260 likes | 362 Views
Quick Review. What is genetic information stored as? What organelle is this information found in?. First Model of DNA. 1953: James Watson, Francis Crick and Maurice Wilkins examined an amazing photograph made by Rosalind Franklin using a technique she developed called X-ray crystallography
E N D
Quick Review • What is genetic information stored as? • What organelle is this information found in?
First Model of DNA • 1953: James Watson, Francis Crick and Maurice Wilkins examined an amazing photograph made by Rosalind Franklin using a technique she developed called X-ray crystallography • With what they had discovered about the composition of DNA and Franklin's photographs, Watson & Crick developed and proposed the first model for the structure of DNA
Watson and Crick Model • consisted of two nucleotide chains that wrap around each other to form a double spiral. • This shape is called a double helix.
DNA DeoxyriboNucleic Acid Genetic code of life Located inside the nucleus NEVER leaves the nucleus Double Stranded Shape of DNA is a double helix Made of nucleotides
Primary functions of DNA: • Store and Transmit genetic information • Direct its synthesis/replication • Code for protein synthesis
So, what is RNA? • RiboNucleic Acid • Copy of a gene in DNA • Responsible for delivering genetic information from the DNA in the cell nucleus to the ribosome in the cytoplasm • Located outside the nucleus • Responsible for completion of the process of protein synthesis • Single stranded • 3 Types of RNA: Messenger, Transfer, Ribosomal • Made of nucleotides
Nucleotides • Monomers that make up DNA & RNA
Each nucleotide is composed of: • A sugar, • A nitrogen base • A phosphate group:
Sugar • Deoxyribose - a 5-carbon sugar in DNA • Ribose - a 5-carbon sugar in RNA. • This sugar has more oxygen than the sugar in DNA. Notice: Oxygen placement DEoxy (de means to remove. DNA has an Oxygen removed!!!
Nitrogen Base Purines • have a double ring of carbon and nitrogen atoms. • Adenine & Guanine Pyrimidines • have a single ring of carbon and nitrogen atoms. • Thymine & Cytosine (in DNA) • Uracil & Cytosine ( in RNA)
Phosphate Group • -PO4
The phosphate group is attached to the sugar, and the sugar is attached to the nitrogen base
RNA – single stranded DNA – double stranded
Two nucleotides pair to form one of the "rungs" of the ladder in a DNA double helix.
The sugar and phosphate groups form the "backbone" or outer support of the DNA ladder-like double helix. Sugar phosphate backbone
Base Pairing Rules These rules describe the behavior of the bases. • Cytosine always bonds with guanine by forming three hydrogen bonds. (C - G) • Adenine always bonds with thymine by forming two hydrogen bonds. (A - T) In the RNA nucleotide, thymine is replaced by Uracil (A – U). • A pair of bases that always bond together is known as a complementary base pair.
3 Basic Types of RNA • Messenger RNA – mRNA • Transfer RNA – tRNA • Ribosomal RNA - rRNA
Messenger RNAmRNA • carries genetic information from nucleus to cytoplasm
Transfer RNAtRNA • carries amino acids from cytoplasm to ribosomes
Ribosomal RNArRNA • consists of RNA nucleotides in globular form
Celebration of Learning Moment! You are to create a comparison between RNA and DNA. Be sure to include: • Type of Sugar • Type of nucleotides • Strand type