BioTech #3
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Transcript of BioTech #3
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
M I C R O B I O L O G Ya n i n t r o d u c t i o n
ninth edition TORTORA FUNKE CASE
Part A8Microbial Genetics
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Genetics: The study of what genes are, how they carry
information, how information is expressed, and how
genes are replicated.
Gene: A segment of DNA that encodes a functional
product, usually a protein.
Terminology
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Genome: All of the genetic material in a cell
Genomics: The molecular study of genomes
Genotype: The genes of an organism
Phenotype: Expression of the genes
Terminology
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Chromosome Map
Figure 8.1b
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Flow of Genetic Information
Figure 8.2
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
DNA
Polymer of nucleotides: Adenine,
thymine, cytosine, and guanine
Double helix associated with
proteins
"Backbone" is deoxyribose-
phosphate
Strands are held together by
hydrogen bonds between AT and
CG.
Strands are antiparallel.
Figure 8.3b
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
DNA
DNA is copied by DNA polymerase
In the 5' → 3' direction
Initiated by an RNA primer
Leading strand is synthesized continuously
Lagging strand is synthesized discontinuously
Okazaki fragments
RNA primers are removed and Okazaki fragments
joined by a DNA polymerase and DNA ligase
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Important Enzymes
Table 8.1
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
DNA Replication
Figure 8.5
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
DNA
DNA replication is semiconservative.
Figure 8.6
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Transcription
DNA is transcribed to make RNA (mRNA, tRNA, and
rRNA).
Transcription begins when RNA polymerase binds to
the promotor sequence
Transcription proceeds in the 5' → 3' direction
Transcription stops when it reaches the
terminator sequence
PLAY Animation: DNA Replication
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Transcription
Figure 8.7 (1 of 2)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Transcription
PLAY Animation:Transcription
Figure 8.7 (2 of 2)