Unit 4: Genetic Information, Variation and Relationships between Organisms Lesson 1 Genetic Organisation IN PROKARYOTIC CELLS, DNA MOLECULES ARE SHORT, CIRCULAR AND NOT ASSOCIATED WITH PROTEINS. IN THE NUCLEUS OF EUKARYOTIC CELLS, DNA MOLECULES ARE VERY LONG, LINEAR AND ASSOCIATED WITH PROTEINS, CALLED HISTONES. TOGETHER A DNA MOLECULE AND ITS ASSOCIATED PROTEINS FORM A CHROMOSOME. THE MITOCHONDRIA AND CHLOROPLASTS OF EUKARYOTIC CELLS ALSO CONTAIN DNA WHICH, LIKE THE DNA OF PROKARYOTES, IS SHORT, CIRCULAR AND NOT ASSOCIATED WITH PROTEIN. A GENE IS A BASE SEQUENCE OF DNA THAT CODES FOR: THE AMINO ACID SEQUENCE OF A POLYPEPTIDE A FUNCTIONAL RNA (INCLUDING RIBOSOMAL RNA AND TRNAS). A GENE OCCUPIES A FIXED POSITION, CALLED A LOCUS, ON A PARTICULAR DNA MOLECULE.

Starter: Label these diagrams Look at this diagram, complete it and label the parts. Challenge: draw the mRNA counterpart to the strand on the left. Learning Outcomes: 1)Recall the structures of DNA and RNA 2)Describe how DNA is organised in eukaryotic and prokaryotic cells 3)Explain what a gene is and the role it plays 4)Compare mitochondria and chloroplasts to prokaryotes in terms of genetic organisation

Genetic Organisation of Eukaryotes Learning Outcomes: 1)Recall the structures of DNA and RNA 2)Describe how DNA is organised in eukaryotic and prokaryotic cells 3)Explain what a gene is and the role it plays 4)Compare mitochondria and chloroplasts to prokaryotes in terms of genetic organisation

Genetic Organisation of Prokaryotes DNA not organised into chromosomes. Not associated with histones. Long circular loop of DNA. Small loops of DNA called plasmids. Learning Outcomes: 1)Recall the structures of DNA and RNA 2)Describe how DNA is organised in eukaryotic and prokaryotic cells 3)Explain what a gene is and the role it plays 4)Compare mitochondria and chloroplasts to prokaryotes in terms of genetic organisation

Chloroplasts and Mitochondria These organelles contain their own DNA and ribosomes separate from the DNA contained in chromosomes in the nucleus. What is strange about this? DNA is not associated with proteins. Small circular loops Ribosomes are smaller than in the cytoplasm Learning Outcomes: 1)Recall the structures of DNA and RNA 2)Describe how DNA is organised in eukaryotic and prokaryotic cells 3)Explain what a gene is and the role it plays 4)Compare mitochondria and chloroplasts to prokaryotes in terms of genetic organisation

Central Dogma of Genetics Learning Outcomes: 1)Recall the structures of DNA and RNA 2)Describe how DNA is organised in eukaryotic and prokaryotic cells 3)Explain what a gene is and the role it plays 4)Compare mitochondria and chloroplasts to prokaryotes in terms of genetic organisation

What is a gene? A gene is a base sequence of DNA that can code for: - a polypeptide (protein) - a functional RNA (either Ribosomal RNA or tRNA). Genes are found on fixed positions on chromosomes called loci Learning Outcomes: 1)Recall the structures of DNA and RNA 2)Describe how DNA is organised in eukaryotic and prokaryotic cells 3)Explain what a gene is and the role it plays 4)Compare mitochondria and chloroplasts to prokaryotes in terms of genetic organisation

Whiteboards 1.What DNA made up of? 2.What is RNA made up of? 3.How is DNA organised in a eukaryote? 4.How is DNA organised in a prokaryote? 5.Identify the differences between chloroplast/mitochondria and the rest of the eukaryotic cell 6.Identify the similarities between these organelles and a prokaryotic cell 7.Describe the potential roles of a gene 8.Define the term loci. Learning Outcomes: 1)Recall the structures of DNA and RNA 2)Describe how DNA is organised in eukaryotic and prokaryotic cells 3)Explain what a gene is and the role it plays 4)Compare mitochondria and chloroplasts to prokaryotes in terms of genetic organisation