Genes And Chromosomes

Front 1

character

Back 1

heritable feature that varies amont individulas

Front 2

trait

Back 2

each variant for a character

Front 3

true breeding

Back 3

produce only the same variety as the parent plant
ex) plant with purple flowers is true breeding if the seeds produced by self-pollination in successive generations

Front 4

hybridiztion

Back 4

crossing of two true breeding varieties

Front 5

law of segregation

Back 5

two alleles for a heritable character segregate (separate from each other) during gamete formation and end up in different gametes

Front 6

homozygous

Back 6

organism that has a pair of identical alleles for a character

Front 7

heterozygous

Back 7

organism that has two different alleles for a gene

Front 8

testcross

Back 8

breeding an organism of unknwon genotype with a recessive homozygote, reveal the genotype of that orgnaimsm

Front 9

multiplication rule

Back 9

states that to determine this probability, we multiply the probability of one event by the probability of the other event

Front 10

addition rule

Back 10

the probability that any one of two or more mutually exclusive events will occur is calculated by adding their individual probabilities

Front 11

complete dominance

Back 11

one allele was dominant over the other, phenotypes of the heterozygote and dominant homozygote the same

Front 12

incomplete dominance

Back 12

neither allele is completely dominant, hybrids have a phneotype somewhere between those of the two parental varieties

Front 13

codominance

Back 13

two alleles can affect the phenotype in separate, distinguishable ways ex) human blood

Front 14

Tay-Sachs

Back 14

only childrent who inherit two copies of the tay sachs allele have the disease, recessive gene

Front 15

pleiotropy

Back 15

"more", one gene has multiple phenotype effects

Front 16

epistasis

Back 16

"standing upon" phenotype expression of a gene at one locus alters that of a gene at a second locus

Front 17

polygenic inheritance

Back 17

additive effect of two or more genes on a single phenotype character (converse of pleiotropy)

Front 18

norm of reaction

Back 18

phenotype is associated with a range of phnotypic possibilities due to environmental factors

Front 19

multifactorial

Back 19

many factors, bot genetic and environmental, collectively influence phenotype

Front 20

carriers

Back 20

phenotypically normal with regard to disorder heterozygoes may transmit recessive allele to offspring (albinism, cystic fibrosis)

Front 21

dominantly inherited disorders

Back 21

achondroplasia, dominant allels that cause a lethal disease much less common that recessive allels that have lethal effects

Front 22

chromosome theory of inheriance

Back 22

mendelian genes have specific loci (positions) along chromosomes, and chromosomes undergo segregation and independent assortment

Front 23

wild type

Back 23

phenotype for a character most common in natural populations

Front 24

sex linked gene

Back 24

a gene located on either sex chromosome

Front 25

linked genes

Back 25

genes located enar each other on the same chromosome tend to be inherited together

Front 26

genetic recombination

Back 26

the production of offspring the combinations of traits that differ from those found in either parent

Front 27

genetic map

Back 27

ordered list of the genetic loci along a particular chromosome

Front 28

linkage map

Back 28

genetic map based on recombination frequencies

Front 29

nondisjunction

Back 29

members of a pair of a homologous chromosomes do not move apart properly during meiosis I or sister chromatids fail to separate during meiosis II

Front 30

aneuploidy

Back 30

abnormal number of particular chromosome

Front 31

deletion

Back 31

occurs when a chromosomal fragment is lost

Front 32

duplication

Back 32

deleted fragment may become attached as an extra segment to a sister chromatid

Front 33

inversion

Back 33

chromosomal fragment could attach to a non-sister chromatid of a homolgous chromosome

Front 34

translocation

Back 34

fragment to join a nonhomologous chromosome

Front 35

genomic imprinting

Back 35

traits depend on which parent passed along the alles for those traits

Front 36

transformation

Back 36

change in phenotype and genotype due to the assimilation of outside DNA

Front 37

bacteriophages

Back 37

bacteria eaters

Front 38

virus

Back 38

DNA or RNA enclosed by protective coat

Front 39

chargaff's rules

Back 39

1) base combination varies between species
2)within a species, number of A and T are equal, number of C and G are equal

Front 40

antiparallel

Back 40

subunits run in opposite directions

Front 41

semiconservative model

Back 41

each 2 daughter molecules have one old strand

Front 42

origins of replicaton

Back 42

replication of DNA begins at particular sites

Front 43

Replication fork

Back 43

y shaped region, parental strands of DNA are being unwound

Front 44

helicases

Back 44

enzymes that untwist the double helix at the replication forks, separating the two parental stands

Front 45

single strand binding proteins

Back 45

bind to unpaired DNA stands, keeping them from re-pairing

Front 46

topoisomerase

Back 46

helps relieve strain by breaking, swiveling and rejoining DNA stands

Front 47

primase

Back 47

starts complementary chain, adding RNA nucleotides one at a time

Front 48

DNA polymerase

Back 48

catalyze the synthesis of new DNA by adding nucleotides to preexisting chain