5.1.2 Photosynthesis: Twentieth-Century Breakthroughs Flashcards
1
Q
C.B. Van Neil, and Ruben and Kamen
A
- led to a more clear understanding of photosynthesis.
2
Q
van Neil
A
- At first van Neil thought that the bacteria were able to take carbon dioxide (CO2), split it, and combine the carbon with hydrogen sulfide (H2S) to make a CH2S-type of compound and O2 gas. This was not what happened. Oxygen gas was not being produced. Instead, van Neil found that the H2S was being split and the CO2 was combining with H to make carbohydrate. In the process, elemental sulfur was given off.
- Photosynthesis seems somewhat similar to the sulfur reaction except that instead of H2S, it involves H2O. van Neil suggested that perhaps water was split in photosynthesis, rather than carbon dioxide, to produce oxygen gas and carbohydrate.
3
Q
Ruben and Kamen
A
- In 1941, through the use of isotopes, Ruben and Kamen
proved that water was indeed split in the process of
photosynthesis rather than carbon dioxide. - The oxygen in water was tagged with an isotope and given to plants. The oxygen gas that was released by the plantsalso had the isotope.
4
Q
Cornelius van Niel discovered that
A
- some bacteria are able to combine the hydrogen from hydrogen sulfide with carbon dioxide to produce carbohydrates
5
Q
The main source of carbon in photosynthesis is from
A
- carbon dioxide
6
Q
Which of the following statements regarding water’s role in photosynthesis is the most accurate?
A
- Water is split during photosynthesis
7
Q
What happens when water containing an oxygen isotope is supplied to a plant?
A
- The oxygen isotope is released into the air.
8
Q
True or false?
Water provides the source of electrons in the formation of carbohydrate from CO2 during photosynthesis.
A
- true
9
Q
Based on his findings, Cornelius van Niel was able to conclude
A
- that it was possible that plants split water to release oxygen and make carbohydrates
