Transcript Viruses - mrkeay

VIRUSES
LESSON OBJECTIVES
 Learning Goals
 Yesterday’s Recap
 Minds ON
 Virus Lesson (Specifics and Clips)
LEARNING GOALS
 We are / will be learning to…
 Analyze the risks and benefits of human intervention (e.g. pesticide use, fish stocking, tree planting, etc.)
 Analyze how climate change could impact the diversity of living things (e.g. Global warming, increase in
precipitation)
 Become familiar with terms such as: species diversity, structural diversity, bacteria, fungi, binomial
nomenclature, morphology
 Classify, apply, and draw dichotomous keys to identify and classify organisms according to kingdom
 Explain concepts of taxonomic rank such as genus, species and taxon
 Compare/contrast characteristics of prokaryotes, eukaryotes and viruses
 Compare/contrast anatomical and physiological characteristics of organisms representative of each kingdom
 Explain structural and functional changes of organisms as they have evolved over time
 Explain why biodiversity is important for maintaining viable ecosystems
YESTERDAY’S RECAP
 Bacteria
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Characteristics: single cell, prokaryote, anatomy
Shapes and groupings
Gram Staining (Gram +, Gram -)
Cell Movement: Flagellum, Cilia, Non-Motile
Bacterial Respiration: Aerobic, anaerobic, obligate aerobe, obligate
anaerobe, facultative anaerobes
Bacteria Metabolism: autotroph, heterotroph, chemotroph
Bacteria terms
Reproduction of bacteria: binary fission, spores, conjugation
Characteristics: Archaebacteria, eubacteria
MINDS ON
 News article
http://www.theglobeandmail.com/report-on-business/cfia-probes-
link-between-feed-and-pig-virus/article16791906/
 Cell Phones
http://www.youtube.com/watch?v=4lmwbBzClAc&feature=related
WHAT IS A VIRUS?
 Latin: toxin, poison
 a microscopic organism consisting of genetic material
(RNA or DNA) surrounded by a protein, lipid (fat), or
glycoprotein coat.
 Exists between living and non-living (lacks characteristics
of six Kingdoms)
 Parasitic existence
Source: Medical News Today
EXAMPLES OF VIRUSES
 Measles, also known as Rubeola or morbilli, is a highly infectious illness caused
by a virus - a viral infection caused by the rubeola virus
 AIDS (Acquired immune deficiency syndrome or acquired immunodeficiency
syndrome) is a disease caused by a virus called HIV (Human Immunodeficiency
Virus). The illness alters the immune system. This susceptibility worsens as the
disease progresses.
 SARS stands for Severe Acute Respiratory Syndrome. It is a contagious disease
that is caused by the SARS Coronavirus (SARS CoV) and typically leads to a
potentially fatal form of pneumonia.
Source: Medical News Today
CHARACTERISTICS OF A
VIRUS
 Size: 20-400 nm(nanometers)
 Make: Mostly of nucleic acid and capsid
• Capsid: Protein covering (made of hundreds of
protein molecules); makes up 95% of virus
• Nucleic acid: Single strand of DNA or RNA
VIRUS SHAPES
Bacteriophage: most complex and largest ; attack and infect bacteria
VIRUS SPECIFICITY
Viruses must enter cells to carry out life
processes.
Not every virus is considered to be diseasecausing.
Viruses are generally selective, and in most cases,
specific viruses enter only specific host cells.
VIRUS REPRODUCTION
FOUR BASIC STEPS – copy onto handout
 Attachment and entrance: Virus chemically
recognizes a host cell and attaches to it. Either the
whole virus or only its DNA or RNA material
enters the cell’s cytoplasm.
VIRUS REPRODUCTION
Synthesis of protein and nucleic acid units:
molecular information contained in the viral DNA
or RNA directs the host cell in replicating viral
components (nucleic acids, enzymes, caspid
proteins, and other viral proteins)
VIRUS REPRODUCTION
 Assembly of the units: The viral nucleic acids,
enzymes, and proteins are brought together and
assembled into new virus particles.
VIRUS REPRODUCTION
Release of new virus particles: newly formed
virus particles are released from the infected cell and
the host cell dies.
TWO REPRODUCTIVE
CYCLES
Depending on the type of virus, virus reproduction can occur two ways:
 Lytic Cycle – host cell bursts
http://www.youtube.com/watch?v=Rpj0emEGShQ
 Lysogenic Cycle – virus waits before hijacking cell; cell multiplies
http://www.youtube.com/watch?v=_J9-xKitsd0
CULTURE LAB
We will be completing a lab in which we culture
bacteria from various objects around Adam Scott
Lab due on Tuesday, February 18th.
This lab will be mostly formal---more info to
come.
EXIT CARD
What Kingdom does algae belong to?
How is it not Plantae (list
characteristics)?