DNA The fingerprint that’s inside your body!!!!!

STUDENTS WILL: Identify the parts of a DNA molecule and its structure. Explain how DNA copies itself. Describe the structure and function of each kind of RNA.

Vocabulary: DNA (Deoxyribonucleic Acid) RNA (Ribonucleic Acid) Gene Mutation

Fun DNA Facts! DNA stands for: D: Deoxyribose N: Nucleic A: Acid DNA is too small to see, but under a microscope it looks like a twisted up ladder! DNA stands for: D: Deoxyribose N: Nucleic A: Acid Every living thing has DNA. That means that you have something in common with a zebra, a tree, a mushroom and a beetle!!!!

What is DNA? A chemical code used by the cell Contains GENETIC information important for cell growth and function.

HISTORY OF DNA C. Watson and Crick A. Rosalind Franklin X-ray photo of DNA. (1952) B. Maurice Wilkins- X ray pattern of DNA C. Watson and Crick - described the DNA molecule from Franklin’s X-ray. (1953)

Watson and Crick: 3-D model of DNA

Nobel Prize for 3-D model of DNA

DNA STRUCTURE: 2 chains molecules in a spiral form Shaped like a spiral staircase or a twisted ladder  -

DNA STRUCTURE Steps of the ladder (rungs) are made up of pairs of nitrogen bases Sides of the ladder are made up of Sugar Phosphates

DNA Double Helix “Rungs of ladder” Nitrogenous Base (A,T,G or C) “Legs of ladder” Phosphate & Sugar Backbone

Watson & Crick proposed… DNA had specific pairing between the nitrogen bases: ADENINE (A) – THYMINE (T) CYTOSINE (C) –GUANINE (G) DNA was made of 2 long stands of nucleotides arranged in a specific way called the “Complementary Rule”

Rosalind Franklin’s DNA image “Chargaff’s rule” A = T & C = G

BASE-PAIRINGS C G H-bonds T A

Genetic Diversity… -Different arrangements of NUCLEOTIDES in a nucleic acid (DNA) provides the key to DIVERSITY among living organisms.

The Code of Life… A T C G T A T G C G G… The “code” of the chromosome is the SPECIFIC ORDER that bases occur. A T C G T A T G C G G…

DNA is wrapped tightly around histones and coiled tightly to form chromosomes

ACTCATGGTCATG TGAGTACCAGTAC Note: THIS IS AN EXAMPLE OF A GENETIC CODE THAT MAY BE FOUND IN YOUR BODY.

EXAMPLE: ATCGTCAGG MAY BE FOR HAIR COLOR. BUT ATCGTCAGC MAY BE FOR EYE COLOR

DNA Replication DNA-copied = identical DNAs When? Interphase Steps: Enzyme (helicase) unzips the DNA strand. New bases pair with bases on original DNA 2 new identical DNA are produced.

GENES? A section of DNA that contains instructions for making PROTEINS What are Proteins? Proteins (amino acids) build tissues and cells or work as enzymes GENES?

RNA (Ribonulceic acid) Made inside DNA ( TRANSCRIPTION) 4 Bases: Adenine (A) Guanine (G) Cytosine (C) Uracil (U) How are PROTEINS made?

Sugar (Ribose) 3 Main Kinds m (RNA) r (RNA) messenger t (RNA) Ribosomal t (RNA) Transfer RNA m (RNA) – carries the DNA code to the ribosomes r (RNA) – makes up part of the Ribosomes t (RNA) – bring amino acids to the ribosomes to be assembled into proteins

DNA Transcription -DNA can “unzip” itself and RNA nucleotides match up to the DNA strand. -Both DNA & RNA are formed from NUCLEOTIDES and are called NUCLEIC acids.

TRANSLATION - PROCESS WHERE THE RIBOSOMES SYNTHESIZE PROTEINS WITH THE HELP OF mRNA

DNA vs RNA RNA DNA Deoxyribonucleic acid Found in nucleus Bases are A,G,T,C Can be damaged by exposure to ultra violet rays. Double-stranded molecule Ribonucleic acid Found in nucleus and cytoplasm Bases are A,G,C,U More resistant to damage by ultra-violet rays. Single stranded molecule

Continue… DNA RNA A-T, G-C Contain the genetic instruction used in the development and functioning of all cells A-U, G-C Responsible for making proteins

Mutation? -A change in the sequence of DNA that codes for a gene or a change in the number of chromosome.

What cause Mutation? X-ray Sunlight Chemicals Results of Mutation: Harmful Beneficial Neutral

(a library of about 1,000 books) AMAZING DNA FACTS… -DNA from a single human cell extends in a single thread for almost 2 meters long!!! -It contains information equal to some 600,000 printed pages of 500 words each!!! (a library of about 1,000 books)