1. Molecular & Cellular Biology Department of Biological Sciences
Functional Groups
Molecular & Cellular Biology
Department of Biological Sciences
05/2002 RGratreaks
11/21/2018
Based on Interactive Study Partner for Biology, 5th edition.

2. Functional Groups
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3. Functional Groups
Groups of atoms with distinctive properties, called functional groups, attached to the carbon skeleton.
This is an organic molecule called a tripeptide.
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4. Functional Groups Carboxyl Hydroxyl Carbonyl Sulfhydryl Amino
Phosphate
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5. What is this Functional Group?

6. Amino

7. What is special about Amino?
The slightly electronegative nitrogen atom in this group tends to pick up hydrogen ions from the surrounding solution, and thus this functional group acts as a base. Because of the added hydrogen ion, this group usually has a +1 charge in the cell. This group is characteristic of organic molecules called amines.

8. What is this Functional Group?

9. Carbonyl

10. What is special about Carbonyl?
This group is polar because oxygen has a strong attraction for electrons. If this group is at the end of a carbon skeleton, the molecule is called an aldehyde; otherwise it is called a ketone.

11. What is this Functional Group?

12. Carboxyl

13. What is special about Carboxyl?
The two electronegative oxygens of this group pull electrons away from the hydrogen atom. This weakens the bond between oxygen and hydrogen, and the hydrogen atom tends to dissociate from the molecule as a hydrogen (H+) ion. Because it donates hydrogen ions, this group is acidic, and molecules that contain these groups are known as carboxylic acids.

14. What is this Functional Group?

15. Hydroxyl

16. What is special about Hydroxyl?
This functional group is polar because the electronegative oxygen has a strong attraction for electrons. Water is attracted to this group, and therefore molecules that have this group (such as sugars) tend to dissolve in water. Alcohols are characterized by this functional group.

17. What is this Functional Group?

18. Phosphate

19. What is special about Phosphate?
The electronegative oxygens of this functional group draw electrons, and as a result the group acts as an acid, losing hydrogen ions to the surrounding solution. This dissociation leaves the group with a negative charge. This group is important in ATP and the transfer of energy between organic molecules.

20. What is this Functional Group?

21. Sulfhydryl

22. What is special about Sulfhydryl?
Molecules termed thiols are characterized by this group, which resembles a hydroxyl group. These groups interact to help stabilize the structure of many proteins.