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1. Introduction to Microbiology3h 21m
2. Disproving Spontaneous Generation1h 18m
3. Chemical Principles of Microbiology3h 38m
4. Water1h 28m
5. Molecules of Microbiology2h 23m
6. Cell Membrane & Transport3h 28m
7. Prokaryotic Cell Structures & Functions5h 52m
8. Eukaryotic Cell Structures & Functions2h 18m
9. Microscopes2h 46m
10. Dynamics of Microbial Growth4h 36m
11. Controlling Microbial Growth4h 10m
12. Microbial Metabolism5h 16m
13. Photosynthesis2h 31m
14. DNA Replication2h 25m
15. Central Dogma & Gene Regulation7h 14m
16. Microbial Genetics4h 44m
17. Biotechnology3h 0m
18. Viruses, Viroids, & Prions4h 56m
19. Innate Immunity7h 15m
20. Adaptive Immunity7h 14m
21. Principles of Disease6h 57m

5. Molecules of Microbiology

Functional Groups

5. Molecules of Microbiology

Functional Groups: Videos & Practice Problems

Video Lessons Practice Worksheet

Topic summary

Functional groups are specific groups of atoms that confer reactivity to biomolecules, typically extending from a carbon backbone. Key functional groups include the methyl group (–CH₃), hydroxyl group (–OH), carbonyl group (C=O), carboxyl group (–COOH), amino group (–NH₂), phosphate group (–PO₄), and sulfhydryl group (–SH). Understanding these groups is essential for recognizing their roles in various biomolecules, such as lipids and carbohydrates, and their significance in biological processes.

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Functional Groups

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Functional Groups Video Summary

Functional groups are specific groups of atoms within molecules that are responsible for the chemical reactions of those molecules. They are commonly found in biomolecules and extend off the carbon backbone, which is often represented by squiggly lines in structural formulas. Understanding these functional groups is essential as they play a crucial role in the structure and function of various biological molecules.

In biology, there are seven primary functional groups that are important to know:

The methyl group consists of a carbon atom bonded to three hydrogen atoms, typically found in lipids. This group is represented as -CH₃.

The hydroxyl group features an oxygen atom bonded to a hydrogen atom (-OH). This group is prevalent in carbohydrates and contributes to the polarity of molecules, enhancing their solubility in water.

The carbonyl group is characterized by a carbon atom double-bonded to an oxygen atom (C=O). This group is significant in various biomolecules, including sugars and fatty acids.

The carboxyl group combines both a carbonyl and a hydroxyl group, represented as -COOH. This functional group is acidic and is commonly found in amino acids and fatty acids.

The amino group contains a nitrogen atom bonded to two hydrogen atoms (-NH₂). This group is fundamental in the structure of amino acids, which are the building blocks of proteins.

The phosphate group is identified by the presence of a phosphorus atom bonded to four oxygen atoms, typically represented as -PO₄^3-. This group is crucial in energy transfer, particularly in ATP (adenosine triphosphate).

Lastly, the sulfhydryl group consists of a sulfur atom bonded to a hydrogen atom (-SH). This group is important in the structure of proteins, particularly in forming disulfide bonds that stabilize protein structure.

Familiarity with these functional groups will aid in recognizing their roles in various biomolecules and understanding their chemical behavior. As you progress in your studies, you may need to memorize their structures and functions, as they will frequently appear in discussions about biological processes and molecular interactions.

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Functional Groups Example 1

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Functional Groups Example 1 Video Summary

In this example, we analyze a molecule to identify which functional group is absent. The first functional group considered is the carboxyl group, which consists of a carbonyl group (C=O) and a hydroxyl group (–OH). In the given molecule, a carbon is double-bonded to an oxygen and also has a hydroxyl group attached, confirming the presence of a carboxyl group. Therefore, we can eliminate this option.

Next, we observe a hydroxyl group, characterized by the –OH structure. This group is present in the molecule, allowing us to cross off this option as well.

We then look for the amino group, which contains a nitrogen atom. The presence of a nitrogen atom in the molecule indicates that the amino group is also present.

Finally, we check for the sulfhydryl group, which is defined by the presence of a sulfur atom bonded to a hydrogen atom (–SH). Since there are no sulfur atoms in the molecule, we conclude that the sulfhydryl group is the only one not present. Thus, the correct answer is the sulfhydryl group.

Problem

What is the name of the functional group shown in the figure?

a) Carbonyl.
b) Ketone.
c) Carboxyl.
d) Methyl.
e) Phosphate.

Carbonyl.

Ketone.

Carboxyl.

Methyl.

Phosphate.

Problem

All of the following are examples of functional groups in biology except:
a) -CH₃.
b) -COOH.
c) -H₂O.
d) -NH₂.
e) -OH.

-CH₃

-COOH

-H₂O

-NH₂

-OH

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What are functional groups in organic chemistry?

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. They typically extend from a carbon backbone and confer specific reactivity and properties to the molecule. Common functional groups include the methyl group (–CH₃), hydroxyl group (–OH), carbonyl group (C=O), carboxyl group (–COOH), amino group (–NH₂), phosphate group (–PO₄), and sulfhydryl group (–SH). Understanding these groups is essential for recognizing their roles in various biomolecules, such as lipids and carbohydrates, and their significance in biological processes.

Why are functional groups important in biology?

Functional groups are crucial in biology because they determine the properties and reactivity of biomolecules. They play a key role in the structure and function of molecules like proteins, nucleic acids, carbohydrates, and lipids. For example, the hydroxyl group (–OH) is important in carbohydrates, while the amino group (–NH₂) is essential in amino acids, the building blocks of proteins. Functional groups also participate in chemical reactions that are vital for life, such as enzyme catalysis, energy transfer, and cell signaling.

What is the difference between a carbonyl group and a carboxyl group?

The carbonyl group (C=O) consists of a carbon atom double-bonded to an oxygen atom. It is found in aldehydes and ketones. The carboxyl group (–COOH) is a combination of a carbonyl group and a hydroxyl group (–OH) attached to the same carbon atom. It is found in carboxylic acids and is important in amino acids and fatty acids. The carboxyl group can donate a proton (H⁺), making it acidic, whereas the carbonyl group does not have this property.

How do you identify a phosphate group in a molecule?

A phosphate group (–PO₄) is identifiable by the presence of a phosphorus atom bonded to four oxygen atoms. It is unique among common functional groups because it contains phosphorus. Phosphate groups are crucial in energy transfer molecules like ATP (adenosine triphosphate) and in the backbone of nucleic acids like DNA and RNA. They often participate in energy transfer and signaling processes within cells.

What role does the amino group play in proteins?

The amino group (–NH₂) is a fundamental component of amino acids, which are the building blocks of proteins. In amino acids, the amino group is attached to the alpha carbon along with a carboxyl group (–COOH), a hydrogen atom, and a variable R group (side chain). The amino group can act as a base, accepting a proton (H⁺), which is important for the protein's structure and function. It also participates in peptide bond formation during protein synthesis.