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How Does DNA work?

How Does DNA work?. To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code. First : What is the structure of DNA? What is a gene?. What is gene?.

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How Does DNA work?

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  1. How Does DNA work? To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code First: What is the structure of DNA? What is a gene?

  2. What is gene? To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code DNA contains genes which are small sections of DNA (specific sequences of bases). These genes code for amino acids. Amino acids join to make a long chain – called a polypeptide. Polypeptides then form proteins. Proteins then control reactions within the body.

  3. What is gene? To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code There are 20 amino acids in the body – how can 4 bases code for 20 amino acids?

  4. What is gene? To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code Paired bases can only code for 20 amino acids. Still not enough. So..

  5. How does the base sequence work? To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code The TRIPLET code Triplet meaning – 3. Therefore this is the code formed from 3 bases. Each sequence of 3 bases code for a specific amino acid. How many different possible codes are there?

  6. How does the base sequence work? To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code There are 64 possible codes. BUT there are only 20 amino acids. Therefore, some amino acids are coded for by several different codes and not just one.

  7. The Triplet Code To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code Main Features: • The code is known as the ‘degenerate code’ as each amino acid has more than one triplet code. • The triplet code is only ‘read’ in one certain direction. • The start sequence is always the same (coding for methionine – the first amino acid, which is later removed). • Three triplet codes code for a ‘stop code’ – the end of the chain.

  8. To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code Charm Instructions Use the codes below to work out your DNA code for your name. For example: FRED BLOGGS would be:

  9. Step 1:Cut the elasticized cord into a 10 cm-long piece. Knot one end of the cord in order to prevent the beads from sliding off. Step 3: String the lanyard hook on the elasticized cord and secure it to the cord with a double knot. Cut off any extra cord.

  10. To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code Bracelets Only: If you are making the bracelet, then you need to also work out the pairing codon. DNA has a pairing system where each base pairs (A, G, C, T) always pairs up with the same partner C with G and A with T, so:

  11. Different types of cells To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code The difference between prokaryotic and eukaryotic cells.

  12. Seeing DNA To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code DNA is only visible during cell division. When visible they appear as two threads, joined at a single point. Each thread is called a chromatid. DNA form a long chain – therefore it folded and coiled to compact itself. To help this the DNA is wound around proteins to fix it in position. Lets have a look.

  13. Seeing DNA To describe how genes code for polypeptides. Proteins

  14. Remember To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code Each chromosome contain one long length of DNA. On that DNA there are many genes.

  15. What would you be? To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code As humans we have 46 chromosomes.

  16. What would you be? To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code As humans we have 46 chromosomes.

  17. Homologous Pairs To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code Chromosomes appear in pairs (one from each parent – maternal and paternal chromosomes). These pairs are known as homologous pairs. In total there are 46 chromosomes in a human – this is called the diploid number.

  18. Allele To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code Homologous pairs carry genes which code for characteristics. These though maybe different, i.e. one code for brown eyes and another blue eyes. These are called alleles.

  19. Creating Gametes To describe how genes code for polypeptides. To explain how genes are arranged in a DNA molecule. To know what a gene is. Keywords: Gene, Polypeptide, Bases, Amino Acids, Triplet Code For our sex cells to be produced, our bodies first halve the number of chromosomes that our sex cells carry. We now have a haploid number of chromosomes. Therefore when the egg and sperm fuse together – there is a full complement of chromosomes – the diploid number is reformed.

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