PowerPoint PresentationCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor
From PowerPoint® Lectures for Biology: Concepts & Connections
CHAPTER 10
Modules 10.1 – 10.5
Saboteurs Inside Our Cells
The invasion and damage of cells by the herpesvirus can be compared to the actions of a saboteur intent on taking over a factory
The herpesvirus hijacks the host cell’s molecules and organelles to produce new copies of the virus
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Viruses provided some of the earliest evidence that genes are made of DNA
Molecular biology studies how DNA serves as the molecular basis of heredity
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
10.1 Experiments showed that DNA is the genetic material
The Hershey-Chase experiment showed that certain viruses reprogram host cells to produce more viruses by injecting their DNA
THE STRUCTURE OF THE GENETIC MATERIAL
Head
Tail
Tail
fiber
DNA
The Hershey-Chase Experiment
labeled phages with bacteria. The phages infect the bacterial cells.
Phage
Bacterium
Radioactive
protein
DNA
Empty
1
2
Agitate in a blender to separate phages outside the bacteria from the cells and their contents.
3
Centrifuge the mixture so bacteria form a pellet at the bottom of the test tube.
4
Batch 1
Phage reproductive cycle
Phage injects DNA.
Phage DNA directs host cell to make more phage DNA and protein parts. New phages assemble.
Cell lyses and releases new phages.
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10.2 DNA and RNA are polymers of nucleotides
DNA is a nucleic acid, made of long chains of nucleotides
Figure 10.2A
Thymine (T)
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DNA has four kinds of bases, A, T, C, and G
Figure 10.2B
RNA is also a nucleic acid
RNA has a slightly different sugar
RNA has U instead of T
Figure 10.2C, D
Uracil (U)
10.3 DNA is a double-stranded helix
James Watson and Francis Crick worked out the three-dimensional structure of DNA, based on work by Rosalind Franklin
Figure 10.3A, B
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The structure of DNA consists of two polynucleotide strands wrapped around each other in a double helix
Figure 10.3C
Hydrogen bonds between bases hold the strands together
Each base pairs with a complementary partner
A pairs with T
G pairs with C
Three representations of DNA
10.4 DNA replication depends on specific base pairing
In DNA replication, the strands separate
Enzymes use each strand as a template to assemble the new strands
DNA REPLICATION
Parental molecule
of DNA
Figure 10.4A
Untwisting and replication of DNA
Figure 10.4B
10.5 DNA replication: A closer look
DNA replication begins at specific sites
Figure 10.5A
Parental strand
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Each strand of the double helix is oriented in the opposite direction
Figure 10.5B
5 end
3 end
3 end
5 end
How DNA daughter strands are synthesized
5 end