Which step in photosynthesis does not need light

Question

1. water splits into hydrogen and oxygen
2. oxygen is released
3. chlorophyll absorbs energy
4. carbon dioxide and hydrogen combine to form glucose

Answer 1

The step in photosynthesis that does not need light is:

4. carbon dioxide and hydrogen combine to form glucose.

This process occurs during the Calvin cycle, which is part of the light-independent reactions of photosynthesis. In contrast, the other steps you mentioned involve light energy, particularly those involving the splitting of water and the absorption of energy by chlorophyll.

Answer 2

A scientist preforms an experiment by placing petroleum jelly on the underside of plant leaves. This blocks the leaves' stomata. The plant is watered and placed in a sunny spot. What will the scientist observe?

Answer 3

In the experiment where petroleum jelly is applied to the underside of plant leaves to block the stomata, several observations can be expected:

1. Reduced Transpiration: The blocking of stomata will significantly reduce or inhibit the transpiration process, which is the loss of water vapor from the plant to the atmosphere. The plant may become less efficient at regulating water loss.

2. Wilting or Leaf Curling: Due to reduced transpiration, the plant may start to show signs of water stress, such as wilting or curling of the leaves. This occurs because the plant is unable to effectively manage its internal water levels.

3. Increased Temperature and Water Accumulation: The surface temperatures of the leaves may rise, as the lack of transpiration prevents evaporative cooling. Additionally, excess water may accumulate within the plant if it is still being watered, leading to potential problems such as root rot.

4. Stunted Growth or Other Stress Indicators: Over time, the plant may exhibit stunted growth or other signs of stress due to the inability to exchange gases properly (CO2 intake for photosynthesis) or maintain suitable moisture levels.

In summary, the scientist is likely to observe negative effects on the plant's health and growth due to the blockage of stomata, even in a sunny environment where photosynthesis would typically be active.

Answer 4

Who many carbon atoms combine in the photosynthesis reaction?

Answer 5

In the overall photosynthesis reaction, six carbon atoms combine to form one glucose molecule. The balanced chemical equation for photosynthesis can be written as:

\[ 6 , \text{CO}_2 + 6 , \text{H}_2\text{O} \rightarrow \text{C}6\text{H}{12}\text{O}_6 + 6 , \text{O}_2 \]

In this equation:

• 6 \( \text{CO}_2 \) (carbon dioxide molecules) provide a total of 6 carbon atoms.
• The reaction produces one glucose molecule (\( \text{C}6\text{H}{12}\text{O}_6 \)), which contains 6 carbon atoms.

Therefore, six carbon atoms from carbon dioxide are used to produce one molecule of glucose during the process of photosynthesis.