Lesson 4

The Central Dogma

What are the dangers of UV radiation?

RNA vs. DNA

Protein Synthesis

Central Dogma

Replication, Transcription & Translation

Double Stranded Single Stranded

Transcription involves the copying of the information in DNA to messenger RNA (mRNA) and translation involves ribosomes using the mRNA as a blueprint to synthesize a protein composed of amino acids.

In easier terms: to transcribe, you copy from one medium to another, but when you translate, you are converting information into another language.


When transcribing from DNA to mRNA:

Adenine pairs with Uracil (A pairs with U)

Guanine pairs with Cytosine (G pairs with C)

The three forms of RNA:

mRNA: (messenger RNA) the end product of transcription of a gene, mRNA is translated by ribosomes into protein

tRNA: (transfer RNA) a form of RNA that is responsible for delivering amino acids to the ribosomes during the process of translation

rRNA: (ribosomal RNA) a form of RNA that binds with ribosomal protein to form ribosomes

How to read a Codon Chart



Start codon: specific codon (AUG) that signals to the ribosome that the translation starts at that point

Stop codon: specific codons that signal the end of translation to a ribosome

Codon: sequence of three bases in DNA or complementary mRNA that serves as a code for a particular amino acid

Anticodon: sequence complementary to that of a corresponding codon in a messenger RNA (mRNA) sequence

DNA -> RNA -> Protein

Example #1:

DNA: AGA CGG TAC CTC CGG TGG GTG CTT GTC TGT ATC CTT CTC AGT ATC

mRNA: UCU GCC AUG GAG GCC ACC CAC GAA CAG ACA UAG GAA GAG UCA UAG


mRNA: UCU GCC AUG GAG GCC ACC CAC GAA CAG ACA UAG GAA GAG UCA UAG

Protein: start-glu-ala-thre-hist-asp-glu-threo-stop


Example #2:

DNA: CCT CTT TAC ACA CGG AGG GTA CGC TAT TCT ATG ATT ACA CGG TTG CGA TCC

mRNA: GGA GAA AUG UGU GCC UCC CAU GCG AUA AGA UAC UAA UGU GCC AAC GCU AGG


mRNA: GGA GAA AUG UGU GCC UCC CAU GCG AUA AGA UAC UAA UGU GCC AAC GCU AGG

Protein: met (start)-cys-ala-ser-hist-ala-met-stop


Example #3:

DNA: TAA ACT CGG TAC CTA GCT TAG ATC TAA TTA CCC ATC

mRNA: AUU UGA GCC AUG GAU CGA AUC UAG AUU AAU GGG UAG

Protein: met-asp-arg-ile-stop