2 (e) Nutrition in Flowering Plants

Photosynthesis definition

The process by which plants use light energy trapped by chlorophyll to turn carbon dioxide and water into glucose

Word equation for photosynthesis

carbon dioxide + water —> glucose + oxygen

symbol equation for photosynthesis

6CO2 +6H2O —> C6H12O6 + 6O2

Explain photosynthesis process

• Inside the chloroplasts, chlorophyll absorbs the sunglisht

• and uses its energy to convert carbon dioxide and water into glucose and oxygen

how does carbon dioxide concentration affect the rate of photosynthesis

• CO2 is one of the raw materials needed for photosynthesis

• increasing CO2 will increase rate of photosynthesis up to a point

• after this the graph flattens out, showing that CO2 is no longer the limiting factor

how does carbon light intensity affect the rate of photosynthesis

• chlorophyll uses light energy to perform photosynthesis

• if the light intensity is increased, the rate of photosynthesis will increase steadily, but only up until a certain point

how does temperature affect the rate of photosynthesis

• temperature affects the enzymes involved

• as temperature increases, so does the rate of photosynthesis, up to a point

• if the temperature is too high, the plant’s enzymes will be denatured so the rate of photosynthesis rapidly decreases

how are the stomata of leaves adapted for efficient photosynthesis

they let CO2 diffuse directly into the leaf

how are the broadness of leaves adapted for efficient photosynthesis

leaves are broad, so there’s a large surface area exposed to light

how is the palisade mesophyll layer of leaves adapted for efficient photosynthesis

most of the chlorplasts are found in the palisade layer, so they’re near the top of the leaf where they can get the most sunlight

how is the upper epidermis of leaves adapted for efficient photosynthesis

the upper epidermis is transparent so that light can pass through it to the palisade layer

how are the vascular bundles of leaves adapted for efficient photosynthesis

• leaves have a network of vascular bundles,

• the transport vessels xylem and phloem, which deliver water and other nutrients to every part of the leaf and take away the glucose produced by photosynthesis,

• they also help to support the leaf structure

how is the waxy cuticle of leaves adapted for efficient photosynthesis

the waxy cuticle helps to reduce water loss by evaporation

what are nitrates for in plants

• contain nitrogen for making amino acids and proteins

• needed for cell growth

• nitrate deficiency will make it stunted and older leaves turn yellow

what are phosphates for in plants

• contain phosphorus for making DNA and cell membranes and needed for respiration and growth

• phosphate deficiency will make the plant have poor root growth and their older leaves turn purple

what is potassium for in plants

• to help the enzymes needed for photosynthesis and respiration

• potassium deficiency means that plants have poor flower and fruit growth and discolored leaves

what is magnesium for in plants

• for making chlorophyll needed for photosynthesis

• magnesium deficiency leads to yellow leaves

how to test a leaf for starch

• dunk the leaf in boiling water, holding it with tweezers or forceps

• this stops any chemical reactions happening inside the leaf

• then put the leaf in a boiling tube with ethanol and heat it in an electric water bath until it boils which gets rids of any chlorophyll and makes the leaf a white-ish colour

• finally, rinse the leaf in cold water and add a few drops of iodine solution, if starch is present the leaf will turn blue-black