BIOL 310: Exam 2
48 Cards in this Set
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what is a "virus"?
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a noncellular particle that must infect a host cell, where it reproduces
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what is a "virion"?
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virus particle that contains an infective nucleic acid
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what is a "capsid"?
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a protective shell made of protein
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what is a "viroid"?
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infectious naked nucleic acid that is not part of the virus
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what is a "prion"?
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infectious agent that causes the CJ virus (mad cow)
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what are the 2 types of symmetrical virus particle structures?
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icosahedral
filamentous
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what are the 3 types of axis in icosahedral capsid symmetry?
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twofold
fivefold
threefold
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can viruses have complex multipart structures?
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yes
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what are the 7 Baltimore Classification groups?
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group 1 - DS-DNA
group 2 - SS-DNA
group 3 - DS-RNA
group 4 - SS (+) positive sense RNA
group 5 - SS (-) negative sense RNA
group 6 - retrovirus
group 7 - pararetrovirus
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what is an "ortholog"?
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a gene that is present in two different species that encodes the same function
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what are the 4 things that all viruses need for host infection?
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attach to a host cell receptor that the virus can use
genome entry
assembly of virions
exit the cell
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what do bacteriophages utilize to attach to the appropriate host cell?
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integral protein
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what are the 3 main types of bactertiophage reproductive cycles?
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lytic
lysogenic
slow release
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what is an example of a bacterial defense mechanism against bacteriophage infection?
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CRISPR
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what are the three types of horizontal gene transfer?
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conjugation
transformation
transduction
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what is the definition of "serovar"?
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strain
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what is the definition of "genes"?
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functional unit of heredity
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what is a "structural gene"?
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string of nucleotide that are going to encode for a functional RNA molecule
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what is "monocistronic"?
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makes one protein
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what is "polycistronic"?
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codes for more than one protein
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what is a "promoter region"?
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gene sequence needed to activate gene expression
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what is an "operon"?
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multiple genes that are going to code for multiple proteins, but all have the same function
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what is a "regulon"?
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gene organization
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what is a "regulatory protein"?
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protein that controls the function of the operon
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what is a "control protein"?
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a protein that stimulates or inhibits other protein function
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what is the basic chemical structure of DNA? (6)
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2 deoxy positions
4 nucleotides (ATCG)
sugar phosphate backbone
antiparallel
major/minor grooves
hydrogen bonded for stability
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what is "supercoiling"?
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adding an extra turn to the DNA helix (either + or -)
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negative supercoiling increases DNA winding? (True/False)
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False
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Twisting in the same direction of a helical turn ___ the number of twists, creating a ___ supercoil. This type of supercoil is found in ___ DNA
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increasing
positive
overwound
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twisting in the opposite direction of a helical turn ___ the number of twists, creating a ___ supercoil. This type of supercoil is found in ___ DNA
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decrease
negative
underwound (most common type of DNA)
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why would you want to change the number of supercoils
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in order for DNA to be accessible to enzymes, the DNA must be unwound
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if DNA is left-handed, the helix turns in which direction?
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counterclockwisewise
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what are topoisomerases?
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enzymes that change the surface structure of DNA
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what is the function of topoisomerase 1?
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decrease supercoiling
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what is the function of topoisomerase 2?
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increase positive supercoiling
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what are plasmids?
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a small DNA molecule within a cell that is physically separated from a chromosomal DNA
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what type of replication do plasmids undergo?
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autonomous replication
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what are the two ways in which plasmids can undergo autonomous replication?
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unidirectionally
bidirectionally
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what are the 3 known plasmid genes used in segregation?
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parC
parR
parM
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what are restriction endonucleases?
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enzymes that recognize specific base pairs and cleave phosphodiester
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what are the two types of restriction endonucleases?
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sticky
blunt
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how do bacteria cut foreign DNA and not destroy their own DNA?
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methylating enzymes
methyl groups are placed on beginning and ends of native DNA, which prevent cutting of own DNA
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what does PCR stand for?
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polymerase chain reaction
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what is required for PCR? (4)
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template DNA strand
taq polymerase
DNA primers
DNTPs (free nucleotides)
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what is a DDNTP?
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an enzyme that prevents formation of phosphodiester bonds
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what are phosphodiester bonds?
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bonds between DNA nucleotides
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what is sanger sequencing?
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similar to PCR, but uses d-deoxy groups instead of deoxy groups
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what is illumina dna sequencing?
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able to make millions of gene sequences, at one time
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BIOL 310: Chapter 10