Bell taskBell task

1.1. What are What are plasmodesmata?plasmodesmata?

2.2. What is transpiration?What is transpiration?

3.3. What is translocation?What is translocation?

Starter – answer the following Starter – answer the following questions - sentencesquestions - sentences

1.1. Which tubes carry water in plants?Which tubes carry water in plants?

2.2. Which tubes carry sucrose in plants?Which tubes carry sucrose in plants?

3.3. Draw a diagram of the arrangement of these Draw a diagram of the arrangement of these tubes in the stem of a plant. (p134)tubes in the stem of a plant. (p134)

4.4. Explain why they are arranged in this way.Explain why they are arranged in this way.

5.5. Draw a diagram of the arrangement of these Draw a diagram of the arrangement of these tubes in the leaves of plants. (p134)tubes in the leaves of plants. (p134)

6.6. Explain why they are arranged in this way.Explain why they are arranged in this way.

7.7. Draw a diagram of the arrangement of these Draw a diagram of the arrangement of these vessels in the root of the plant. (p131)vessels in the root of the plant. (p131)

8.8. Give a reason for this arrangement.Give a reason for this arrangement.

• Which tubes carry water in plants? Which tubes carry water in plants? XylemXylem• Which tubes carry sucrose in plants? Which tubes carry sucrose in plants?

PhloemPhloem• Stem: Explain why they are arranged in this Stem: Explain why they are arranged in this

way.way.

Reduce water loss through stemReduce water loss through stem• Leaves:Explain why they are arranged in Leaves:Explain why they are arranged in

this way.this way.

Reduce water loss through leafReduce water loss through leaf• Root:Give a reason for this arrangement.Root:Give a reason for this arrangement.

Move water away from root hair to preserve Move water away from root hair to preserve water potential gradientwater potential gradient

Lesson objectivesLesson objectives

KnowKnow the functions of xylem and the functions of xylem and phloem tissuesphloem tissuesKnowKnow the arrangement of Xylem and the arrangement of Xylem and Phloem vessels in the roots and leaves, Phloem vessels in the roots and leaves, and the reasons for themand the reasons for themBe able to Be able to IdentifyIdentify the key parts of the key parts of xylem and phloem on diagramsxylem and phloem on diagramsUnderstandUnderstand how xylem vessels are how xylem vessels are formedformed

Using Fg10.7 P133 and Fig 10.15 Using Fg10.7 P133 and Fig 10.15 p140 answer the following p140 answer the following

questionsquestions

1.1. Which type of vessel have Which type of vessel have organelles?organelles?

2.2. Which organelles are missing from Which organelles are missing from the vessel?the vessel?

3.3. Are a) xylem and b) phloem alive or Are a) xylem and b) phloem alive or dead? Explain your answerdead? Explain your answer

1.1. Which type of vessel have organelles?Which type of vessel have organelles?PhloemPhloem

1.1. Which organelles are missing from the Which organelles are missing from the vessel? vessel? Nucleus; RER/ribosomes; vacuole Nucleus; RER/ribosomes; vacuole (tonoplast); (tonoplast);

1.1. Are a) xylem and b) phloem alive or dead? Are a) xylem and b) phloem alive or dead? Explain your answerExplain your answer

a)a) Dead – nothing in them to maintain lifeDead – nothing in them to maintain lifeb)b) Alive – however cannot survive without Alive – however cannot survive without

companion cellscompanion cells

Xylem formation – Quick studyXylem formation – Quick study

A series of normal plant cells (end to end)A series of normal plant cells (end to end)Lignin deposits in the cell walls Lignin deposits in the cell walls (impermeable and waterproof) continues (impermeable and waterproof) continues through timethrough timePits form where no lignin is laid due to Pits form where no lignin is laid due to plasmodesmataplasmodesmataDue to lack of essential substances, contents Due to lack of essential substances, contents of the cell dieof the cell dieEnd sections of the cells break down, End sections of the cells break down, causing a tube like structure to form causing a tube like structure to form

Normally a tube like this would collapse in on Normally a tube like this would collapse in on itself, however the lignin gives support which itself, however the lignin gives support which

prevents thisprevents this

Spend 5 minutes adding to Spend 5 minutes adding to your notes on Xylem – page your notes on Xylem – page

133/4133/4

It is obvious who is showing commitment to their studies

Phloem – quick studyPhloem – quick study

Living cells which are lined up end to end (called Living cells which are lined up end to end (called sieve elements)sieve elements)Small pores/gaps in the end parts of the cells which Small pores/gaps in the end parts of the cells which allow substances to pass through (sieve plates)allow substances to pass through (sieve plates)Very small amount of cytoplasm arranged around Very small amount of cytoplasm arranged around the edge of the cellthe edge of the cellNo nucleus or ribosomes (no protein synthesis)No nucleus or ribosomes (no protein synthesis)Companion cells lined up alongside sieve elements Companion cells lined up alongside sieve elements and are linked/connected to them. These cells and are linked/connected to them. These cells provide the things that the sieve element cannot provide the things that the sieve element cannot provide for themselves (many mitochondria and provide for themselves (many mitochondria and ribosomes)ribosomes)

Spend 5 minutes adding to Spend 5 minutes adding to your notes on Phloem – Page your notes on Phloem – Page

140140

Lesson objectives – have we met Lesson objectives – have we met them????????them????????

KnowKnow the functions of xylem and the functions of xylem and phloem tissuesphloem tissuesKnowKnow the arrangement of Xylem and the arrangement of Xylem and Phloem vessels in the roots and leaves, Phloem vessels in the roots and leaves, and the reasons for themand the reasons for themBe able to Be able to IdentifyIdentify the key parts of the key parts of xylem and phloem on diagramsxylem and phloem on diagramsUnderstandUnderstand how xylem vessels are how xylem vessels are formedformed

Plenary – link the structure to the Plenary – link the structure to the descriptiondescription

Xylem

Sieve tube element

Companion cell

Living cells which have no nucleus or ribosomes, whose cell walls develop gaps/pores in their ends

Closely associated with another cell, death usually leads to death of associated cell Dense cytoplasm with the usual organelles.

Metabolically very active

Elongated and lignified dead cells with empty lumens. Formed by fusion of many cells