Transport In Plants Flashcards
_____ proposed that plants change light energy to chemical energy by transferring an electron in an organised array of pigment molecules and other substances .
Melvin Calvin
The mapping of the pathway of carbon assimilation in photosynthesis earned _______ Noble prize in 1961 .
Melvin Calvin
Over SMALL distances , substances move by ______ and by ______ , SUPLEMENTED by ________.
Diffusion
Cytoplasmic streaming
Active transport
Transport over long distances , proceeds through ___ system .
Vascular ( xylem/phloem_
Transport over LONG distance is called -
Translocation
Cytoplasmic streaming is supplemented by -
Active transport ( involved in short distance transport )
ORGANIC and MINERAL NUTRIENTS undergo _______uni/multi directional transport .
Multi
______ compounds are synthesised in the photosynthetic leaves are exported to all plants of the plants including STORAGE ORGANS .
Organic
____ are taken up by the roots and transported upwards into the stem , leaves and growing regions .
Mineral nutrients
When any part undergoes ______ , nutrients may be withdrawn from such regions and moved to the growing parts .
Senescence
_______ and other chemical signals are also transported , though in ver. Small amounts .
Hormones Or PGRs (plant growth regulators )
Plant hormones or PGRs are transported in very small amounts , sometimes in a strictly _______ or_______ manner from where they are synthesised to other parts .
Polarised
Unidirectional
In a _____ plant ,there is a traffic of compounds ( but very orderly ) moving in diff directions
Flowering -angios
Movement by DIFFUSION is ______ and may be from ONE CELL TO THE OTHER or from CELL-TO-CELL or from the INTERCELLULAR SPACES OF THE LEAVES TO THE OUTSIDE .
Passive
Movement by diffusion is over _______ distances .
Short
Cell-to-cell
In ______ molecules move in. A random fashion .(means of transport )
Diffusion
What is the NET RESULT of the random motion of the molecules in diffusion .
Substances moving from region of HIGER CONC to LOWER conc
Energy expenditure takes place in diffusion .T/F
F
Diffusion is a slow/fast process .
Slow
Diffusion is not dependent on -
A living system
Diffusion is very important to ___ . Why ?
Plants
It is the ONLY MEANS OF GASEOUS MOVEMENT WITHIN THE PLANT BODY .
DIFFUSION in ____ and _____ is obvious but diffusion __solids is more likely rather than diffusion ____ solids .
Gases
Liquids
In. , Of
Diffusion is the only means of ______ transport _____ the plant body .
Gaseous
Within
Diffusion rates are affected by -
4 things Gradient of conc Permeability of membrane separating them Temp Pressure
Diffusion rates are affected by pressure .T/F
T
Both T and P affect the rate
A gradient must already be present for _____ to occur .
Diffusion
Facilitated diffusion
Diffusion rates also depends on _____ of substances .
Size
Smaller substances diffuse faster
The diffusion of any substance across a membrane also depends on its SOLUBILITY in _____ .
Lipids - major constituent of the membrane
Substances ______ in lipid , diffuse through the membrane faster .
Soluble
Substances that have a ______ moiety find it difficult to pass through the membrane .
Hydrophilic
(Water loving = water soluble = lipid insoluble
Membrane is made of lipid .)
The movement of which substances is facilitated ( facilitated diffusion )?
Substances that have a hydrophilic moiety ,(which are lipid insoluble )
_____ provide sites at which hydrophilic substances cross the membrane .
Membrane PROTEINS
A _____ must already be present for molecules to DIFFUSE even if facilitated by proteins .
Conc gradient
In facilitated diffusion , special proteins help move substances across a membrane without ______ .
Expenditure of ATP energy
Facilitated diffusion can cause net transport of molecules from LOW to HIGH conc .T/F
F
Becoz this would require energy
Transport rate ( of facilitated diffusion ) reaches a ____ when ALL of the protein transporters are BEING USED ( SATURATION)
Max
_____diffusion is very SPECIFIC .
Facilitated
Why is facilitated diffusion specific ?
Becoz it allows cells to select substances for uptake . Sensitive to inhibitors
Facilitated diffusion is sensitive to ______ which react with ______.
Inhibitors
Protein side chains
The proteins form ______ in the membrane for molecules to pass through. (facilitated diffusion)
Channels
Some channels are open , others may be ______ . Some are ____ allowing a variety of molecules to pass through .
Closed
Large
The ______ are proteins that form LARGE PORES in the OUTER membrane of plastids ,mitochondria and some bacteria .
Porins
Porins are _____
Proteins
Porins are proteins that form large pores in the _____ membrane of plastids , mitochondria and some bacteria .
Outer
Porins form pores in the outer membrane of-
Plastids
Mitochondria
Some bacteria 🧫
Porins allow molecules upto the size of _______ to pass through .
Small proteins
The transport _____ and releases the bound extracellular molecule inside the cell .
Rotates
Eg - water channel made of 8 types of aqua porins
Water channels are made of ______ different types of AQUAPORINS .
8
Some carrier or transport proteins allow diffusion only if two types of molecules move together .T/F
T
In _______ both molecules cross the membrane in the same direction .
In ______ they move in opposite directions .(types of facilitated difffusion )
Symposium
Antiport
Symports and antiports are ______ active/passive
Passive
Symports ,antiports and uniports are types of -
Facilitated diffusion
When a molecule moves across a membrane INDEPENDENT f the other molecules , the process is called -
Uniport - a type of facilitated diffusion
_____uses energy to transport and pump molecules against a conc gradient .
Active transport
Active transport is carried out by _____.
Specific membrane-proteins
Different proteins in the membrane play a major role in both ____ and _______ transport .
Active
Passive
______ are proteins that use energy to carry substances across the cell membrane .
Pumps
Pumps can transport substances from a __ low conc to a ___conc .
Low to high
UPHILL TRANSPORT
When does the transport rate reach a maximum ? In active transport
When all the protein transporters are being used or are saturated .
The carrier protein in active transport is very ____ in what it carries across the membrane .
Specific
Like enzymes
The carrier proteins are sensitive to ______ that react with protein sidechains .
Inhibitors
Proteins in the membrane are responsible for _____ and ______ transport .
Facilitated diffusion
Active
Proteins in the membrane show a common characteristic of being -
Highly selective
______ in the membrane are liable to saturate , respond to inhibitors and are under hormonal regulation .
Proteins
Diffusion whether facilitated or not , take place _____ a conc gradient and ___ energy . ( use / do not use )
Along
Do not
Simple diffusion is highly selective .T/F
F
Facilitated transport requires ATP energy or not ?
No . Does not require
Out of facilitated , simple diffusion and active tran which one is UPHILL transport ?
Only active ( against the gradient )
Which transport mechanism is highly selective ?
Facilitated diffusion
Active transport
Which transport mechanism has TRANSPORT SATURATES ?
Facilitated
Active transport
The _______of cell is nothing but water in which diff molecules are dissolved and suspended .
Protoplasm
a watermelon has ____ % of water . Most hebaceous plants have only about _____ % of its fresh weight as dry matter .
92%
10-15%
In a plant , _____ parts have relatively very little water but ___ parts mostly contain water .
Woody
Soft
A seed appears dry but has water for respiration because it is ALIVE .
T/F
T
A mature CORN pant absorbs almost ______ water in a day ,
While a ____ plant absorbs water equal to its own weight in 5 hours .
3 L
Mustard
Mustard plant absorbs water equal to its own weight in about _____ .( time)
5 hours
Water is often the _____ for plant growth and productivity in both agricultural and natural environments .
Limiting factor
______ is the concept fundamental to understanding water movements .
Water potential
_____ and ______ are the 2 main components to determine WATER potential .
Solute potential
Pressure potential
Water molecules possess _____ . The grater the conc of water in a system , _______ is its K.E .
KE
Greater
The greater the conc of water in a system , greater is its ______ , or _______.
KE
Water potential
(KE = water potential )
Pure water has the ______ WATER POTENTIAL .
Highest
Becoz pure water has only water molecules and therefore , an the greater the conc of water molecules = greater their KE = greater water potential
Net movement of water molecules in a system occurs from a system with ______ energy to a system with _____ energy .
Higher
Lower
Water will move from a system containing ______ water POTENTIAL to the one having ______ W.P .
Higher
Lower
( higher to lower energy )
Process of movement of water from high WP to low WP is called -
Diffusion
Along conc gradient
Water potential is denoted by_____ symbol Psi and is expressed in PRESSURE units such as _______.
Greek
Pascal
If some solute is dissolved in pure water , the solution has fewer ______ molecules , hence the free energy / conc of _____ dec reducing its _______ .
Water
Water
Water potential
All solutions have a ______ water potential than PURE water .
Lower
The magnitude of the lowering of water potential due to dissolution of a SOLUTE is called -
Solute potential
Solute potential is always ______ (+/-)
-ve
Becoz WP of pure water is 0 . And lowering would be -ve
The more the ______ molecules , lower ( more -ve ) is solute potential .
Solute
For a solution at ATMOSPHERIC PRESSURE ,_______ potential = ______ potential .
Water
Solute
If pressure greater than Atmospheric press is applied to pure water or a solution , its ________ INCREASES .
Water potential
When water enters a plant cell due to diffusion , pressure builts up against _______ making the cell TURGID .
Cel wall
When the pressure builts up against the cell wall making the turgid ( due to diffusion of water inside the cell ) , the ____INCREASES .
Pressure potential
Pressure potential is usually +/-ve.
+ve
Exception - plants , -ve potential or tension in water column of xylem helps in transport of water .
_______ potential or tension in the water column in the xylem plays a major role in water transport up a stem .
-ve pressure potential
Cell membrane / wall is FREELY permeable to water and substances in solution hence is not a barrier t movement .
Cell wall
In plants , the cell contains a large vacuole whose contents are -
Vacuolar sap - contribute to the SOLUTE potential
The vacuolar sap contributes to the _____ potential in a plant cell .
Solute potential
In plant cells , the ____ and ______ together are important determinants of movement of molecules in or out of the CELL .
Cell membrane
Tonoplast-membrane of vacuole
______ is the term used to refer to the diffusion of water across a DIFFERENTIALLY or SELECTIVELY PERMEABLE membrane .
Osmosis
Osmosis occurs ____ in response to a DRIVING FORCE .
Spontaneously
The NET DIRECTION and RATE of osmosis depends on what factors ??
2
Pressure gradient
Conc gradient
Water will move from its region of __ to _____ .
Higher chemical potential (conc)
Lower chemical potential
Place the egg shell in dil . _______ for a few hours . The egg shell dissolves leaving the membrane intact .
HCL
The PRESSURE required to PREVENT WATER FROM DIFFUSING is -
Osmotic pressure
Osmotic pressure is the function of ______.
SOLUTE CONCENTRATION
More the ______ greater will be the PRESSURE required to prevent water from DIFFUSING IN .
Solute conc .
Osmotic pressure is the ______ (+/-) pressure applied while osmotic potential is ______ (+/-).
+ve
-ve
The behaviour of the plant cells with regard to water movement depends on the -
Surrounding solution
If the external solution balances the ________ of the cytoplasm , it is said to be ISOTONIC .
Osmotic pressure
If the external solution is more DILUTE than the cytoplasm , it is called ______
Hypotonic solution
If the external solution is more CONCENTRATED than the surrounding solution , it is called -
Hypertonic
Cells ______ in hypertonic solution and _____ in hypotonic solution .
Shrink
Swell
________. Occurs when water moves out of the cell and the cell membrane shrinks away from the cell wall .
Plasmolysis
Plasmolysis occurs when the cell is placed in a ___ solution TO THE PROTOPLASM .
Hypertonic (has more solutes )
During plasmolysis ______ shrinks away from the _______ . (Cell wall/membrane )
Cell membrane
Cell wall
during plasmolysis ,when water moves out ,it is first lost from the _____and then from the _______ .
CYTOPLASM
VACUOLE
During plasmolysis , water is first lost from the vacuole.T/F
F
The water when drawn out of the cell through diffusion into the EXTRACELLULAR (outside the cell ) FLIUD causes the _________ to shrink away from the walls .
Protoplast
During plasmolysis , the movement of water occurred across the membrane moving from an area of ___( THE CELL) to an area of ____OUTSIDE THE CELL .
High water potential
Lower water potential
If the external solution balances the OSMOTIC PRESSURE of the cytoplasm ,it is said to be -
Isotonic
When water flows into the cell and out of the cell and re in EQUILIBRIUM , the cells are said to be -
Flaccid
When water flows INTO and OUT of the cell and are in ____ , he cells are said to be FLACCID .
Equilibrium
The process of PLASMOLYSIS is usually _______ (reversible/irreversible)
Reversible
When a cell is placed in a______ solution , water diffuses into the cell causing the CYTOPLASM to build up a pressure AGAINST THE WALL .
Hypotonic (higher water potential or DIL .solution as compared to the cytoplasm )
When the cell is placed in hypotonic solution , the cytoplasm builds up a pressure against the CELL WALL , that is called -
Turgor pressure
The pressure exerted by the protoplasts due to the entry of water against the rigid WALLS ( cell wall) is called -
Pressure potential
Becoz of the RIGIDITY of ______ , the cell does not rupture due to turgor pressure .
Cell wall
The ________ is ultimately responsible for ENLARGEMENT and EXTENSION growth of cells .
Turgor pressure
The pressure exerted by ___ due to ____ against the ____ is called PRESSURE POTENTIAL (Wp).
Protoplast
Entry of water
Rigid walls
Turgor pressure is developed when the cell is placed in a hypertonic/hypotonic .
Hypotonic
When the cell is placed in a hypotonic solution , ___ builds up a pressure against the _____ .
Cytoplasm
Cell wall
(Turgor pressure )
What is the TURGOR PRESSURE responsible for ?
Enlargement and extension growth of cells
_______ is a special type of DIFFUSION when water is absorbed by SOLIDS-COLLOIDS causing them to INCREASE IN VOLUME .
Imbibition
