dna …… solving the puzzle of life
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
DNA …… solving the puzzle of
life
Pieces of the Puzzle
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!
1. DNA Basics 2. DNA Replication
3. Mutations 4. Case Study
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
DNA – covering the basicsThe 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.
Task 1You have been given the basic
building blocks of DNA.Colored styrofoam balls (3 types /
phosphate, sugar and base), skewersBuild and draw part of a DNA
molecule that includes one codon.Identify the pairs and how they
match.
DNA ReplicationAs 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)
ReplicationReplication 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……
Task 2Replication 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?
MutationA 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
Mutations …. good, bad, and
indifferentEach 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
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
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
Case StudyThere 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 AnaemiaSummary
Sickle Cell Anaemia
In this case, a single change has effects at many levels.
Sickle Cell - effects
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
Evolution todayGenes 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
Task 4Today 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?