5’ 5’
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
5’ 5’
Deoxyribonucleic Acid
t leaves
Genetic Material, Blueprint of life, Genome, Double Helix, Nucleic Acid, Genes, Chromosome, Chromatin
Scientist Rosalind Franklin – 1952 – studied
DNA using X-rays. These photos suggested that DNA was double stranded and that the strands twisted around each other.
Watson and Crick – 1953 – made
the first structure model of DNA.
What are the four Biomolecules?
What are the monomers for each Biomolecule? Polymer- Proteins Carbohydrates Lipids Nucleic Acids
Monomer- Amino Acids Monosaccharide / Simple
Sugars Fatty acids Nucleotide
6
Remember Biomolecules Biomolecules-are large organic molecules that make up life. There are 4 Biomolecules
Monomer(Simple) Polymer(Complex) Saccharide (Sugar) Carbohydrate Fatty Acids Lipids Amino Acids Proteins Nucleotide Nucleic Acids
Nucleotide
Phosphate
Pentose Sugar
Nitrogenous Base
Nucleotides The phosphate and sugar form the backbone
of the DNA molecule, whereas the bases form the “rungs”.
There are four types of nitrogenous bases.
Double Helix
Nucleotides Purines Pyrimidines
A
Adenine
T
Thymine
G
Guanine
C
Cytosine
Nucleotides
Chargaff ’s Rule Each base will only bond with one other
specific base. Adenine (A) Thymine (T) Cytosine (C) Guanine (G)
Form a base pair.
Form a base pair.
G
G
A
T
T
A
A
C
T
G
C
A
T
C
Because of this complementary base pairing, the order (sequence) of the bases in one strand determines the order of the bases in the other strand.
G
G
A
T
T
A
A
C
T
G
C
A
T
C
The two strands are held by weak bonds know as
hydrogen bonds.
5’
5’
3’
3’
DNA Structure To crack the genetic code found in DNA we need to look at
the sequence of bases.
The bases are arranged in triplets called codons.
A G G - C T C - A A G - T C C - T A G T C C - G A G - T T C - A G G - A T C
https://www.youtube.com/watch?v=zwibgNGe4aY&index=6&list=PLtOkRdk851ktbZhjBVWfNMq2e4c1_1jFh https://www.youtube.com/watch?v=o_-6JXLYS-k&index=54&list=PLtOkRdk851ktbZhjBVWfNMq2e4c1_1jFh
Chromosome structured in Eukaryotes Humans have approximately 3 billion base pairs (1 m long) 60,000 to 100,000 genes
DNA molecule in eukaryotes exists in three main forms - DNA double Helix Chromatin Chromosome
DNA in eukaryotes is found in the nucleus. Most of the time it is in the form of chromatin.
Chromosome
Chromatin
Double Helix
E. coli bacterium Bases on the chromosome
Chromosome Structure in Prokaryotes
DNA molecule in bacteria is SINGLE AND CIRCULAR. It is found in the cytoplasm (NO nucleus).
Approximately 5 million base pairs 3,000 genes
Chromosome
Remember….. Cell Theory Cells are the basic unit of life All living things are made up of cells All cells come from preexisting cells
Prokaryotic Cell Division Binary Fission Simple Division 3 steps DNA is copied Cell doubles in size Cell divides, each cell gets a new circle (plasmid) of DNA.
Body (Somatic) Cell Division
21
The Life of a Eukaryotic Cell • Interphase Includes
• G1 Phase - cell growth
• S Phase - DNA replication • (Chromosome duplication)
• G2 Phase – cell checks for mistakes
• M Phase cell division in stages: • Prophase • Metaphase • Anaphase • telophase
• Cytokinesis – cell separates into 2 identical daughter cells
Synthesis Phase: DNA Replication
HOW IS DNA COPIED?
Each strand has all the info needed to construct the matching other half. Base pairing rules allow it to make a new complementary strand.
Sites where strand separation and replication occur are called replication fork.
http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/dna-rna2.swf
REPLICATION STEPS
1. Enzymes “unzip” molecule by breaking Hydrogen Bonds that hold the strands together and unwind it. 2. DNA polymeraze joins nucleotides using original strand as template and Spell checks for errors. 3. Copying happens in opposite directions along the two strands & in multiple places at once.
DNA Replication
Related Documents
