Name ______Test Date______
UNIT XI–VIRUSES &CLASSIFICATION
I. VIRUSES
- Living or non-living?
- Lack a ______
- Do not contain ______for ______
- Lack ______for protein synthesis
- DO contain ______
- ______, although they require a ______cell
- Typically referred to as a ______or ______.
A. Structure of Viruses
The following structures are found in all viruses:
- Genetic Material – The genome of a virus may be either ______or______, but never both. It can be ______stranded or ______stranded, ______or ______.
- Protein Coat – The DNA or RNA is surrounded by a protein coat called a capsid. The proteins making up the capsid are known as ______and play an important role in the ______of the virus. In addition, the capsid has ______ID tags known as ______which can ______to enable the virus to escape detection by a host cell’s immune system.
The following additional structures may be present:
- Viral Envelope – Many viruses have an outer membrane known as an envelope. A viral particle “steals” the components for its envelope from the host cell membrane, so a viral envelope is primarily composed of ______. It aids in the attachment of the virus to the host cell, but a virus enclosed by an envelope is also more sensitive to ______. Examples of viruses with envelopes are ______.
- Tail Fibers – Viruses that infect ______are known as ______. They have “tail fibers” to aid in attachment.
B. Host Range
The host range of a virus is the range of host cells that it can infect. It is based on a complementary fit between viral
______and receptor ______on the host cell membrane.
- Some viruses have broad host ranges which can include several species; for example, swine flu and rabies
- Some viruses have narrow host ranges where they infect only a single species; for example, the ______that attacks E. coli.
- Some viruses only infect a particular type of tissue or cell within a single species; for example the human cold virus infects only cells of the ______; HIV binds to receptors on certain ______.
C. Viral Replication
A virus can infect a host cell and use it for reproduction in two ways:
- Lytic Infection – ______cycle in which virus ______host cell DNA. Examples are ______
- Lysogenic Infection – ______cycle in which viral DNA is incorporated into ______
______. Examples are ______.
There are twoinitial steps that are common to all types of viral infections:
1)Virus attaches to ______of ______cell.
2)Virus releases ______into cell, either by ______
cell or ______genetic material into it.
…………………………………………………………………………………………………………………………………………………
D. Viruses and Disease
All viruses are ______, meaning they require a living host and they cause harm to that host.
1. Herpesvirus– Group of viruses that are ______and have many forms. Results in lifelong infections, although
virus can move back and forth from ______to ______cycle. Group includes viruses that cause
cold sores, chicken pox, genital warts, shingles, and mononucleosis.
2. HIV - ___________ – Affects ______blood cells and immune system.
The HIV virus is a ______. Retroviruses contain ______and the enzyme, ______
which allows the viral RNA to be ______into ______. Initial symptoms are flu-like, then
virusenters ______cycle and replicates in lymph nodes, sometimes for years. When the HIV virus
becomesactive, it causes ______- Acquired ImmunoDeficiency Syndrome. Death of the patient results from
______.
3. Human Papilloma Virus – Diverse group of DNA viruses; common cause of skin warts. Danger comes from group of sexually-
transmitted HPV which can cause genital warts, but more seriously, ______. Controversial
______has been produced; effective against most types of sexually-transmitted HPV.
4. Other viral diseases – hepatitis, influenza, smallpox, measles, common cold, rabies, Ebola
II. BIOLOGICAL CLASSIFICATION
Classification is the ______.
Scientistsclassifyorganisms to ______
______.
The branchofbiology concerned with the grouping and naming of organisms is called ______.
Taxonomy utilizes______relationships between organisms to correctly identify and group them.
A. Early Taxonomists
1. Aristotle – first taxonomist; organized living things into ______& ______. Subdivided
according to their ______.
2. John Ray - a ______; first used ______for naming organisms.
3. Carolus Linnaeus – classified organisms according to their ______; called the “Father of Taxonomy”;
developed the modern system of naming known as ______. Binomial
nomenclature is the universal classification system used today in which groups are formed according to
______and then each organism is assigned a 2-word scientific name. The scientific
name is the ______and ______of the organism. The genus and species names are always
______or written in ______. ______is capitalized, ______is not.
B. Categories of Classification
1. Kingdom – broadest category, groups of closely related ______
2. Phylum – groups of closely related ______
3. Class – groups of closely related ______
4. Order – groups of closely related ______
5. Family – groups of closely related ______
6. Genus – groups of closely related ______
7. species - ______and most similar group; organisms that share specific
characteristics and can ______.
C. Scientific Classification of a Human
Kingdom ______
Phylum ______
Class ______
Order ______
Family ______
Genus ______
species ______
III. THE EVOLUTION OF CLASSIFICATION
______, the science of classification, is a work in progress, in large part, because of evolution, both
asascience and a process.
A. Evolution As A Science – As the study of evolution becomes more sophisticated due to DNA sequencing, scientists are
realizingthat organisms, or entire groups of organisms, have been ______
1. The Kingdoms of Life
DNA analysis has had a major impact on the classification system, changing the long accepted system of 5 kingdoms to
______kingdoms. The two prokaryotic kingdoms, ______and
______were originally classified together as Kingdom ______.
2. The Three Domains of Life
Recently, further studies have led taxonomists to propose a classification system which includes three “super-kingdoms”
called ______.
a. Domain Archaea – Includes the ______
b. Domain Bacteria – Includes all remaining prokaryotes or the ______
c. Domain Eukarya – Includes the four eukaryotic kingdoms - ______
IV. THE SIX KINGDOMS OF LIFE
A. Kingdom Archaebacteria
1. Cell Type - ______
2. Cell Structure - ______
______
3. Body Form - ______
4. Nutrition - ______
______
5. Other characteristics – considered to be the most
______of organisms; live in very
______conditions like ______
temperatures, high ______concentration, etc.
Another group of Archaebacteria live in the ______
system of animals and produce ______gas.
6. Examples - ______
______
B. Kingdom Eubacteria
1. Cell Type - ______
2. Cell Structure______
______
______
3. Body Form - ______
4. Nutrition – Mostly ______; some are ______
5. Other characteristics – Most ______bacteria. They are ubiquitous which means they are ______.
Very important ______. Some are ______, but most are ______.
6. Examples - ______
C. Kingdom Protista
1. Cell Type - ______
2. Cell Structure – May have ______;
may have ______; may be
______and have
______or
______.
3. Body Form – Mostly ______;
may be ______
4. Nutrition - ______
______
5. Other Characteristics – Nicknamed “ ______” kingdom or “______”.
Contains______that don’t “fit” into other kingdoms. Protists aresub-grouped according to which
______kingdomthey’re most like; for example, ______-like, ______-like,
or ______-like.
6. Examples - ______
D. Kingdom Fungi
1. Cell Type - ______
2. Cell Structure – Have ______made of ______. Fungi do NOT have______.
3. Body Form – Mostly ______; may be ______. Single-
celled fungi are known as ______.
4. Nutrition – All ______! Obtain nutrients through a process called ______,
meaning food is digested ______by secretion of ______, then absorbed by
fungi.
5. Other Characteristics – Principle ______. Also important in ______and______.
6. Examples - ______
E. Kingdom Plantae
1. Cell Type - ______
2. Cell Structure – Have ______made of
______; ______present.
3. Body Form – All ______
4. Nutrition – All ______
5. Other Characteristics – Most contain ______
and ______. All
______with specialized
______structures.
6. Examples - ______
______
F. Kingdom Animalia
1. Cell Type - ______
2. Cell Structure – Never have ______
______
3. Body Form – All ______
4. Nutrition – All ______
5. Other Characteristics – Most
______of all kingdoms.
Most organisms contain ______
and______. All
membersare capable of ______
sometime during their lifetime.
Most animals are ______
meaning they ______a backbone. All
vertebrates belong to Phylum
______
6. Examples - ______
______
______