Transcript
Photosynthesis
Objective 1• To trace the primary food source in
a food chain to the green plant
The Primary Food Source
• Green plants always found at the beginning of the food chain.
• Why?
• The only organisms that can produce their own food
• They are called producers
Objective 2• To define photosynthesis
PHOTOSYNTHESIS
• Photo = light• Synthesis = building up
DEFINITION
PhotosynthesisProcess by which plants use water & carbon dioxide to make carbohydrates in the
presence of light and chlorophyll.
Oxygen is given off during the process.
Objective 3• To understand the conditions
necessary for plants to make their own food
INTRODUCTION
Yummy!!!What are the similarities
between baking a cake and photosynthesis?
REQUIREMENTS
• Raw materials– Carbon dioxide– Water
• Conditions– Chlorophyll– Light energy
Answers• Review 1
1. An organism that make its own food, e.g. green plant
2. They make their own food by photosynthesis
• Review 21. Textbook pg 19
• Review 3– Raw materials: water & carbon dioxide– Conditions: sunlight & chlorophyll– End products: oxygen & glucose
Objective 4• To outline the process of
photosynthesis by which plants manufacture carbohydrates using raw materials
• To state that food is stored as starch in the plant
CARBON DIOXIDE
• From air• Enters leaf by diffusion• Pores: Stomata/Stoma• Found underside of the leaf
Carbon dioxide
WATER
• From soil• Absorb by root hair• Enter by osmosis• Transport by xylem vessel
Soil
Water
Water
Root Hair
To Xylem Vessel
Water
Water
CHLOROPHYLL
• Structure: Chloroplast• Green pigment: Chlorophyll• Absorb light energy
Leaf
Plant Cell
Chloroplast
LIGHT ENERGY
• Chlorophyll absorbs light energy from sun
• Light energy converted into chemical energy
• Chemical energy is needed to convert carbon dioxide to carbohydrate
• Series of chemical reactions
Xylem
H2O
CO2
H2O
H2O
CO2
Carbon Dioxide +Water
Light
ChlorophyllGlucose + Oxygen
O2
O2
Surroundings
STARCH
WORD EQUATION
CARBON DIOXIDE + WATER
GLUCOSE + OXYGEN LIGHT ENERGY CHLOROPHYLL
Review 4
1. Water, carbon dioxide, sunlight2. Chlorophyll3. It absorb the sunlight/light energy4. Chloroplasts5. The root hair absorb the water by osmosis6. Xylem vessel7. It enters through the stomata by diffusion8. Carbon dioxide + water glucose +
oxygen
Light energy
Chlorophyll
Objective 5• To state the conditions that affect
the rate of photosynthesis
LIMITING FACTORS
• Rate of photosynthesis is affected by:– carbon dioxide, – light intensity and – temperature
LIGHT INTENSITY
• Higher light intensity, faster the rate of photosynthesis
• After awhile, the rate will remain constant
• Due to limiting factors such carbon dioxide concentration or temperature
CARBON DIOXIDE
• Carbon dioxide in the air is 0.03%• Increasing the carbon dioxide
concentration to 0.1% increases the rate of photosynthesis
• After awhile the rate will remain constant due to limiting factor such as temperature and light intensity
TEMPERATURE
• Temperatures below 40°C, as it rises, the rate of photosynthesis is faster
• At 40°C, photosynthesis begins to decrease
• As temperature rises above 40°C, photosynthesis stop as the enzymes denatured
Other important things that plant need to grow
• Minerals– Found in soil and fertilizers– Magnesium: chlorophyll formation– Nitrogen: for making proteins
Objective 6• To compare the conditions for
healthy growth of ornamental plants and large scale crop productions
Ornamental Plants
• Use for decoration
• Usually grown in greenhouses
Ornamental Plants• Conditions needed
– Types of soil – sand, organic matter– Minerals – artificial or natural fertilizers– Humidity - humid conditions better, by
spraying and misting– Temperature - warm– Light - bright– Carbon dioxide – burning fuels– Water – watering plants– Pests – hand pick/pesticides
Large scale crops
• Includes rice, wheat, vegetables
• Relies on farming methods and agricultural technology
• Plant in open field
Large scale crops
• Light, humidity, temperature and water – cannot be controlled
• Fertilizers – mostly used artificial fertilizers, machines
• Pests – planes to spray pesticides over farm areas
Experiment Question
Experiment: Testing for starch in green leaves
• What does hot water do to the leaf?– Kills the leaf to stop photosynthesis
• What does the alcohol do to the leaf?– Breaks down chlorophyll – take the green colour
out of the leaf
• What is the original colour of iodine?– brown
• What does it mean when iodine turn blue-black?– Starch is present
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