What are two questions you developed from reading this passage? Everyone has heard of DNA, but what does it do? What does it look like?DNA or Deoxyribonucleic acid is a molecule that contains the instructions anorganism needs to develop, live, and reproduce. These instructions are found insideevery cell, and are passed down from parents to their children. The chemicalinformation found inside of DNA affects how our body looks and functions. It'sinteresting to note that about 99.9% of the DNA of every person on the planet is exactlythe same. The remaining 1% that is different makes each one of us unique.DNA is made up of subunits (or smaller, repeatingphosphatemolecules) called nucleotides. Each nucleotide containsa phosphate molecule and a sugar sugar molecule(deoxyribose). These repeating phosphates and sugarsmake up the backbone of DNA. Additionally, eachbasedeoxyribose sugarnucleotide contains a nitrogen base. The four types ofnitrogenous bases are:Adenine (A)Oscienceaid.co.uk• Thymine (T)Guanine (G)• Cytosine (C)The sequence (order) of these bases is what determines DNA's instructions, orgenetic code. Similar to the way the order of letters in the alphabet can be used to forma word, the order of nitrogen bases in a DNA sequence forms genes, which in thelanguage of the cell, tells cells how to make proteins. Cells then use these proteins tobuild our bodies and make all of the molecules that help us to complete all of our lifeprocesses such as digesting our food. In fact, the DNA of all living organisms isorganized in this way. That means that humans share common DNA with worms,bacteria, and even plants!Although DNA looks like long, clumpy strings under a microscope, it actually hasa specific shape. This shape is called a double helix, which looks like a twisted ladder.On the outside of the double helix are two sets of backbones (phosphate and sugar molecules) that hold the DNA together. Between the backbones are the nitrogen basesrepresented by the letters A, T, C, and G. A different nitrogenous base connects to eachbackbone unit, and then connects to another base in the center. Only certain sets ofnitrogenous bases can connect, or fit together. You can think of them as pieces of apuzzle -- A only connects with T and G only connects with C. This is calledcomplementary base pairing, because these specific pairs always match or connectonly with each other.The structure of DNA– so long, in fact, that they can't fitinto cells without the right packaging. If you were able tounravel all the DNA molecules from all of the cells in your bodyDNA molecules are long-and placed them end to end, it would stretch to the Sun andback several times! In order to fit inside cells, DNA is coiledtightly to form structures we call chromosomes. Humans have23 pairs of chromosomes, which are found inside the cell'sAdnne AThe (Cyenucleus. Although all organisms share the basic structure ofDNA, each species may have different amounts of DNA ornumber of chromosomes. For example, dogs have 39 pairs ofchromosomes and a cat has only 19 pairs.

Question

Accepted Answer

DNA stands for Deoxyribnucleic acid. It is the genetic material present in the nucleus.