2.7) What is DNA and How does it build an organism?
There is another area of Science that is very important towards improving our quality of life and it is GENETICS. This is the study of HEREDITY or how the characteristics of living organisms are inherited from their parents. To the left is an image of pairs of chromosomes. Inside these chromosomes are the long DNA strands. So what is DNA????? Why is it so important ALL organisms??? And how do we use DNA to improve our quality of life?
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Task 1) Learn about DNA, Chromosomes and Genes
The chromosome is the unit of inheritance in our cells. They carry all of the instructions that our cells need to survive and perform their functions. When cells divide to make new copies, either by mitosis or meiosis, they first need to make a copy of their DNA. DNA is found within the nucleus of the cell and can be extracted using a series of chemical processes. 1A) Watch this video and make notes in your exercise books to understand more about how chromosomes make an organism and where they are found. 1B) Work through the interactive DNA, Chromosomes and Genes in clickview - 13 minutes long and very helpful in developing your picture of genetics. Just ignore some of the more complex information in this video such as polypeptides - unless you are interested! |
Task 2) Flow Chart - What is DNA??? What does it look like???
Use the following two resources as well as the internet to complete the information in the document "2.7) DNA flow chart" provided so to build your understanding of DNA and where we find these inherited characteristics. a) Core Science Stage 5 (CS5) Section 11.2 and 11.6 b) The article "DNA - The Molecule of Life" |
Task 3) Make a DNA Model
You can pick ONE and complete it
a) Conduct a practical to extract real DNA from Strawberries
b) Make an origami model of DNA
c) Make a labelled DNA using lollies
You can pick ONE and complete it
a) Conduct a practical to extract real DNA from Strawberries
b) Make an origami model of DNA
c) Make a labelled DNA using lollies
Task 3a) Practical: Extraction of DNA from Strawberries
All things have DNA: the chemical instructions on how to make a living organism. DNA can easily be seen with the naked eye when collected from thousands of living cells. This simple method allows you to extract DNA from strawberries and view it. It can be done using lots of other things such as wheatgerm and kiwi fruits. Home Experiment) Extraction of DNA from a Strawberry - Strawberry (x1) - Zip-lock plastic bag - 5 mL liquid dish washing detergent or shampoo - 0.75g salt - Piece of stocking (the “strainer”) and an elastic band - 150 mL beaker or glass - test-tube (x2) or 2 small glasses - small glass of ice-cold ethanol or rubbing alcohol - glass rod or skewer |
Task 3b) Make a Origami DNA model
1) Instructions and the printable template OR 2) CSIRO DNA Model template |
Task 3c: Make a model of DNA out of LOLLIES!!!!!!
You will need 1 pkt of jelly babies (6 x 4 colours) 1 pkt of black liquorice 1 pkt of red liquorice toothpicks paper to make labels of the following sugar group, phosphate group, adenine, guanine, thymine and cytosine Use the toothpicks to join the bases together and the liquorice together. You can also break the toothpicks into smaller pieces if needed. |
Watch the video on What is DNA and How does it work. Make additional notes from the video in your workbook.
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Question: Why Are Babies Born with Blue Eyes?
Answer: You inherit your eye color from your parents, but no matter what the color is now, it may have been blue when you were born. Why? Melanin, the brown pigment molecule that colors your skin, hair, and eyes, hadn't been fully deposited in the irises of your eyes or darkened by exposure to ultraviolet light. The iris is the colored part of the eye that controls the amount of light that is allowed to enter. Some other animals are born with blue eyes, too, such as kittens.
Melanin is a protein. Like other proteins, the amount and type you get is coded in your genes. Irises containing a large amount of melanin appear black or brown. Less melanin produces green, gray, or light brown eyes. If your eyes contain very small amounts of melanin, they will appear blue or light gray. People with albinism have no melanin in their irises and their eyes may appear pink because the blood vessels in the back of their eyes reflect light.
Melanin production generally increases during the first year of a baby's life, leading to a deepening of eye color. The color is often stable by about 6 months of age. However, several factors can affect eye color, including use of certain medications and environmental factors. Some people experience changes in eye color over the course of their lives. People can have eyes of two colors. Even the genetics of eye color inheritance isn't as cut-and-dried as was once thought, as blue-eyed parents have been known (rarely) to have a brown-eyed child!
Answer: You inherit your eye color from your parents, but no matter what the color is now, it may have been blue when you were born. Why? Melanin, the brown pigment molecule that colors your skin, hair, and eyes, hadn't been fully deposited in the irises of your eyes or darkened by exposure to ultraviolet light. The iris is the colored part of the eye that controls the amount of light that is allowed to enter. Some other animals are born with blue eyes, too, such as kittens.
Melanin is a protein. Like other proteins, the amount and type you get is coded in your genes. Irises containing a large amount of melanin appear black or brown. Less melanin produces green, gray, or light brown eyes. If your eyes contain very small amounts of melanin, they will appear blue or light gray. People with albinism have no melanin in their irises and their eyes may appear pink because the blood vessels in the back of their eyes reflect light.
Melanin production generally increases during the first year of a baby's life, leading to a deepening of eye color. The color is often stable by about 6 months of age. However, several factors can affect eye color, including use of certain medications and environmental factors. Some people experience changes in eye color over the course of their lives. People can have eyes of two colors. Even the genetics of eye color inheritance isn't as cut-and-dried as was once thought, as blue-eyed parents have been known (rarely) to have a brown-eyed child!