MCAT BIO CH. 5 PART 1 Flashcards
What is a virus?
An obligate intracellular parasite
A vrirus can reproduce outside a cell. T/F
They are obligated to reproduce within (intra) a cell
What must occur for a virus to begin reproducing?
Commandeer the cellular machinery of the host and make copies of themselves
What is the definition of a virus to remember?
A virus is an obligate intracellular parasite that relies on host machinery whenever possible
Some viruses can store what?
ATP in their capsid
How is the viruses genome protected?
Nucleic acid genome packaged in a protein shell
A virus is inside its host cell. T/F
A virus is not inside a host cell, it contains only its genome
What type of nucleic acid do mature viruses have?
Does not contain nucleic acid other than its genome
What is a limiting factor of viral genomes? What size are viruses?
Size; small
What is a difficulty with the exterior protein shell of virus?
A rigid structure of fixed size that cannot expand to accommodate a larger genome
What is the likely result if a visa genome is tripled in size?
Viral genome will probably no longer fit within the normal viral structures
What is a bacteriophage?
Virus that infects bacteria
To adapt to size constraint, how has viruses adapted to?
Viral genomes have evolved to be extremely economical
What are the two adaptation for the viral genomes?
- Few genes
2. Encoding
What is the few genes adaptation fo viral genomes?
Viral genome to carry very few genes and for the virus to rely on host-encoded proteins for transcription, translation and replication
What is the encoding adaptation fo viral genomes?
Ability to encode more than one protein in a given length of genome
How can viral genomes encode more than one protein in a given length of genome?
Utilizing more than one reading frame within a piece of DNA so that genes may overlap with each other
What is capsid?
Protein coat surrounding the viral nucleic acid genome
What is used to classify viruses?
External morphology of the capsid
How is the capsid made?
From repeating patterns of only a few protein building blocks
How do helical capsid look? How do polyhedral capsids look like?
Helical capsids are rod-shaped
Polyhedral capsids are multiple-sided geometric
Which virus is commonly used in research and what is it?
T4 bacteriophage and its host is bacterium E. coli
What do tail fibers do for a virus?
Attach to the surface of the host cell
What do base plate do for a virus?
Attach to the surface of the host cell