Photosynthesis Flashcards
Describe the purpose of photosynthesis
To produce food (glucose)
What is chlorophyll?
Chlorophyll is the green pigment in chloroplasts that absorbs light energy to change CO2 + water into glucose and the by-product oxygen
Give the word equation for photosynthesis
Light energy
Carbon dioxide + water ➡️ glucose + oxygen
Chlorophyll
How do each of the reactants get into the plant?
Plants make their food from carbon dioxide + water in a chemical reaction called photosynthesis. Carbon dioxide from the air, water from the soil
Sketch and label a basic plant cell
…
State the location of photosynthesis within a plant cell
Chloroplasts
Give the symbol equation for photosynthesis
6CO2 + 6H2O ➡️ C6H12O6 + 6O2
Explain how broad leaves relate to their role in photosynthesis
Large surface area so increases the rate of photosynthesis as more sunlight is absorbed
Explain how stem/stalk support relates to its role in photosynthesis
They can grow upwards making it more likely for them to reach light. Stem supports plant and is turgid providing structure for the plant.
Explain how many chlorophyll in the chloroplasts of palisade mesophyll relate to their role in photosynthesis
More chloroplasts = more photosynthesis
Explain how a network of veins relate to their role in photosynthesis
To support the leaf and transport water and carbohydrates
Explain how thin leaves relate to their role in photosynthesis
Easier to absorb oxygen, light and water
Explain how the transparent epidermis relates to its role in photosynthesis
To allow more light to reach the palisade cells
Explain how tightly packed palisade cells relate to their role in photosynthesis
Contains many chloroplasts to absorb all light
Explain how many stomata relate to their role in photosynthesis
Allows carbon dioxide to diffuse into the cell
Explain how guard cells relate to their role in photosynthesis
To open and close the stomata depending on the conditions
Explain how spongy mesophyll relates to its role in photosynthesis
Air spaces allow carbon dioxide to diffuse through the leaf, and increase the surface area
Name the chemical used to test starch, and describe the colour change if the test is positive
Iodine turns black
What is the function of starch in a plant?
As a food store
How could starch be removed from a leaf?
Keep it in the dark for over 12 hours
What is the wax cuticle for?
Prevents the leaf from losing water
What is the palisade mesophyll for?
Tightly packed, lots of chloroplasts - good for photosynthesis
What is the spongy mesophyll for?
Gas exchange
What is the guard cell with chloroplasts for?
Controls gases in/out of leaf
What is the stoma for?
Allows gases to exchange (CO2 in + O2 out)
What is the air space for?
Air spaces mean air can get in and out
What is the upper epidermis for?
Transparent so the light can pass through easily
Light intensity affects photosynthesis because…
The chlorophyll is able to absorb more light
What is the glucose used for in photosynthesis?
1) Converted into chemicals required for growth of plant cells such as cellulose
2) Converted into starch, then be converted back to glucose when the plant requires it
3) Can be broken down during the process of respiration, releasing energy stored on the glucose molecule
What are the three limiting factors in plants?
Light intensity
Temperature
Carbon dioxide concentration
Explain why chlorophyll is needed in photosynthesis
Chlorophyll is necessary in order for plants to convert carbon dioxide and water, using sunlight, into glucose and oxygen
Before testing for starch why is it important that you leave the plant in a dark place for 24 hours and what is the process called?
This is important so that the plant uses up its stores of starch, this is called de-starching. This mean that any starch identified by the test is the result of photosynthesis during the investigation.
What minerals are needed for healthy plant growth?
Nitrates to make amino acids
Magnesium to make chloroplasts
Phosphate to make DNA
