Name: _________________________________________________ Date: _______________ Period: ________ Biology Notes: Viruses Directions: Fill in the blanks as we cover the topic in the PowerPoint. Corresponds to textbook pages 544 ‐ 551 What is a virus? Additional Info
• Virus: A biological _________________ composed of ________________________ and _______________. • Intracellular Parasites: organism that _______________ “live” inside a _________________ Are viruses alive? (these are some reasons for both arguments) • YES – __________________ – Have ________________ ________________ (genetic material) – __________________ to surroundings – Have __________________ • NO – __________________ made of _________________ or __________________ – __________________ reproduce on __________________ – Don’t metabolize __________________ – Don’t __________________ cellular__________________ Virus Parts • All Have: – 1) Capsid: coat of ________________ that surrounds ________________________________. – 2) Nucleic Acid: _______________ or ________________ • Some Have: – Tail Fibers: Used for _____________________ (___________ legs) – Shape & size __________________ Viral Replication – Bacteriophages AKA phages (__________________ that attack ________________) are often studied – Replication is __________________ with many animal viruses – Two “life” cycles: __________________ & __________________ The Lytic Cycle • 1st Step: Attachment •
•
–
Virus __________________ on cell __________________ –
Virus __________________ to a cell _______________ –
Virus acts as __________________; __________________ acts as __________________ –
No attachment = No __________________ 2nd Step: Entry –
Virus enzyme ________________ cell __________________ –
Genetic material (__________________or __________________) _______________ host cell 3rd Step: Replication –
–
Virus DNA/RNA uses __________________ to make ________________ proteins Virus ________________ created by ______________________________________________________ –
•
4th Step: Assembly •
•
Viral DNA ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐> Viral RNA ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐> Proteins ________________ virus proteins are assembled in the cell’s ________________ 5th Step: Release –
Virus enzyme causes cell membrane _________________ (burst) –
Viruses are ________________ to find new ________________ –
Cycle repeats Lysogenic Cycle: • 1st step: Attachment = Same as _________________ cycle •
•
Virus lands on cell membrane. Virus attaches to a cell receptor. 2nd Step: Entry = Same as _________________ cycle -
Virus enzyme weakens cell membrane -
Genetic material (DNA or RNA) enters host cell 3rd step: Replication –
_________________ created (it is called a PROPHAGE for Bacteriaphages) –
______________________ combines with cell _____________________ = ___________________! Draw them combined: –
Infected cell _______________ by _______________ and copies the ________________ –
Each _______________ cell will contain the ________________ –
Provirus remains ___________________ (until next step) •
4th Step: Assembly: Same except, many new _______________ are assembled in _______________cells. •
5th Step: Release: Same except, many cells ________________, releasing _______________ more viruses. Retrovirus • Type of __________ virus • Contain enzyme called “_____________________________” • Steps – 1) Virus RNA ___________ host cell – 2) _______________ transcription changes the virus ________ into ________ – 3) Virus DNA ___________ with ________l DNA (___________ created) • Viral DNA lays _____________ – 4) Infected cell _________________ and _________________ the virus – 5) Eventually, the _________________ DNA becomes _________________ in _____________ cells • Viral ________  Viral ________  Viral ______________ How is HIV Contracted? • High risk activities: • Low risk activities: – 1) Sex – 3) ___________ to__________ in ________ (__________,___________, ________) – 4) ___________________ milk – 2) Sharing needles – 5) Blood __________________________ (___________,___________,________) HIV Prevention • 100% Effective: _______________ (not participating in sexual ____________) • If sexually active: ________________ condoms are the only forms of _______________ control that prevent _________________ and ____________________ • If drug user: _______________ needles What is AIDS? • A___________________ I____________________ D___________________ S___________________ • AIDS results when: – 1) Amount of ______________ drop (below __________ T‐cells per ____mm³ blood) – 2) Multiple ____________________/infections appear • _________________, fever, headache, sore throat, ______________________________ • Therefore, the ___________ virus __________________ the ____________________ AIDS by killing your ____________________ Review 1) Circle the correct answer to the statement: True or False All viruses have a capsid, nucleic acid, and tail fibers. 2) List 3 reasons why viruses may be living: Nonliving: 1. _______________________________________ 1. _______________________________________ 2. _______________________________________ 2. _______________________________________ 3. _______________________________________ 3. _______________________________________
3) What is the virus capsid made from? _________________________________________________________ 4) What type of organism do phages infect? _____________________________________________________ 5) In order list the stages of the lytic and lysogenic cycles: _______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
_______________________________________
6) In which stage… - Does the host cell explode? _____________________ - Are virus proteins built to make new viruses? ______________________________________ - Is a provirus created? _________________________ - Does a virus connect with the host cell’s receptors? ______________________________ 7) Which two objects make up a provirus? ______________________________________________________ 8) Which virus “life” cycle is considered the most harmful? Why? ____________________________________ _______________________________________________________________________________________ 9) Place the following steps of the lytic cycle in order (#1 = First) – this question isn’t on the PowerPoint. 10) Name the enzyme found within retroviruses: ___________________________________________ 11) The picture shows the normal steps of protein synthesis. Fill in the question marks with the words: Translation, Protein, Transcription, DNA 12) The picture below shows the steps of a retrovirus. Fill in the question marks with the words: viral DNA, transcription, translation, reverse transcription, cell DNA