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DNA …… solving the puzzle of life

DNA …… solving the puzzle of life. Pieces of the Puzzle. 1. DNA Basics. 2. DNA Replication. Click on any picture to begin your journey deep into the cell. You will need to visit all legs of the trip and complete all tasks to really investigate DNA and its mutations.

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DNA …… solving the puzzle of life

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  1. DNA …… solving the puzzle of life

  2. Pieces of the Puzzle 1. DNA Basics 2. DNA Replication Click on any picture to begin your journey deep into the cell. You will need to visit all legs of the trip and complete all tasks to really investigate DNA and its mutations. Choosing will bring you back here! 3. Mutations 4. Case Study

  3. DNA – covering the basics Today DNA is a term everyone uses but not so long ago, we did not really understand or know how our cells got their “instructions: to grow and develop. An historical view of understanding DNA Current understandings

  4. DNA – covering the basics The structure of DNA is like a twisted ladder – the outer structure supports the rungs where the information is coded. What is DNA? What is a gene? Build a DNA molecule DNA Structure – review the first part of the animation by clicking on Start.

  5. Task 1 • You have been given the basic building blocks of DNA. Colored styrofoam balls (3 types / phosphate, sugar and base), skewers • Build and draw part of a DNA molecule that includes one codon. • Identify the pairs and how they match.

  6. DNA Replication • As cells multiply, a new exact copy of the genetic code must be created for each cell. This occurs through the process of replication. • The process is highly exact due to the pairs of bases that make up the code. Replication (start the animation at Part 2 by clicking Replication Initiation and follow through to the end)

  7. Replication • Replication happens in the cell rapidly, at over 1000 base pairs a second. This video will show you that process, even slowed down hundreds of times. Replication Animation Try it yourself – Click on play …. See how many pairs you can match while the cell matches thousands……

  8. Task 2 • Replication is a very accurate process with very few errors. • What is the key to this accuracy? Explain using a diagram. • If there were many errors, what would be the problem? (Remember that genes often make proteins). • How can we tell that an error has been made?

  9. Mutation • A mutation is any change to the “normal” pattern of the DNA of an organism. • There are many causes of this, including simple replication errors. Overviews of mutation

  10. Mutations …. good, bad, and indifferent • Each mutation results in a change in the commands of the cell – they may stop production of a protein, produce an inactive enzyme so a reaction cannot occur, or actually make no difference at all. Types of mutations No real effect …. maybe

  11. Mutations – specific examples • Today, many illnesses have been identified as genetic – having their cause in errors in an individual’s DNA. • Those errors can be passed on through the family or may occur due to environmental factors. Mutations – types and causes

  12. Task 3 • There are many human genetic traits, things passed on through families. • Doing your own research starting with the site below, examine one type of mutation and a known medical problem associated with it. • Identify the disease and its genetic cause. • What are the effects? How are they caused in the person’s cells and body? • Prepare a report for the class that describes your research and findings. A detailed description of mutations

  13. Case Study • There are many genetic illnesses that are caused by changes in the DNA code. • We will take a close look at one of these which is well known: Sickle Cell Anaemia Summary

  14. Sickle Cell Anaemia • In this case, a single change has effects at many levels. Sickle Cell - effects

  15. Responding to the Environment • Most DNA changes come and go – often the organism dies or is unable to reproduce and does not pass on the change. • In cases where the change is retained in the population, it usually has a positive effect that outweighs the negatives. Sickle Cell in West Africa

  16. Evolution today • Genes are transmitted through each generation. In organisms that have short lives, e.g. microorganisms, new mutations are occurring all the time. Today, swine flu, tuberculosis, and other infections are always in the news. Change is still happening, at the molecular level and in our lives. Tuberculosis – still evolving

  17. Task 4 • Today in the news swine flu is a big deal. In other eras, it was the plague, pneumonia, measles, and other pandemics. • Based on what you know about mutation, why is it so important to understand DNA and mutations as we fight these diseases? • Will this change ever end?

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