Question

How many possible primary structures exist for a small polypeptide containing four individual amino acids?

Short answer

There are \(160,000\) possible primary structures for a small polypeptide containing four individual amino acids.

Step-by-step solution

Understand the concept of permutations

A permutation is an arrangement of objects in a specific order. In this case, we need to find the number of possible permutations of a small polypeptide containing four individual amino acids, where each amino acid can be any of the 20 different amino acids.

Calculate the number of permutations

To find the number of permutations, we can use the formula: n^r where 'n' is the total number of amino acids (20) and 'r' is the number of amino acids in the small polypeptide (4). Using the formula, we have: (20)^4

Calculate the result

Now, we can calculate the number of possible primary structures: (20)^4 = 160,000 There are 160,000 possible primary structures for a small polypeptide containing four individual amino acids.

Key concepts

Amino Acids

Amino acids are the building blocks of proteins. They play a crucial role in various biological processes. Each amino acid has a basic structure that consists of:

• An amino group \(-NH_2\)
• A carboxyl group \(-COOH\)
• A hydrogen atom \(H\)
• A distinctive side chain, known as the R-group, which determines the unique characteristics of each amino acid

The diversity in these side chains results in 20 different amino acids, all of which combine in unique sequences to create proteins.
These sequences dictate the structure and function of proteins, affecting everything from their shape to their biological activity.
Understanding amino acids is vital because they lay the groundwork for creating proteins and, ultimately, the functions of living organisms.

Primary Structure

The primary structure of a protein refers to the specific sequence of amino acids in a polypeptide chain. It is the most fundamental level of protein structure.
The primary structure is held together by covalent peptide bonds that link the amino acids together.
Think of it as a sequence of letters in a word. Just as rearranging letters can form different words, altering the sequence of amino acids results in different proteins, each with unique properties and functions.

• Determines how the protein will fold into its secondary and tertiary structures, thus influencing its final shape and function.
• The order and nature of the amino acids are critical because they directly affect the protein's biological role.

Mutations in the primary structure can lead to diseases or functional changes in the proteins, making this an essential concept in biology.

Polypeptide

A polypeptide is a chain of amino acids linked together by peptide bonds. These chains are the result of multiple amino acids being joined during protein synthesis.
Polypeptides vary in length and can be made up of dozens to thousands of amino acids, depending on the protein.

• A specific sequence of amino acids in a polypeptide dictates the protein's primary structure.
• Polypeptides can fold and form complex structures, which determine their function in the body.

Each polypeptide will fold into a particular shape due to interactions among its amino acids, leading to distinct functional properties.
Additionally, one or more polypeptides can come together to form a protein with complex and specific functions, such as enzymes, antibodies, or receptors. Understanding polypeptides is key to unveiling the intricate nature of proteins and how they carry out various life-sustaining tasks.