Frederick Griffith Live Smooth Bacteria Live Rough Bacteria Dead Smooth Bacteria Live R+ dead S Bacteria
Live Smooth Bacteria Frederick Griffith Live Rough Bacteria Dead Smooth Bacteria Live R+ dead S Bacteria Was it the capsule that made the mice sick? No! Conclusion There was a part of the live R bacteria that was able to make the dead S dangerous- transformation- a change caused when cells take up foreign DNA
Erwin Chargaff adenine thymine cytosine guanine
Rosalind Franklin & Maurice Wilkins
James Watson & Francis Crick
Think back to organelles... DNA is located in the nucleus What type of organic compound is DNA? Nucleic Acid
What is DNA? The function of DNA is to store genetic information- a complete set of instructions for manufacturing all of the proteins for an organism. Why do we need proteins? Some proteins provide structure for living things. All living things contain proteins called enzymes which are needed for the functions of life.
The Structure of DNA DNA is a polymer made of repeating subunits (monomers) called nucleotides. Nucleotides have 3 parts: sugar phosphate group nitrogen base
The Structure of DNA The sugar in DNA is called deoxyribose. The phosphate group is composed of one atom of phosphorous and four atoms of oxygen. (PO 4 ) A nitrogen base is a carbon ring structure that contains one or more atoms of nitrogen.
A NUCLEOTIDE 1. 3. 1. Phosphate Group 2. 5-Carbon Sugar (Dexoyribose or Ribose) 3. Nitrogen Base O 1. 2. 3. Nucleotides, too O P O 2. C H 3 O O C H 2 O C H H C C H C H H O H O C C H N C C O N H
There are four nitrogen bases: adenine (A) guanine (G) cytosine (C) thymine (T) purines pyrimidines DNA is made of two chains of nucleotides joined together by the nitrogen bases (Watson and Crick). The two strands twisted together make a shape called a double helix.
1. Phosphate Group 2. 5-Carbon Sugar (Dexoyribose or Ribose) 3. Nitrogen Base
Rules for Base Pairing: A. Cytosine Guanine (C G) B. Adenine = Thymine (A = T) Nitrogen bases are held together by hydrogen bonds
Phosphate Sugar Nitrogen Bases C G A A T G
Fun Facts If you wrote down all of the bases in one cell, you would fill a stack of 1,000 phone books with A's, T's, G's and C's
Fun Facts If you unraveled all your chromosomes from all of your cells and laid out the DNA end to end, the strands would stretch from the Earth to the Moon about 6,000 times.
What does the DNA of all these organisms have in common? They all share the same 4 nitrogen bases (A,T,G,C).
Nucleotide Sequences Differences in organisms are a result of the differences in the sequence of the four nucleotides along the DNA strands. The sequence forms unique genetic information. The closer the relationship between two organisms, the greater the similarity in their order of DNA nucleotides. Scientists use nucleotide sequences to determine evolutionary relationships among organisms.
What is RNA? sugar nitrogen base DNA must have a helper molecule. RNA stands for RiboNucleic Acid phosphate
What are the main functions of RNA? Carries DNA s message code Helps make protein Types of RNA Messenger RNA (mrna) Transfer RNA (trna) Ribosomal RNA (rrna)
Transcription RNA enzyme, polymerase, binds to DNA and separates DNA stands. One strand of DNA is used as a template for a strand of RNA to assemble. *Always begins at promoters * DNA Base Pairs: ATGC RNA Base Pairs: AUGC
Translation The decoding of mrna into a protein Produces proteins Takes place on ribosome s Use info from mrna
RNA Nucleotides A. Sugar (ribose) B. Phosphate Group C. Nitrogen Bases B A C
RNA Identify the parts of the RNA strand. Nitrogen Base Sugar (ribose) Phosphate Group
Differences between DNA and RNA # of strands? Sugar? DNA Double stranded deoxyribose RNA Single stranded ribose Also, base pairing rules differ slightly
Rules for Base Pairing in RNA: A. Cytosine Guanine (C G) B. Adenine = Uracil (A = U) Notice that RNA has Uracil (not Thymine)
Rules for Base Pairing DNA strand C G A T G C T A DNA strand
Rules for Base Pairing DNA strand C G A T G C T A DNA strand
Rules for Base Pairing DNA strand C G A U G C T A RNA strand DNA strand
Comparing DNA & RNA Sugar is deoxyribose Sugar is ribose Adenine base is present Cytosine base is present DNA RNA
Comparing DNA & RNA Guanine base is present Thymine base is present Uracil base is present Shape is double helix DNA RNA
Comparing DNA & RNA DNA RNA Shape is single stranded Located in nucleus Located in cytoplasm Stores genetic information
DNA Replication & why it is important! Copying of DNA in chromosomes Without DNA replication, new cells would have only half the DNA of their parents Species could not survive, reproduce, or grow
DNA Replication During replication, each strand serves as a template to make a new DNA molecule a. DNA is unzipped b. Free floating nucleotides attach by base pairing *Hydrogen holds base pairs together* Each strand is a complement of one of the original parent strands c. Results in the formation of two DNA molecules, identical to the original strand
DNA Replication *Remember: 1. DNA RNA Proteins 2. Hydrogen holds the nitrogen bases (Base pairs) together.
Factors affecting DNA Replication There are many different factors can alter or stop the replication of DNA. Here are a few: 1. Ultraviolet Light (UV Light): aka: Sun damage!! (in limited amounts can be beneficial) 2. Electromagnetic Radiation: ex. Radio waves, microwaves, X-Rays (listed in increasing frequency) 3. Heat: can break DNA molecule
Mutations Are changes in the nucleotide sequence (changes in the base pairs). Can be caused by: 1. Copying errors during cell division 2. Exposure to UV Light 3. Cell itself Are all mutations bad? Harmful Mutations 1. Genetic disorders 2. Hereditary disease 3. Cancer NO Beneficial Mutations 1. Anything that can help an organism Only the strong survive
Mutations Cont. How they can occur: 1. Point mutation:most common is the transition that exchanges a purine for a purine (A G (or C)) or a pyrimidine for a pyrimidine, (C T (or A)). Ex. AACGT should have TTGCA 2. Insertion: add one or more extra nucleotides into the DNA. can also be called a Frameshift 3. Deletions: remove one or more nucleotides from the DNA
Insertion Mutation
Point Mutation
Deletion Mutation