3.1.3 Transport in plants

Question 1

what is the structure of a leaf? can you draw and label it?

Answer 1

https://docs.google.com/document/d/1QvZjp8E7MVP3gmx2N8aOllihCILTQ0KnTHvnnKtUGGU/edit?usp=sharing

Question 2

what is the parenchyma

Answer 2

Parenchyma tissue is made up of simple, living plant cells with thin cellulose cell walls

https://docs.google.com/document/d/1QvZjp8E7MVP3gmx2N8aOllihCILTQ0KnTHvnnKtUGGU/edit?usp=sharing

Question 3

what is the collenchyma?

Answer 3

• Collenchyma tissue is made from simple plant cells strengthened by Lignin
• Can be found in the stem or around the vascular bundle of in the leaves
• IS NOT FOUND IN ROOTS

https://docs.google.com/document/d/1QvZjp8E7MVP3gmx2N8aOllihCILTQ0KnTHvnnKtUGGU/edit?usp=sharing

Question 4

what is the sclerenchyma?

Answer 4

• Sclerenchyma tissue is made up of dead cells that have thickly lignified walls
• THEY ARE NOT FOUND IN ROOTS

https://docs.google.com/document/d/1QvZjp8E7MVP3gmx2N8aOllihCILTQ0KnTHvnnKtUGGU/edit?usp=sharing

Question 5

Why is there no collenchyma or sclerenchyma tissue found in the roots?

Answer 5

because the roots don’t need any structural support underneath the ground

Question 6

Why do (multicellular) plants need transport systems?

Answer 6

-Because some are very large, and so have a low SA to Vol ratio

Question 7

How have plants adapted to combat their low SA to vol ratio?

Answer 7

-They have branched structures, increasing SA
-They are immobile, and so have a low metabolism so have a lower requirement
for energy
-They have Vascular bundles with Xylem and Phloem, instead of a pump (e.g. heart)

Question 8

How is water, mineral ions, sucrose, amino acids etc transported through the vascular bundles? (xylem and phloem)

Answer 8

-Both xylem and phloem transport things via Mass flow.

Question 9

what is Mass flow?

Answer 9

When mineral ions,amino acids, water, sucrose etc is transported in bulk from one place to another in a plant.
-from sources to sinks

Question 10

what is the mechanism of mass flow?

Answer 10

• A companion cell of the phloem transports some sucrose into the sieve tube elements from the source cell
• the increased amount of solute causes water to move into it via osmosis, increasing the hydrostatic pressure within the phloem
• the solutes will then move from high to low hydrostatic pressure, towards the sink
• the sucrose will then move into the sink cell, leaving the sieve tube elements and increasing its water potential, causing water to leave by osmosis

Question 11

What is a dicotyledon what is monocotyledon ?

Answer 11

• Dicotyledon is a flowering plant with broad leaves with 2 cotyledons (plant embryos) in its seed
• Monocotyledon is a flowering plant with long thin leaves with 1 cotyledon in its seed

Question 12

describe dicotyledon roots and stems

Answer 12

-The vascular bundle is in the center of a young root
-There is a central core of xylem tissue, in the shape of an X, while the phloem
exists in the 4 corners
-this arrangement provides strength to the pulling forces acting on the roots

Question 13

Where are the xylem and phloem located?

Answer 13

in the vascular bundle

Question 14

what is the structure of the xylem?

Answer 14

They are dead cells made of porous lignin, they have bordered pits and transport water up the cell, from the roots up the stem and into the leaves.

Question 15

name the structure of the phloem sieve tube elements

Answer 15

• Living cell, connected to a companion cell via plasmodesmata that provides energy for the both of them, allowing for:
  - Transports sucrose, amino acids and ions around the plant
  - Transports up and down from sources to sinks
• They do not contain lignin

Question 16

show the structure of of a root cross-section

Answer 16

https://docs.google.com/document/d/1QvZjp8E7MVP3gmx2N8aOllihCILTQ0KnTHvnnKtUGGU/edit?usp=sharing

Question 17

how are the xylem and phloem arranged?

draw it.

Answer 17

https://docs.google.com/document/d/1QvZjp8E7MVP3gmx2N8aOllihCILTQ0KnTHvnnKtUGGU/edit?usp=sharing

Question 18

what are the 3 pathways?

Question 19

how does water enter the root?

Answer 19

It enters the root via osmosis, going down a water potential gradient, towards the vascular bundle.

Question 20

draw a labelled diagram of a stem, horizontal crossection.

Question 21

if a cell had water potential of -500Ψ and another at -200Ψ, where will the liquid travel?

Answer 21

Water will travel from the most positive to the most negative that is adjacent to it
so it will fo from -200Ψ –> -500Ψ

Question 22

what is a hypertonic solution?

Answer 22

a solution with a high water potential

A solution that has more extra in in outside then inside the cell, and so will have a water potential gradient leaving the cell, causing the plasma membrane to plasmolyse (shrink from the cell wall)

Question 23

what is a hypotonic solution?

Answer 23

A solution with a low water potential, and so water will leave a cell via osmosis too go into it

think hyp-O-tonic = LOW

Question 24

what is the apoplast pathway?

Answer 24

when water and ions travel though the cell walls and intracellular spaces. which is the fastest transportation pathway

Question 25

what is the symplast pathway?

Answer 25

When water and ions cross the plasma membrane from the epidermis and into the cell

Question 26

What are the characteristics of water?

Answer 26

water molecules are polar
they form intermolecular hydrogen bonds
>this bonding lets water have tension, adhesion and cohesion qualities
this allows water molecules to pull each other along

Question 27

What does cohesion do for water in plant transport?

Answer 27

attraction of the polar H2O molecules to eachother bu H bonding allos a continuous colmn of H2Oin the xylem

Question 28

What does adhesion do for water in plant transport?

Question 29

what does tension do for water in plant transport?

Question 30

What is the mechanism of Transpiration in plants

Question 31

How is a potometer used?
How do you set it up?
How do you use it to get VALID results?

Answer 31

-You need to measure the rate of water uptake so we assume that a similar amount is being transpired, but really some of it is being used to keep the cell turgid or in biological processes

CALCULATION
If the bubble was moves 5mm along the capillary tube of diameter 3mmin 10 mins? what is the rate of water uptake in mm^3 s^-1

use area of a circle πr^2xLength / seconds

MAKE SURE YOU USE THE RIGHT UNITS

Question 32

what are the different names of plants that have adapted to specific environments?

Answer 32

Mesophytes : plants adapted to a habitat with adequate water

Xerophyte

Halophyte

Hydrophyte: