Download BELL WORK: Explain the difference between a PROKARYOTE and

Set up today’s page in your journal…
• Page 63/64
• Date: 2-6-2017
• Title: Viral Structure
• Essential Question: How does the
structure of a virus compare to a cell?
• YES - Cornell notes, please!
Content Objective
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•
•
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BIO.4C
The student will:
compare the structures of viruses to cells,
describe viral reproduction
describe the role of viruses in causing diseases
such as human immunodeficiency virus (HIV)
and influenza.
Our new unit:
Viruses
Essential Vocabulary
Virus: a non-cellular (or acellular) pathogen
Pathogen: any disease-causing agent
Virology: the study of viruses
Virion: a viral particle (piece of a virus)
Viral components
– Genetic material (core)
• DNA or RNA
• Surrounded by the capsid
– Capsid
• “Coat” Made of proteins
• Surrounds the DNA/RNA core
– Envelope
• Made of lipids (like cell
membranes!)
• ONLY ON SOME VIRUSES
– Spikes
5
• Made of glycoproteins
• Used to attach to cells
• ONLY ON VIRUSES WITH
ENVELOPES
Viruses can be…
Naked viruses
OR…
Lack (don’t have)
envelopes
Enveloped viruses
have envelopes
So, based on what we see here. What are some
differences we see between viruses and cells?
CAPSID
DNA
RNA
RNA
CAPSID
CAPSID
ENVELOPE
Draw and Label these in your notes!
8
Cellular Organisms vs Acellular Particles
Eukaryotic Cell
Virus
A virus’s size helps it to
reproduce. We’ll talk
about this tomorrow.
Prokaryotic
Cell
If a cell was the
size of our
classroom, then
an average virus
would be the
size of a
softball.
Eukaryotic
Nucleus
1 ųm (1000 nm)
Viral Size
Specificity: viruses are highly specific to the cells
they infect
Examples:
1) plant viruses infect plant cells
2) animal viruses infect only certain
related species of animals
3) bacterial viruses (bacteriophage)
infect only certain types of bacteria.
So, what about
zombies?
- Retroviruses: contain RNA instead of DNA.
The RNA is copied backward, from RNA to DNA.
- HIV is a retrovirus you will need to know.
AZT is a medication used to treat HIV by
stopping an enzyme called reverse
Write this
transcriptase
on your
notes!
Think-Pair-Share
Are viruses alive?
(Justify your answer)
Viruses are parasites (use
other organisms to grow and
reproduce)
Viruses are NOT alive
because they do not:
a) grow and develop
b) obtain and use
energy (metabolism)
c) respond to the
environment
d) consist of cells
Vaccines
1. Viral diseases cannot be treated with antibiotics.
2. Vaccines are the best way to protect against viruses
a) A vaccine is a dead or weakened version of a
virus
b) Vaccines provide protection only if they are
used before an infection begins.
Most viruses are not harmful to humans.
1. A pathogen is a disease-causing agent.
2. Viruses cause disease by disrupting the
body’s normal equilibrium or homeostasis.
3. Viruses attack and destroy certain cells in the
body, causing the symptoms of the disease.