Presentation on theme: "Nucleic Acids and protein synthesis Higher Human Biology."— Presentation transcript:
Nucleic Acids and protein synthesis Higher Human Biology
Lesson Aims To examine the structure of DNA To compare the structure of DNA and RNA To discuss the differences and similarities between mRNA and tRNA To examine the role of the nucleus and nucleolus during RNA synthesis To study the synthesis of proteins
It was Francis Crick and James Watson who unraveled the DNA molecule.
An international team of scientists began the project to map the human genome.
1990 Gene therapy was used on patients for the first time.
1994 The FDA approved the first genetically engineered food -- FlavrSavr tomatoes engineered for better flavour and shelf life.
1997 Dolly the Sheep - the first adult animal clone.
Dolly the sheep, pictured here with her first lamb Bonnie
2000 J. Craig Ventor, along with Francis Collins, jointly announce the sequencing of the entire human genome.
The Central Dogma DNA codes for the production of DNA (replication) and of RNA (transcription). RNA codes for the production of protein (translation).
The Central Dogma Genetic information is stored in a linear message on nucleic acids. We use a shorthand notation to write a DNA sequence: –5'-AGTCAATGCAAGTTCCATGCAT.... A gene determine the sequence of amino acids in proteins. We use a shorthand notation to write a protein sequence: NH 2 -Met-Gln-Cys-Lys-Phe-Met-His.... (or a one letter code: M Q C K F M H)
Comparison of DNA and RNA DNARNA Found in nucleus Found in nucleus and cytoplasm Double strands Single strand Bases – A, T, G, C Bases – A, U, G, C Deoxyribose sugar Ribose sugar
Transcription First stage of protein synthesis Occurs in the nucleus Double helix uncoils Double strands split DNA strand acts as template for formation of mRNA (messenger RNA) Part of chain B sequence. Uncoiled DNA double helix which has split exposing bases
Transcription Free RNA nucleotides in the nucleus base pair with DNA nucleotides A-T, T-U, G-C, C-G Strong bonds form between phosphate group and ribose sugar of neighbouring RNA nucleotides Catalysed by enzyme RNA polymerase mRNA moves out of nucleus through nuclear pore Single strand of DNA coding for Chain B Strand of mRNA copied from DNA
Comparison of mRNA and tRNA mRNA Messenger RNA Made in nucleus during transcription Moves to cytoplasm Codes for protein Base triplets - codons tRNA Transfer RNA Found in cytoplasm Involved in translation Assembles amino acids into correct order for proteins Anti-codons present