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DNA Replication, Transcription & Translation. DNA/ RNA structure and function. How does your body use its genetic code? Your body is made up primarily.

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Presentation on theme: "DNA Replication, Transcription & Translation. DNA/ RNA structure and function. How does your body use its genetic code? Your body is made up primarily."— Presentation transcript:

1 DNA Replication, Transcription & Translation

2 DNA/ RNA structure and function. How does your body use its genetic code? Your body is made up primarily of 4 biomolecules. They are: 1. Carbohydrates 2. Proteins 3. Fats 4. Nucleic Acids

3 DNA/ RNA structure and function. DNA is a nucleic acid and is short for deoxyribonucleic acid **It is the structure of DNA that makes each person unique!

4 http://www.people.virginia.edu/~rjh9u/gif/griffithexp.gif I. DNA Structure A. The “ Backstory ”— how do we know about DNA ’ s structure and how it works? 1. Frederick Griffith — killed off some mice with dead bacteria — how ’ d he do that???

5 A. The “Backstory” continued… This is called transformation—process of genetic materials being absorbed from the environment into a bacterium’s DNA Griffith’s work led to more work by Avery & other scientists—trying to figure out if it was RNA or DNA. The results showed that the “transforming factor” is DNA—the nucleic acid that stores & transmits genetic information from one generation to the next.

6 http://web.mit.edu/esgbio/www/dogma/images/hersheychase The “backstory” … continuedbackstory 2. Alfred Hershey and Martha Chase — did some work with “ bacteriophages “ — literally “bacteria-eaters” aka viruses (which are NOT living organisms) Bacteriophages are composed of two simple parts: DNA core (contains P-32) & protein coat (contains S-35)

7 B. Each nucleotide of DNA is made of three things. They are: 1. sugar—deoxyribose 2. nitrogen base ( connected to sugar) 3. phosphate group 1 2 3

8 C. The only difference between the four possible DNA nucleotides is the nitrogen base. The four possible nitrogen bases are A= adenine G= guanine C= cytosine T= thymine

9 Hydrogen bonding in DNA Adenine always binds to thymine (2 H bonds), and cytosine always binds to guanine (3 H bonds).Chargoff’s rule C. The bond between the sugar and the phosphate causes the DNA strand to twist. This shape is called a double helix  think of a twisted ladder.

10 II. DNA Replication A. DNA is replicated in a process called DNA synthesis or replication. B. There are 3 steps to DNA replication 1. initiation 2. elongation 3. termination **the result of this process is two identical strands of DNA

11 http://www.geneticengineering.org/chemis/Chemis-NucleicAcid/Graphics/Replication.gif  One strand on each copy is from the original.

12 III. MAKING PROTEINS!! The Genetic Code What purposes do an organism’s proteins serve?  as enzymes AND provide cell structure It is said that DNA is the “master plan”. What does that mean?  all information needed is in the DNA

13 A. Proteins are made of amino acids. The human body has 20 different amino acids. B. Each unit of the genetic code is called a codon and is made up of 3 bases (of RNA). C. Each codon specifies a certain amino acid 1 codon is a start code. It is AUG (also stands for methionine). 3 codons are stop codes. They are UAA, UAG, UGA

14 IV. RNA structure and function **RNA copies the genetic code so the ribosome can use the code to make new proteins. RNA= ribonucleic acid

15 How is RNA different from DNA? RNADNA single-strandeddouble-stranded Found in nucleus nucleus & cytoplasm uracilthymine

16 A. RNA also contains four nitrogen bases: 1. adenine 2. cytosine 3. guanine 4. uracil A binds with U and G binds with C

17 B. Three types of RNA we need to know for protein synthesis are: 1. Messenger RNA: m-RNA carries code from DNA to the ribosomes 2. Transfer RNA: t-RNA carries/transfers amino acids to the ribosomes 3. Ribosomal RNA: r-RNA is used to construct ribosomes where protein synthesis takes place

18 C. RNA copies DNA (this process is called transcription) and carries the code to the ribosome so a protein can be made. D. Each DNA codon produces a corresponding RNA codon—this is called transcription. If the DNA codon was CCA,then the RNA codon would be GGU

19 http://campus.queens.edu/faculty/jannr/Genetics/images/FG13_01dogma.jpg

20 E. Translation: 1. When mRNA binds to the ribosome, a protein can be synthesized. 2. t-RNA bring amino acids to the ribosomes according to the m-RNA. Each tRNA has an anticodon that pairs up with the codon. **Amino acids are the building blocks of proteins. After they are sequenced the amino acids link together to make proteins. Protein synthesis—epic on cellular level


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