Transcript DNA and RNA - Effingham County Schools

Quick Review
1. What is genetic information stored as?
2. 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:
1. Store and Transmit genetic information
2. Direct its synthesis/replication
3. 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
DNA and RNA
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.
1. Cytosine always bonds with guanine by
forming three hydrogen bonds. (C - G)
2. Adenine always bonds with thymine by
forming two hydrogen bonds. (A - T) In the
RNA nucleotide, thymine is replaced by
Uracil (A – U).
3. 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 RNA
mRNA
• carries genetic information from
nucleus to cytoplasm
Transfer RNA
tRNA
• carries amino acids from cytoplasm to
ribosomes
Ribosomal RNA
rRNA
•
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:
1. Type of Sugar
2. Type of nucleotides
3. Strand type
DNA & RNA Comparison
DNA
RNA
Sugar molecule is
Ribose
Is single stranded
Sugar molecule is
Deoxyribose
Is double stranded
Uses Uracil
Uses Thymine
Is smaller and leaves
the nucleus
Has 3 basic types
Remains in the nucleus
COPY of genetic code
Is THE genetic code
Only one kind of DNA