genetics test 2

extranuclear inheritance / cytoplasmic inheritance

inheritance patterns involving genetic material outside the nucleus

nucleoid

where genetic material of mitochondria and chloroplasts are located, can contain several copies of the chromosome

oxidative phosphorylation

main function of the mitochondria, a process used to generate ATP

genome

all the genetic material an organism possesses

euploidy

variation in the number of complete sets of chromosomes

aneuploidy

variation in the number of particular chromosomes, occurs through nondisjunction

trisomy

textra copy of all the genes, can express too much of the genes on this chromosome

monosomy

one less copy of all genes, can express too little of the genes on this choromosome

nondisjunction

occurs when homologs are pulled to the same pole or the centromere does not split

familial down syndrome

trisomy 21, chromosome 21 and 14 are fused together

deletion / chromosomal deficiency

occurs when a chromosome breaks and a fragment is lost

cri-du-chat

results from a deletion of a small terminal portion of the short arm of chromosome 5

gene family

consists of two or more genes that are derived from the same ancestral gene

homology

descent from a common ancestor

orthology

decent from a common ancestor by genome division

paralogy

descent from a common acestor by duplication within a genome

globin gene

encode subunits of proteins that bind oxygen, 14 paralogs on three different chromosomes

inversion

total amount of genetic information stays the same, linear sequence is rearranged

balanced translocation

formed by breakage and reunion of chromosomes, recombination between repeate sequences

reciprocal translocations

DNA gets swapped between non-homologous chromosomes or broken DNA's reactive ends created by breaks are recognized by repair enzymes and joined together

nonreciprocal translations / unbalaned translocations

the transfer of genetic material occurs in only one directio

robertsoninan translocation

fusion of two telocentric chromosomes in the centromere region

PAR

psuedoautosomal regions, critical to segregation of x and y chromosomes during male gametogenesis

MSY

male-specific region Y

SRY

sex-determining region y

TDF

testis-determining factor, triggers testes formation, binds DNA and regulates gene expression

psuedoautosomal inheritance

the very few genes found on both X and Y chromosomes, has gotten shorter in evolutionary time

polypoid

have multiple complete sets of chromosomes

monoploid set

basic chromosome set, from which all the other genomes are formed

autopolyploids

have all chromosomes in the polyploid sepcies derive from a single diploid ancestral

allypolyploids

comeplete sets of chromosomes from two or more different ancestral species, much more common

anitbiotics

chemicals that kill or inhibit the growth of bacteria, used to treat bacterial infections. will target different cellular processes to restrict bacterial growth

carbon-source mutatns

cannot utilize a particular carbon source (sugar) for energy

lac-

a mutant that lost the ability to break down and use the sugar lactose as its only carbon source

auxotrophic

unable to synthesize an essential nutrient

leu-

a bacterium that has lost the ability to synthesize the amino acid leucine

prototroph

synthesizes all essential compounds

antibiotic resistance

bacterium can grow in the presence of antibiotic that it was formerly sensitive to

rich / complete media

all nutrients are supplied

minimal media

has very few nutrients

selection

only the organism with the phenotype of interest grows -- live or die only

screening

all phenotypes will grow, but they will be different (ie. colony shape, color, growth rate, enzyme production)

conjugation

direct DNA transfer between a donor and recipient bacterium, requires interaction between bacterial cells

transduction

transfer of DNA from one bacterium to another via a bacteriophage

transformation

uptake of extracellular DNA released from dead bacterium, requires a receptor and competence factors

lederberg and tatum experiment

demonstrated genetic transfer by bacterial conjugation, bacteria were able to transfer DNA so all necessary nutrients are produced

pilus

how bacteria physically interact during conjugation

fertility factor / f factor

confers the ability to donate DNA (fertility) during conjugation

episome / plasmid

small, extrachromosomal circular piece of DNA that determines f factor, also contains genes for tranferring itself to cells that lack f factor

f+ cells

have the f factor, serve as donors (recipients become f+)

f- cells

lack f factor, act as recipients, can act as donors once converted to f+

plasmid

small circular pieces of DNA, contain one or more genes, replicate independently of the bacterial chromosomr plasmidse

r plasmids

confer antibiotic resistance

col plasmids

encode colicins that can kill neighboring bacteria

virulence plasmids

carry genes that turn bacterium into pathogenic strains

conjugative plasmids

plasmids which are transmitted via conjugation, also carry the genes requires for conjugation

tra & trb

play a role in a the transfer of DNA

hfr cells

high frequency of recombination, derived from f+ strains. act as donor strains, created when an f factor integrates into the chromosome. recipients of hfr strains do not become f+ or hfr (stay f-)

interrupted mating experiments

demonstrated that specific genes in an hfr strain are transferred and recombined sooner than others, used a map gene order on the chromosome based on their time-of-entry from a donor hfr strain into a f- recipient strain

f' plasmids

f plasmids excised along with some chromosomal DNA, recipient cells become f'

merozygote / merodiploid

partially diploid, seen in f' plasmids

bacteriophage

a virus that specifically attacks bacterial cells, composed of genetic material surrounded by a protein coat, can follow the lytic cycle, the lysogenic cycle, or both

virulent phages

only undergo a lytic cycle

temperate phages

can follow both lytic and lysogenic cycles

generalized transduction

any piece of bacterial DNA can be incorporated into the phage

transduction step 1

infection of the donor cell, gene can be inseted in phage particle (rare)

transduction step 2

infection of the recipient cell, gene combined with recipient genome

natural transformation

DNA uptake occurs without help

artificial transformation

DNA uptake occurs with the help of special techniques

competence factors

proteins that facilitate the binding, uptake, and incorporation of DNA into the bacterial chromosome

competent

cells that can take up DNA

helicase (DnaB)

unwinds the DNA helix as replication proceeds, travels 5' to 3'

ssDNA binding protein (SSB)

binds and protects ssDNA

primase

RNA polymerase which can synthesize a RNA primer for initiation, requires DNA template and ribonucleotide triphosphates

DNA polymerase 1,3

synthesize DNA, prooofread, involved in replication

gyrase

reduce increased coiling generated during unwinding

DNA polymerase 1

remove RNA primers, active on the lagging end, proofreads, synthesizes DNA to fill in gaps from primer removal

ligase

join the gap-filling DNA to the adjacent strand, joins 3'-OH with 5'-phosphate

temperature sensitive mutants

can survive at a low/permissive temperature, and will fail to grow at the nonpermissive temperature (which is higher)

oriC

origin of replication, where replication starts

DnaA box

a DNA sequence that is bound by the protein DnaA

DnaA protein

binds DnaA boxes and to each other, causes DNA bending --> separation of strands in the AT-rich region

DNA adenine methyltransferase (Dam)

methylates the A on both strands of GATC immediately after replication -- the parental strands are methylated but it takes several minutes for the daughter strands

exonucleases

cut DNA from an end

endonucleases

cut DNA internally

DNA polymerase 2,4,5

involved in the repair of damaged DNA

DNA polymerase 3 holoenzyme

has all of it's protein subunits, processive (stays on the DNA template for a long time)

core enzyme

has just the bare essentals to do the job

processitivity

the measure of the number of nucleotides added by a DNA polymerase enzyme before it falls off/disassociates from the template

B-subunit clamp

prevents the core enzyme from falling off the template during DNA synthesis

leading strand

3' end points into the replication fork

lagging strand

5' end points into the replication fork

replication bubble

bidirectional synthesis of leading and lagging strands from one origin of replication

ter

termination sequence, on opposite side to oriC

protein tus

termination utilization substance, binds to the ter sequences, stops the movement of replication forks

catenanes

intertwined circular molecules as a result of DNA replication

ORC

origin recognition complex, multi-subunit protein binds to origins

MCM

mini-chromosome maintenance, includes helicase and ATPase

CDC6, CDT1

load MCM tonto DNA, considered RLF

RLF

replication licensing factors, their removal allows replication to proceed, which limits replication to once per cell cycle