B8 - Photosynthesis Flashcards
Definitions - What does the word ‘endothermic reaction’ mean?
a reaction that requires a transfer of energy from the environment
Definitions - What is glucose?
A simple sugar
Definitions - What is a ‘limiting factor’?
limit the rate of a reaction. e.g photosynthesis
Definitions - What is photosynthesis?
the process by which plants make food using carbon dioxide, water, and light.
B8.1 - Describe how plants get the materials needed for growth.
- water: up through the roots - xylem cells
- co2: through stomata on leaves
- light: through top of the leaves
- chlorophyll: in chloroplasts of palisade cells
B8.1 - State the word equation for photosynthesis.
Light
CO2 + Water ——–> glucose + oxygen
Chlorophyll
B8.1 - Why do plants need light to carry out photosynthesis??
Plants use light to create glucose from water and carbon dioxide.
B8.1 - Describe how the leaf is adapted for photosynthesis
Large surface area for maximum light absorption. Thin structure - short distance for CO2 to diffuse into leaf cells
B8.1 - Write the balanced symbol equation for photosynthesis.
6CO2 + 6H2O → C6H12O6 + 6O2.
B8.1 - Explain how adaptations of the leaf make photosynthesis efficient.
•Large surface area and contain openings called stomata to allow CO2 into the leaf and oxygen out.
B8.1 - Explain why chlorophyll is needed for photosynthesis
Chlorophyll absorbs the sunlight used for photosynthesis.
B8.2 - What factors affect the rate of photosynthesis?
temperature, carbon dioxide concentration, light intensity
B8.2 - Explain why a high temperature affects the rate of photosynthesis
The rate of photosynthesis slows down because the enzymes involved in chemical reactions of photosynthesis are sensitive to temperature and become denatured at higher temp.
B8.3 - List some ways in which plants use glucose
make celluose, make starch, respiration, storage, photosynthesis.
B8.3 - What are some safety rules for testing for starch?`
Safety goggles
B8.3 - describe all the ways plants use glucose, including how they make proteins
Some of the glucose is used for respiration and converted into cellulose for making cell walls. Glucose is combined with nitrates to make amino acids, which are then made into proteins.
B8.3 - Explain how and why plants convert glucose to starch for storage
Glucose is converted into starch by a process called polymerization. Glucose is converted into starch as glucose is soluble and starch is insoluble in water so it won’t affect the way water moves in and out of the plant
6 Marker Answer - Remember, just bullet point for 6 marks
A - Upper epidermis (protects leaf) they are transparent and let light through.
B - Palisade cells (has lots of chloroplasts) and is where most of the photosynthesis takes place.
C - air space for diffusion of gases and lets oxygen out.
D - guard cells (opens and closes the stomata) - controls the size of the stomata
E - lower epidermis - this lets water vapour in and out of the cell
F - Xylem tubes - transports water and minerals
G - Phloem - transports dissolved sugars
What is the inverse square law for photosynthesis?
The rate of photosynthesis is directly proportional to light intensity and inversely proportional (one value increases and one decreases) to the distance from a light source. The inverse square law tells us that the intensity of light is inversely proportional to the square of the distance from the source.
What is the inverse square law equation?
New light intensity = original light intensity x original distance from lamp squared over the new distance squared
