Pick up a book (pg 338) and present trp operon with your team

Viruses & the Lytic Cycle Biolog everl Y

What is a Virus? Virus: A biological particle composed of nucleic acid and protein Intracellular Parasites: organism that must use a host cell to reproduce

Kingdom of Life?

Are Viruses Alive? Cellular Respiration Photosynthesis Transcription No Not made of cells or organelles Can’t reproduce without host Don’t metabolize energy Don’t perform cellular processes Yes Replication Transcription Active Transport Translation Cellular Respiration Photosynthesis

Are Viruses Alive? No Not made of cells or organelles Can’t reproduce without host Don’t metabolize energy Don’t perform cellular processes Yes Replicate Have nucleic acid Adapt to surroundings Have organization

Virus Structure Tail fibers Shape & size varies All Have: Some Have: 1) Capsid: coat of protein that surrounds nucleic acid 2) Nucleic Acid: RNA or DNA Some Have: Tail Fibers: Used for attachment (not legs)

Viral Replication Bacteriophages (viruses that attack bacteria) are often studied Replication is similar with many animal viruses Two “life” cycles: Lytic & Lysogenic

Lytic Cycle 1st Step: Attachment Virus lands on cell membrane Viral nucleic acid Capsid RNA DNA ribosome receptor 1st Step: Attachment Virus lands on cell membrane Virus attaches to a cell receptor Virus acts as key; receptor acts as lock

Lytic Cycle 2nd Step: Entry DNA/RNA enters the host cell Viral nucleic acid Capsid RNA DNA ribosome 2nd Step: Entry DNA/RNA enters the host cell DNA/RNA injected DNA/RNA swallowed by the cell

Lytic Cycle 2nd Step: Entry DNA/RNA enters the host cell Viral nucleic acid Capsid RNA DNA ribosome 2nd Step: Entry DNA/RNA enters the host cell DNA/RNA injected DNA/RNA swallowed by the cell

Lytic Cycle 2nd Step: Entry DNA/RNA enters the host cell Viral nucleic acid Capsid RNA DNA ribosome 2nd Step: Entry DNA/RNA enters the host cell DNA/RNA injected DNA/RNA swallowed by the cell

Lytic Cycle 3rd Step: Replication DNA Replication Translation Viral nucleic acid Capsid RNA DNA ribosome DNA Replication Process of creating additional copies of DNA DNA polymerase Transcription Process of creating RNA RNA polymerase Translation Process of creating proteins Performed by ribosomes 3rd Step: Replication Virus DNA performs replication to make more viral DNA Virus DNA/RNA uses ribosomes to make virus proteins Virus proteins created by transcription/translation

Lytic Cycle 4th Step: Assembly Viral nucleic acid Capsid RNA DNA ribosome 4th Step: Assembly New viruses self-assemble in the cytoplasm

Lytic Cycle 5th Step: Release Viral nucleic acid Capsid RNA DNA ribosome 5th Step: Release Virus enzyme causes cell membrane to lyse (burst) Viruses are released Cycle repeats

Lytic Cycle 5th Step: Release Viral nucleic acid Capsid RNA DNA ribosome receptor 5th Step: Release Virus enzyme causes cell membrane to lyse (burst) Viruses are released Cycle repeats

Lysogenic Cycle

Compare and contrast the lytic and lysogenic cycles

In order list the stages of the lytic cycle. Review In order list the stages of the lytic cycle. In order list the stages of the lysogenic cycle.

Transcription/Translation Lab Activity

3A1 Quiz

Genes Segments of DNA that are the codes for certain characteristics