Biology 10: Transport In Multicellular Plants

Front 1

How do exchange of substances in an organism take place?

Back 1

Passive and active transport

Front 2

If the rate of transport is effective and rapid, what does this tell you about the distance?

Back 2

Short distance

Front 3

In what case there is no need for a special transport system?

Back 3

When an unicellular and multi-cellular organism has large surface are to volume ration

Front 4

When will specialized long distance transport systems which can move substances more rapidly become necessary?

Back 4

when it is larger, active and complex organisms

Front 5

What are plant cells requirements in order to survive?

Back 5

1.CO2 (Diffuse into and out of the cells)
2. O2 (Diffuse into and out of the cells)
3. Organic nutrient (non-photosynthetic cells need to be supplied with organic nutrients from photosynthetic cells)
4. Inorganic ions and water
5. Sunlight (for photosynthetic region of plants)

Front 6

What are the 2 transport systems in plants?

Back 6

1. Root system
2. Shoot system

Front 7

Describe how the Root system works

Back 7

Carry water and inorganic ions from roots to parts above the ground.

Front 8

Describe how the Shoot system works

Back 8

Carry substances made by photosynthesis from leaves to other areas.

Front 9

Why the plant transport system does not carry oxygen and carbon dioxide?

Back 9

This is because the gases travel to and from cells and their environment by diffusion alone.

Front 10

What are the 3 types of simple plant tissues?

Back 10

Parenchyma
Collenchyma
Sclerenchyma

Front 11

Describe the main function of the parenchyma cells

Back 11

as packing tissue

When turgid, provide support in hebaceous plants

Metabolically active (site of many activities)

Intercellular air space allows gaseous exchange

Food storage e.g. potato tubers

Transport of water and mineral salts through cells or cell walls

Front 12

What is the cell wall material of a parenchyma cell made of?

Back 12

Cellulose, pectins and hemicelluloses

Front 13

What is the shape of a Parenchyma cell like?

Back 13

Roughly spherical to elongated

Front 14

Where are the parenchyma cells found?

Back 14

Cortex, pith, packing tissue in xylem or phloem

Front 15

how are Collenchyma characterized?

Back 15

Deposition of extra cellulose at the corners of cells

Front 16

Describe the main function of the Collenchyma cells

Back 16

Support and mechanical strength

Front 17

What is the cell wall material of a Collenchyma cell made of?

Back 17

Cellulose, pectins and hemicelluloses

Front 18

What is the shape of a Collenchyma cell like?

Back 18

Elongated and polygonal with tapering ends

Front 19

Where are the Collenchyma cells found?

Back 19

Below the epidermis, in the outer region of the cortex.

Front 20

Sclenchyma Cells can be categorized into 2 types. What are they?

Back 20

Fibres and Sclereids

Front 21

What is the main function of a Fiber?

Back 21

Strong support

Front 22

What are the cell walls of fibers made of?

Back 22

Lignin, cellulose, pectins and hemicelluloses

Front 23

Describe the shape of a Fiber cell

Back 23

Elongated and polygonal with tapering interlocking ends

Front 24

Where are Fibers found?

Back 24

Outer regions of cortex, pericycle of stem, xylem and phloem

Front 25

What is the main function of a Sclereids?

Back 25

Confer firmness or rigidity on structures

Front 26

What are the cell walls of sclereids made of?

Back 26

Lignin, cellulose, pectins and hemicelluloses

Front 27

Describe the shape of a sclereids cell

Back 27

Roughly spherical or irregular

Front 28

Where are sclereids found?

Back 28

cortex, pith, phloem, seeds, stones of fruits

Front 29

What are the 3 different pathways in which water moves across the root?

Back 29

Apoplast pathway
Symplast pathway
Vacuolar pathway

Front 30

Describe Apoplast pathway

Back 30

It is a system of adjacent cell walls which is continuous throughout the plant.

Spaces between cell walls are filled with water and the water moves through the cell walls

Cell walls are freely permeable so dissolved ions or molecules can move freely through them

Front 31

Describe Symplast pathway

Back 31

Is is a system of interconnected protoplasts whereby the neighboring cytoplasms of protoplasts are linked by plasmodesmata

Once taken into the cytoplasm, water or other solutions no longer have to cross any further membranes

Movement of the cytoplasm might be aided by cytoplasmic streaming

Front 32

Describe Vacuolar pathway

Back 32

This is where water moves from vacuole to vacuole through neighboring cells. it crosses the symplast and apoplast in the process.

The water molecules moves through the membranes and tonoplasts by osmosis

Front 33

What is the order in which water is transported in a plant?

Back 33

Soil, root hairs, xylem tissues, move upwards through the roots, stem, leaves

Front 34

Describe the process of transport of water.

Back 34

Water from the soil enters a plant through its root hairs and them moves across the root into the xylem tissue in the center. once inside the xylem vessels, the water moves upwards through the root to the stem, and from the stem into the leaves

Front 35

Describe Root hairs

Back 35

The root tip is covered by a tough protective root cap and is not permeable to water.

Root hairs are long and thin extension of epidermal cells

These reach into spaces between the soil particles from where they absorb water that coat every soil particle

Water moves into the root hairs by osmosis.

Front 36

Does soil water have high or low water potential? why?

Back 36

High water potential. This is because even if they contain some inorganic ions in solution, it is relatively dilute solution

Front 37

Does cytoplasm and cell sap have high or low water potential? why?

Back 37

Low water potential. This is because the have considerable quantities of inorganic ions and organic substances, such as proteins and sugars, dissolved in them

Front 38

How does water enter the cytoplasm and vacuole of the root hair cell?

Back 38

Water diffuses down the water potential gradient, through a partially permeable membrane

Front 39

How do you increase the rate at which water can be absorbed into the plant?

Back 39

Large umber of root hair will provide a very large surface area

Front 40

How are minerals and ions absorbed into the root hairs?

Back 40

Facilitated diffusion

Front 41

What happens if a particular ion has high concentration outside the root hair?

Back 41

It will move passively into the cell by facilitated diffusion

Front 42

What kind of fungi are sometimes found in or on the root hair cells? what are their functions?

Back 42

Mycorrhizas, they act like a mass of fine roots which absorb nutrients, especially phosphate and nitrate, from the soil and transport it into the plant. in return, these fungi receive organic nutrients from the plants.

Front 43

Why do ions need to be taken up by active transport from the soil?

Back 43

This is because ions required by the plant are relatively low in the soil so they need to be taken up against the concentration gradient by active transport which uses ATP.

Front 44

How are water taken transported from root hairs to xylem?

Back 44

Water taken up by root hairs crosses the cortex and enters the xylem in the centre of the root. it does this because the water potential inside the xylem vessel is lower than the water potential in the root hairs so water moves down this water potential gradient across the root.

Front 45

What are the 3 possible routes for water to cross the cortex?

Back 45

Apoplast, Symplast and Vacuolar

Front 46

What section of the plant stops the water?

Back 46

Endodermis

Front 47

When water move through spaces in the cell wall, it reaches the endodermis. Its progress is barred by a thick, waterproof, waxy substance. what is this substance?

Back 47

Waxy band of Suberin called the casparian strips. It i the impenetrable barrier to water in the walls in the endodermis cells.

Front 48

What happens to the water once it is blocked by the endodermis cells?

Back 48

They are forced to use the symplast and apoplast pathway.

Front 49

What is the reason for plants having casparian strips?

Back 49

This is because cell wall is freely permeable and cell membrane is partially permeable so by forcing the water to take the symplast and Vacuolar pathway, ii is forced to cross the cell membrane which will act as a filter to solutes and inorganic materials. This will allow the plant to control what inorganic ions pass into its xylem vessels

Front 50

What happens as endodermal cells get older?

Back 50

The suberin deposits become more extensive, except in certain cells called passage cells, through which water can pass freely

Front 51

What happens when the water is across the endodermis cells?

Back 51

The water continues to move down the water potential gradient across the pericycle and towards the xylem vessels

Front 52

What is a Xylem tissue?

Back 52

It is made up of vessel elements, tracheids, fibres and parenchyma cells.

Front 53

What is the function of Xylem tissues?

Back 53

It has a dual function serving as mechanical support and transport of water and inorganic ions

Front 54

What is a xylem vessel made up of?

Back 54

Many elongated vessel elements arranged end to end

Front 55

Explain the process at which a Vessel element is formed

Back 55

Each began as a normal plant cell then lignin is deposited at the cell wall. As it is built up around the cell, the living content of the cell dies and this will leave an empty space inside called the lumen.

Front 56

What is lignin?

Back 56

It is a strong substance which is impermeable to water

Front 57

Why do the Xylem vessels have pits

Back 57

This is because no lignin was deposited at the plasmodesmata.

Front 58

What are Pits on a Xylem vessel?

Back 58

They are not open pores; they crossed by permeable, unthickened cellulose cell wall

Front 59

How does all the neighbouring cells join up together to form a xylem vessel?

Back 59

The end walls of neighbouring vessel elements breakdown completely to form a continuous tube.

Front 60

What usually rely on xylem vessels for their water transport?

Back 60

Angiosperms (flowering plants)