Presentation on theme: "Transcription and Translation"— Presentation transcript:
1 Transcription and Translation How DNA and RNA work together to make a protein
2 Proteins are made at RIBOSOMES by a process called PROTEIN SYNTHESIS Proteins are made at RIBOSOMES by a process called PROTEIN SYNTHESIS. The instructions for making proteins comes from DNA.Proteins are synthesized with the help of THREE (3) types of RNA molecules:Messenger RNA (mRNA)Transfer RNA (tRNA)Ribosomal RNA (rRNA)
3 mRNA – type of RNA that copies the genetic code from DNA in the nucleus of a cell. tRNA – type of RNA that transfers specific amino acids to the ribosome rRNA – type of RNA that binds with a protein to form a complete ribosome
4 Transcription...Is the process by which a segment of a DNA molecule, or gene, is copied into a strand of mRNA.Takes place in the NUCLEUS of a cell because that is where DNA is stored.
5 In order for transcription to take place… A small segment of a chromosome, or GENE, must be UNTWISTED and UNZIPPED.To untwist and unzip the DNA molecule, an ENZYME called DNA Polymerase is activated.
6 DNA PolymeraseAn ENZYME called DNA POLYMERASE separates a PORTION of a chromosome (GENE). This allows ONE STRAND of DNA to act as a TEMPLATE, or pattern, for a molecule of mRNA.
7 The Beginning of Transcription Template DNA strand
8 The strand acting as the TEMPLATE is used to create a single strand of mRNA. The mRNA strand is formed one base at a time by matching the complementary bases in the template strand of DNA. However, since RNA does not contain the base thymine, the nitrogen base called URACIL takes its place.NOTE : A strand of mRNA is being formed above the DNA strand.
9 Once the mRNA strand has completely formed, it will leave the NUCLEUS and travel to a RIBOSOME in the CYTOPLASM.NOTE: The separated strands of the DNA molecule rejoin after the mRNA molecule has been produced.
10 The mRNA molecule finds a ribosome to connect with so that the process of TRANSLATION may begin. After mRNA molecule attaches to the ribosome.Before mRNA molecule attaches to the ribosome.
11 Once the mRNA molecule bonds to the ribosome, TRANSLATION may begin Once the mRNA molecule bonds to the ribosome, TRANSLATION may begin. TRANSLATION is…The process by which a strand of mRNA is de-coded and turned into a chain of AMINO ACIDS, which make up a PROTEIN.The mRNA “code” is read three (3) letters at a time. These 3 letters are known as a CODON.
12 Translation occurs when the 3 base CODON on mRNA is matched up with molecule of tRNA tRNA molecules carry AMINO ACIDS to the mRNA chain.