Leaf Challenge! Cell wall Nucleus Chloroplast Cell membrane Vacuole Cytoplasm Chlorophyll Stoma Upper epidermis Waxy cuticle Mesophyll Air space Lower epidermis Guard cell with chloroplast Palisade mesophyll Waxy cuticle Spongy mesophyll

Palisade Cell

Palisade Cell

Testing For Starch Lesson Objectives C/W Date……………………….. Testing For Starch Lesson Objectives To describe how plants store excess glucose as starch. To be able to test for starch in leaves. Success Criteria Starch is stored in the leaves Describe the test for starch in leaves

Key Challenge! What we need for photosynthesis? What is the pigment that captures the sunlight? What do we make in the process of photosynthesis? Photosynthesis song – You tube

What is photosynthesis? light energy chlorophyll carbon dioxide +  water oxygen glucose What is the symbol equation for this reaction? light energy 6 CO2 + 6 H2O +  C6H12O2 6 O2 chlorophyll Is this a balanced symbol equation? How would you balance the equation?

glucose What do plants with the glucose made by photosynthesis? Some glucose is used straight away in respiration. Plants also carry out respiration to release the energy they need for life processes. glucose Some glucose is converted into starch and other substances for storage. These stores of energy can be used later when the plant needs them. Some glucose is used to make new chemicals such as proteins, sugars and fats that the plant also needs to function properly.

A plant will store excess the GLUCOSE as starch once it has been made. We can test whether the leaf has photosynthesised or not by testing the leaf for starch. Lets get practical!!

Aim:Test whether the leaf has photosynthesised or not by testing the leaf for starch. 2 Ethanol Boiling Water Testing 2 leaves: one that has been in the light and one that has been in the dark. Cut the end off the leaf that has been in the dark. Place both leaves (in light and one in dark) in a beaker of boiling water = 1 minute with forceps. Half fill a boiling tube with ethanol. Place both leaves in test tube of ethanol and stand for 8 to 10 minutes. – Place it in the beaker to support the boiling tube. Complete the following while waiting: Aim,Diagram,Method

Starch is only made in a leaf when photosynthesis has happened!! Aim:Test whether the leaf has photosynthesised or not by testing the leaf for starch. 4. Remove both leaves with forceps and wash with tap water. 5. Place both leaves in petri dish and add 5 drops of iodine solution to each leaf. Leave for 2 mins. 5. Starch present = Blue/Black colour ! Starch is only made in a leaf when photosynthesis has happened!!

Answer questions 1 to 5 on the worksheet ‘Testing a leaf with starch’ Aim, Method, Diagram Conclusion: What have you found out? Describe what colour the leaf turned. Why did the leaf turn this colour? How could you have improved your experiment? Extension: Answer questions 1 to 5 on the worksheet ‘Testing a leaf with starch’

glucose What do plants with the glucose made by photosynthesis? Some glucose is used straight away in respiration. Plants also carry out respiration to release the energy they need for life processes. glucose Some glucose is converted into starch and other substances for storage. These stores of energy can be used later when the plant needs them. Some glucose is used to make new chemicals such as proteins, sugars and fats that the plant also needs to function properly.

What is photosynthesis? light energy chlorophyll carbon dioxide +  water oxygen glucose What is the symbol equation for this reaction? light energy 6 CO2 + 6 H2O +  C6H12O2 6 O2 chlorophyll Is this a balanced symbol equation? How would you balance the equation?

Key Questions How do we know that oxygen is produced during photosynthesis? How can we measure the rate of photosynthesis? What are dependent and independent variables?

Oxygen relights a glowing splint Test for Oxygen Oxygen relights a glowing splint

HOT SEAT! Volunteer needed. You can only ask questions with a Yes or No answer. Am I furry? Am I large?

Chloroplasts

stomata

Limiting Factors

Sunlight

Carbon dioxide

Temperature

Glucose

Leaf

Anagrams