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What does DNA stand for?What does DNA stand for?
DeDe oxy-riboseoxy-ribose NucleicNucleic Acid Acid
Type of monosaccha
ride
Found in the nucleus (eukaryote) or nucleoid (prokaryote)
of cells
As in acids and bases
DNA can also be written as Deoxyribonucleic Acid
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Where do you find DNA?Where do you find DNA?All mature cells contain DNA except the red blood cellsAll mature cells contain DNA except the red blood cells
DNA is found in the nucleus DNA is found in the nucleus Small amounts of DNA are also present in the Small amounts of DNA are also present in the
chloroplasts and mitochondriachloroplasts and mitochondria
Nucleus
Source: Source: http://www.tokyo-med.ac.jp/genet/picts/cell-e.jpghttp://www.tokyo-med.ac.jp/genet/picts/cell-e.jpg
Chloroplast
Mitochondrion
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Building blocksBuilding blocks
A single unit of DNA is called a A single unit of DNA is called a nucleotide it is made up of:nucleotide it is made up of: A Sugar Molecule (Deoxy-ribose)A Sugar Molecule (Deoxy-ribose) A Phosphate molecule A Phosphate molecule A Nitrogenous BaseA Nitrogenous Base
P
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Building blocksBuilding blocks
P
P
P
P
P
The nucleotides are The nucleotides are bound together via bound together via covalent bonds covalent bonds between the between the phosphate groups, phosphate groups, forming a strand of forming a strand of DNADNA
These covalent These covalent bonds are very bonds are very strong and difficult strong and difficult to breakto break
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DNADNA
DNA is made up of 2 strands.
The strands are held together by weak bonds between the nitrogen bases
The bonding between the strands is so weak that the two strands will easily separate at 100˚C
http://academy.d20.co.edu/kadets/lundberg/dnapic2.html
http://www.tokyo-med.ac.jp/genet/picts/dna.jpg
There are four types of nitrogen bases:
Cytosine (C), Guanine (G), Adenine (A) and Thymine (T)
What pairs with C?
What pairs with A?
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DNADNA
Once the 2 strands of DNA are bound together, the strands coil to form a helical
shape
This is why DNA is often called a double helix
In this diagram, the 2 DNA strands have backbones that are shown in blue and red
The nitrogen bases are shown in yellow
http://academy.d20.co.edu/kadets/lundberg/dnapic2.html
http://www.tokyo-med.ac.jp/genet/picts/dna.jpg
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The Gene CodeThe Gene Code The order of the nitrogenous bases A, The order of the nitrogenous bases A,
T, G & C is very important. T, G & C is very important. The sequence provides cells with The sequence provides cells with
templates for the production of every templates for the production of every protein in the bodyprotein in the body
These proteins play many different These proteins play many different roles in the body roles in the body
Each segment of DNA which Each segment of DNA which determines the structure of one protein determines the structure of one protein is called a is called a genegene
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The DNA in the nucleus of your cells is tightly wound up to form chromosomeschromosomes so as to take up less space and avoid being tangled
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ChromosomesChromosomes
Each chromosome Each chromosome carries carries approximately approximately 30,000 genes 30,000 genes
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What does RNA stand for?What does RNA stand for?
RiboseRibose NucleicNucleic Acid Acid
Type of monosaccha
ride
Found in the nucleus or nucleoid
of cells
As in acids and bases
RNA can also be written as Ribonucleic Acid
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Building blocksBuilding blocks
Like DNA, a single unit of RNA is called Like DNA, a single unit of RNA is called a nucleotide. It is made up of:a nucleotide. It is made up of: A Sugar Molecule (Ribose)A Sugar Molecule (Ribose) A Phosphate molecule A Phosphate molecule A Nitrogenous BaseA Nitrogenous Base
Notice that the sugar molecule in RNA is Notice that the sugar molecule in RNA is different than in DNAdifferent than in DNA
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RNARNA
There are 2 other major differences in the make up of RNA compared with DNA:
• RNA is made up of only 1 strand of nucleotides
• In RNA, the four types of nitrogenous bases are: Cytosine (C), Guanine (G), Adenine (A) and Uracil (U)
•Note that RNA does not contain the base thymine but contains uracil instead.
http://academy.d20.co.edu/kadets/lundberg/dnapic2.html
http://www.tokyo-med.ac.jp/genet/picts/dna.jpg
So in RNA:
• Cytosine pairs with Guanine
• Adenine pairs with Uracil
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RNARNA There are 3 different types of RNA:There are 3 different types of RNA: Messenger RNA (mRNA)Messenger RNA (mRNA) – copies and carries – copies and carries
the genetic code from the DNA in the nucleus the genetic code from the DNA in the nucleus to the ribosomesto the ribosomes
Ribosomal RNA (rRNA)Ribosomal RNA (rRNA) – makes up – makes up ribosomes which are responsible for ribosomes which are responsible for assembling the proteins according to the assembling the proteins according to the instructions on mRNAinstructions on mRNA
Transfer RNA (tRNA)Transfer RNA (tRNA) – molecules which – molecules which carry the amino acids to the ribosomes carry the amino acids to the ribosomes where they are used to construct the proteinwhere they are used to construct the protein
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Where do you find RNA?Where do you find RNA?All mature cells contain RNA All mature cells contain RNA
RNA is found in the nucleus as messenger RNARNA is found in the nucleus as messenger RNAIn the ribosomes as ribosomal RNAIn the ribosomes as ribosomal RNA
In the cytoplasm as transfer RNA and messenger RNAIn the cytoplasm as transfer RNA and messenger RNA
Nucleus
Source: Source: http://www.tokyo-med.ac.jp/genet/picts/cell-e.jpghttp://www.tokyo-med.ac.jp/genet/picts/cell-e.jpg
Ribosomes
Cytoplasm
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Protein ProductionProtein Production1. 1. Transcription:Transcription: DNA code on DNA code on genes copied genes copied to mRNA to mRNA templatetemplate2. mRNA is 2. mRNA is able to pass able to pass through through nuclear pores nuclear pores and travel to and travel to ribosomesribosomes3. Translation:3. Translation: Amino acids Amino acids are carried to are carried to the ribosomes the ribosomes by tRNA where by tRNA where they are they are assembled into assembled into a polypeptide a polypeptide chain chain according to according to the mRNA the mRNA sequencesequence
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Protein ModificationProtein Modification4. Bending and 4. Bending and folding: The folding: The polypeptide is polypeptide is then able to then able to enter the RER enter the RER where it is where it is folded, bended folded, bended and further and further modified. modified. Small parts of Small parts of RER RER containing the containing the protein then protein then pinch off, pinch off, forming forming vesicles which vesicles which then travel to then travel to the Golgi Body the Golgi Body
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Protein ExportProtein Export5. Finishing 5. Finishing touches: In the touches: In the Golgi body, the Golgi body, the protein may be protein may be further modifiedfurther modified
6. Export: Part of 6. Export: Part of the Golgi body the Golgi body containing the containing the finished product finished product will then pinch will then pinch off, forming a off, forming a vesicle which is vesicle which is transported to transported to the cell the cell membrane where membrane where it fuses with the it fuses with the membrane and membrane and expels its expels its contents outside contents outside the cell. This is the cell. This is called exocytosis.called exocytosis.
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SummarySummary
DNADNA RNARNA
Double Stranded, Double Stranded, helicalhelical
Single stranded, 3 Single stranded, 3 different forms – different forms – mRNA, rRNA, rRNAmRNA, rRNA, rRNA
Nucleotides: C, G, A, TNucleotides: C, G, A, T Nucleotides: C, G, A, UNucleotides: C, G, A, U
Sugar: DeoxyriboseSugar: Deoxyribose Sugar: RiboseSugar: Ribose
Function: Carries code Function: Carries code for protein productionfor protein production
Function: Assembles Function: Assembles proteins using DNA proteins using DNA codecode