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ATP is an abbreviation - Leaving Cert Biology - Question 11 - 2004
Question 11
ATP is an abbreviation. What does it stand for? Explain briefly the role of ATP in the energy exchanges of a cell. The first stage of photosynthesis is commonly kno... show full transcript
Worked Solution & Example Answer:ATP is an abbreviation - Leaving Cert Biology - Question 11 - 2004
Step 1
What does ATP stand for and its role in energy exchanges?
Answer
ATP stands for Adenosine Triphosphate. It plays a crucial role in cellular energy exchanges by acting as a energy currency for the cell. ATP stores energy in its high-energy phosphate bonds, which can be released when ATP is broken down into ADP (Adenosine Diphosphate) and an inorganic phosphate. This energy is then used to power various cellular processes, including metabolic reactions, muscle contractions, and active transport across cell membranes.
Step 2
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Step 4
What is the fate of each of the products of the light-dependent stage?
Answer
The primary products of the light-dependent stage are ATP and NADPH. ATP is used in the Calvin cycle to help convert carbon dioxide into glucose during the dark reactions. NADPH is also used in the Calvin cycle to facilitate the reduction stages of the cycle. Oxygen produced is typically released into the atmosphere.
Step 5
Why is a water plant rather than a land plant used in this experiment?
Answer
A water plant like Elodea is used because it is easier to measure photosynthesis by observing oxygen release underwater. Land plants may lose water or show different rates of photosynthesis influenced by environmental factors that are harder to control in an experiment.
Step 6
How is the temperature kept constant in this experiment?
Answer
The temperature can be kept constant by using a water bath to maintain a consistent temperature throughout the experiment, ensuring that any variations in photosynthesis rates are due solely to light intensity or carbon dioxide concentration.
Step 7
Suggest two possible sources of carbon dioxide in pond water.
Answer
- Carbon dioxide could naturally dissolve from the atmosphere into the pond water, especially if the water is agitated by movement.
- Respiration from aquatic organisms, such as fish and microorganisms, releases carbon dioxide as a byproduct, which then dissolves into the water.
Step 8
Explain how light intensity or carbon dioxide concentration may be varied.
Answer
Light intensity can be varied by changing the distance of the light source from the pondweed or using different wattage lamps. Carbon dioxide concentration can be varied by adding sodium bicarbonate or varying the amount of pond water to adjust its natural carbon content.
Step 9
What is this precaution and why is it necessary?
Answer
A precaution necessary when varying light intensity or carbon dioxide concentration is to allow time for the plant to adjust or equilibrate to the new conditions. This is necessary to ensure the plant has stabilized under the new conditions before measuring rates of photosynthesis, as immediate changes could lead to inaccurate readings.