Presentation 06 - Cellular and Plant Transport
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Transcript of Presentation 06 - Cellular and Plant Transport
Transport and CirculationTransport and Circulation
We’ll be We’ll be discussingdiscussing
1.1. Cellular TransportCellular Transport2.2. Plant Tissues and Plant Tissues and
Transport in PlantsTransport in Plants3.3. Trends and Trends and
Various Strategies Various Strategies Used by Animals to Used by Animals to Transport Transport MaterialsMaterials
4.4. Transport in ManTransport in Man5.5. Disorders of the Disorders of the
Circulatory SystemCirculatory System
Membranes and cellular Membranes and cellular transporttransport
Active vs Passive Active vs Passive TransportTransport
Transport Transport of large of large
moleculesmolecules
Summary of Transport Summary of Transport ProcessesProcesses
Diffusion Osmosis Facilitated Diffusion
Pumps Endocytosis/exocytosis
Direction High to Low High to Low High to Low Low to High N/A
Transport Mechanism
Pores Pores Channels Pumps Membrane
Energy Required?
No No No Yes 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
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
TRANSPORT IN PLANTS
VASCULAR VASCULAR TISSUES: TISSUES: XYLEM AND XYLEM AND PHLOEMPHLOEM
Xylem Tracheids* Vessel elements* Parenchyma cells Fiber
Phloem Sieve-tube members Companion cells Sclerenchyma fibers Parenchyma cells
Both are continuous throughout the plant body
OVERVIEW OF TRANSPORT IN A VASCULAR PLANT
CELLULAR LEVEL TRANSPORT
Plant cells can maintain an internal environment different from their surroundings
SHORT-DISTANCE H2O TRANSPORT IN THE ROOT
WATER AND MINERALS ASCEND THROUGH THE XYLEMROOT PRESSURETRANSPIRATION–COHESION–TENSION THEORY
Tension – negative pressure
STOMATA HELP REGULATE THE RATE OF TRANSPIRATION
Leaves – broad surface areas Increase photosynthesis Increase water loss
through stomata (transpiration)
Lower epidermaltissue
Trichomes(“hairs”)
CuticleUpper epidermal tissue
Stomata 100 m
Turgid Flaccid
TurgidFlaccid
ORGANIC NUTRIENTS ARE TRANSLOCATED THROUGH THE PHLOEM(PRESSURE – FLOW MODEL)
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
Vessel(xylem)
H2O
H2O
Sieve tube(phloem)
Source cell(leaf)
Sucrose
H2O
Sink cell(storageroot)
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Sucrose
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
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2This 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 tubeat the sink.
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4In the case of leaf-to-roottranslocation, xylem recycles water from sinkto source.T
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