Problem 8 - Biology Concepts and Applications

Question

Most codons specify a(n)_____. a. protein c. amino acid b. polypeptide d. mRNA

Step-by-Step Solution

Answer

Most codons specify an amino acid (Option c).

Step 1: Understand Codons

Codons are sequences of three nucleotides found in messenger RNA (mRNA) that correlate to specific genetic instructions for constructing proteins.

Step 2: Examine Options

Review the provided options: a. protein, b. polypeptide, c. amino acid, d. mRNA. Determine which option relates to what codons specify.

Step 3: Identify the Correct Association

Codons in mRNA are translated during protein synthesis to specify amino acids, which are the building blocks of proteins.

Step 4: Choose the Correct Answer

Given that codons specify amino acids, the correct answer, "c. amino acid," matches the definition of what codons encode.

Key Concepts

mRNA

Messenger RNA, commonly abbreviated as mRNA, acts as a crucial intermediary in the process of protein synthesis. It is derived from DNA through a process called transcription. During transcription, a particular segment of DNA is copied into RNA, forming mRNA. This process is essential because DNA never leaves the nucleus in eukaryotic cells. Instead, mRNA, which can travel to different parts of the cell, serves as a transcript carrying the genetic instructions.

The primary role of mRNA is to convey the genetic information required for protein synthesis:

• It carries the genetic code from DNA to the ribosome, the cell's protein factory.
• The ribosome reads the sequence of mRNA codons.
• This procedure allows for the synthesis of proteins as guided by the instructions encoded in the DNA.

Understanding mRNA's role is vital for comprehending how genetic information is translated into functional proteins.

amino acids

Amino acids are organic compounds that serve as the building blocks of proteins. Each amino acid has a specific structure, comprising a central carbon atom, an amino group, a carboxyl group, and a unique side chain or R-group. The properties of the side chains determine the characteristics and behaviors of the protein.

There are 20 different amino acids encoded by the genetic code. These amino acids are linked together by peptide bonds, forming a polypeptide chain, which folds into a functional protein. Here are some key points about amino acids:

• They are specified by codons during the process of translation.
• Each codon in mRNA corresponds to one of these amino acids, as specified by the genetic code.
• The sequence and combination of amino acids determine the structure and function of a protein.

The correct sequence of amino acids ensures that a protein folds into its intended structure, enabling it to perform its specific function.

protein synthesis

Protein synthesis is a fundamental cellular process that transforms genetic information into functioning proteins. This process occurs in two main stages: transcription and translation.

During transcription, the DNA sequence of a gene is transcribed to form mRNA, as described earlier. Next, translation occurs, translating mRNA into a polypeptide chain at the ribosome. Here's how translation progresses:

• The mRNA sequence is "read" by the ribosome in sets of three nucleotides known as codons.
• Each codon corresponds to a specific amino acid, assembled into a polypeptide chain in the correct order.
• Transfer RNA (tRNA) molecules bring the appropriate amino acids to the ribosome, matching them to the mRNA codons.
• This gradually leads to the building of a protein, as encoded by the original DNA sequence.

Protein synthesis is vital since proteins carry out essential functions within organisms, including enzyme catalysis, DNA replication, and the regulation of cellular processes.