Question

identify the purpose of each of the following steps in the photosynthesis experiment. hole - punching the leaves standardize the s adding bicarbonate buffer to the syringe. provide a source exposing the disks to a vacuum in the syringe remove oxygen fi adding a plain buffer to the syringe choose provide a source of water and carbon dioxide add oxygen into the leaves to expose the chloroplasts to light provide a source of water only (no carbon dioxide) remove oxygen from the leaves to make them sink standardize the surface area of the leaves remove carbon dioxide from the leaves to make them sink question 2 the percentage of floating leaf disks is a reasonable measure of photosynthetic rate because the leaves float

Explanation:

1. Hole - punching the leaves: This creates leaf disks of relatively uniform size, standardizing the surface area for consistent experimental results in terms of photosynthetic capacity per unit area.
2. Adding bicarbonate buffer to the syringe: Bicarbonate can dissociate to release carbon dioxide, which is a key reactant for photosynthesis, providing a source of carbon dioxide.
3. Exposing the disks to a vacuum in the syringe: This removes air (including oxygen) from the intercellular spaces of the leaf disks, causing them to sink initially. As photosynthesis occurs and oxygen is produced, the disks will float again.
4. Adding a plain buffer to the syringe: A plain buffer provides a source of water and can maintain a stable pH environment, but it does not provide a significant source of carbon dioxide like the bicarbonate buffer. So it provides a source of water only (no carbon dioxide).

Answer:

1. Hole - punching the leaves: standardize the surface area of the leaves
2. Adding bicarbonate buffer to the syringe: provide a source of carbon dioxide
3. Exposing the disks to a vacuum in the syringe: remove oxygen from the leaves to make them sink
4. Adding a plain buffer to the syringe: provide a source of water only (no carbon dioxide)