BIOLOGY M.C.Q (1 Marks)

Osmosis.

Imbibition.

Abscisic acid.

Temperature.

Hydathodes are also called water stomata through which guttation occurs.
The term stomata is a misnomer, because stomata is an opening, which can be regulated but the opening in hydathodes cannot be regulated. Hydathodes are the modified pores at the margin or tip of the leaves.

Xylem vessels.

swelling of seed in soil is an example of imbibitions. Imbibition is a type of diffusion process along the concentration gradient enabling the solid to absorb water and increase in volume. When seed is put in the soil it absorbs water which activates enzymes present in seed and this induces the seed germination. The other option, i.e., uptake of water by root hair is an example of absorption, exchange in of gases Stamata is an example of diffusion and opening of stomata is an example of turgor pressure or turgidity.

No exchange of water takes place.

Imbibition is the process of absorption of water by the dry surface, in which there is an increase in the volume of the seeds.
The increase in volume generates an imbibitional pressure, which is responsible for the explosion of the jar in this case.

Plasmolysis is the shrinking of the protoplasm as a result of water loss from osmosis when a cell comes in contact with a hypertonic solution.Plant cells kept in hypertonic solution will start losing water by the process of exosmosis as there is lesser concentration of solvent molecules than the fluid inside the cell so the solvent molecules are forced outside the cell from the region of higher concentration to the lower concentration.The cell turns flaccid. On further loss of water, the protoplasm shrinks and moves away from the cell wall and the cell gets plasmolysed.

Hypertonic solution.

Imbibition

Exosmosis is a movement of water from the cell to outside.
This leads to plasmolysis. Plasmolysis is the phenomenon in which protoplasm of the cell of the leaves moves away from the cell wall and starts to shrink.
The plasmolysis leads to drooping of leaves, which is known as wilting.

Remain always open.

For increased absorption of water.

Concentration, volume and temperature change directs and increases the rate of osmosis.
Pressure opposes the osmosis as it prevents the flow of solvent across the membrane.
When osmotic pressure is applied to the system, the osmosis stops.

Imbibition.

Diffusion rate is affected by the gradient of concentration, permeability of the membrane separating them, temperature and pressure.

Imbibition is a physical process in which water is adsorbed on the surface.
Proteins show higher imbibition capacity than cellulose and fats.
Thus, pea seed gets swelled more due to imbibition.

The root dies first.

In a highly concentrated salt solution, water is present at a low concentration as compared to the concentration inside the potato cells.
This leads to loss of water from cells of potato and potato is plasmolysed.

Increase.

Endodermal transpiration

Saturated air is the air that holds water vapor at its highest level.
Guttation is an important process that occurs when conditions are humid and transpiration loss is limited.
Under such conditions, excess water absorbed by roots oozes out through hydathodes in liquid form.

In hypertonic solution, external solution is more concentrated as compared to cytoplasm.
Cells shrink in hypertonic solutions.

Apoplast is nonliving spaces and cell walls.

Imbibition is a physical process of adsorption of water on the surface of the adsorbent material.
During the rainy season the concentration of water vapor is more in the air and if the doors are not properly protected by paints and/ or varnish the wood in them will imbibe water from water vapors present in the air.

Xylem.

Negative water potential.

Water potential depends on the number of water molecules in the solution.More the number of water molecules, more the water potential.Water potential of pure water is maximum.By convention the water potential of pure water is fixed as zero.Water potential of all solutions is hence negative.

Osmosis is a passive process.It does not requires energy.It is defined as movement of water or solvent molecules through a semipermeable membrane along the concentration gradient.If the concentration of solutions on both the sides of semipermeable membrane is same i.e., solutions are isotonic, there is no driving force for osmosis and osmosis shall cease.

Zero and zero

Translocation.

Its vascular bundles are not present in a ring.

Diffusion results in slow speed of movement.

Water potential gradient.

Apoplast.

Multidirectional.

If a pressure greater than atmospheric pressure is applied to pure water, the water potential increases.

Solvent from low concentration of solution to higher concentration of solution.

The location of the stomata primarily on the lower surface of the leaf, the side turned away from the direct sun rays.

Change in turgor pressure of guard cells.

Diffusion is a slow process, it is not dependent on the living systems.

Cytoplasmic streaming.

The stomata control gas exchange in the leaf. Each stoma can be open or closed, depending on how turgid its guard cells are.
In the light, the guard cells absorb water by osmosis, become turgid and the stoma opens.
In the dark, the guard cells lose water, become flaccid and the stoma closes.

Light, temperature, atmospheric humidity and wind.

Transpiration.

Imbibition is a special type of diffusion where solid particles absorb water, causing increase in their volume.
The movement of water is surface potential in nature and it moves along the direction of concentration gradient.
The classical example of imbibition is absorption of water by seeds and dry wood.

With the increase in humidity in atmosphere, rate of transpiration decreases.

Pumps in active transport are proteins that bind molecules to pass them through the membrane.

Diffusion rate is affected by the gradient of concentration, permeability of the membrane separating them, temperature and pressure.

Capillary water.

If pressure greater than the osmotic pressure is applied to the membrane can be reverse. This is called reverse osmosis. higher concentration, the direction of water flow through the Reverse osmosis occurs when water is moved across the membrane against the concentration gradient, from lower concentration to higher concentration. Reverse osmosis is an active process.

Osmotic pressure of a solution is equivalent to the pressure, which must be exerted upon it to prevent the flow of solvent into it across a semipermeable membrane.

Guttation.

Stomatal opening.

Passive absorption.

Guttation is the excretion of drops of xylem sap on the tips or edges of leaves of some vascular plants through hydathode, such as grasses.
It occurs in the absence of light.
i.e., at night and thus it is present on the edge of leaves in the early morning.

Sucrose.

Turgor pressure of guard cells.

Imbibition

Guttation is the loss of water in liquid form as a dilute solution from the leaf tips.
The uninjured leaf tips have hydathodes or water stomata.
Under conditions of low transpiration dilute solution of minerals oozes out through them under the influence of increased root pressure.

Movement of solvent always takes place from high solvent concentration to low solvent concentration. Solute never moves through a semipermeable membrane.

From high chemical concentration to low chemical concentration.

Increased salt concentration

Water potential gradient.

Imbibition is a type of diffusion in which water is absorbed by solids or colloids which leads to increase in volume. This happens in case of dry wood and seeds.

Organic food moves upwardly and downwardly through phloem.

Imbibition.

Plasmolysis occurs due to shrinkage of protoplasm when a plant cell is kept in a hypertonic medium.
In a hypertonic medium, water flows out from a cell to the surrounding medium is called as exosmosis leading to plasmolysis.

The exudation of xylem sap at the edges or tips of the leaves of some vascular plants, like grasses is called guttation.
Unlike transpiration, it takes place only in certain conditions like cool and highly humid atmosphere.
It is because plants can absorb up a limited amount of water.
The excess water is secreted from the roots through the xylem and out through the hydathodes or water glands.

Osmotic pressure develops due to addition of solute particles.
As a solution is expected to have more solute particles as compared to a pure solvent.
The solution will always have more osmotic pressure than pure solvent.

By convention, water potential of pure water at standard temperature is taken as zero.

Active transport.

Nerium.

Guttation.

Root pressure.

Hypertonic solution.

Osmosis is regulated by the inflow and outflow of water molecules from the cell or body through a semipermeable membrane.
Endosmosis is the inflow of water or solvent whereas, exosmosis is the outflow of water or solvent from the cell through a semipermeable membrane.

Potassium.

Hypertonic solution.

Movement is in bulk.

Plasmolysis in a plant cell is defined as the process of shrinkage of the protoplasm as a result of loss of water from the cell.
It occurs when plant cells are placed in a solution that has a higher concentration of solutes than the cell does.
In this, plant cell is kept in hypertonic solution. When cell is placed in hypotonic solution, it is called as turgidity.
If plant cell is kept in an isotonic solution so that it is neither turgid nor plasmolyzed, it is called as flaccidity.

Diffusion is a slow process, it is not dependent on the living systems.

Imbibition is the first phenomenon in seed germination.
Imbibition is a passive physical process and is actually adsorption of water by the dry surface.
It causes swelling of dry seeds. Water is the medium for all the metabolic reactions in the living system.
Hence, the most important requirement of seed germination is water.
Dry seeds adsorb water which marks the beginning of seed germination.

They become turgid.

Active absorption.

Sucrose is a disaccharide. It is the most inactive form of sugar so used in transport.

Hypertonic solution.

Passive absorption.

From hydathodes water is lost in liquid form through a process called as guttation.
The force responsible for guttation is root pressure.
Guttation occurs when loss of water through transpiration is less and excess water is absorbed by plant roots.

Guttation is the phenomenon of the release of small water droplets from the pores of the plants.
It is done in order to release the extra water out of the plant in very humid conditions.
It is commonly seen in mesophytes.
During the absence of sunlight stomata are closed so there is minimal transpiration.
Hence there is a need for guttation.

Broader lumen and perforated cross walls.

Excessive transpiration.

Guttation is the loss of water in liquid form as a dilute solution of water, salts, and sugars from uninjured leaf tips.
The uninjured leaf tips have hydathodes or water stomata.
Under conditions of low transpiration dilute solution of minerals oozes out through them under the influence of increased root pressure.

Guttation is the loss of water in the form of liquid through hydathodes.
The most important force responsible for guttation is root pressure, which develops in conditions of high humidity, because when roots absorb mineral salts water follows passively but transpiration loss of water is less.

Phenyl mercuric acetate.

The seawater is hypertonic to cell sap because of the higher concentration of dissolved solutes.
Thus, water will move out of the cells towards the surrounding solution i.e. from high water potential to low water potential.
This leads to the shrinking of protoplasm away from the cell wall of a plant or bacterium. This is known as plasmolysis.
Hence, if we place a plant cell in seawater it will undergo plasmolysis.

Transpiration is the process in which water vapours are released from the stomata.
Respiration is a metabolic process in which oxygen is used to break down food and carbon dioxide and energy are released.
Evaporation is the process of conversion of liquid water into water vapour.
Guttation is the process of loss of water droplets from pores known as hydathodes and tips of leaves.

Amyloplasts are the colorless plastids which store starch but not the protein granules. Other pairs are correctly matched.

External factors affecting the rate of transpiration are : atmospheric temperature, relative humidity, light, wind velocity, atmospheric pressure and available soil water. Some internal factors also affect rate of transpiration e.g., leaf area, leaf structure and age of plants. Chlorophyll content of leaves does not directly affect rate of transpiration.

Potometer.

Leaching.

This condition does not allow oxygen to enter the soil.

Guttation is loss of water in liquid form as a dilute solution from uninjured leaf tips.
The uninjured leaf tips have hydathodes or water stomata.
Under conditions of low transpiration dilute solution of minerals oozes out through them under the influence of increased root pressure.

Transpiration is the loss of water through stomata in vapour form.
Transpiration is regulated through guard cells.
Guttation is the loss of water in liquid form through hydathodes.
Hydathodes are free ends of vascular supply of leaves.
Hydathodes are always open and not regulated by any cells.

Negative water potential

Hypertonic.

Osmosis and imbibition

Osmosis is the process of net movement of water across a permeable membrane driven by a difference in solute concentration on two sides of the membrane.

Guttation occurs when loss of water is minimum. Usually, early morning, when transpiration is low especially when the previous night was warm and humid, plants show liquid drops on leaves.These are not dew drops but the water that has oozed out through hydathodes.

Xylem tissue is comprised of dead cells involved in the process of transport of water and minerals.
Transport of water is under the influence of transpiration pull and is a physical process.
Phloem tissue is comprised of living cells involved in the process of translocation of sugars.
Translocation of sugars requires living cells and is a physiological process.
The sugars are transported under the influence of pressure difference between source and sink, which leads to mass flow

Zero and zero

In symport, two types of molecules cross the membrane in the same direction.

Capillary water.

Transport of sap.

Changes in the turgor pressure of guard cells.

Transpiration at the leaf surface.

Guttation is the loss of water in liquid form as a dilute solution from uninjured leaf tips.
The uninjured leaf tips have hydathodes or water stomata. Under conditions of low transpiration dilute solution of minerals oozes out through them under the influence of increased root pressure.

Pumps in active transport are proteins that bind molecules to pass them through the membrane.

Root pressure.

Hydrophilic.

Water is absorbed from soil by root hair. This is then carried by cortex, then passed to endodermis.
Endodermis passes water to Perivale then to protoxylem and metaxylem.

Root pressure.

Henry Dixon.

The cell will burst, swell or become turgid when endosmosis occurs i.e., water enters the cell.
In case exosmosis occurs water moves from inside the cell to surrounding solution and the plant cell becomes flaccid.

When a plasmolyzed cell is kept in pure water or hypotonic medium, the cell will uptake water due to the process of endosmosis.
This water uptake will increase turgor inside the cell and cell will become deplasmolysed.

The initial stage of water absorption is always imbibition.
Imbibition is a process of absorption water by dry surface and causing them to enormously increase in volume.
The classical examples of imbibition are the absorption of water by seeds and dry wood.

Guttation is the loss of water in a dilute solution form which consists salts and minerals and waters when transpiration is low.
Guttation is not shown by all the plants and is especially common in humid tropics.
It occurs in the absence of light or at night and thus present at the tip of leaves in early morning.

Plasmolysed

Through cell wall