DNA What are nucleic acids? Why is it important? Structure of DNA Scientists
Nucleic Acid • Nucleic Acids are large complex molecules containing genetic material • Made of nucleotides • sugar, phosphate group, and nitrogen base Two types: 1. Deoxyribonucleic Acid- DNA 2. Ribonucleic - RNA • DNA carries instructions that regulate cells activities • RNA–uses information from DNA to make proteins
Nucleic Acids • Nucleotides: • Phosphate • 5 carbon sugar (deoxyribose in DNA, ribose in RNA) • Nitrogen Base (Adenine, Thymine, Guanine, Cytosine)
What is DNA? • DNA- deoxyribonucleic acid • DNA contains the genetic information that makes you, you… animals, animals and plants, plants… • DNA is composed of: • Double helix • Phosphate group • 5 carbon sugar (deoxyribose) • Nitrogen containing base • Weak hydrogen bonds Make up a Nucleotide
Why is DNA Important? • DNA is in all living things • It is found in the cytoplasm of bacteria and in the nucleus of protists, fungi, plants, and animals.
S P The Structure of DNA • Nucleotides- subunits (monomers) that make up DNA • Phosphate group • 5 carbon sugar (deoxyribose) • Nitrogen containing base (nitrogenous base): • Adenine Thymine (A – T) • Guanine Cytosine (G – C) * Weak hydrogen bonds hold bases together
The Structure of DNA • Double helix- two strands of nucleotides twisted around each other, like a winding staircase • Complementary base pairs- the sequence of bases on one strand that determines the sequence of the other strand • Adenine Thymine • Cytosine Guanine
A T C G G C T A T A The Structure of DNA • So, if the sequence on one side is:
C A The Structure of DNA 5’ • Label: • Phosphate (P) • 5 carbon sugar • (S) • Correct base pairs • (A, T, C, G) • Draw hydrogen bonds 3’ 5’ 3’
The Sequence of DNA • The sequence (order) of nucleotides determines an individuals traits • If the nucleotide sequence of nitrogenous bases (adenine, guanine, cytosine, thymine) are in a similar order, the more related two things are • This concept is used in forensic science and is called DNA fingerprinting
The Structure of DNA *Note about bases: • Pyrimidines- single ring of carbon • Tymine and Cytosine • Purine- two rings of carbon • Adenine and Guanine A purine must always bond with a pyrimidine!
DNA Discoveries and Scientists • Alfred Hershey and Martha Chase- discovered that DNA stores genetic information in living cells • James Watson and Francis Crick- pieced together the structure of DNA • Rosalind Franklin—developed X-ray pictures of DNA • Chargaff- noticed the rules for base pairing (Adenine- Thymine and Cytosine – Guanine)
Why is DNA important? • DNA is the basis of genetic material and serves as the template for making proteins. • Proteins make: • your eye color and hair color • antibodies in your blood • enzymes vital to your metabolism • skin and muscles • Proteins make you, you!