BIO 14 - Virus Flashcards
VIRUSES
- have no ____, ____, ___, or ____
- cannot carry out _____ ____
- process of replication?
- size?
- consist of 2 parts?
- what type of nucleic acid?
- no nucleus, cytoplasm, organelles, or cell membrane
- cellular functions
- infection host cells and using their organelles and enzymes
- 20 nm - 250 nm
- nucleic acid & protein coat (capsid)
- may be DNA or RNA but not both
Some viruses have a ____ -like structure outside the ____ called an ___
- it is made of an ___ ____ layer and an ___ ___ layer
- membrane-like
- capside
ENVELOPE
- outer lipid
- inner protein
3 cell theory
- all living things are made of cells
- all cells come from pre-existing cells
- cells carry out energy flow necessary for life (respiration, photosynthesis, enzyme reactions)
INFLUENZA VIRUS
- 4 main parts
- Envelope
- ssRNA (8 strands)
- Capsid
- Projections (for recognition and attachment)
Most viruses contain ___ as genetic material, but some contain ___ instead
DNA
RNA
the ____ in a capsid are determined by the ____ in the virus
- proteins
- genes
HIV VIRUS
- 5 parts
- Envelope
- Capsid
- Reverse Transcriptase
- RNA genome
- Glycoprotein
Why is the HIV virus only transmitted through certain fluids?
HIV virus is concentrated in an infected person’s fluids like genital, blood, and breast milk
- primarily infects CD4+ T cells, which are commonly present in stated fluids
- other bodily fluids (saliva, sweat, and urine) contain enzymes that may destroy the virus
Other examples of viruses (3)
- Tobacco Mosaic Virus
- Polio Virus (simplest)
- Bacteriophage (most complicated)
The _______ the structure of the virus, the easier to create vaccines
- simpler
SARS-CoV 2
- full name
- 5 parts
- which are considered as MAJOR STRUCTURAL PROTEINS
- Severe acute respiratory syndrome coronavirus 2
- Spike Glycoprotein (S) *
- Membrane Protein (M) *
- Envelope Glycoprotein (E) *
- Nucleocapsid protein (N)
- Lipid bilayer
SARS-CoV 2 - S
- required for the ___ of the ____ _____ ____
- entry
- infectious virion
- particle
SARS-CoV 2 - M
- most ____ viral ____
- abundant
- protein
SARS-CoV 2 - E
- the ___ among the major structural proteins
smallest
SARS-CoV 2 - N
_____-stranded _____ sense ____ genome
- single
- positive
- RNA
4 steps in VIRUS INVASION
- Attachment of virus to host cell
- Injection of viralDNA
- Integration of the viral DNA into host genome
- Multiplication of the host cell with the viral DNA
HIV is a type of _____ virus that uses ____ as its genetic material and, upon entering a ___ cell, uses an ____ called ____ ____ to convert its ____ into ____, which is then _____ into the ___ cell’s ____
- retrovirus
- RNA
- host cell,
- an enzyme called reverse transcriptase
- RNA into DNA
- integrated
- host cell’s DNA
HIV - INVASION TO HOST CELL
5 steps
- HIV attaches to the cell
surface - Virus core enters host cell and its RNA is converted to DNA (reverse transcription)
- Viral DNA enters nucleus and combines with host cell DNA
- RNA copies of virus are made (viral assembly)
- The assembled viral particles leave the cell through lysis or budding.
Analysis of viral ____ ___ suggests viruses _____ ____ _____ from a _____ common _____
- genetic material
- DO NOT COME
- single common ancestor
ORIGIN OF VIRUSES
3 main hypothesis + 3 other hypothesis
MAIN
1. Devolution
2. Escapist
3. Self-Replication
OTHER
1. Virus-first
2. Escape
3. Reduction
VIRUS ORIGIN - DEVOLUTION
- other term
- states that ____ ancestors were _____ organisms similar to ____
- evolved into ____ ____ that lost _____ components for ______ _____
REGRESSION
- viral
- cellular
- bacteria
- obligate parasites
- cellular
- reproduction efficiency
VIRUS ORIGIN - ESCAPIST
- other term
- states that _____ ____ from a ____ ____ (____ - ____) cell “____” wrapped in a _____ ____
- explains ____-_____ _____ meaning that viruses are able to ____ and ___ ____ host because they ____ ___ them
PROGRESSIVE
- genetic material
- free living (non-parasitic)
- “escaped”
- protein coat
- viral-host specifity
- attack and take over
- came from
VIRUS ORIGIN - SELF-REPLICATION
- other term
- particles with the ability to ___-_____ ____ alongside the _____
- as new ____ types ___, new ____ that could ____ that cell _____ as well
- states that viruses came from ____ ____: a.) pool of _____ -> ______ -> _______ -> ______
CO-EVOLUTION
- self-replicate evolved
- cells
- cell
- evolved
- viruses
- target
- evolved
- complex polymers: nucleotides -> polynucleotides -> self-replicating RNA -> biomolecules
VIRUS ORIGIN - VIRUS-FIRST HYPOTHESIS
- stated that at dawn of life, there were ___ ____ ___ but only first _____ ____ possessing _____ ____ and capable of ____ ____
- other term
- no cellular forms
- RNA molecules
- enzymatic activities
- self-replication
- selfish genetic elements
VIRUS ORIGIN - ESCAPE HYPOTHESIS
- stated that viruses derived from ____ ____ or/and ____ fragments such as ____ and ______
- during ____ cell _____, a _____ could have _____ engulfing a….(2)?
- cellular RNA/DNA
- plasmids and transpozons
- asymmetrical cell fission
- vesicle could have formed
1. self-replicating DNA
2. coat encoding RNA segment
what is a VESICLE
smaller cell-like entity
VIRUS ORIGIN - REDUCTION HYPOTHESIS
- underline a possible involvement of viruses in ______
- states that viruses might have descended from ____
- eukaryogenesis
- LUCA
what is EUKARYOGENESIS
the evolutionary process by which eukaryotic cells emerged from ancestral prokaryotic cells
what is LUCA
Last Universal Common Ancestor
the single-celled microorganism hypothetical ancestor from which all known life on Earth is believed to have descended
why do VIRUSES mutate?
- errors in gene replicate due to environmental conditions or introduction of vaccines in order to survive
- thus vaccines can be less effective over time
- but take note that viruses may evolve to non-existence due to mutation
WHAT is the process of naming viruses and placing them into a taxonomic system
VIRUS CLASSIFICATION
2 basis for CLASSIFICATION OF VIRUSES
- Phenotypic Characteristics (4)
- morphology
- nucleic acid
- mode of replication
- hsot organism - Disease caused
2 main schemes for classification of viruses
- International Committee on Taxonomy of Viruses (ICTV)
- Baltimore Classification System
HOW ARE viruses named?
Host - Symptom - “virus”
ICTV
- original name
- the ONLY body charged by the??
- with what tasks (3)?
- how does it differ from nomenclature of living organisms (2)?
- International Committee on the Nomenclature of Viruses
- International Union of Microbiological Societies
- developing
- refining
- and maintaining a universal virus taxonomy
a.) order until species is ITALICIZED
b.) language is ENGLISH
ICTV
- adopted the principle that a “____ species is a ____ class of _____ that ____ a _____ ___ and ____ a ____ ____ ___”
” A virus species is a POLYTHETIC class of viruses that constitutes a replicating lineage and occupies a particular ecological niche”
ICTV PRINCIPLE - definitions
- Polythetic
- Replicating Lineage
- Occupation of an ecological niche
- a class whose members always have several properties in common although NO SINGLE COMMON attribute is present in all members
- members of a species experience EVOLUTION OVER TIME with CONSEQUENCE VARIATION but still share a common ancestor
- acknowledges that the BIOLOGY OF A VIRUS are fundamental components of the CHARACTERIZATION of a virus
What taxonomic category is added to viruses?
realm
6 realms of viruses
- Riboviria
- Monodnaviria
- Duplodnaviria
- Varidnaviria
- Adnaviria
- Ribozyviria
BALTIMORE CLASSIFICATION
- places viruses in how many groups?
- that are dependent on (4)? and designated by ____ ____
- named after?
- 7 groups
- nucleic acid type (DNA or RNA)
- strandedness (single or double)
- sense (+ or -)
- method of replication
- Roman Numerals
- David Baltimore
SENSE STRAND vs ANTISENSE STRAND
- transcribed or not into RNA
- nucleotide sequence
- contains codons or anti-codons
- bonds between it and the synthesizing RNA
+ (sense strand)
- not transcribed
- same nucleotide sequence as mRNA except thymine
- codons
- no hydrogen bonds
-
- transcribed (antisense)
- complementary nucleotide sequence to mRNA
- anti-codons
- hydrogen bonded
BALTIMORE CLASSIFICTION - 7 groups
I : dsDNA
II : ssDNA
III : dsRNA
IV : +ssRNA
V : -ssRNA
VI : ssRNA-RT
VII : dsDNA-RT
