Functional Groups: Role in Macromolecules - Biology Essay

This essay explores the significance of functional groups in organic molecules. It delves into the structure and properties of six key functional groups: hydroxyl, carbonyl, methyl, sulfhydryl, amino, and phosphate. The essay examines how each group contributes to the characteristics of macromolecules such as proteins, lipids, carbohydrates, and nucleic acids. It highlights the polarity, reactivity, and bonding capabilities of each group, providing examples like alcohols, aldehydes, ketones, and amino acids. The essay emphasizes the role of these functional groups in influencing chemical reactions, solubility, and the overall behavior of organic compounds, ultimately concluding that these groups are fundamental to the formation and function of biological molecules. The essay uses references to support the information presented.

Running head: FUNCTIONAL GROUPS
Functional groups
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Author’s note

1FUNCTIONAL GROUPS
Organic molecules have their own specific type of functional groups that plays a role in
the formation of proteins, lipids, carbohydrates and proteins. They confer specific properties to
macromolecules. Six types of functional groups include hydroxyl, carbonyl, methyl, sulfhydryl,
amino and phosphate. It is mainly formed by chains of carbon atoms where occasionally nitrogen
or oxygen atoms are substituted. This essay will explore the structure and functional properties
of each functional group and provide examples of specific macromolecules.
Hydroxyl group comprise one carbon atom and one hydrogen atom. The chemical
formula of the group is R–OH. The R in the formula stands for carbon backbone. Hydroxyl
group is mainly found in sugars and alcohols. Some examples of alcohols containing this
functional groups include methanol and propenol. Hydroxyl groups are polar in nature and they
play a role in many chemical reactions. They take part in hydrogen binding and it makes many
water insoluble compound water soluble if they posses two or more functional groups (Brown &
Poon, 2016). Examples of some molecules with hydroxyl groups include glucose and nucleic
acids like adenine.
The second important functional group is carbonyl which is also polar and reactive in
nature. Carbon atoms are double bonded to an oxygen atom to form this functional group. The
structure of carbonyl group is given in figure 1. The polarity is thee main feature of carbonyl
group which works to influence the solubility of any compound by changing melting and boiling
points. Aldehydes and ketones mostly possess carbonyl groups. The third type of function groups
includes methyl which is mainly non-polar in nature. It mainly consists of one carbon atom
bonded to three hydrogen atoms. Some of the unique functions of methyl group are that they are
able to form non-polar covalent bond and it is hydrophobic. Methyl groups property of sharing

2FUNCTIONAL GROUPS
electrons cease to exist when they are placed in water (Dorr, Denniston & Topping,
2017). Examples of compounds with methyl include Methyl chloride and methanol.
Figure 1: Types and properties of different function groups
Sulfhydryl group is an organic compound having one R group bonded to a sulphur atom and a
hydrogen atom. The molecular formula of this compound is R-SH. It has strong odour like rotten
eggs. It has low boiling point a. Thiol and Dithiol are some of the groups containing this
functional group. Due to its polarity, it cannot form hydrogen bond and hence, it cannot react

3FUNCTIONAL GROUPS
with water. The fifth functional group includes phosphate where phosphorous atom is attached
to four oxygen atoms. Nucleotides are compound that are made of one or more phosphate groups
along with base and sugar. Because of the chemical bonding between phosphates, they are able
to carry energy. Phosphate group has the ability to activate proteins too by attaching to specific
protein. The process is known as phosphorylation. The last functional groups are the amino
group and amino acid is the main compound containing amino groups. They are charged
compounds and basic in nature (Gupta, 2019).
From the review of function and structure of each functional groups, it can be concluded
that each of them have their unique functional properties. They not only help in the formation of
various important macromolecules, instead it plays a role in influencing various chemical
reactions too. They are the backbone of macromolecules. Four important macronutrients like
proteins, fats, carbohydrates and nucleic acids have different sets of functional groups that lend
different chemical properties to each of them.

4FUNCTIONAL GROUPS
References
Brown, W. H., & Poon, T. (2016). Introduction to organic chemistry. John Wiley & Sons.
Dorr, D. Q., Denniston, K. J., & Topping, J. J. (2017). General, organic, and biochemistry.
McGraw-Hill.
Gupta, A. (2019). Protein and Amino Acids. In Comprehensive Biochemistry for Dentistry (pp.
35-65). Springer, Singapore.