Protein Synthesis
Protein Synthesis is the process whereby DNA (deoxyribonucleic acid)
codes for the production of essential proteins, such as enzymes and
hormones. Proteins are long chains of molecules called amino acids.
Different proteins are made by using different sequences and varying
numbers of amino acids. The smallest protein consists of fifty amino
acids and the largest is about three thousand amino acids long.
Protein synthesis occurs on ribosomes in the cytoplasm of a cell but
is controlled by DNA located in the nucleus.
Protein synthesis is a two-part process that involves a second type of
nucleic acid along with DNA. This second type of nucleic acid is RNA,
ribonucleic acid. RNA differs from DNA in three main respects.
First, the sugar units in RNA are ribose as compared to DNA's
deoxyribose. Because of this difference, RNA does not bind to the
nucleotide base Thymine (T), instead, RNA contains the nucleotide base
Uracil (U) in place of T. (RNA also contains the other three bases:
Adenine (A), Cytosine (C) and Guanine (G). Secondly, RNA, unlike DNA
is a single stranded molecule and is therefore not bonded to a
complimentary base.
The third difference between RNA and DNA is that there are three
different types of RNA, mRNA (messenger RNA), tRNA (transfer RNA) and
rRNA (ribosome RNA). mRNA carries the genetic code (instructions how
to assemble the protein) from the DNA in the nucleus to ribosomes in
the cytoplasm. tRNA picks up and transfers amino acids from cytoplasm
to the mRNA on the ribosomes and is shaped similar to a cloverleaf.
rRNA forms a structural part of ribosome that helps join the amino
acid...
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...RNA
strand can then either be used again to create more proteins or be
broken down into their separate nucleotides.
Protein Synthesis is the process whereby DNA codes for the production
of essential proteins. This process can be divided into two parts,
transcription and translation. Transcription is the production of mRNA
from a DNA template. mRNA carries the information from the nucleus to
the cytoplasm, which is where protein synthesis occurs. Before the
synthesis of a protein begins, amino acids are attached to the tRNA
molecule, which transport and attach them to the mRNA with the aid of
rRNA, this is known as translation. Peptide bonds then form between
the amino acids. Once the chain is completed the polypeptide chain
separates from the tRNA and move in to the cytoplasm and in this way a
protein is formed.