Finding out more about DeoxyriboNucleic Acid:
What is DNA?
A nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms. DNA lies within individual chromosomes, in the DNA helix of DNA strands. It encodes a detailed set of plans, like a blueprint, for building different parts of a cell. A DNA molecule comes in the form of a twisted ladder called a "double helix", built with the four letter DNA alphabet: A, C, T and G. DNA consists of two long polymers of simple units called nucleotides, with backbones made of sugars and phosphate groups joined by ester bonds. A always pairs with T and C always pairs with G, the the letters are connected via a hydrogen bond.
A - Adenine
C - Cytosine
T - Thymine
G - Guanine
A combination of many of these nucleobases form genes, which tell the cell to produce protein, which is essential for the cell to perform specific functions.
Animation of DNA: click to see it move!
What is a Gene?
Genes are made up of DNA. They contain the instructions on building the proteins that enable our bodies to function. For instance, out of the 25,000 genes in our body, only very few contain the specific information to make haemoglobin, while other genes contain information for other specific functions.
What is a Chromosome?
The actual length of our DNA in a single human cell is actually 3 meters long, so in order for that to fit into a cell, the DNA is packaged into compact units called chromosomes. Starting with the double helix DNA, it is wrapped around several proteins, which are packed tightly together, forming chromosomes. Each human cell has 46 chromosomes, and the DNA is organised into 23 sets of chromosomes. You can tell a person's gender from chromosomes. Also, if a human has an extra chromosome, he or she will have down syndrome.
What is a Protein?
Every cell contains thousands of different proteins, which work together to run the cell.
1) Receptor proteins are responsible for picking up nerve signals and transferring it to the next cell. For example, if someone gets hurt in the leg, the receptor proteins will transmit the pain signal all the way to the brain.
2) Structural proteins are not round but are instead column-like, stacking together to help cells extend "branches" to hold them in place, giving them their unique shapes.
Ribosomes produce these proteins, which will travel to the part of the cell where it is needed and begin to work.
What is Heredity?
The passing on of traits from parents to offspring. Our genes encode the instructions that define our traits, which are made of DNA and reside in our chromosomes. Humans have two complete sets of 23 chromosomes. Parents each contribute one set of 23 chromosomes to their offspring, passing genes to the child. When the sperm and egg cells join during conception, they create a single, 46 chromosome cell, a zygote. Each child's set of chromosomes can contain any number of their parent's chromosomes, just that each child must receive exactly one of each chromosome.
What is a Trait?
A notable feature or quality in a person. Traits are passed on from generation to generation. Types of traits include: physical traits, behavioral traits and predisposition to a medical condition. Our genes as well as the physical environment that we are exposed to (e.g. the sun) play important roles in defining our traits. When a dominant and recessive gene are placed together, the result will always be the dominant gene. Alleles can also work together to form incomplete dominance. Traits influenced by just one gene are rare. All humans share 99.9% identical DNA!
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| All the tested samples! |
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| Before adding hydrogen peroxide: Top right, sample 1, top middle, sample 2, top left, sample 3, bottom right, sample 4 and so on. |
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| After adding hydrogen peroxide: Samples 4,5,6 bubbled. You can even see that Sample 5 changed colour! |
Test 2 : Identify which is blood using Luminol (Samples 4-6)
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| Observe Sample 4 (left): it glows! |
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| Sample 5 (right) changes colour as well. |
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| Before spraying Luminol to Samples 4,5,6. |
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| After spraying Luminol to Samples 4,5,6. You can see that the colour of Samples 4 and 5 are much lighter than before. The light is quite bright here, so you can't see it glow, but you can see the colour change in Samples 4 and 5. |
Test 3: Kastle Meyer reagent (Sample 4 and 5)
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| Before adding reagent. |
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| After adding reagent. Sample 4 turns pink, showing that it is blood. |
DNA Extraction:
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| The DNA strands are three markings below the edge of my palm:) |
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