2. Rosa Macaya IES La Pobla de Segur

3. What does DNA do? DNA is made up of genes. A gene is a sequence of DNA which codes for the sequence of amino acids in a particular protein. Rosa Macaya IES La Pobla de Segur

4. What does DNA do? DNA is made up of genes. A gene is a sequence of DNA which codes for the sequence of amino acids in a particular protein. A gene codes for A protein. Rosa Macaya IES La Pobla de Segur

5. What does DNA do? DNA is made up of genes. A gene is a sequence of DNA which codes for the sequence of amino acids in a particular protein. 1 gene codes for 1 protein. How does DNA determine the sequence of a.a.s? Rosa Macaya IES La Pobla de Segur

6. What does DNA do? DNA is made up of genes. A gene is a sequence of DNA which codes for the sequence of amino acids in a particular protein. 1 gene codes for 1 protein. How does DNA determine the sequence of a.a.s? A group of three bases coding for an amino acid is called a codon, and the meaning of each of the 64 codons is called the genetic code Rosa Macaya IES La Pobla de Segur

7. What does DNA do? DNA is made up of genes. A gene is a sequence of DNA which codes for the sequence of amino acids in a particular protein. 1 gene codes for 1 protein. How does DNA determine the sequence of a.a.s? A group of three bases coding for an amino acid is called a codon, and the meaning of each of the 64 codons is called the genetic code Rosa Macaya IES La Pobla de Segur

8. What does DNA do? DNA is made up of genes. A gene is a sequence of DNA which codes for the sequence of amino acids in a particular protein. 1 gene codes for 1 protein. How does DNA determine the sequence of a.a.s? A group of three bases coding for an amino acid is called a codon, and the meaning of each of the 64 codons is called the genetic code DNA is in the nucleus Rosa Macaya IES La Pobla de Segur

9. What does DNA do? DNA is made up of genes. A gene is a sequence of DNA which codes for the sequence of amino acids in a particular protein. 1 gene codes for 1 protein. How does DNA determine the sequence of a.a.s? A group of three bases coding for an amino acid is called a codon, and the meaning of each of the 64 codons is called the genetic code DNA is in the nucleus Rosa Macaya IES La Pobla de Segur

10. What does DNA do? DNA is made up of genes. A gene is a sequence of DNA which codes for the sequence of amino acids in a particular protein. 1 gene codes for 1 protein. How does DNA determine the sequence of a.a.s? A group of three bases coding for an amino acid is called a codon, and the meaning of each of the 64 codons is called the genetic code DNA is in the nucleus Proteins are made in the cytoplasm  the information contained within DNA must be carried to the cytoplasm. This process is called TRANSCRIPTION. Rosa Macaya IES La Pobla de Segur

11. Template strand DNA unwinds & unzips at the start of a particular gene. H bonds break Free activated mRNA nucleotides in the nucleus complementary base pair with exposed DNA bases. (A – U, T – A, C – G, G – C) Start of gene RNA polymerase joins the mRNA nucleotides together, releasing the phosphoryl groups for energy. This continues until the end of the gene. mRNA chain drops off the DNA DNA re-winds. mRNA exits nucleus via a nuclear pore. Carrying the information/ message Rosa Macaya IES La Pobla de Segur

12. The Genetic Code There are 20 essential amino acids Only 4 bases If each coded 1 a.a only 4 different types. How many if a pair coded for 1 a.a? 16 Still inadequate What about if 3 coded for 1 a.a? 64 Yeah! The genetic code is a TRIPLET CODE 3 bases code for 1 amino acid The codon (a triplet) AAU would code for…….. Rosa Macaya IES La Pobla de Segur

13. A bit more about tRNA Anti-codon VAL Amino-acid attachment site ACCACC Amino-acid Amino acids must combine with the tRNA molecule. The tRNA molecule is then said to be ACTIVATED ATP This is then called AMINO-ACYL tRNA This is catalysed by amino- acyl tRNA synthetase Rosa Macaya IES La Pobla de Segur

14. The 2nd tRNA molecule is released. These steps are repeated until the ribosome reads a STOP codon. (ELONGATION the TERMINATION) MET GLN MET GLN MET GLN VAL ILE MET GLNVAL mRNA enters the cytoplasm & joins to the small subunit of a ribosome Ribosome reads along until a start codon (AUG) is found 2 codons (6 bases) are exposed tRNA with a complementary anticodon (UAC) base pairs with the start codon Ribosome reads the 2nd codon. Another tRNA molecule with the complementary anti-codon binds to this 2nd codon. A peptide bond is formed between the 2 amino acids on top of the 1st and 2nd tRNA molecules. The ribosome moves along the mRNA to the 3rd codon. This releases the 1st tRNA molecule but not the a.a. Another tRNA molecule with the complementary anti-codon binds to the 3rd codon. A peptide bond is formed between the 2 amino acids on top of the 2nd and 3rd tRNA molecules. Rosa Macaya IES La Pobla de Segur

15. Base deletion Where 1+ base pairs are deleted Intended txt: Actual txt: A FRIEND WILL COLLECT MY MONEY A FIEND WILL COLLECT MY MONEY Consider this…. Normal:UCA CAU UAC UGU GGU Mutated:UCA CAU UAU GUG GU Rosa Macaya IES La Pobla de Segur

16. Phenylalanine hydroxylase catalyses the reaction: Phenylalanine → tyrosine ( → melanin) (brown pigment) PKU is caused by a gene mutation Haemophilia Sufferers: Lack of a blood clotting protein (Mutation in the factor (protein) blood clotting factor gene) Rosa Macaya IES La Pobla de Segur