinks or shrivels or plasmolysed. On contrary when the cell is placed in hypotonic solution the water flows into the cell causing the cells to swell and finally leading to their lysis. However, when the cells are placed in isotonic solutions there will be continuous flow of water in and out of the cell and the cell is said to be in flaccid condition. Thus, the correct option of C.

The osmotic pressures of $0.1$ glucose and $0.1$M sucrose solutions are the same because ______________________.

  1. Both are carbohydrates

  2. These are different compounds having different molecular weights

  3. Both are present in the same concentration

  4. Glucose is reducing sugar while sucrose in non-reducing sugar


Correct Option: A

In plant cells, which of the following are important determinants of movement of molecules in or out of the cell?

  1. Cell wall and cell membrane

  2. Cell wall and tonoplast

  3. Cell wall and glycocalyx

  4. Cell membrane and the membrane of the vacuole


Correct Option: A

When a plasmolysed cell is placed in a hypotonic solution then water will move inside the cell this will happen due to which force

  1. DPD

  2. OP

  3. WP

  4. None of them


Correct Option: B
Explanation:
The force produced because of the osmotic pressure between the plasmolyzed cell and the hypotonic solution is responsible for the movement of water inside the cells.
So, the correct answer is 'OP'.

When a plasmolysed cell is placed in a hypotonic solution then water will move inside the cell. Which force causes this?

  1. DPD

  2. OP

  3. WP

  4. None of these


Correct Option: A
Explanation:
The DPD or diffusion pressure deficit represents the water absorbing capacity of a cell. It is given by, DPD = osmotic pressure (OP)- turgor pressure (TP). Since turgor pressure is negative in a plasmolysed cell the DPD will be high (maximum). This will cause water to enter into the cell when it is placed in a hypotonic solution. The entry of water will stop only when the cell is fully turgid. In such condition, the OP and Tp will be equal and hence DPD will be 0. Therefore, DPD determines the ability of the cell to absorb water. So, the correct option is ' DPD'.

Which of the following statements is correct?

  1. Bacteria do not survive in salted pickles because they get plasmolyzed in hypertonic medium.

  2. Osmotic potential is numerically equal to the osmotic pressure but is negative in sign.

  3. Kneading of wheat flour is accompanied by release of heat as a result of water being imbibed by the protein in the flour

  4. All of these


Correct Option: D
Explanation:

A- Salting is used because most bacteria, fungi and other potentially pathogenic organisms cannot survive in a highly salty environment, due to the hypertonic nature of salt. Any living cell in such an environment will become dehydrated through osmosis and die or become temporarily inactivated.

B- The modern plant physiologists have substituted the term osmotic pressure (O.P.) by osmotic potential. However, it is to be noted here that osmotic potential is numerically equal to the osmotic pressure but is negative in sign and it (osmotic potential) is denoted by ψ(psi). Thus
O.P = – ψ or ψ = –O.P.

So, the correct option is  'Option D'.

Which of the following statements does not apply to reverse osmosis?

  1. It is used for water purification

  2. In this technique, pressure greater than osmotic pressure is applied to the system

  3. It is a passive process

  4. It is an active process


Correct Option: C
Explanation:

Osmosis is passive transport where water follows down the gradient across a semi-permeable membrane from a higher concentration to a  lower concentration. Reverse osmosis simply means that the cumulative pressure gradients cause the flow of water molecules to go against the osmotic pressure gradient from a lower concentration to the higher concentration. 
As the process of reverse osmosis requires energy for transporting molecules against the concentration gradient, it is an active process.

The concentration of solute in four cells is $0.4\,M$. They are placed in four separate containers I, II, III and IV, filled with saline water of concentration $0.1\,M$, $0.4\,M$, $2\,M$ and $3\,M$ respectively. In which container will the cell swell?

  1. $I$

  2. $II$

  3. $III$

  4. $IV$


Correct Option: A
Explanation:

Concentration of container-I with respect to the cell is hypotonic, therefore, endosmosis occurs and water will move from its higher concentration towards its lower concentration(i.e., from container to cell), as a result of which cell in container-I will swell.

The maximum pressure developed in a solution when separated from pure water by a semipermeable membrane is called

  1. Turgor pressure

  2. Wall pressure

  3. Osmotic pressure

  4. DPD


Correct Option: C
Explanation:

Osmotic pressure refers to the maximum amount of pressure, which gets developed in a solution after separating from a pure solvent with the help of a semipermeable membrane. In other words, osmotic pressure is the maximum pressure required to prevent the flow of pure water into a given solution through osmosis.

A plant cell placed in pure water will

  1. expand until the osmotic potential or solute potential reaches that of water

  2. becomes more turgid until the pressure potential of cell reaches its osmotic potential

  3. become more turgid until the osmotic potential reaches that of pure water.

  4. becomes less turgid until the osmotic potential reaches that of pure water.


Correct Option: B
Explanation:

Plant cells are enclosed by a rigid cell wall. When the plant cell is placed in a hypotonic solution, it takes up water by osmosis and starts to swell, but the cell wall prevents it from bursting. The plant cell is said to have become "turgid" i.e. swollen and hard. The pressure inside the cell rises until this internal pressure is equal to the pressure outside. This liquid or hydrostatic pressure called the turgor pressure prevents further net intake of water. 

So the correct answer is 'becomes more turgid until the pressure potential of the cell reaches its osmotic potential'.

If a red blood cell (interior concentration of 0.9% salt) was placed into a test tube of 10% salt, what would happen to the red blood cell?

  1. It would fill with water and burst

  2. Nothing, the solution is isotonic to the interior of the red blood cell

  3. The red blood cell would shrink as it loses water to the salt solution in the test tube

  4. None of these


Correct Option: C
Explanation:

In this case, the concentration of solution outside the blood cell is more and is thus called as hypertonic. It infers that the cell will shrink, as the water inside the cell moves outside making the cell flaccid. This process is called exosmosis. It happens because of the variation in the concentration gradient.

So, the correct answer is option C.

What will happen if a plant and animal cell is put in a hypotonic solution?

  1. Cell swells

  2. Cell shrinks

  3. Cell bursts

  4. None of these


Correct Option: A
Explanation:

Hypotonic solution is a solution which, contains lesser solute concentration. If animal and plant cells are kept in a hypotonic solution then endosmosis will occur. Endosmosis is a process in which the water molecules move from outside of the cell of lower solute concentration to the inside of the cell of higher solute concentration through the cell membrane or cell wall. Due to endosmosis, both animal and plant cells will swell. So, the correct answer is option A.

What will be observed when a plant or animal cell is put in a hypertonic solution?

  1. Cell swells

  2. Cell shrinks

  3. Cell bursts

  4. None of these


Correct Option: B
Explanation:

A Hypertonic solution is a solution, which contains higher solute concentration. If animal and plant cells are kept in hypertonic solution then exosmosis will occur. Exosmosis is a process in which the water molecules move from inside of the cell of lower solute concentration to the outside of the cell of higher solute concentration through the cell membrane. Due to exosmosis, both animal and plant cells will shrink. 

So, the correct answer is option B.

If cells of onion peel and RBC are separately kept in hypotonic solution, what among the following will take place? 

  1. Both the cells will swell

  2. RBC will burst easily while cells of onion peel will resist the bursting to some extent

  3. Both A and B

  4. RBC and onion peel cells will behave similarly


Correct Option: C
Explanation:

Hypotonic solution is a solution which contains lesser solute concentration. If RBC is kept in hypotonic solution, then the water molecules will move from hypotonic solution to RBC. This process is called as endosmosis in which the water molecules move from lower solute concentration to higher solute concentration through the membrane of RBC. Due to this, the cell membrane of RBC will not be able to tolerate the pressure and it will burst eventually. If onion peel is kept in hypotonic solution, then endosmosis will occur. As onion cell possess cell wall along with the cell membrane the onion cell will take a longer time to burst than RBC, but it will burst eventually.

So, the correct answer is option C.

Mammalian liver cells will swell, if they are kept in 

  1. Hypertonic solution

  2. Hypotonic solutions

  3. Isotonic solution

  4. Isothermal solutions


Correct Option: B
Explanation:

A Hypertonic solution is a solution, which contains higher solute concentration. If mammalian liver cells are kept in hypertonic solution then exosmosis will occur. Exosmosis is a process in which outward movement of water molecules takes place from inside of lower solute concentration to the outside of higher solute concentration through the cell membrane. Due to exosmosis, mammalian liver cells will shrink. So, the correct answer is option B.

Grapes were put in a concentrated sugar solution. On examination after 12 hours, the grapes were shrunken. This is because

  1. Grapes become sweeter

  2. Water evaporates from the solution

  3. Sugar induces disintegration of grapes

  4. Loss of water from grapes by osmosis


Correct Option: D
Explanation:

Grapes were put in sugar solution i.e., in hypertonic solution. Due to which exosmosis occurs in which outward movement of the water molecules from the lower solute concentration to higher solute concentration takes place through grapes covering. It results in shrinking of grapes. Therefore, option D is correct.

When amoeba is placed in a hypertonic medium, it shrinks. Why does this happen? 

  1. Due to exosmosis

  2. Due to endosmosis

  3. Due to both

  4. None of the above


Correct Option: A
Explanation:

If amoeba is kept in hypertonic solution then exosmosis occurs in which the water molecules move outward from cell of lower solute concentration to surrounding medium of higher solute concentration through the cell membrane. Due to exosmosis, amoeba will shrink. 

Therefore, option A is correct. 

A single-celled organism which has contractile vacuole to move water from inside to outside of the cell was studied in an experiment in which the organism was placed in water with different salt concentrations. The rate at which the contractile vacuole contracted to pump out excess water was recorded.

Salt conc. Rate of contractile vacuole contractions per minute
Very high 2
High 8
Medium 15
Low 22
Very Low 30

Which of the following explains the observed relationship between the rate of contractile vacuole contraction and the salt concentration?

  1. When the salt concentration outside the cell is very low, osmosis causes body salts to move outside the cell, increasing water content in body and the contractile vacuole needs to contract rapidly

  2. When the salt concentration outside the cell is very high, diffusion causes water to move outside the cell, and the contractile vacuole does not need to contract as rapidly

  3. When the salt concentration outside the cell is very low, diffusion causes water to move outside the cell, and the contractile vacuole contractions are increased

  4. When the salt concentration outside the cell is very high, osmosis causes water to move outside the cell, and the contractile vacuole does not need to contract as rapidly


Correct Option: D
Explanation:

The lower the concentration of the salt solution, the higher will be the water potential of that solution. The higher the water potential, the greater is the tendency for water to enter the cell by osmosis. If there is more water entering by osmosis, then the contractile vacuole will have to fill up and empty more frequently. 

So, the correct answer is option D.

All of the following involves osmosis except

  1. Water passing from a root hair to adjacent cells.

  2. Water passing from a xylem vessel element to xylem vessel element above it.

  3. Water entering a mesophyll cell from the xylem vessel element.

  4. Water from soil entering a root hair.


Correct Option: B
Explanation:

Water passing from a xylem vessel element to xylem vessel element above it due to the transpiration pull exerted by the mesophyll cells. However, the transfer of water from the soil to the root is due to osmosis.

Therefore, the correct answer is option B.

OP of a cell can be measured by 

  1. Manometer

  2. Photometer

  3. Calorimeter

  4. Plasmolysis


Correct Option: D
Explanation:

Manometer is a device that is used to measure pressure. Photometer is a device that is used to the intensity of light. Calorimeter is a device that is used to measure the amount of heat involved in a reaction. Osmotic pressure is the pressure that must be applied in order to prevent the passage of solvent due to osmosis. The OP of a cell can be measured by plasmolysis. The OP of a cell is equal to the OP of a solution that results in the incipient plasmolysis in the cell.

Thus, the correct answer is option D.

In root hair, water enters due to 

  1. Diffusion

  2. W.P.

  3. T.P.

  4. O.P.


Correct Option: D
Explanation:

(A) Diffusion is the movement of the water molecule from higher concentration to lower concentration.

(B) Wall pressure is the pressure applied by the cell wall against the turgor pressure.
(C) Turgor pressure is pressure applied against the wall pressure.
(D) Osmotic pressure is the pressure applied to prevent osmosis that is the movement of the water molecule from a lower solute concentration to a higher concentration through a semi-permeable membrane. Absorption of water through roots is by osmotic pressure.
So, the correct answer is 'Osmotic pressure'.

A cell with DPD = 5 is surrounded by A, B, C and D cells having O.P. and T.P. 5 and 4, 7 and 5, 3 and 2, zero and zero respectively. From which cell will the water withdraw faster?

  1. D

  2. C

  3. B

  4. A


Correct Option: A
Explanation:

DPD is the difference between Osmotic pressure and Turgor pressure. 

For cell A the DPD is 1.
For cell B the DPD is 2.
For cell C the DPD is 1
For cell D the DPD is 0.
So, the correct answer is 'D'.

Colligative property is :
1. Osmotic pressure
2. Vapour pressure
3. Cohesive force
4. Surface tension

  1. 1, 2, 3

  2. 1, 2

  3. 2, 4

  4. 1, 3


Correct Option: B
Explanation:

Colligative properties are the characteristics of solutions which depend on the ratio of the number of solute particles to the number of solvent molecules in a solution. It does not depend on the quality of the chemical species present.

Colligative properties include vapor pressure, elevation of boiling point, depression of freezing point and osmotic pressure because, over here all depends only on the number of dissolved particles.
So, the correct answer is option B.

A RBC and a plant cell having same O.P. are placed in distilled water, then 

  1. None undergoes any change.

  2. Plant cell swells up and bursts but plant cell remains about the same size.

  3. RBC swells up and bursts but there is no change in plant cell.

  4. Both decrease in size and collapse.


Correct Option: C
Explanation:

Distilled water is a hypotonic solution contained within the red blood cell membranes that is why distilled water will diffuse into the red blood cells and cause them to burst.

So, the correct answer is 'RBC swells up and burst but there is no change in the plant cell'.

If cells of onion peel and RBC are separately kept in hypotonic solution, what among the following will take place?

  1. Both the cells will swell

  2. RBC will burst easily while cells of onion peel will resist the bursting to some extent

  3. A and B both are correct

  4. RBC and onion peel cells will behave similarly


Correct Option: C
Explanation:

Hypotonic solution is a solution which contains lesser solute concentration. If RBC is kept in hypotonic solution then the water molecules will move from hypotonic solution to RBC. This process is called as osmosis in which the water molecules move from lower solute concentration to higher solute concentration through cell membrane RBC. Due to this, the cell membrane of RBC will not be able to tolerate the pressure and it will burst eventually. 
If onion peel is kept in hypotonic solution then the water molecules will move from hypotonic solution to onion cells. This process is called as osmosis in which the water molecules move from lower solute concentration to higher solute concentration through the cell wall of onion. As onion cell possess cell wall along with the cell membrane the onion cell will take a longer time to burst than RBC but it will burst eventually. 
So, the correct answer is option B.

Cells of onion peel and RBC are separately kept in hypotonic solution, what among the following will take place?

  1. Both the cells will swell

  2. RBC will burst easily while cells of onion peel will resist the bursting to some extent

  3.  RBC and onion peel cells will behave similarly

  4. Both A and B


Correct Option: D
Explanation:

When the cells are kept in a hypotonic solution, endosmosis occur, i.e., inward movement of water. This results in the swelling up of the cells. The RBCs burst easily because they are animal cells and do not have cell wall. The onion peel possess cell wall which makes it resistant to bursting due to swelling caused by endosmosis. Therefore, option D is correct.

What will happen when a Red Blood Cell (RBC) is kept in concentrated saline solution?

  1. It will lose water and shrink

  2. It will absorb water and swell

  3. It will be remain unaffected

  4. None of the above


Correct Option: A
Explanation:

When RBCs are kept in concentrated saline solution then such solution is said to be hypertonic. Hence, exosmosis i.e., water will move from inside to outside of RBC through its cell membrane due to this, RBCs will shrink.

So, the correct answer is option A.

Choose the correct answers from the alternatives given :
The relationship between osmotic pressure, turgor pressure and wall pressure is represented by

  1. TP=OP+WP

  2. OP=TPWP

  3. WP = TP OP

  4. OP = TP + WP


Correct Option: B
Explanation:

Wall pressure is equal and opposite to the turgor pressure.

TP =  WP 
Also, DPD/SP = OP- WP 
           WP = TP 
        DPD = OP - TP 
In fully turgid cells, turbo pressure is equal to osmotic pressure. Hence, division pressure deficit is zero in such case 
           OP = TP (in turgid cell) 
           DPD = 0 (zero) 
In fully plasmyzed cells, the value of turgor pressure becomes zero due to decrease in TP and increase of OP.
       TP = 0 
      SP/DPD = OP (in plasmolyzed cells) 
Now a days water potential is used which is equal to DPD.
    WP = DPD 
So, the correct option is 'Op= TP WP'.

Most common type of absorbent for $H _{2}S$ removal is

  1. Lead

  2. ethanolamines

  3. Fluorides

  4. CO


Correct Option: B

According to fluid mosaic model (proposed by Singer and Nicolson), plasma membrane is composed of 

  1. Cellulose, hemicellulose

  2. Phospholipid and integrated protein

  3. Phospholipid, extrinsic protein, intrinsic protein

  4. Phospholipid and hemicellulose


Correct Option: C
Explanation:
According to fluid mosaic model, plasma membranes are quasifluidic structures with a viscous lipid bilayer made up of phospholipids having proteins at places distributed as mosaic both on the surface and inside. Singer and Nicolson have described cell membrane as protein icebergs floating in sea of lipids. External proteins are called extrinsic proteins or peripheral proteins while the internal proteins are named intrinsic or integral.
So, the correct answer is 'Phospholipid, extrinsic protein, intrinsic protein'.

The cell membrane engulfs its food by a process called as 

  1. Exocytosis

  2. Endocytosis

  3. Osmosis

  4. Diffusion


Correct Option: B
Explanation:

Endocytosis is the process in which cells absorb molecules by engulfing them. The cell membrane engulfs food and other materials by endocytosis. The plasma membrane creates a small deformation inward, called as an invagination, in which the substance to be transported is captured. The deformation then pinches off from the membrane on the inside of the cell, creating a vesicle containing the captured substance. Endocytosis is a pathway for internalizing solid particles, small molecules and ions and macromolecules. Endocytosis requires energy and is thus, a form of active transport.

Thus, the correct answer is 'Endocytosis'.

Water uptake in Imbibition takes place through ________

  1. Absorption

  2. Adsorption

  3. Sorption

  4. All of the above


Correct Option: A
Explanation:

Imbibition is a special type of diffusion when water is absorbed by solids- colloids causing an enormous increase in volume. Examples include the absorption of water by seeds and dry wood.

Imbibition occurs due to?

  1. Increase in volume of imbibate

  2. Adsorption of imbibate by imbibant

  3. Absorption of imbibant by imbibate

  4. Loss of energy in the form of heat


Correct Option: A
Explanation:
Imbibition is a special type of diffusion when water is absorbed by solids and colloids causing an enormous increase in volume. The substance that imbibes water is called imbibant, and the liquid which is imbibed is called imbibate. Imbibition occurs due to the increase in the volume of imbibate.

 Hence, the correct answer is option A.

Which of the following statements is correct?

  1. Cells shrink in hypertonic solution and swell in hypotonic solution.

  2. Imbibition is a special type of diffusion when water is absorbed by no living parts.

  3. Most of water flow in the roots occur via the apoplast.

  4. All of the above


Correct Option: D
Explanation:

Following are the correct statements: 

(1) Cells shrink in a hypertonic solution and swell in the hypotonic solution.
(2) Imbibition is a special type of diffusion when water is absorbed by no living parts.
(3) Most of the water flow in the roots occur via the apoplast.
So, the correct answer is (d).

The principle used in pickling is

  1. Imbibition

  2. Endosmosis

  3. Plasmolysis

  4. None of the above


Correct Option: A

Absorption of water from soil by seeds increases the _________ thus helping seedlings to come out of soil.

  1. DPD

  2. Diffusion pressure

  3. Imbibition pressure

  4. Solute potential


Correct Option: C
Explanation:

Imbibition is the initial step in the germination of the seeds. When mature seeds are sown in soil they imbibe water and swell. The water is imbibed first by seed coat and then by other tissues of embryo and endosperm. The process of imbibition is important ot initiate the seed germination. the pressure that an imbibant develops when submerged in pure imbibing liquid is called imbibition pressure.

The practice of breaking of rocks during rainy season by inserting wooden pegs in them is based on the phenomenon of ______________.

  1. Imbibition pressure

  2. Turgor pressure

  3. Osmotic pressure

  4. Wall pressure


Correct Option: A
Explanation:

Imbibition pressure generated during germination of seeds and spores is so enormous that it can break asphalt roads and concrete pavements. In older times, the imbibition pressure was used in breaking the rocks and stones. Dry wooden stakes, if driven into a small crack in a rock and then soaked, can develop enough pressure to split the rock.

Movement of solvent molecule from a region of its higher concentration to a region of its lower concentration through a semi-permeable membrane, is referred to as.

  1. Simple diffusion

  2. Facilitated diffusion

  3. Osmosis

  4. Active transport


Correct Option: C
Explanation:

When the two solutions having different osmotic concentrations are separated by means of a semipermeable membrane, the molecules of solvent or water move from the region of their higher diffusion pressure (or free energy) to the region of their lower diffusion (or free energy). This movement of water or solvent is called osmosis.

Choose the correct answers from the alternatives given.
The first process by which water enters into the seed coat when a seed is placed in a suitable situation for germination is

  1. Root pressure

  2. Absorption

  3. Osmosis

  4. Imbibition


Correct Option: D
Explanation:

Imbibition is the process of absorption of water by hydrophilic solid particles. It is a special type of diffusion as the water moves along its concentration gradient. The classical example includes the absorption of water by seeds. This process plays an important role in the germination of seed, rupturing of the seed coat, and the emergence of seedlings is due to imbibition pressure developed by the seed kernel.

Hence, the correct answer is 'Imbibition'.

The uniformly sweet taste of coffee or tea is due to

  1. Spreading

  2. Permeability

  3. Distribution

  4. Diffusion


Correct Option: D
Explanation:

Coffee and tea tastes uniformly sweet due to the diffusion of solvent from the high concentration to the lower concentration. There is no membrane and it is not the case of osmosis and permeability.

So the correct optoin is D.

Read the given statements and select the correct ones.
(i) A membrane which permits the passage of pure solvent molecules to pass through it and not the solute particles is called semi-permeable.
(ii) A membrane which allows some substances to pass through it more readily than others is known as selectively/differentially permeable.
(iii) All living biological membranes are perfectly semipermeable.

  1. (i) and (iii)

  2. (ii) and (iii)

  3. (i) and (ii)

  4. (i), (ii) and (iii)


Correct Option: A
Explanation:
There are certain membranes, which allow penetration of only solvent molecules but not the solute particles. Such membranes are known as semi-permeable. Examples of such membranes are cellophane, fish and animal bladders, egg membrane, plasma membrane, etc. The biological membranes are not perfectly semi-permeable. They allow to pass solute molecules only up to a certain extent and are, therefore, selective in nature. They are known as selectively or differentially permeable membranes. All living biological membranes are differentially permeable membranes, which allow some substances to pass through it more readily than others.
So, the correct answer is '(i) and (iii)'.

Essence of environmental sciences involve:

  1. Social aspect

  2. Political aspect

  3. Economic aspect

  4. All of above


Correct Option: D

Monovalents like $Na^+$, $K^+$ .......... membrane permeability, while divalents like $Ca^{2+}$ .......... the same.

  1. Increase, Decrease

  2. Decrease, Increase

  3. Increase, Increase

  4. Decrease, Decrease


Correct Option: B
Explanation:
The permeability of plasma membrane increase with small sized ions and decrease with large sized ions because small sized molecules can easily diffuse across the plasma membrane.
Since, divalent molecules are smaller than monovalent molecules, hence, the permeability of plasma membrane increase with divalent cations like calcium and decrease with monovalent ions like sodium and potassium..
So, the correct answer is 'Decrease, Increase'.

A semi-permeable membrane allows larger molecules to pass through but prevents the smaller ones.

  1. True

  2. False


Correct Option: B
Explanation:

A semi-permeable membrane doesn't allow larger molecules. It will allow dissolved molecules and water to pass through according to the concentration gradient and the chemical nature of the substances.

Hence, the statement is false.

Term plasmodesmata was first used by

  1. Leuwenhock

  2. De Duve

  3. Strasburger

  4. Porter


Correct Option: C
Explanation:
In plants, cell wall possesses minute cytoplasmic bridges between adjacent cells. They are called plasmodesmata. Term plasmodesmata was first used by Strasburger in 1901.
So, the correct answer is 'Strasburger'.
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