Transport and Circulation

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Transport and Circulation
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Well be discussing

• Cellular Transport
• Plant Tissues and Transport in Plants
• Trends and Various Strategies Used by Animals to
  Transport Materials
• Transport in Man
• Disorders of the Circulatory System

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FACTORS AFFECTING TRANSPORT OF MATERIALS

• SOLUBILITY OF MOLECULES
• LIKE DISSOLVES LIKE
• 2. CONCENTRATION
• 3. SIZE
• 4. CHARGE
• 5. TEMPERATURE/PRESSURE/ ENVIRONMENTAL CONDITONS

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FLUID MOSAIC MODEL OF A UNIT MEMBRANE
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Membranes and cellular transport solubility -
LIKE DISSOLVES LIKE phosholipids can bridge 2
envts and bind H2O-soluble molecules(proteins)
to H2O-insoluble matls
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Active vs Passive Transport
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Transport of large molecules
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Summary of Transport Processes
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Transport within the eukaryotic cell

• Endomembrane system
• Endoplasmic reticulum
• manufacturing and transport facility
• proteins produced in rough ER are packaged in
  vesicles
• Golgi apparatus
• modification and storage facility
• receiving end and shipping end
• Vacuole
• large membrane bound sacs
• usually stores undigested nutrients
• Cyclosis/cytoplasmic streaming

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Transport in Plants
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Core Concepts

• Transport at cellular level depends on the
  selective permeability of membranes.
• Transport at the cellular level may involve any
  one or a combination of the following
• Passive transport (diffusion, facilitated
  diffusion, osmosis) through the cell membrane
• Active transport (e.g. proton pumps )through
  the cell membrane
• Transport of large molecules involving
  endocytosis, vesicles, and exocytocis
• Cyclosis (cytoplasmic streaming
• Endoplasmic reticulum, Golgi Apparatus, Vacuole
• Plant Transport
• Root hairs, mycorrhiza , and a large surface area
  of cortical cells enhance water and mineral
  absorption.
• The waxy Casparian strip of the endodermis
  regulates movement of water and minerals from the
  cortex to the stele.
• Nutrients from the soil and air are transported
  within a plant by the vascular tissue which are
  continuous throughout the plant body.
• Uptake and release of water and solutes by
  individual cells, such as the absorption of water
  and minerals from the soil by the root cells.
• Short distance or lateral transport of minerals
  and water in the roots either move across the
  root cortex to the vascular cylinder in 3 ways or
  a combination of routes
• through a continuum of cytosol based on the
  plasmodesmata which are protoplast connecting
  channels through walls (symplast).
• Through a continuum of cell walls and extra
  cellular spaces (apoplast).
• by repeated crossing of the plasma membranes and
  walls of the cells along the pathway
  (trans-membrane)
• Long-distance transport of sap is accomplished by
  the xylem and phloem
• The xylem vessels and tracheids are the main
  conducting vessels that move water and minerals
  to various plant parts as described in the
  Cohesion-Tension theory.
• The sieve tubes of the phloem are the main
  conducting vessels that move food to various
  plant parts as described in the Pressure Flow
  Theory.

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Vascular tissues xylem and phloem

• Xylem
• Tracheids
• Vessel elements
• Parenchyma cells
• Fiber
• Phloem
• Sieve-tube members
• Companion cells
• Sclerenchyma fibers
• Parenchyma cells
• Both are continuous throughout the plant body

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Transport occurs on three levels

• Uptake and release of water and solutes by
  individual cells
• Short-distance transport of substances by tissues
  and organs
• Long-distance transport of minerals in water and
  sap within xylem and phloem by the whole plant
  body

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Transport in Plants occurs in three levels

• 1. uptake and release of water and solutes by
• individual cells
• e.g. absorption of water and minerals from
• the soil by the root cells.
• 2. short-distance transport of substances from
• cell to cell at the level of tissues
  and organs, e.g. sugar loading from
  photosynthetic cells
• of mature leaves into the
  sieve tubes of
• phloem
• 3. long-distance transport of sap
• e.g. within the xylem and phloem at the
• level of the whole plant.

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A variety of physical processes are involved in
the different types of transport
CO2
O2
Light
H2O
Sugar
Sugars are transported as phloem sap to
roots and other parts of the plant.
O2
H2O
CO2
Minerals
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ACTIVE TRANSPORT (USE OF PUMPS)TRANSPORT OF
IONS AT THE CELLULAR LEVEL DEPENDS ON SELECTIVELY
PERMEABLE MEMBRANES

• Controls the movement of solutes into and out of
  the cell
• With specific transport proteins
• Enable plant cells to maintain an internal
  environment different from their surroundings

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Short-distance H2O transport from the soil to the
root xylem occurs through diffusion
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Short distance or lateral transport of minerals
and water in the roots either move across the
root cortex to the vascular cylinder in 3 ways or
a combination of routes

• through a continuum of cytosol based on the
  plasmodesmata which are protoplast connecting
  channels through walls (symplast).
• Through a continuum of cell walls and extra
  cellular spaces (apoplast).
• by repeated crossing of the plasma membranes and
  walls of the cells along the pathway
  (trans-membrane)

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WATER AND MINERALS ASCEND FROM ROOTS TO SHOOTS
THROUGH THE XYLEMROOT PRESSURETRANSPIRATIONCOHE
SIONTENSION THEORY
Tension negative pressure
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Stomata help regulate the rate of transpiration

• Leaves broad surface areas
• Increase photosynthesis
• Increase water loss through stomata
  (transpiration)

Turgid
Flaccid
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Turgid
Flaccid
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ORGANIC NUTRIENTS ARE TRANSLOCATED THROUGH THE
PHLOEM(PRESSURE FLOW MODEL of PHLOEM SAP
TRANSPORT)

• Translocation transport of organic molecules in
  the plant
• Phloem sap
• Mostly sucrose
• Sugar source ? sugar sink
• Source is a producer of sugar
• Sink is a consumer/storage facility for sugar

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Pressure flow model

• high solute concentration at sugar source
• increase in hydrostatic pressure at source end of
  phloem attracts draws more H2O from xylem
• bulk flow of H2O from source end of phloem move
  sugars towards a sugar sink

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