Transport and Circulation by grapieroo6

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									Transport and Circulation
We’ll be discussing
1. Cellular Transport
2. Plant Tissues and
   Transport in Plants
3. Trends and Various
   Strategies Used by
   Animals to Transport
   Materials
4. Transport in Man
5. Disorders of the
   Circulatory System
   FACTORS AFFECTING
 TRANSPORT OF MATERIALS
1. SOLUBILITY OF MOLECULES
      “LIKE DISSOLVES LIKE”
2. CONCENTRATION
3. SIZE
4. CHARGE
5. TEMPERATURE/PRESSURE/ ENVIRONMENTAL
    CONDITONS
FLUID MOSAIC MODEL OF A UNIT
        MEMBRANE
Membranes and cellular transport
 solubility - “LIKE DISSOLVES LIKE”
phosholipids can bridge 2 env’ts and bind H2O-soluble molecules(proteins) to
H2O-insoluble mat’ls
Active vs Passive Transport
Transport of
      large
  molecules
 Summary of Transport Processes
              Diffusion    Osmosis     Facilitated   Pumps      Endocytosis/e
                                        Diffusion                 xocytosis

 Direction     High to    High to Low High to Low    Low to         N/A
                Low                                   High
Transport      Pores        Pores      Channels      Pumps       Membrane
Mechanism

 Energy          No          No            No          Yes           Yes
Required?
  Type of      Small,       Water        Small-       Ions       Small-large
  particle    nonpolar                  medium
Examples of   CO2, O2        H2O       Glucose,      Na+, K+,    Food, waste
  particles                            fructose,       H+
                                       Na+, Ca+2
Transport within      Endomembrane system
                      • Endoplasmic reticulum
the eukaryotic cell      – 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
TRANSPORT IN
     PLANTS
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.
VASCULAR TISSUES:
XYLEM AND PHLOEM

 Xylem
     Tracheids*
     Vessel elements*
     Parenchyma cells
     Fiber
 Phloem
     Sieve-tube members
     Companion cells
     Sclerenchyma fibers
     Parenchyma cells
 Bothare continuous
 throughout the plant
 body
TRANSPORT OCCURS
ON THREE LEVELS

1.   Uptake and release
     of water and solutes
     by individual cells
2.   Short-distance
     transport of
     substances by tissues
     and organs
3.   Long-distance
     transport of minerals
     in water and sap
     within xylem and
     phloem by the whole
     plant body
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.
    A VARIETY OF PHYSICAL PROCESSES ARE
    INVOLVED IN THE DIFFERENT TYPES OF
    TRANSPORT

                                                               5 Sugars are produced by
  4 Through stomata, leaves                                    photosynthesis in the leaves.
take in CO2 and expel O2.
                                                CO2    O2
The CO2 provides carbon for                                        Light
photosynthesis. Some O2
produced by photosynthesis          H2O               Sugar
is used in cellular respiration.

       3
      Transpiration, the loss of water
          from leaves (mostly through
       stomata), creates a force within
  leaves that pulls xylem sap upward.                                          6  Sugars are transported as
                                                                               phloem sap to roots and other
                                                                               parts of the plant.
                  2Water and minerals are
                 transported upward from
              roots to shoots as xylem sap.


   1
Roots absorb water
and dissolved minerals                                                         7 Roots exchange gases
from soil                                                     O2              with the air spaces of soil,
                                                                              taking in O2 and discharging
                                     H2O                                      CO2. In cellular respiration,
Root hairs & mycorrhizae                                       CO2
increase surface area for            Minerals                                 O2 supports the breakdown
absorption                                                                    of sugars.
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
SHORT-DISTANCE H2O TRANSPORT FROM THE
SOIL TO THE ROOT XYLEM OCCURS THROUGH
DIFFUSION
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)
MINERALS ASCEND
FROM ROOTS TO
SHOOTS THROUGH
THE XYLEM
ROOT PRESSURE
TRANSPIRATION–COHESION–
TENSION THEORY

                          Tension –
                          negative
                          pressure
STOMATA HELP                      Cuticle Upper epidermal tissue


REGULATE THE RATE
OF TRANSPIRATION

Leaves – broad surface areas
   Increase photosynthesis
   Increase water loss through
    stomata (transpiration)        Lower epidermal Trichomes Stomata
                                   tissue          (“hairs”)
                                                                       100 m




Turgid                       Flaccid
Flaccid   Turgid
ORGANIC NUTRIENTS ARE
TRANSLOCATED THROUGH THE           Vessel                        Sieve tube             Source cell       Loading of sugar (green
                                  (xylem)                         (phloem)              (leaf)        1   dots) into the sieve tube
PHLOEM                                                                                                    at the source reduces
(PRESSURE – FLOW MODEL                                                                                    water potential inside
                                                                                                          the
of PHLOEM SAP TRANSPORT)                                   H2O
                                                                         1              Sucrose           sieve-tube members.
                                                                                                          This causes the tube to
                                                                                        H2O               take up water by
                                                                                                          osmosis.
   Translocation –                                                 2
                                                                                                      2
    transport of organic                                                                                  This uptake of water
                                                                                                          generates a positive

    molecules in the plant                                                                                pressure that forces




                                    Transpiration stream
                                                                                                          the sap to flow along
                                                                                                          the tube.
   Phloem sap
                                                                                                      3




                                                                        Pressure flow
                                                                                                          The pressure is relieved
       Mostly sucrose                                                                                    by the unloading of sugar
                                                                                                          and the consequent loss
       Sugar source  sugar                                                                              of water from the tube
                                                                                                          at the sink.
        sink                                                                                          4
                                                                                                          In the case of leaf-to-root
       Source is a producer of                                                         Sink cell
                                                                                        (storage          translocation, xylem
                                                                                                          recycles water from sink
        sugar
                                                                                        root)


                                                                                                          to source.

       Sink is a
        consumer/storage                          4
                                                                                   3
                                                                                         Sucrose
        facility for sugar                                 H2O
     high solute concentration at sugar source
P
1.

2.
                     –
     RESSURE FLOW MODEL
     increase in hydrostatic pressure at source end of
     phloem attracts & draws more H2O from xylem
3.   bulk flow of H2O from source end of phloem move
     sugars towards a sugar sink

								
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