Rucete ✏ Campbell Biology In a Nutshell
Unit 1 THE CHEMISTRY OF LIFE — Concept 4.1 Organic Chemistry is the Study of Carbon Compounds Practice Questions
(Multiple Choice — Click to Reveal Answer)
1. What element is the central focus of organic chemistry?
Show Answer
3. Carbon
2. Which of the following is a simple organic molecule?
Show Answer
2. Methane (CH₄)
3. Who conducted the 1953 experiment on early Earth simulation?
Show Answer
3. Stanley Miller
4. What did the electric sparks in the experiment represent?
Show Answer
2. Lightning
5. What did the boiling water simulate?
Show Answer
3. The primeval sea
6. Which gas was NOT included in Miller’s original atmosphere mix?
Show Answer
3. Oxygen (O₂)
7. What was the role of the condenser in the Miller apparatus?
Show Answer
3. It cooled gases to form rain
8. Which of the following was a product in the Miller experiment?
Show Answer
3. Amino acids and hydrocarbons
9. What was the key conclusion of Miller’s experiment?
Show Answer
3. Organic molecules could form abiotically
10. What feature of carbon makes it so versatile?
Show Answer
4. Its ability to form four covalent bonds
11. Which NASA rover found organic compounds on Mars in 2018?
Show Answer
2. Curiosity
12. What is the correct list of elements common in living organisms?
Show Answer
1. C, H, O, N, S, P
13. Which term describes molecules composed of only carbon and hydrogen?
Show Answer
4. Hydrocarbons
14. Why are variations in organic molecules important?
Show Answer
1. They contribute to the diversity of life
15. What kind of bonds does carbon typically form?
Show Answer
1. Single and double covalent bonds
16. What did the control experiment (no spark) show?
Show Answer
2. Organic molecules didn’t form without energy input
17. What does a molar ratio of 1.8 × 10⁻³ for methionine mean?
Show Answer
4. Much less methionine was formed than glycine
18. Which compound was detected in greater amounts than glycine in the H₂S experiment?
Show Answer
3. Alanine
19. What gas was included in the 1958 volcanic simulation but not the original experiment?
Show Answer
1. Hydrogen sulfide (H₂S)
20. Why is carbon considered the backbone of life?
Show Answer
2. It can form a variety of stable, complex structures
21. Why was Stanley Miller’s 1953 experiment significant in understanding the origin of life?
- It proved life existed on Mars
- It showed organic molecules could form without life
- It discovered DNA in space
- It recreated fossils in the lab
Show Answer
2. It showed organic molecules could form without life
22. What major revision was made to Miller’s hypothesis after later studies?
- Lightning could not form amino acids
- The early Earth’s atmosphere was more oxidizing
- Water was not abundant on early Earth
- Organic molecules need enzymes to form
Show Answer
2. The early Earth’s atmosphere was more oxidizing
23. Which of the following best explains why carbon can form a wide variety of molecules?
- It is a noble gas
- It easily gains electrons
- It can form four covalent bonds
- It has a full outer shell
Show Answer
3. It can form four covalent bonds
24. Which condition in the 1958 H₂S experiment mimicked volcanic activity?
- High-pressure chambers
- Use of hydrogen sulfide gas (H₂S)
- Radiation exposure
- Boiling the ocean sample
Show Answer
2. Use of hydrogen sulfide gas (H₂S)
25. What was discovered in the sealed vials from Miller’s 1958 experiment?
- DNA strands
- Living cells
- Multiple amino acids
- Oxygen-rich gases
Show Answer
3. Multiple amino acids
26. Which of the following molecules was found in lower abundance compared to glycine in the H₂S experiment?
- Alanine
- Serine
- Glycine itself
- Water
Show Answer
2. Serine
27. What is the molar ratio of methionine to glycine in the H₂S experiment?
- 1.1
- 3.0 × 10⁻²
- 1.8 × 10⁻³
- 2.5
Show Answer
3. 1.8 × 10⁻³
28. If glycine has a molar ratio of 1.0, how many molecules of glycine are in one mole?
- 1.0
- 6.02 × 10²³
- 3.0 × 10⁻²
- 1.8 × 10⁻³
Show Answer
2. 6.02 × 10²³
29. Based on Miller’s experiments, which element is likely limiting in the synthesis of methionine?
- Hydrogen
- Carbon
- Sulfur
- Oxygen
Show Answer
3. Sulfur
30. Which compound could be made in the H₂S experiment but not in the original 1953 experiment?
- Glycine
- Alanine
- Methionine
- Serine
Show Answer
3. Methionine
31. What would happen if the concentration of NH₃ was increased in the original experiment?
- Less HCN and CH₂O would form
- More water would be produced
- The relative amounts of HCN and CH₂O would change
- The system would explode
Show Answer
3. The relative amounts of HCN and CH₂O would change
32. What does the diversity of organic molecules suggest about carbon?
- Carbon rarely bonds with other atoms
- Carbon only forms simple compounds
- Carbon’s bonding ability leads to complexity
- Carbon is unstable in water
Show Answer
3. Carbon’s bonding ability leads to complexity
33. What is the significance of finding organic molecules on Mars?
- It proves alien life exists
- It suggests Mars had oceans recently
- It implies life may have once existed there
- It confirms Miller’s theory was wrong
Show Answer
3. It implies life may have once existed there
34. Which compound had a molar ratio almost equal to glycine?
- Methionine
- Serine
- Alanine
- Formaldehyde
Show Answer
3. Alanine
35. Why is glycine used as the standard in molar ratio comparisons?
- It is the most abundant molecule
- It is the most complex amino acid
- It is a control variable
- It has a molar ratio of 0.5
Show Answer
1. It is the most abundant molecule
36. In molecular terms, what does a molar ratio of 3.0 × 10⁻² for serine mean?
- 3 molecules of serine per 10 of glycine
- 3 serine molecules per 100 glycine molecules
- Serine is more abundant than glycine
- Serine cannot form abiotically
Show Answer
2. 3 serine molecules per 100 glycine molecules
37. What type of bonds form between carbon atoms in organic molecules?
- Ionic bonds
- Hydrogen bonds
- Single and double covalent bonds
- Peptide bonds
Show Answer
3. Single and double covalent bonds
38. Which of the following best describes the early Earth atmosphere used in Miller's 1953 experiment?
- Oxygen-rich and acidic
- Oxidizing and high-pressure
- Reducing and lacking oxygen
- Nitrogen-rich and dry
Show Answer
3. Reducing and lacking oxygen
39. What do the results of both the 1953 and 1958 experiments imply?
- Life only started from volcanoes
- Abiotic synthesis of amino acids is possible under varied conditions
- Only glycine forms in early-Earth simulations
- Volcanic gases block amino acid formation
Show Answer
2. Abiotic synthesis of amino acids is possible under varied conditions
40. What distinguishes organic from inorganic compounds?
- Organic compounds contain metals
- Organic compounds always contain nitrogen
- Organic compounds always contain carbon
- Inorganic compounds contain carbon and hydrogen
Show Answer
3. Organic compounds always contain carbon