Classification & Virology

Question 1

species

Answer 1

basic unit of classification

Question 2

taxonomy

Answer 2

naming and classifying of orgs

Question 3

binomical nomenclature

Answer 3

unique 2 part name (genus + specific epithet)
Rules…(1) latin (2) italics/underlined (3)Genus capitalized/abbreviated, unique (4) specific epithet lowercase, not unique

Question 4

classification

Answer 4

arranged to show evolutionary relationships and understand relationships

Question 5

phylogeny

Answer 5

evolutionary history

Question 6

systematics

Answer 6

process of class

Question 7

heirarchical classification

Answer 7

each level “down” is more exclusive; each spp at X level shares all characteristics of that level

Question 8

phylogenetic trees

Answer 8

branching diagram that represents evo history; shows patterns of descent; NOT always in line w/ pheno similarities; represents hypothesis through a series of dichotomies

Question 9

nodes

Answer 9

branch points; divergence from CA

Question 10

sister taxa

Answer 10

groups of orgs that share same immediate CA

Question 11

rooted tree

Answer 11

has one branch pnt that represents most recent CA of all taxa on tree

Question 12

basal taxon

Answer 12

lineage that diverged early; on branch near CA

Question 13

polytomy

Answer 13

evo relationships are NOT clear bc of multiple branching

Question 14

extant spp

Answer 14

currently alive at tips

Question 15

homologous

Answer 15

similar due to shared ancestry

Question 16

analogous

Answer 16

convergent evo result

Question 17

evolution

Answer 17

accumulation of genetic change over time; changes in AFs in pops not inds; NS is mechanism and acts on inds (effects variation)

Question 18

biological diversity

Answer 18

that collection of all living orgs

Question 19

tree of life

Answer 19

3 domain system of classification: Archaea, Bacteria, Eukarya (Archaea and Bacteria are prokaryotes)

Question 20

viruses

Answer 20

not alive; not on tree of life; can’t metabolize or reproduce on their own; have DNA or RNA never both; too small to be seen under light microscope; obligate intracellular parasites: must be associated w/ host, parasitic w/i host cell (+/-)

Question 21

tabacco mosaic virus (TMV)

Answer 21

infects tabacco plants; Adolf Mayer; transmitted TMV from infected plant to healthy plant

Question 22

Martinus Beijernick

Answer 22

disease “agent” was smaller than bacteria bc bacteria couldn’t pass through filter; “agent” replicates in plants; unable to grown “agent” in nutrient medium, test tube, or petri dish

Question 23

viral genetic material

Answer 23

all viruses have genetic material in form of nucleic acids; either RNA or DNA; DS or SS depending on virus type; linear, circular, or segmented genome; 3-100 genes, all info needed to replicate in HC

Question 24

capsid

Answer 24

all bacteria have this protein coat; surrounds genetic material; consists of subunits: capsomeres; may play a role in attachment; determines shape of virus

Question 25

accessory component

Answer 25

some viruses have an envelope; acquired from moving through host PM; lipid bilayer structure: host phospholipids and proteins + viral proteins and glycoproteins

Question 26

viral host range

Answer 26

usually narrow (ex: measles only affects humans) but sometimes broad (ex: West Nile affects humans, birds, horses, mosquitos); limited to particular tissues in multicellular eukaryotes (ex: cold virus affects upper respiratory system)

Question 27

viral specificity

Answer 27

need recognition btwn host cell and virus, interaction btwn viral surface proteins and specific receptor molecules on outside of HC

Question 28

viral replication

Answer 28

(1) virus binds to HC based on specificity (2) viral genome enters HC (injected, endocytosis, PM fusion) (3) viral genome directs protein production (HC takeover) (4) HC copies viral genome and produces viral proteins (5) viral NAs and capsomeres spontaneously self-assemble, new viruses, exit cell

Question 29

lytic cycle

Answer 29

bacteriophages, results in death of HC, “virulent phages”

Question 30

lytic cycle steps

Answer 30

(1) attachment (2) entry of phage DNA and degradation of host DNA (3) synthesis of viral genomes and proteins (4) self assembly: tail, head, fibers (5) release = cell lyses

Question 31

bacterial defenses

Answer 31

NS favors mutants w/o surface receptors recognized by viruses (i.e. stop step 1); restriction enzymes recognize foreign DNA and destroy it while protecting own DNA by methylation

Question 32

lysogenetic cycle

Answer 32

HC will not die (immediately), allows for replication of phage genome w/o destroying host cell, “temperate phage”

Question 33

temperate phage

Answer 33

capable of lytic and lysogenic cycle, phage lambda

Question 34

temperate phage steps

Answer 34

(1) attachment and entry (2) DNA forms and circle (3) viral genes convert host cell into factory (takeover) enters lytic cycle (3) or lysogenic viral DNA is incorporated into host chromosome (“prohage”)

Question 35

lysogenic cycle steps

Answer 35

(1) lysogenic viral DNA incorporated into host chromosomes (2) coding of viral genes for protein that prevents txn of other viral genes; since genes aren’t expressed virus doesn’t enter lytic cycle but replicated w/ host host chromo (3) eventually certain external conditions trigger lytic cycle

Question 36

cellular origin hypothesis

Answer 36

viruses are derived from bits of NAs that “escaped” from cellular orgs; ex: plasmids = circular DNA in prokaryotes (phage lambda); explains why viruses are so specific; supported by genetic similarity btwn most viruses and HCs

Question 37

coevolution hypothesis

Answer 37

viruses appeared early in the history of life before 3 domains diverged

Question 38

order of classification

Answer 38

(1) species (2) genus (3) family (4) order (5) class (6) phylum (7) kingdom (8) domain; Dear King Phillip Come Over For Good Soup