Warm-Up. Describe how the Hershey-Chase experiment proved that DNA is the heritable molecule of genes.

Transcription

1 Warm-Up Describe how the Hershey-Chase experiment proved that DNA is the heritable molecule of genes.

2 Yesterday s Pictures 3D χ " = $ (o e)" e

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4 DNA protein protein protein protein protein Host Cell DNA protein

5 Some viruses enter the lytic cycle, consisting of:

6 Some viruses enter the lytic cycle, consisting of: Replication of DNA and synthesis of viral proteins Make more proteins and DNA

7 Some viruses enter the lytic cycle, consisting of: Replication of DNA and synthesis of viral proteins Assembly of new viruses Make more proteins and DNA

8 Some viruses enter the lytic cycle, consisting of: Replication of DNA and synthesis of viral proteins Assembly of new viruses Lysis of host cell releasing many viral progeny. Lysis Make more proteins and DNA

9 Some viruses enter the lytic cycle, consisting of: Replication of DNA and synthesis of viral proteins Assembly of new viruses Lysis of host cell releasing many viral progeny. The lytic cycle multiplies viral populations extremely quickly. Generation ,000 Number of Viruses 2 1,000, ,000,000,000, ,000,000,000,000, 000,000,000,000

10 Some viruses enter the lytic cycle, consisting of: Replication of DNA and synthesis of viral proteins Assembly of new viruses Lysis of host cell releasing many viral progeny. The lytic cycle multiplies viral populations extremely quickly. The quicker the population increase, the quicker the evolution. * * * * * * * ** * one thousand mutations * one mutation

11 CTQ #1 Draw a virus infecting a cell with its DNA being injected in, the host cell s transcription and translation machinery producing RNA and protein, respectively, and new viruses being assembled from the proteins. Draw the cell bursting after this process is repeated many times and many viruses leaving the cell. Represent mutations on some of these new viruses to show genetic variation introduced as a result of viral replication. Title your drawing The Lytic Cycle (LO 3.30).

12 Other viruses enter the lysogenic cycle, consisting of: viral DNA Host Cell DNA

13 Other viruses enter the lysogenic cycle, consisting of: Integration of viral DNA into host cell s genome Host Cell DNA viral DNA

14 Other viruses enter the lysogenic cycle, consisting of: Integration of viral DNA into host cell s genome Host Cell DNA viral DNA

15 Other viruses enter the lysogenic cycle, consisting of: Integration of viral DNA into host cell s genome Host Cell DNA integrated viral DNA

16 Other viruses enter the lysogenic cycle, consisting of: Integration of viral DNA into host cell s genome Replication of viral DNA during host cell reproduction. interphase + mitosis

17 Other viruses enter the lysogenic cycle, consisting of: Integration of viral DNA into host cell s genome Replication of viral DNA during host cell reproduction. mrna Integrated viral DNA can be expressed, changing the phenotype of the host cell. viral proteins

18 Other viruses enter the lysogenic cycle, consisting of: Integration of viral DNA into host cell s genome Replication of viral DNA during host cell reproduction. Avery, MacCarthy and MacLeod (1944) Integrated viral DNA can be expressed, changing the phenotype of the host cell. Example: host bacteria become pathogenic (cause disease).

19 CTQ #2 Draw a virus infecting a bacterium with its DNA being injected in, and the DNA integrating into the host cell s genome. Show how the host bacterium has new properties because of the new proteins being produced. Title your drawing The Lysogenic Cycle (LO 3.30).

20 Closure Explain how viruses are able to evolve very rapidly. (LO 3.29)