Chargaffs rule states DNA of any species contains equal amounts of guanine and cytosine and also equal amounts of adenine and thymine This pattern is found in both strands of the DNA They were discovered by Austrian chemist Erwin Chargaff ID: 910491
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Transcription
Slide2Chargaff's rule
Chargaff's rule
states DNA of any species contains equal amounts of guanine and cytosine and also equal amounts of adenine and thymine.
This pattern is found in both strands of the DNA. They were discovered by Austrian chemist Erwin Chargaff
Human29.320.720.030.0
A
T
G
C
Slide3The central dogma includes three processes.
RNA is a link between DNA and proteins.
replication
transcription
translation Replication Transcription Translation24
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The central dogma states that information flows in one direction from DNA to RNA to proteins.
Slide4Transcription
Process of copying the information from DNA to RNA
Happens in the nucleus
With DNA so large and contained in the nucleus, RNA allows for a smaller more flexible form.
Slide5Transcription is catalyzed by RNA polymerase.
1. RNA polymerase and other proteins form a transcription complex.
The transcription complex recognizes the start of a gene and unwinds a segment of it.
start site
nucleotides
transcription complex
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Slide6RNA polymerase bonds the nucleotides together.
The DNA helix winds again as the gene is transcribed
.
2. Nucleotides pair with one strand of the DNA.DNA
RNA polymerase moves along the DNA
Slide73. The RNA strand detaches from the DNA once the gene is transcribed.
RNA
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Slide8Similarities between replication and transcription
Transcription and replication both involve complex enzymes and complementary base pairing.
The two processes have different end results.
Replication copiesall the DNA;transcription copiesa gene.Replication makes
one copy;transcription canmake many copies.growing RNA strandsDNAonegene