Unit 4 DNA- Lesson 1

4.1.1 What is DNA?

DNA is what makes up our chromosomes in the nucleus and stores our genetic information. Your genetic information tells your cells what to do.

Source: Eukaryote_DNA-en.svg by Eukaryote_DNA.svg: *Difference_DNA_RNA-EN.svg: *Difference_DNA_RNA-DE.svg: Sponk (talk)translation: Sponk (talk)Chromosome.svg: *derivative work: Tryphon (talk)Chromosome-upright.png: Original version: Magnus Manske, this version with upright chromosome: User:Dietzel65Animal_cell_structure_en.svg: LadyofHats (Mariana Ruiz)derivative work: Radio89derivative work: Radio89 - This file was derived from:Eukaryote_DNA.svg. / CC BY-SA 3.0

 A gene is a small segment of DNA that codes for a specific protein (trait).

Gene by National Human Genome Research Institute / Public Domain 

The Structure of DNA

DNA (deoxyribose nucleic acid) is a long chain of nucleotides. Nucleotides are made up of three parts: 1) a phosphate group, 2) a 5-carbon sugar (deoxyribose) and 3) a nitrogen-containing base.In each nucleotide the only difference is the type of nitrogen base.The four bases are adenine (A), guanine (G), cytosine (C), and thymine (T).

DNA Nucleotides by OpenStax College / CC BY 3.0

DNA’s three dimensional shape is a double helix and hydrogen bonds between the bases hold the helix together. James Watson and Francis Crick won the Nobel Prize for determining the structure of DNA. Rosalind Franklin and Maurice Wilkins also played important roles in this discovery. The structure of DNA is two strands of nucleotides in a double helix. The sugar and phosphate groups are on the outside and paired bases connect the two stands on the inside.

The paired bases always bond using the base pair rules. Adenine (A) always bonds with thymine (T) and cytosine (C) bonds with guanine (G). If one strand of DNA reads ATCGTAC the complementary strand would be made up of TAGCATG.

Quick Write:

Write a 3-4 sentence summary of the text above. What was the main idea and what is the text most importantly about?

Go on to the next section for a presentation on DNA, genes, and chromosomes.

Sources:

Life Science, CK12 Flexbook http://cafreetextbooks.ck12.org/science/CK12_Life_Science.pdf