1. How do plants recycle carbon during photosynthesis?(1 point)
Responses
The carbon in carbon dioxide is recycled during photosynthesis.
The carbon in carbon dioxide is recycled during photosynthesis.
The carbon in oxygen molecules is recycled during photosynthesis.
The carbon in oxygen molecules is recycled during photosynthesis.
The carbon in glucose is recycled during photosynthesis.
The carbon in glucose is recycled during photosynthesis.
The carbon in water is recycled during photosynthesis.
2. How do plants recycle hydrogen during cellular respiration?(1 point)
Responses
The hydrogen in hydrogen gas is recycled when glucose is formed.
The hydrogen in hydrogen gas is recycled when glucose is formed.
The hydrogen in glucose is recycled when water is formed.
The hydrogen in glucose is recycled when water is formed.
The hydrogen in glucose is recycled when hydrogen gas is formed.
The hydrogen in glucose is recycled when hydrogen gas is formed.
The hydrogen in water is recycled when glucose is formed.
3. How many molecules of water are recycled when one molecule of glucose is created during photosynthesis?(1 point)
Responses
6
12
1
3
4. Scientists used radioactive hydrogen to make water. They grew plants using the radioactive water. What happened to the radioactive hydrogen during photosynthesis?(1 point)
Responses
It was recycled when light energy was formed.
It was recycled when light energy was formed.
It was recycled when water was formed.
It was recycled when water was formed.
It was recycled when glucose was formed.
It was recycled when glucose was formed.
It was recycled when hydrogen gas was formed.
It was recycled when glucose was formed.
answer 1 - 4
1. The carbon in carbon dioxide is recycled during photosynthesis.
2. The hydrogen in water is recycled when glucose is formed.
3. 6 molecules of water are recycled when one molecule of glucose is created during photosynthesis.
4. The radioactive hydrogen was recycled when water was formed.
1. How do plants recycle carbon during photosynthesis?
The correct answer is: The carbon in carbon dioxide is recycled during photosynthesis.
During photosynthesis, plants use carbon dioxide (CO2) from the atmosphere and convert it into glucose, a sugar molecule that plants use for energy. This process takes place in the chloroplasts of plant cells, specifically in the chlorophyll molecules found in the thylakoid membranes. The carbon atoms in CO2 are rearranged and combined with hydrogen and oxygen atoms from water to form glucose. This way, the carbon atoms are recycled and incorporated into the glucose molecule.
2. How do plants recycle hydrogen during cellular respiration?
The correct answer is: The hydrogen in glucose is recycled when water is formed.
During cellular respiration, plants break down glucose to release energy that fuels their cellular processes. This process occurs in the mitochondria of plant cells. As glucose is broken down, hydrogen atoms are released. These hydrogen atoms are combined with oxygen atoms from inhaled oxygen to form water (H2O). In this way, the hydrogen atoms from glucose are recycled and used to form water.
3. How many molecules of water are recycled when one molecule of glucose is created during photosynthesis?
The correct answer is: 6
During photosynthesis, plants use energy from sunlight to convert carbon dioxide and water into glucose and oxygen. The balanced equation for photosynthesis is:
6 CO2 + 6 H2O + sunlight → C6H12O6 + 6 O2
From this equation, we can see that for every molecule of glucose (C6H12O6) produced, 6 molecules of water are used. Therefore, during the process of photosynthesis, 6 molecules of water are recycled to create one molecule of glucose.
4. Scientists used radioactive hydrogen to make water. They grew plants using the radioactive water. What happened to the radioactive hydrogen during photosynthesis?
The correct answer is: It was recycled when glucose was formed.
When scientists used radioactive hydrogen (a form of hydrogen with an unstable nucleus) to make water and then grew plants using this radioactive water, the hydrogen became incorporated into glucose during photosynthesis. During photosynthesis, plants take in water (H2O) through their roots and then break it down into its component elements, hydrogen and oxygen. The hydrogen atoms from the radioactive water are used to build glucose. Therefore, the radioactive hydrogen is recycled and becomes part of the glucose molecule formed during photosynthesis.