1. Nucleic Acids and Protein Synthesis
Photo credit: Jacob Halaska/Index Stock Imagery, Inc.
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2. Two Types of Nucleic Acids:
1. DNA
2. RNA
Together they have the code and capability to make all necessary proteins.
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DNA
Deoxyribonucleic Acid
-our genetic code
-code for making all proteins/enzymes
= all our traits and cell reactions
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DNA is:
Located:
in the nucleus of all our cells.
Makes up our:
Chromosomes
Number of chromosomes in each of our cells? 46
23 from mom
23 from dad
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Chromosomes:
-46 linear segments of DNA
-Super coil into “bow tie” shaped structures
during cell division.
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6. Approximately 6ft/cell ~ supercoils into mere nanometers
Supercoiling of DNA
Approximately 6ft/cell ~ supercoils into mere nanometers
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Human Genome:
- our complete set of genes that makes up a human.
-22,000 genes in our genome.
-99.9% of every humans genes is identical. There is only a .1% sequence variation from person to person
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Genes:
segments of DNA that codes for 1 or more proteins.
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Every cell in your body has an exact copy of all 46 chromosomes but…….
Cells are selective on what
genes are read and proteins
made.
Ex/ skin makes collagen
pancreas makes insulin
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10. -Mapped all of our genes. -Headed by James Watson
-Completed in 2003
-Headed by James Watson
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Structure of DNA:
1. is a nucleic acid
2. made up of nucleotides
Each nucleotide is made up of:
1. Pentose sugar (5 sided)
“deoxyribose”
2. Phosphate/phosphoric acid
3. Nitrogen Base (4 types)
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13. The Components and Structure of DNA
3. There are four kinds of DNA nitrogen bases:
Adenine
Guanine
Cytosine
Thymine
Purines: double ring
DNA is made up of nucleotides. Each nucleotide has three parts: a deoxyribose molecule, a phosphate group, and a nitrogenous base. There are four different bases in DNA: adenine, guanine, cytosine, and thymine.
Pyrimidines: single ring
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4. DNA is made up of a double strand of nucleotides held together with weak hydrogen bonds.
5. DNA has a double helix shape (twisted).
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DNA follows the “Base Pairing Rule”
Adenine only bonds to Thymine
Cytosine only bonds to Guanine
Why?
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DNA’s structure
Was determined
By James Watson
and Francis Crick
In 1953.
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17. The Components and Structure of DNA
DNA Double Helix
DNA is a double helix in which two strands are wound around each other. Each strand is made up of a chain of nucleotides. The two strands are held together by hydrogen bonds between adenine and thymine and between guanine and cytosine.
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18. The Components and Structure of DNA
X-Ray evidence of DNA’s structure was provided by: 
Rosalind Franklin and Maurice Wilkens
-took an X-ray of DNA
Rosalind aimed an X-ray beam at concentrated DNA samples and recorded the scattering pattern of the X-rays on film.
This X-ray diffraction photograph of DNA was taken by Rosalind Franklin in the early 1950s. The X-shaped pattern in the center indicates that the structure of DNA is helical.
Photo credit: ©Cold Spring Harbor Laboratory Archives/Peter Arnold, Inc.
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19. Nobel Prize winners in 1962 ~ Crick, Watson and Wilkens
Died in 1958
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Watson: current head
of the Human Genome
Project
Crick: died in 2004
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DNA Replication:
-DNA makes an exact copy of itself
-Why?
So cells can divide
and each new cell has an
exact copy of DNA.
-Occurs in all cells
-Some cells lose the ability to divide.
Example: nerve, brain, heart
-Some cells divide all the time:
Example: skin, bone
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22. -DNA replication requires enzymes.
-Each chromosomes is over 20,000 nitrogen
bases long so it happens in sections.
Interesting but useless bits of knowledge:
DNA is an invisibly thin, very long double strand of nucleotides.
The DNA found in each human cell is almost 2 meters or 6 feet long.
If all the DNA in a human adult were laid end to end the DNA molecule would stretch 113 billion miles.
That would equal 610 trips to the sun and back.
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23. Steps to DNA Replication:
DNA helicase unwinds and unzips DNA by breaking the hydrogen bonds between nitrogen base pairs at several places along each strand.
Creating several “replication bubbles”.
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3. Two DNA polymerase enzymes, one on each side of the DNA strand add new nucleotides following the base pair rule.
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4. This continues until all “replication bubbles” converge to create 2 new DNA molecules.
5. The separate strands of DNA are joined with DNA ligase to create two continuous new strands.
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6. Two new strands recoil and two new,
identical molecules are formed. T A G C A T C G T A G C A T C G
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DNA Replication
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