dna - introduction
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DNA - Introduction. Deoxyribonucleic Acid Structure: Replication Transcription Translation. DNA. DNA- Deoxyribonucleic Acid. What is this?. POLYMER. A polymer is a large molecule made up of smaller molecules called monomers DNA is a polymer made up of Nucleotides. NUCLEOTIDES. - PowerPoint PPT PresentationTRANSCRIPT
DNA - Introduction Deoxyribonucleic
Acid Structure: Replication Transcription Translation
DNA
DNA- Deoxyribonucleic Acid
What is this?
•
POLYMER
A polymer is a large molecule made up of smaller molecules called monomers
DNA is a polymer made up of Nucleotides.
NUCLEOTIDES
Nucleotides are the smaller sub-units that make up a DNA
Each Nucleotide is made up of a
Sugar, Phosphate and Nitrogen Base
4 NITROGEN BASES
A d en in e(A )
G u an in e(G )
Th ym in e(T)
C ytos in e(C )
D N A N itrog en B ases4 B ase P a irs
H e ld Tog e th er b y H B on d s
Complementary Base Pairs: Cytosine always
bonds with guanine by forming three hydrogen bonds. (C-G)
Adenine always bonds with thymine by forming two hydrogen bonds. (A-T)
DOUBLE HELIX
The DNA molecule consists of two nucleotide chains that wrap around each other to form a double spiral
Looks like a twisted ladder
DNA makes you UNIQUE :) The order of nucleotides
(NB) will vary in every organism
The closer you are in Evolutionary History- the closer your DNA will resemble
The sequence of nucleotides forms the unique genetic information of an organism
DNA Replication: The process of copying DNA Takes place during the “S” phase of the cell
cycle…Remember?
Steps of DNA Replication
DNA will unwind DNA will “unzip”
down the middle separating the sides of the ladder
Steps of DNA Replication
Free-Floating nucleotides will come in and attach to each existing side of the original DNA
This process will continue until the entire molecule has replicated
Outcome of DNA Replication Replication will make 2 identical
strands of DNA which can then be passed on to a new cell during mitosis or meiosis
When all the DNA in all the cells has replicated, there are 2 copies of the organism’s genetic information.
DNA
DNA is the “Master” copy of an organisms information code. This information contains instructions used to form nearly all enzymes and proteins.
DNA- Major Functions
Directing Protein Synthesis Controlling Cell Division Inheritance
Why is it called Universal?
The codons represent the same amino acids in all organisms
Same in humans and virtually every other known organism
Figured out by studying the DNA of the bacteria E. Coli
The Other Nucleic Acid- RNA
RNA stands for Ribonucleic Acids RNA and DNA are very similar but
they do have three key differences.
Differences between RNA & DNA
RNA: Single Sided Sugar molecule
called RIBOSE 4 Bases- Cytosine,
Guanine, Adenine and URACIL
DNA: Double sided Sugar molecule
called DEOXYRIBOSE
4 Bases-Cytosine, Guanine, Adenine and THYMINE
RNA in involved in an important process called transcription.
The process in which RNA makes a copy of DNA
Similar to Replication.
Transcription!! Proteins are
made on ribosomes in the cytoplasm of the cell. Yet DNA is found only in the nucleus. How is information brought to the ribosomes for protein synthesis?
RNA Transcription .
DNA must first unwind. Enzymes unzip DNA molecule Free-floating RNA nucleotides pair
with complementary DNA nucleotides on one of the DNA strands
Guanine pairs with Cytosine Adenine pairs with Uracil
RNA Transcription .
When the process of base pairing is completed, the mRNA molecule breaks away as the DNA strands rejoin
The mRNA leaves the nucleus and enters the cytoplasm to a ribosome.
RNA Transcription
(Messenger) mRNA is the form in which information moves from DNA in the nucleus to the ribosomes in the cytoplasm
Enzymes make a RNA copy of a DNA strand
The Genetic Code
DNA holds the instructions to make proteins.
Like DNA..Protein is also a polymer made up of smaller subunits called Amino Acids
There are 20 A.A. They combine in various ways to make various proteins.
The Genetic Code You need to look at DNA as being similar to
the alphabet. The alphabet has 26 letters which combine to
form 1000’s of words. The DNA alphabet only has 4 letters and all
the words are made up of only 3 letters. When you “read” DNA you read in group of 3
Nitrogen Bases at a time. Groups of 3 are called CODONS Each codon will code for a specific Amino
Acid
Translation- Protein Synthesis
The process of converting the information of mRNA into a sequence of Amino Acids that will make a protein
On your ribosome is your mRNA with all the codons and information from DNA
Another Form of RNA
tRNA Transfer RNA Single strand Purpose is to bring the
appropriate amino acid to the ribosome
Carries the anti-codon
Mutations Gene: sequence of DNA nucleotide bases Gene Mutation: any change in this DNA
sequence of nucleotide bases Point Mutation: a change in a single base
pair, mistake may or may not interfere with protein function
Frameshift Mutation: where a single base pair is added or deleted, this causes a shift in the reading of the codons by one base
These mutations can occur when the DNA is replicated, during transcription and translation