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DNA’s Role
DNA’s Role
DNA is the blueprint for the construction of proteins. DNA does not make anything, it is simply instructions. Cells make proteins, and proteins maintain cell homeostasis.
Without proteins you could not have muscle tissue, cell membrane receptors and gates, hormones, antibodies, neurotransmitters, or enzymes for that matter. All chemical reactions would stop.
mRNA’s Role
mRNA’s Role
Proteins are synthesized in the ribosomes of a cell. The DNA is stored in the nucleus of a cell.
The instructions in the DNA must get from the nucleus to the ribosome, but the DNA is trapped in the nucleus, kept safe and sound. So a messenger molecule is sent out to the ribosome, carrying the code that was on one gene in the nucleus. This messenger is called mRNA.
Construction of mRNA from the code of a gene is called TRANSCRIPTION.
RNA is nucleic acid and codes for information using nucleotides just like DNA but…
- RNA is only half of a double helix (single strand)
- Ribose is the sugar backbone instead of deoxyribose (so it's RNA, not DNA)
- Uracil is present instead of Thymine (no T’s in DNA… U’s instead)
Ribosome's Role
Ribosome's Role
The ribosome synthesizes protein molecules by reading three mRNA nucleotides in a row (referred to as a codon) and matching a specific Amino Acid to that triplet code. Each CODON specifies a particular amino acid that is added to a chain and forms a specific protein. This process is called TRANSLATION because the cell is changing the coded language of nucleotides into another 'language': amino acids.
tRNA's Role
tRNA's Role
A second kind of RNA molecule supplies the ribosome with the correct amino acids in the correct order. Transfer RNA (tRNA) is a single strand of RNA nucleotides folded into a specific shape. On one end of tRNA, an amino acid is attached. On the opposite end of the tRNA, there are three nucleotides exposed, called an anti-codon. When the anti-codon matches correctly with the mRNA codon inside the ribosome, the tRNA drops off it's amino acid and floats away.
ORDER OF EVENTS:
ORDER OF EVENTS:
- DNA is transcribed into mRNA
- mRNA travels from nucleus to ribosome
- mRNA is translated by ribosome into an amino acid sequence with the help of tRNA molecules
- the amino acid sequence determines how the protein folds up into a specific shape
- the protein's shape determines its function
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