Chapter 5 Solute Transport Flashcards
is described as the movement of molecules and ions from one place to
another.
Transport
movement of solutes into cells or within cells is primarily controlled by __
.
membranes
fluid nature of the plasma membrane is due to its composition of (4)
phospholipids, proteins, carbohydrates, and cholesterol
The ____head
points outwards and is in contact with water inside and outside the cell
hydrophilic
the ___
tails composed of fatty acid chains point inwards, forming the membrane’s interior.
hydrophobic
two classifications of proteins that are linked to the lipid bilayer.
Integral
and peripheral proteins
___proteins are situated within the lipid bilayer where they aid in transporting molecules
through the membrane and serve as cell receptors
Integral
___proteins are connected to
the lipid bilayer’s surface and play a role in cell signaling and interactions.
peripheral
molecules move naturally from an area of higher
concentration to an area of lower concentration across a semipermeable membrane; no energy needed
Passive Transport
Types of Passive Transport (3)
Diffusion
Osmosis
Facilitated diff
Solute molecules moving from an area of high concentration to an area of low
concentration.
Diffusion
___
drives diffusion
Random motion
the Random motion Movement is based on (3)
kinetic energy (speed),
charge, and mass of molecules
movement of water molecules from an area of high concentration to an area of low
concentration. Cell membranes are completely permeable to water
Osmosis
osmotic solutions (3)
hypertonic
hypotonic
isotonic
high concentration of solute relative to another solution; water diffuses out of the cell, causing cell shrinkage.
Hypertonic Solutions
loss of
water causes the cell to shrink, a process called __in animal cells or ___in plant
crenation ;
plasmolysis
low concentration of solute relative to another solution; water diffuses into the cell; swelling or bursting may occur
Hypotonic Solutions
same concentration of solute as another solution; water diffuses into and out of the cell at the same rate
Isotonic Solutions
Movement of molecules across a semi-permeable membrane with a protein and it does
not require energy
Facilitated Diffusion
___ is a process that helps larger or polar molecules cross the cell membrane
with the help of specific transport proteins. This allows substances that cannot pass through the
membrane by simple diffusion to enter the cell more efficiently
Facilitated diffusion
mode of transportation in plants, which uses stored energy to move the particles
against the concentration gradient with a protein from lower concentration to higher
concentration.
Active Transport
active transport type
pumps
pumps (2)
endocytosis
exocytosis
eukaryotic cells (except mature erythrocytes) use the fundamental process of
____to capture extracellular molecules by enclosure within membrane vesicles
endocytosis
cells use ___to engulf substances from outside; to feed themselves, to
defend themselves, and to maintain homeostasis
endocytosis
Endocytosis is subdivided into two:
phagocytosis
pinocytosis
___ is the uptake of large particles (solid) into large vesicles called ___( for digestion and breakdown.)
phagocytosis; phagosomes
__ is for the uptake of fluids and solutes into small ___vesicles for nutrient uptake
pinocytosis; pinocytic
vesicle fuses with the cell membrane, releasing the contents to the outside
Exocytosis
___in plants is the process of moving nutrients and organic compounds,
especially sugars, from the leaves—where they are produced through photosynthesis—to other
parts of the plant
Translocation
translocation primarily occurs in the ___tissue, which consists of ____ and ____.
phloem; sieve
tubes; companion cells
translocation process is driven by a ___ mechanism.
pressure flow
translocation mechanism relies on the pressure difference between the __(areas rich in sugars) and
the __(areas where sugars are used or stored)
source;
sink
are long,
hollow columns of cells fused end to end, with partially broken-down end walls
Sieve tube elements
is like a plate with holes to allow the solutes to pass through
Sieve plate
are connected
to companion cells, which are pores in their cell walls that connect the cytoplasm of the two
cells.
Plasmodesmata
specialized cells has a nucleus, numerous ribosomes for protein synthesis, and mitochondria for
energy release; closely associated with sieve tube
elements
Companion cells
is an aqueous
solution that flows through sieve tubes.
Phloem sap
____ refers to the transfer of sugar from mesophyll cells (source) to sieve
tube elements
Phloem loading
___refers to the transfer of sugar from sieve tube elements
to roots or other storage cells.
phloem unloading
two primary mechanisms for loading sugars into the phloem:
symplastic
loading and apoplastic loading.
sugars synthesized in the leaves are transferred directly from cell to cell
through the cytoplasm via plasmodesmata
Symplastic Loading
This method is highly efficient because it allows for the movement of
sugars without crossing cell membranes multiple times
Symplastic Loading
, which are microscopic channels connecting
adjacent plant cells
plasmodesmata
This process involves the movement of sugars through the cell wall spaces, known as
the ___.
Apoplastic Loading ;apoplast
sugars cannot directly enter the phloem cells due to the selective permeability of cell membranes; Instead, once sugars reach the phloem parenchyma, active
transport is required to load them into the sieve tubes.
Apoplastic Loading
____, which are closely associated with sieve elements, utilize ATP to power specific transport proteins that facilitate
this active (apoplastic) loading process
Companion cells
Phloem Unloading two main mechanisms
Passive Unloading
Active Unloading
process of distributing sugars from the phloem to sink tissues
Phloem Unloading
This process relies on concentration gradients;
when the concentration of sugars is higher in the phloem than in the surrounding cells, sugars
naturally move out of the phloem by passive diffusion
Passive Unloading
some sinks—especially those with high metabolic demand, such as actively
growing roots or developing fruits—require more sugars than are readily available; thus active transport mechanisms come into play
Active Unloading
___and other specialized cells utilize ATP to transport sugars against their concentration gradient,
effectively pulling more sugars from the phloem into the sink tissues
Companion cells
a vital process in plant physiology,
responsible for the distribution of essential nutrients and organic compounds throughout the
plant
Sieve Tube Translocation
Translocation relies on 4 key mechanisms
Loading
Osmosis
Bulk flow
unloading
water from the xylem enters the phloem
through ___.
osmosis
Water moves from areas of lower solute concentration (in the ___) to areas
of higher solute concentration (in the ___)
xylem;
phloem
influx of water causes the phloem cells to swell, resulting in increased ____ within the sieve tubes.
turgor
pressure
. Following the unloading of sugars, the concentration
of solutes in the phloem decreases, which reduces the ___ pressure. Water that has entered
the phloem will move back into the xylem through ___
osmotic;
osmosis
