photosynthesis Flashcards
what is photosynthesis
-a complex process that converts radiant energy (light) into chemical potential energy (glucose)
what happens during photosynthesis
-oxygen is released into the atmosphere during photosynthesis
-enzymes in the cells are also needed for the process
-excess glucose is converted into starch
where does photosynthesis take place
-in the chloroplasts of plants
what’s the word equation for photosynthesis
carbon dioxide + water -> (sunlight on top) (chloroplasts on bottom) -> glucose + oxygen
what are the two phases photosynthesis takes place in
-light phase (light required)
-dark phase (no light required)
what is the light phase
-takes place in the grana
-radiant energy absorbed by chlorophyll transferred into chemical energy
-photolysis
-energy rich hydrogen atoms are transferred to dark phase
-oxygen is released into atmosphere
-radiant energy cause’s energy carrier ATP to be formed
what is photolysis
-chemical energy splitting water molecules into energy rich hydrogen atoms and oxygen atoms
what is the structure of a chloroplast
-double membrane
-granum
-lamella
-strong
-lamella
what is the dark phase
-takes place in the stroma of chloroplasts
-energy rich carbohydrates (glucose) are formed
-excess glucose is stored
what is ATP
-important energy carrier in cells
-cells use ATP energy to produce important molecules and helps move substances across cell membranes
what are the factored that influence the rate of photosynthesis
-light
-carbon dioxide
-temperature
what’s the importance of photosynthesis
-food for plants and animals
-atmospheric gasses
-cellular respiration
What is the role of stomata in photosynthesis?
-Stomata are small openings on leaves that allow carbon dioxide in and oxygen out.
How do roots contribute to photosynthesis?
-Roots absorb water and minerals from the soil, which are transported to the leaves for photosynthesis.
What can the glucose produced during photosynthesis be used for?
Glucose can be used for (cellular respiration)
Why is photosynthesis important?
- It produces food for plants and animals and helps maintain the balance of oxygen and carbon dioxide in the atmosphere.
What is carbon fixation?
-The process of converting carbon dioxide (CO2) into organic molecules (like glucose) during photosynthesis.
How can we prove that starch is produced during photosynthesis?
-To prove that starch is produced, a leaf is tested using iodine solution. If photosynthesis occurs, the iodine turns the leaf dark blue/black, indicating starch is present.
What experiments show that light and carbon dioxide are necessary for photosynthesis?
For light, a destarched leaf is partially covered with opaque material and exposed to light. Only the uncovered part shows starch production. For carbon dioxide, sodium hydroxide (which removes CO₂) is placed in a bell jar with the plant. No starch forms without CO₂.
How do we test if chlorophyll is necessary for photosynthesis?
A variegated leaf (with green and white parts) is exposed to sunlight. Only the green parts, containing chlorophyll, produce starch when tested with iodine.
How do we test for oxygen production during photosynthesis?
The oxygen produced by an aquatic plant can be collected and tested using a glowing splint. If the splint re-ignites, oxygen is present.
What are the variables in photosynthesis experiments?
Independent variables: Light intensity, CO₂ concentration, temperature.
Dependent variable: Rate of photosynthesis (measured by oxygen bubbles or starch production).
Control variables: Type of plant, water availability, exposure time.
How can we measure the rate of photosynthesis?
-The rate of photosynthesis can be measured by counting oxygen bubbles produced by aquatic plants or by testing for starch in leaves exposed to different conditions (light, CO₂, etc.).
How can carbon dioxide enrichment improve crop yields in a greenhouse?
leading to faster plant growth and higher yields.
