M3: Transport in Plants Flashcards by Etin <3

3.1.3 Transport in Plants: Exchange of Substance

Why do plants need Transport Systems?

They’re multicellular organisms
Small SA:V ratio
High Metabolic rate

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3.1.3 Transport in Plants: Exchange of Substance

Why would Exchanging Substances through Simple Diffusion be ineffective?

Plants = multicellular
↳ this process would be too slow for their metabolic needs

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3.1.3 Transport in Plants: Exchange of Substance

What materials do Plants Transport?

Carbon Dioxide
Oxygen
Water
Organic Nutrients
Inorganic ions

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3.1.3 Transport in Plants: Useful Ions

What’s the Function of Mg Ions?

Found in chlorophyll
↳ keeps plant green

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3.1.3 Transport in Plants: Useful Ions

What’s the Function of K Ions?

Makes up DNA

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3.1.3 Transport in Plants: Useful Ions

What’s the Function of N Ions?

Makes up proteins

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3.1.3 Transport in Plants: Photosynthesis

What’s Photosynthesis?

Plants producing glucose through sunlight

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3.1.3 Transport in Plants: Transpiration Summary

What’s Transpiration?

Passive process where water is lost through evaporation

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3.1.3 Transport in Plants: Transpiration Summary

In which direction does Transpiration occur?

Up the plant
* roots to leaves

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3.1.3 Transport in Plants: Transpiration Summary

Which Vessel is involved in Transpiration?

Xylem Vessel

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3.1.3 Transport in Plants: Transpiration Summary

What does the Xylem Vessel transport?

Water
Mineral Ions

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3.1.3 Transport in Plants: Translocation Summary

What’s Translocation?

Active movement of sugars
↳ Sucrose acids

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3.1.3 Transport in Plants: Translocation Summary

In which direction does Translocation occur?

All around the plant

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3.1.3 Transport in Plants: Translocation Summary

Which Vessel is involved in Translocation?

Phloem Vessel

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3.1.3 Transport in Plants: Translocation Summary

What does the Phloem Vessel transport?

Sugars/ Assimilates

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3.1.3 Transport in Plants: Vascular System

What’s a Dicotyledonous Plant?

Plant w a Vascular Bundle

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3.1.3 Transport in Plants: Vascular System

What’s the Vascular Bundle?

Vascular tissue distributed throughout the plant

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3.1.3 Transport in Plants: Vascular System

What’s the Vascular Bundle made up of?

Xylem Tissue
Phloem Tissue

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3.1.3 Transport in Plants: Vascular System

What’s the function of the Vascular Bundle?

Transport of substances & structural support purposes

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3.1.3 Transport in Plants: Vascular System

What’s the X structure in the cross-section of a root?

Xylem
↳ provides a ‘drill’ like structure
↳ enables plant to be able to push down to the root

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3.1.3 Transport in Plants: Vascular System

Where are the Xylem & Phloem located in the Roots?

X: centre
P: sorrounds X in 4 separate sections
↳ provide support for root as it pushes through soil

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3.1.3 Transport in Plants: Vascular System

Where are the Xylem & Phloem located in the Stems?

X & P: near the outside
↳ provides a scaffold that reduces bending
X is on top of P

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3.1.3 Transport in Plants: Vascular System

Where are the Xylem & Phloem located in the Leaf?

X & P: make up network of veins
↳ supports thin leaves
X = inner P = outer

Cambium layer contains meristem cells

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3.1.3 Transport in Plants: Xylem Tissue Structure

What’s the Xylem Tissue?

Non-living tissue
↳ made up of dead cells (no cytoplasm) & nucleus disappears during its development

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# **3.1.3 Transport in Plants:** Xylem Tissue Structure What's the structure of the Xylem Vessel?

Long, tube-like structures from vessel elements joined end to end

# **3.1.3 Transport in Plants:** Xylem Tissue Structure What's the structure of Xylem walls?

* Made of Lignin ↳ supports vessel & stops them from collapsing inwards * Lignified ↳ walls made waterproof

# **3.1.3 Transport in Plants:** Xylem Tissue Structure What happens to the Amount of Lignin as the cell gets older?

It increases

# **3.1.3 Transport in Plants:** Xylem Tissue Structure Why are there no end walls in the Xylem Tissue?

* Creates an uninterrupted tube ↳ allows water to pass through middle easily

# **3.1.3 Transport in Plants:** Xylem Tissue Structure What do the End Plates allow?

Prevents vessel from being too rigid & allows some flexibility

# **3.1.3 Transport in Plants:** Xylem Tissue Structure What happens when Lignifications is incomplete?

Gaps in cell wall are formed ↳ forms pits/bordered pits

# **3.1.3 Transport in Plants:** Xylem Tissue Structure What do the Bordered Pits allow?

Water to leave a vessel & pass onto the next

# **3.1.3 Transport in Plants:** Phloem Tissue Structure What's the Phloem Tissue?

Arrangement of multiple sieve tube elements

# **3.1.3 Transport in Plants:** Phloem Tissue Structure Why does the Phloem need Companion cells?

Phloem lacks a nucleus & other organelles ↳ all important functions occur in companion cells

# **3.1.3 Transport in Plants:** Phloem Tissue Structure What are Companion Cells?

Small cells found in sieve tubes w a large nucleus & dense cytoplasm

# **3.1.3 Transport in Plants:** Phloem Tissue Structure What's the Function of Companion Cells?

Has mitochondria to produce ATP needed to carry out the active processes

# **3.1.3 Transport in Plants:** Phloem Tissue Structure What are Sieve Tube Elements?

Living cells w no nucleus & very little cytoplasm that transport solutes through plant * Joined end to end to form Sieve Tubes

# **3.1.3 Transport in Plants:** Phloem Tissue Structure What's the Function of Sieve Tubes?

Allow space for mass flow of sap to occur

# **3.1.3 Transport in Plants:** Phloem Tissue Structure What are Sieve Plates?

Perforated cross-walls at the ends of sieve tube elements

# **3.1.3 Transport in Plants:** Phloem Tissue Structure What's the space between Sieve Tubes & Companion Cells?

Plasmodesmata

# **3.1.3 Transport in Plants:** Movement of Water through Roots What's the movement of water through a plant?

* Water enters through root hair cells & passes through root cortex * Moves up the plant through osmosis * Diffuses out of the plant through the stomata

# **3.1.3 Transport in Plants:** Movement of Water through Roots How does Water move?

From areas of Higher WP to areas of Lower WP

# **3.1.3 Transport in Plants:** Movement of Water through Roots What's the WP in Roots & Leaves?

* Roots = High WP ↳ lots of water in soil * Leaves = Low WP ↳ water constantly evaporates

# **3.1.3 Transport in Plants:** Movement of Water through Roots How does this WP Gradient allow the movement of water?

Keeps water moving through the plant in the right direction

# **3.1.3 Transport in Plants:** Movement of Water through Roots What happens if the WP inside the cell is low?

Water will move in by osmosis

# **3.1.3 Transport in Plants:** Movement of Water through Roots What happens if the WP inside the cell is high?

Water will move out by osmosis

# **3.1.3 Transport in Plants:** Movement of Water through Roots What is meant by the term 'Plasmolysed'?

Plants shrink its cell membrane away from the cell water

# **3.1.3 Transport in Plants:** Movement of Water through Roots When would a Plant be Plasmolysed?

When the external WP is low

# **3.1.3 Transport in Plants:** Movement of Water through Roots How does the size optimise the function of Root Hair Cells?

They can penetrate easily between soil particles

# **3.1.3 Transport in Plants:** Movement of Water through Roots How does a large SA:V ratio optimise the function of Root Hair Cells?

There are thousands on each growing root tip

# **3.1.3 Transport in Plants:** Movement of Water through Roots How does a Thin SA optimise the function of Root Hair Cells?

Diffusion & Osmosis can take place quickly

# **3.1.3 Transport in Plants:** Movement of Water through Roots How does the Conc of Solutes in cytoplasm optimise the function of Root Hair Cells?

Maintains a WP gradient between the soil water & cell

# **3.1.3 Transport in Plants:** Structure of Plants What's meant by Epidermis? | (Epi)

Found towards the outside

# **3.1.3 Transport in Plants:** Structure of Plants What's meant by Endodermis? | (Endo)

Found towards the inside

# **3.1.3 Transport in Plants:** Structure of Plants What's the Waxy Cuticle?

Extracellular hydrphobic layer covering plant's epidermis ↳ waterproofs leaves & creates a layer of protection

# **3.1.3 Transport in Plants:** Structure of Plants What's the Upper Epidermis?

Single layer of cells ↳ transprant **:** light passes through onto next layer

# **3.1.3 Transport in Plants:** Sturcture of Plants What's the Palisade Mesophyll Layer?

Site of Photosynthesis ↳ has lots of chloroplasts

# **3.1.3 Transport in Plants:** Structure of Plants What's the Spongy Mesophyll Layer?

Porous tissue ↳ allows exchange of gases through diffusion

# **3.1.3 Transport in Plants:** Structure of Plants What's the Vascular Bundle?

Tissue composed of Xylem & Phloem

# **3.1.3 Transport in Plants:** Structure of Plants What's the Lower Epidermis?

Protective layer of cells contaning stomata ↳ allow entry & exit of gases

# **3.1.3 Transport in Plants:** Water Movement Pathways Which pathways does water move into the plant?

* Symplast Pathway * Vacuolar Pathway * Apoplast Pathway

# **3.1.3 Transport in Plants:** Water Movement Pathways What's a Apoplast Pathway?

Water is transporetd through cell walls

# **3.1.3 Transport in Plants:** Water Movement Pathways What's a Vacuolar Pathway?

Water is transorted straight through the vacuoles

# **3.1.3 Transport in Plants:** Water Movement Pathways What's a Symplast Pathway?

Water is transported through the cytoplasm around organelles

# **3.1.3 Transport in Plants:** Water Movement Pathways Which Pathway is the fastest?

Apoplast Pathway

# **3.1.3 Transport in Plants:** Water Movement Pathways Which Pathway is the slowest?

Symplast Pathway

# **3.1.3 Transport in Plants:** Casparian Strip Where's the Casparian Strip found?

The Endodermis

# **3.1.3 Transport in Plants:** Casparian Strip What's the function of the Casparian Strip?

Stops flow in the Apoplast Pathway

# **3.1.3 Transport in Plants:** Casparian Strip How's the Casparian Strip able to do this?

It is an impermeable layer of suberin ↳ waxy material

# **3.1.3 Transport in Plants:** Casparian Strip What's the result of the Casparian being able to perform this functiom?

All water in the Apoloplast Pathway is forced into the Symplast Pathway

# **3.1.3 Transport in Plants:** Pulling Water up Xylem How does Water move up the stem?

* Root Pressure (Active Process) * Transpirational Pull (Cohesion-Tension) * Capillary Action

# **3.1.3 Transport in Plants:** Active Transport in Root Pressure What's the Affect of Cyanide?

Cyanide stops the mitochondria from working ↳ less active transport **:**root pressure decreases

# **3.1.3 Transport in Plants:** Active Transport in Root Pressure What's the Affect of Temperature?

Root pressure increases as temp increases & decreases when temp decreases ↳ an enzyme controlled chemical reaction

# **3.1.3 Transport in Plants:** Active Transport in Root Pressure What's the Affect of Reactant Availability?

If oxygen levels or respiratory substrate levels drop ↳ root pressure decreases

# **3.1.3 Transport in Plants:** Active Transport in Root Pressure What's the Affect of Guttation?

Sap & water will move out of cut stems ↳ actively pumped out by transpiration

# **3.1.3 Transport in Plants:** Transpiration What's Transpiration?

Loss of water from the leaves of a plant through evaporation

# **3.1.3 Transport in Plants:** Transpiration What pulls the water up the plant?

Evaporation causes WP of air space in mesophyll to decrease ↳ water moves into air spaces ↳water moves out of xylem into cells

# **3.1.3 Transport in Plants:** Transpiration Why is water pulled up the plant?

* H bonds in water bond to theirselves (**adhesion**) * H bonds in water bond to walls of xylem (**tension**) ↳ capillary tension

# **3.1.3 Transport in Plants:** Transpiration How does water being polar affect its arrangement in the Xylem?

It is spontaneously arranged ↳ + & - charged poles lie next to each other (**cohere**)

# **3.1.3 Transport in Plants:** Evidence for Cohesion Tension Theory How does Changes in tree Diameter support this?

When Transpiration = high, diameter decreases →tension ↳ happens during the day

# **3.1.3 Transport in Plants:** Evidence for Cohesion Tension Theory How does Cut Flowers support this?

They draw air in rather than leaking water out as water moves up cut stem

# **3.1.3 Transport in Plants:** Evidence for Cohesion Tension Theory How does Broken Xylems support this?

Stops drawing up water as air drawn in breaks Transpiration stream ↳ cohesion = broken

# **3.1.3 Transport in Plants:** Stomata What is meant by Turgid?

Stomata = open * Water moves into vacuoles through osmosis * Outer wall more flexible than inner wall ↳ cell bends & stomata opens

# **3.1.3 Transport in Plants:** Stomata What is meant by Flaccid?

Stomata = closed * Water moves out of vacuoles by osmosis * Outer wall is more flexible than inner wall ↳ cell bends & stomata close

# **3.1.3 Transport in Plants:** Factors affecting Transpiration How does Light Intensity affect Transpiration?

More light, stomata open frequently **:** allows gas exchange for photosynthesis ↳ increases T rate

# **3.1.3 Transport in Plants:** Factors affecting Transpiration How does High Temperatures affect Transpiration?

* Increases rate of evaporation **:** water-vapour potential in leaf increases * Increased diffusion rate ↳ water mol have more ke * Decreases water vapour potential in air ↳ more diffusion as there's a steeper conc gradient **:** more T

# **3.1.3 Transport in Plants:** Factors affecting Transpiration How does Humidity affect Transpiration?

High humidity = lower T ↳ smaller water vapour potential gradient between leaf & outside air

# **3.1.3 Transport in Plants:** Factors affecting Transpiration How does Air Movement affect Transpiration?

More air movement = movement of water vapour away from plant ↳ maintains high conc gradient **:** less T

# **3.1.3 Transport in Plants:** Factors affecting Transpiration How does Water Availability affect Transpiration?

Little water in soil = plant unable to replace water lost ↳ stomata close & leaves wilt **:** less T

# **3.1.3 Transport in Plants:** Translocation What's Translocation?

Transport of assimilates around a plant

# **3.1.3 Transport in Plants:** Source Whats meant by source?

Where you are making its assimilates

# **3.1.3 Transport in Plants:** Source What are its Storage Organs?

* Tubers * Root Taps

# **3.1.3 Transport in Plants:** Source How are they stored?

Food stored in seeds

# **3.1.3 Transport in Plants:** Source What % of Sucrose makes up Phloem Sap?

20-30% of Sucrose

# **3.1.3 Transport in Plants:** Sink What's meant by sink?

Where the assimilates are being dropped off

# **3.1.3 Transport in Plants:** Sink Which proccesses use Assimulates?

* Growing roots * Active processes in stem & roots * Meristem cell activity (dividing) * Developing stores

# **3.1.3 Transport in Plants:** Phloem Loading Why is Tranlocation a Vital Process?

Large tree can move up to 250kg of sucrose around its trunk a year

# **3.1.3 Transport in Plants:** Phloem Loading Which 2 Route allows assimilates to be moved into phloem?

* Symplat Route * Apoplast Route

# **3.1.3 Transport in Plants:** What's the Symplast Route? Where are the Assimilates stored? | (Part 1)

Assimilates are stored in vacuoles of cells

# **3.1.3 Transport in Plants:** What's the Symplast Route? Where are the Assimilates moved? | (Part 2)

Assimilates are moved through the cytoplasm of mesophyll cells into the sieve tube sof cross connecting plasmodesmata

# **3.1.3 Transport in Plants:** What's the Symplast Route? What type of Process is this? | (Part 3)

Passive Process

# **3.1.3 Transport in Plants:** What's the Symplast Route? How are the Assimilates moved? | (Part 4)

Assimilates are moved through changes of WP in cells

# **3.1.3 Transport in Plants:** What's the Apoplast Route? How are the Assimilates transported? | (Step 1)

Assimilates diffuse through the cell wall & intermembrane spaces

# **3.1.3 Transport in Plants:** What's the Apoplast Route? What happens when the Assimilates reach the Companion Cells? | (Step 2)

They're transported across the membrane into sieve cell cytoplasm

# **3.1.3 Transport in Plants:** What's the Apoplast Route? What's the Function of H ions in this Route? | (Step 3)

They act as **co-transporters** ↳ actively move assimilates across the membrane

# **3.1.3 Transport in Plants:** How do sugars move along the Phloem? What's Mass Flow at the Source? | (Source)

Sugars are actively moved into the sieve cytoplasm

# **3.1.3 Transport in Plants:** How do sugars move along the Phloem? What happens to the WP when the Sugars are moved into? | (Source)

It decreases ↳ water is moved into the sieve cells through osmosi

# **3.1.3 Transport in Plants:** How do sugars move along the Phloem? What happens to the Hydrostatic Pressure when the Sugars are moved into? | (Source)

It increases inside the phloem ↳ water moves to decrease this pressure

# **3.1.3 Transport in Plants:** How do sugars move along the Phloem? What's the Mass Flow at the Sink? | (Sink)

Assimilates are actively moved/ diffused out of the sieve cells

# **3.1.3 Transport in Plants:** How do sugars move along the Phloem? What happens to the WP when Sugars are moved out? | (Sink)

It increases ↳ water moves out through osmosis ↳ decreasing Hydostatic Pressure

# **3.1.3 Transport in Plants:** Plants Adaptations, Xerophytes What are Xerophytes?

Plants living in arid (dry) conditions

# **3.1.3 Transport in Plants:** Plants Adaptations, Xerophytes What are examples of Xerophytes?

* Cacti * Marram Grass

# **3.1.3 Transport in Plants:** Plants Adaptations, Marram Grass How does a Thick Waxy Cuticle optimise their conditions?

Minimises water loss

# **3.1.3 Transport in Plants:** Plants Adaptations, Marram Grass How does the Lead being rolled Longitudinally optimise their conditions?

Air is trapped inside ↳ air becomes humid & reduce water loss

# **3.1.3 Transport in Plants:** Plants Adaptations, Marram Grass How does the Stomata being located in pits in the Lower Epidermis optimise their conditions?

Folded & covered by hairs ↳ reduces air movement **:** water loss is reduced (They're protected by enclosed air space)

# **3.1.3 Transport in Plants:** Plants Adaptations, Marram Grass How does the Spongy Mesophyll being dense optimise their conditions?

There are a few air spaces ↳ less SA for evaporation of water

# **3.1.3 Transport in Plants:** Plants Adaptations, Cacti How does them being Succulents optimise their conditions?

They're able to store water in stems ↳ stems are often ribbed/fluted **:** it can expans when water is available

# **3.1.3 Transport in Plants:** Plants Adaptations, Cacti How do Spines optimise their conditions?

Reduces SA of leaves ↳ less water loss

# **3.1.3 Transport in Plants:** Plants Adaptations, Cacti How do the Widespread Roots optimise their conditions?

Maximises water absorption

# **3.1.3 Transport in Plants:** Plant Adaptations, Hydrophytes What are Hydrophytes?

Plants adapted to live in aquatic environments

# **3.1.3 Transport in Plants:** Plants Adaptations, Hydrophytes What is an example of a Hydrophytes?

* Water Lily

# **3.1.3 Transport in Plants:** Plants Adaptations, Water Lily How does having Large Air Spaces in leaf optimise their conditions?

Leaf is kept afloat ↳ in air to absorb sunlight

# **3.1.3 Transport in Plants:** Plants Adaptations, Water Lily How does the Stomata being on the Upper Epidermis optimise their conditions?

Exposed to air ↳ allows gaseous gaseous exchange

# **3.1.3 Transport in Plants:** Plants Adaptations, Water Lily How does the Leaf Stem having Large Air Spaces optimise their function?

Helps buoyancy ↳ allows oxygen to diffuse quickly to roots for aerobic respiration