plant nutrition

What kind of reaction is photosynthesis

What kind of reaction is photosynthesis

Endothermic

What does endothermic mean

Takes in energy from surroundings

Explain how plant absorb light

• The chlorophyll from the chloroplasts absorb light energy

• Energy used to convert CO2 and water into glucose (and O2)

What colour is chlorophyll and why is this helpful

• Green pigment

• Reflects green wavelength

• Absorbs other light

Where is the CO2 taken from

The air

• Taken in via stomata

Where is the water taken from

Soil

• Absorbed by roots

• Travels thro stem into leaves

How do they get light

Chloroplasts - chlorophyll

What happens to the oxygen

• Waste product

• Released back into air

• Animals and plant respiration

Why is photosynthesis a vital part to living organisms on earth

• Most organisms other than plant get their energy from their food - plants

What is glucose

A simple sugar - a carbohydrate

State the word equation for photosynthesis

carbon dioxide + water —> glucose + oxygen

(on the arrow - chlorophyll and light energy)

State the balanced symbol equation for photosynthesis

6CO2 + 6H2O —> C6H12O6 + 6O2

(on the arrow - chlorophyll and light energy)

What does the plant do with the glucose produced

• Produce starch for storage

• lipids for an energy source in seeds

• To form cellulose - cell wall

• Amino acids - make proteins when combined with nitrogen

What are the factors that affect the rate of photosynthesis

• Light energy

• CO2

• Temperature

What are the things needed for photosynthesis

• Water

• CO2

• Light

• Temperature?

Do plants have an unlimited supply of raw materials

No - have a limited amount

This limits the rate of photosynthesis

What is a limiting factor

Factors that are in such short supply that it restricts life processes

Is water a limiting factor and why

No

Doesn’t use a lot water in photosynthesis

As temp increases what happens to the rate of photosynthesis

It increases

Kinetic energy of molecules

What happens until optimum temperature in reached in photosynthesis

More collisions between enzyme and substrates

What happens after optimum temperature is reached

Rate do photosynthesis decreases

Enzymes denature

What does the light intensity affect photosynthesis

Affects the amount of energy

What does increasing light intensity lead to

A linear increase in rate of photosynthesis

Only to a certain point

What happens after rate of photosynthesis remains constant in light intensity

Rate remains constant

Another factor is limiting

Which graph is similar to CO2 concentration with rate of photosynthesis

Light intensity

If I increase the number of chloroplasts what will happen

• More chlorophyll

• More light energy

• More photosynthesis

What can affect the chlorophyll amounts

Diseases

What does the waxy cuticle do

• Prevents water from evaporate

• Protective

What does the upper epidermis do

• Thin

• Transparent

• Allows light to pass thro into palaside nesophyll - photosynthesis

Palisade mesophyll

• Tightly oacked

• Chloroplasts - absorbs more light

• Photosynthesis occurs here

Spongy mesophyll

• Internal air spaces - increase SA:Vol

• Efficient absorption of CO2

Stomata

• Movement of gases in and out of lead

Phloem

• Tissue

• Transports sucrose (glucose)

• Away from leaf

Xylem

• tissue

• Transports water and mineral ions

• To the leafy from the roots

Leaves

• B-road

• Large SA:Vol

• Absorbs lots of light

Stem

• Supports the leaf

• Faces the sun

• Transports minerals water sucrose

Network of veins

• Supports leaf

• Transports etc

• Same as stem

Thickness of leaf

• Thin

• Short distnace of CO2

• To diffuse into leaf cells

Amount of stomata

• Lots

• Allows gases (CO2 and O2) in and out

Name two fundamental ions needed by plants

• Nitrogen

• Magnesium

If plants don’t have the two most essential ions what wont happen

Photosynthesis

From where do they absorb the mineral ions

The soil

Root hair cells

Why do plants need chlorophyl

• Make chlorophyll

• DEFICIENCY - causes yellow between veins

Why do plants need nitrogen

• To make amino acids

• To make protein

• DEFICIENCY - stunted growth + yellow

What is the positive test for starch

Iodine

Turns blue/black

What is de-starching

• Place plant in dark place for 24 hrs

• Plant uses up its store of starch(food)

• Means that any starch created is from photosynthesis

What is the method for testing for starch in leaf

1. De-starch plant

2. Remove one LEAFF

3. Place in boiling water for few min

To soften the leaf

4. Place leaf in boiling ethanol heated in beaker of boiling water

   Not over Bunsen burner - ethanol fumes are flammable

   Removes chloroplasts

5. When leaf loses green wash it

6. Place in dish

7. Add iodine - test for starch

How can we chnage the starch experiment of show light is needed

• Cover part of lead before destarching olant brought into light

• Only the part of the leaf that had light should make starch

How can u chnage the starch experiment to show chlorophyll is needed

• Use variated leaves

• Shows the presence of starch

• With chlorophyll

• And without chlorophyll

How can photosynthesis be measured in aquatic plants

By counting the oxygen bubbles produced

Or by using a glass syringe