1. Transport and Circulation

2. We’ll 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

4. FACTORS AFFECTING TRANSPORT OF MATERIALS
SOLUBILITY OF MOLECULES
“LIKE DISSOLVES LIKE”
2. CONCENTRATION
3. SIZE
4. CHARGE
5. TEMPERATURE/PRESSURE/ ENVIRONMENTAL CONDITONS

5. FLUID MOSAIC MODEL OF A UNIT MEMBRANE

6. 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

7. Active vs Passive Transport

8. Transport of large molecules

9. Summary of Transport Processes
Diffusion
Osmosis
Facilitated Diffusion
Pumps
Endocytosis/exocytosis
Direction
High to Low
Low to High
N/A
Transport Mechanism
Pores
Channels
Membrane
Energy Required? No
Yes
Type of particle
Small, nonpolar
Water
Small-medium
Ions
Small-large
Examples of particles
CO2, O2
H2O
Glucose, fructose, Na+, Ca+2
Na+, K+, H+
Food, waste

10. 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

11. Transport in Plants

12. 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.

14. Vascular tissues: xylem and phloem
Tracheids*
Vessel elements*
Parenchyma cells
Fiber
Phloem
Sieve-tube members
Companion cells
Sclerenchyma fibers
Both are continuous throughout the plant body

15. 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

16. 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.

17. A variety of physical processes are involved in the different types of transport
Sugars are produced by
photosynthesis in the leaves. 5
Through stomata, leaves take in CO2 and expel O2. The CO2 provides carbon for
photosynthesis. Some O2 produced by photosynthesis is used in cellular respiration. 4
CO2 O2
Light
H2O
Sugar
Transpiration, the loss of water
from leaves (mostly through
stomata), creates a force within
leaves that pulls xylem sap upward. 3
Sugars are transported as
phloem sap to roots and other
parts of the plant. 6
Water and minerals are
transported upward from
roots to shoots as xylem sap. 2
Roots absorb water
and dissolved minerals
from soil
Root hairs & mycorrhizae increase surface area for absorption 1
Roots exchange gases
with the air spaces of soil,
taking in O2 and discharging
CO2. In cellular respiration,
O2 supports the breakdown
of sugars. 7 O2
H2O
CO2
Minerals

18. 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

19. Short-distance H2O transport from the soil to the root xylem occurs through diffusion

20. 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)

21. WATER AND MINERALS ASCEND FROM ROOTS TO SHOOTS THROUGH THE XYLEM ROOT PRESSURE TRANSPIRATION–COHESION–TENSION THEORY
Tension – negative pressure

22. Stomata help regulate the rate of transpiration
Lower epidermal
tissue
Trichomes
(“hairs”)
Cuticle
Upper epidermal tissue
Stomata
100 m
Stomata help regulate the rate of transpiration
Leaves – broad surface areas
Increase photosynthesis
Increase water loss through stomata (transpiration)
Turgid
Flaccid

23. Turgid
Flaccid

24. Translocation – transport of organic molecules in the plant
ORGANIC NUTRIENTS ARE TRANSLOCATED THROUGH THE PHLOEM (PRESSURE – FLOW MODEL of PHLOEM SAP TRANSPORT)
Vessel
(xylem)
H2O
Sieve tube
(phloem)
Source cell
(leaf)
Sucrose
Sink cell
(storage
root) 1
Loading of sugar (green dots) into the sieve tube at the source reduces water potential inside the
sieve-tube members. This causes the tube to take up water by osmosis. 2 4 3
This uptake of water generates a positive pressure that forces the sap to flow along
the tube.
The pressure is relieved by the unloading of sugar and the consequent loss of water from the tube at the sink.
In the case of leaf-to-root
translocation, xylem recycles water from sink
to source.
Transpiration stream
Pressure flow
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

25. 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