Can be copied and passed from generation to generation.
DNA is a nucleic acid It consists on a long chain of molecules called nucleotides . The nucleotides are joined by a sugar - phosphate backbone. 4 nucleotides Differ in their nitrogenous bases Thymine (T) Cytosine (C) Adenine (A) Guanine (G) !
From DNA to RNA to PROTEIN How an Organism’s Genotype Produces Its Phenotype GENOTYPE : is the Genetic Constitution of an organism or cell , its genetic make up . It is the sequence of nucleotide bases in DNA PHENOTYPE : is the organism’s specific traits , the organism’s total physical appearance and constitution. It is the result of the actions of proteins.
GENOTYPE: eye color gene called: bey2 PHENOTYPE: Example for phenotype and genotype
Nucleus Cytoplasm DNA specifies the synthesis of proteins in 2 stages : DNA Protein 2. TRANSLATION 1. TRANSCRIPTION RNA
TRANSCRIPTION : DNA RNA TRANSLATION : RNA PROTEIN From Nucleic Acid to Amino Acid Different Molecules - Different Languages 1 gene – 1 polypeptide hypothesis: The function of an individual gene dictates the production of a specific polypeptide.
CODONS: triplets of bases Each codon corresponds to an Amino Acid
Genetic information is transferred from DNA to RNA.
An RNA molecule is transcribed from a DNA template.
Transcription done by RNA Polymerase which adds RNA nucleotide 1 by 1 to the newly made RNA sequence. The base of the nucleotide is complementary to the DNA base.
DNA Promoter Terminator RNA polymerase DNA of a gene RNA Initiation Elongation Completed RNA Single strand Termination
1. INITIATION: The “start transcribing” signal is a nucleotide sequence called a promoter . The first phase of transcription is initiation: RNA polymerase attaches to the promoter. RNA synthesis begins. 2. ELONGATION: Second phase. The RNA gets longer. 3. TERMINATION: RNA polymerase reaches a sequence of DNA bases called a terminator . 3 PHASES OF TRANSCRIPTION
But RNA is not ready yet… It needs to be processed.
The eukaryotic cell processes the RNA after transcription by: The Processing of Eukaryotic RNA
Adding a cap and tail
Splicing exons together
What does this mean? What are caps and tails? A cap and a tail are added at the extremities of the newly RNA molecule. It protects the RNA from enzymes; and help the ribosomes recognize it.
A gene contains EXONS and INTRONS What are EXONS and INTRONS? EXONS are kept and will be translated into polypeptides (EX for EXiting the nucleus) INTRONS are rid of. Exon Exon Exon Intron Intron
Remember… 1 gene – 1 polypeptide hypothesis: The function of an individual gene dictates the production of a specific polypeptide. ACTUALLY, it could be several….. 1 gene can give different versions of a protein. By combining (splicing) different exons.
DNA READY TO GO! Exon Exon Exon Intron Intron RNA Transcription Cap and Tail added Introns removed Splicing of exons Coding sequence
Translation: From RNA to PROTEIN From nucleic acid to amino acid