BIO282 Lecture Notes - Lecture 13: C-Terminus, Carboxylic Acid, Peptide Bond
GENE EXPRESSION-TRANSLATION LECT-13-14
RNA Translation
Learning objectives:
In this topic/lecture you will learn about:
• The genetic code and how it is decoded to amino acids,
• How different messages are stored in DNA strands,
• Ribosome and
• Their composition
• How they differ in prokaryotes and eukaryotes
• Their role in translation
• tRNA and their
• Structure
• Role in decoding messages
• The role of different translation factors in the process of translation.
Proteins
• Proteins play a central role in all life processes; they are the working molecules of living
organisms.
• Proteins are polymers of amino acids; there are 20 common amino acids.
• Each amino acid has a minimum of 1 free amino group and 1 free carboxyl group. Different
amino acids join together by peptide bond and hence a chain of amino acid is called a
polypeptide chain.
• Like nucleic acids, polypeptides also have polarity with one end having free amino group
(called amino terminal) and the other end with free carboxyl group ( called carboxyl terminal).
Protein Structure
A. Primary structure: Sequence of amino acids in a polypeptide chain.
B. Secondary structure: Folds and twists in the polypeptide chain through interaction between
neighbouring amino acids. Common secondary structures are alpha helices and beta pleated
sheets
C. Tertiary structure: Further folding of secondary structure results in three-dimensional shape
of proteins.
D. Quaternary structure: In some cases two or more polypeptides interact together to form
Major Components of Translation
1. Ribosomes
2. tRNA
3. Aminoacyl tRNA synthetase
4. mRNA
5. Protein Factors
Ribosomes
• Ribosomes are large ribonucleoprotein particles that contain ribosomal RNA & proteins and
dissociate into large and small subunits.
• During translation ribosome binds to mRNA and tRNAs
mRNA
Leader and trailer sequences (30-100 bases) are not translated.
Document Summary
Different amino acids join together by peptide bond and hence a chain of amino acid is called a polypeptide chain. Like nucleic acids, polypeptides also have polarity with one end having free amino group (called amino terminal) and the other end with free carboxyl group ( called carboxyl terminal). Protein structure: primary structure: sequence of amino acids in a polypeptide chain, secondary structure: folds and twists in the polypeptide chain through interaction between neighbouring amino acids. Common secondary structures are alpha helices and beta pleated sheets: tertiary structure: further folding of secondary structure results in three-dimensional shape of proteins, quaternary structure: in some cases two or more polypeptides interact together to form. Major components of translation: ribosomes, trna, aminoacyl trna synthetase, mrna, protein factors. Ribosomes: ribosomes are large ribonucleoprotein particles that contain ribosomal rna & proteins and dissociate into large and small subunits, during translation ribosome binds to mrna and trnas mrna.
