Table of contents

1. Introduction to Biology2h 42m
2. Chemistry3h 37m
3. Water1h 26m
4. Biomolecules2h 23m
5. Cell Components2h 26m
6. The Membrane2h 31m
7. Energy and Metabolism2h 0m
8. Respiration2h 40m
9. Photosynthesis2h 49m
10. Cell Signaling59m
11. Cell Division2h 47m
12. Meiosis2h 0m
13. Mendelian Genetics4h 44m
14. DNA Synthesis2h 27m
15. Gene Expression3h 6m
16. Regulation of Expression3h 31m
17. Viruses37m
- Viruses
  37m
18. Biotechnology2h 58m
19. Genomics17m
- Genomes
  17m
20. Development1h 5m
21. Evolution3h 1m
22. Evolution of Populations3h 53m
23. Speciation1h 37m
24. History of Life on Earth2h 6m
25. Phylogeny2h 31m
26. Prokaryotes4h 59m
27. Protists1h 12m
28. Plants1h 22m
29. Fungi36m
- Fungi
  19m
- Fungi Reproduction
  17m
30. Overview of Animals34m
- Overview of Animals
  34m
31. Invertebrates1h 2m
32. Vertebrates50m
33. Plant Anatomy1h 3m
34. Vascular Plant Transport1h 2m
- Water Potential
  1h 2m
35. Soil37m
- Soil and Nutrients
  20m
- Nitrogen Fixation
  16m
36. Plant Reproduction47m
- Flowers
  33m
- Seeds
  14m
37. Plant Sensation and Response1h 9m
38. Animal Form and Function1h 19m
39. Digestive System1h 10m
- Digestion
  1h 3m
- Blood Sugar Homeostasis
  7m
40. Circulatory System1h 49m
41. Immune System1h 12m
42. Osmoregulation and Excretion50m
- Osmoregulation and Excretion
  50m
43. Endocrine System1h 4m
- Endocrine System
  1h 4m
44. Animal Reproduction1h 2m
- Animal Reproduction
  1h 2m
45. Nervous System1h 55m
- Neurons and Action Potentials
  1h 8m
- Central and Peripheral Nervous System
  46m
46. Sensory Systems46m
- Sensory System
  46m
47. Muscle Systems23m
- Musculoskeletal System
  23m
48. Ecology3h 11m
49. Animal Behavior28m
- Animal Behavior
  28m
50. Population Ecology3h 41m
51. Community Ecology2h 46m
52. Ecosystems2h 36m
53. Conservation Biology24m
- Conservation Biology
  24m

4. Biomolecules

Carbon

General Biology

4. Biomolecules

Carbon

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Multiple Choice

Pharmaceutical companies are selling billions of dollars' worth of single-enantiomer drugs. Why might it be important to use only one form of an enantiomer?

It is cheaper to manufacture only one of the enantiomers.

It is not important. Both enantiomers will be equally effective.

The left-handed version of the enantiomer is always the effective one.

One enantiomer may provide an effective treatment whereas the other may be ineffective or even toxic.

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Verified step by step guidance

Understand the concept of enantiomers: Enantiomers are molecules that are mirror images of each other, much like left and right hands. They are a type of stereoisomer, which means they have the same molecular formula and sequence of bonded atoms, but differ in the three-dimensional orientations of their atoms.

Recognize the significance of chirality in biology: Many biological molecules are chiral, and the two enantiomers can have very different effects in biological systems. This is because the shape of a molecule can affect how it interacts with biological targets, such as enzymes or receptors.

Consider the implications for drug effectiveness: One enantiomer of a drug may fit well into a biological target and produce the desired therapeutic effect, while the other enantiomer may not fit as well, making it less effective or even inactive.

Evaluate the potential for adverse effects: In some cases, the non-effective enantiomer can interact with other biological targets, potentially leading to side effects or toxicity. This is why it is crucial to use the correct enantiomer in pharmaceuticals.

Conclude with the importance of specificity: Using only the effective enantiomer can improve the safety and efficacy of a drug, which is why pharmaceutical companies invest in producing single-enantiomer drugs despite the potential for higher manufacturing costs.