Genetics Ii

Front 1

chrom's are made up of many ______

Back 1

genes

Front 2

what is the haploid # of chrom's in humans?

Back 2

23

Front 3

________ genes are distributed among human chrom's

Back 3

35,000

Front 4

_______ megabases (over 3 billion nucleotides) in human chrom's

Back 4

3300

Front 5

what is mendels 4th postulate?

Back 5

during gamete formation, segregating pairs of unit factors assort independently of eachother

Front 6

in 1903 _________ discovered that there must be more unit factors than chromosomes

Back 6

Sutton and Boreri

Front 7

t/f Certain genes are transmitted according to the law of independent assortment-

Back 7

F- certain genes are NOT transmitted according to the law of independent assortment

Front 8

describe independent assortment-

Back 8

2 genes on 2 different homologous pairs of chromosomes form 4 genetically distinct gametes

Front 9

when 2 nonallelic genes are on the same chrom, that tend to be inherited together

Back 9

linked

Front 10

when 2 genes are so close to one another that no crossover occurs and parental gametes are produced

Back 10

complete linkage

Front 11

this type of crossover takes place during prophase I

Back 11

crossover of 2 linked genes

Front 12

________ are 2 new allele combinations generated by crossover b/t 2 linked genes

Back 12

recombinant/ crossover gametes

Front 13

t/f it's more likely that crosses involving genes on the same chrom will result in a percentage of offspring from recombinant gametes

Back 13

T

Front 14

the % of offspring from recombinant gametes is variable, depends on the _______ b/t 2 genes

Back 14

distance

Front 15

these 2 men first explained crossover events-

Back 15

Morgan and Sturtervant

Front 16

Morgan discovered ______ in __________ (where the inheritance pattern of genes is located on the X-chromosome)

Back 16

X-linkage, Drosophila

Front 17

during meisosi, these are the pts of genetic exchange-

Back 17

chiasmata- synapsed homologous chrom's

Front 18

these are synapsed homologous chrom's and the pts of genetic exchange during meiosis

Back 18

chiasmata

Front 19

t/f if 2 genes are located relatively close to eachother along a chromosome they are MORE likely to have a chiasma form b/t them and undergo genetic exchange-

Back 19

FALSE, the closer 2 genes are located to eachother the LESS likely they are to form a chiasma and undergo genetic exchange, the FARTHER apart they are, the more likely to undergo genetic exchange

Front 20

physical exchange of chromosomal material during meiosis

Back 20

cross over

Front 21

t/f in drosophila, crossover occurs in females, in humans it occurs in BOTH sexes

Back 21

TRUE

Front 22

who came up w/ the idea of chrom mapping?

Back 22

sturtevant

Front 23

who came up with the idea of x-linkage

Back 23

thomas morgan, by study of the drosophila

Front 24

this involves the data based on recombination events b/t genes that could be used to map a sequence of genes on the chrom

Back 24

chromosomal mapping

Front 25

the frequency of exchange can be taken as an estimate of _________ b/t 2 genes or loci along a chrom

Back 25

relative distance

Front 26

if you have 24 map units you have how many centimorgans (cM's)

Back 26

24

Front 27

__________ represent points of genetic exchange

Back 27

chiasmata

Front 28

the physical exchange leading to recombination

Back 28

crossing over

Front 29

the % of recombinants can be used to determine-

Back 29

relative distance of genes to one another

Front 30

t/f in flies crossover only occurs in females

Back 30

T

Front 31

t/f crossover events occur on autosomal and sex chromosomes

Back 31

T (however in flies, crossover only occurs in females)

Front 32

Sturtevant and Morgans data strongly supports the idea that chrom's contain genes organized in a __________, and that genes are equivalent to Mendel's 'unit factors'

Back 32

linear order

Front 33

who discovered that genes are equivalent to Mendel's theorized unit factors

Back 33

Sturtevant and Morgan

Front 34

t/f crossing over can go undetected

Back 34

T, if the linkage b/t 2 the alleles is unchanged after cross-over

Front 35

this type of crossover involves 3 gene pair's in the exchange

Back 35

double crossover

Front 36

what are the 3 requirements of mapping 3 or more genes-

Back 36

1)the genotype of the organism producing the gametes must be heterozygous for the genes of interest
2)genotypes can be accurately determined by observing phenotype
3)a sufficient # of offspring must be produced

Front 37

this is the crossover event in one region of the chrom that inhibits a second event in nearby regions-

Back 37

interference

Front 38

what is the coefficient of coincidence (c)?

Back 38

c= observed DCO/expected DCO

Front 39

what is the equation for interference-

Back 39

I= 1.0- c

Front 40

t/f interference decreases as the genes in question are located farther apart-

Back 40

TRUE

Front 41

as the ______ b/t 2 genes increases, mapping experiments become more inaccurate

Back 41

distance

Front 42

_______ can be obscured when studying genes of interest on the same chrom

Back 42

pedigrees

Front 43

a statistical method used to determine if 2 genes are linked or unlinked

Back 43

LOD score method

Front 44

this method was important for assigning genes to chrom's and in constructing human chrom. maps-

Back 44

LOD score method

Front 45

describe somatic cell hybridization as a way to assign human genes to a chrom-

Back 45

1) 2 cells in a culture can be induced to fuse, producing a heterokaryon
2) the cell contains 2 nuclei in a single cytoplasm
3) the nuclei fuse, creating a synkaryon
4)as cells are cultured, the human chrom's are gradually lost

Front 46

human deletion syndrom, in which it gets its name from the 'crying like a cat' symptom of the genetic disease-

Back 46

cru du chat
identified in 1963

Front 47

this chromosomal abberation involves 2n + or - a number, X

Back 47

Aneuploidy

Front 48

2n-1

Back 48

monosomy

Front 49

2n+1

Back 49

trisomy

Front 50

chromosomal abberations involving multiples of n-

Back 50

euploidy; polyploidy

Front 51

3n

Back 51

triploidy

Front 52

chromosomal abberation in which multiples of the same genome are present-

Back 52

autopolyploidy

Front 53

chromosomal abberation in which multiples of different genomes are present

Back 53

alloplyploidy

Front 54

the loss of one chromosome (2n-1)

Back 54

monosomy

Front 55

in humans this is the name of the disease caused by the loss of one chrom (monosomy)-

Back 55

turner syndrome (45, X)
-monosomy of autosomes, will die during development

Front 56

this syndrome involves the monosomy of autosomes, and death during development occurs

Back 56

turner syndrome

Front 57

in Drosophila this is the syndrom caused by the loss of 1 chrom (2n-1)

Back 57

Haplo IV, where a loss of Chrom IV occurs and results in reduced body size and low viability

Front 58

this is the syndrome in Drosophila caused bye the loss of 1 chrom (monosomy, 2n-1) in which the loss of chrom IV occurs and results in reduced body size and low viability

Back 58

Haplo IV

Front 59

t/f plants can tolerate the loss of one chrom-

Back 59

TRUE

Front 60

_________ is the partial loss of 1 chrom

Back 60

segmental deletion

Front 61

this syndrome is an example of segmental deletion (loss of 1 part of a chrom as opposed to the whole chrom)

Back 61

cru du chat (crying like a cat)

Front 62

what is the designation for cru du chat syndrome?

Back 62

46, -5p (where -5p indicates the loss of part of the small arm of chrom 5)

Front 63

what chrom is missing in cru du chat syndrome?

Back 63

the p arm of chrom 5
(-5p)

Front 64

__________ births result in cru du chat syndrome (____% die during the 1st year of life)

Back 64

1 in 50,000 and 90% die during the 1st year of life

Front 65

list the problems accompanying the cru du chat syndrome-

Back 65

1) anatomic malformation
2) gastrointestinal and cardiac complications
3) mental retardation
4) abnormal development of larynx

Front 66

t/f in cru du chat the deleted portion of chrom 5 is paternal in origin in most of the cases

Back 66

TRUE, 80% of the cases of cru du chat the deleted portion of chrom 5 is paternal in origin

Front 67

the addition of a chrom to a diploid genome (2n+1)

Back 67

trisomy

Front 68

what syndrome is commonly associate with trisomy in which the designation is 47, XXY

Back 68

Kleinfilder syndrome

Front 69

t/f the addition of an autosome is usually lethal during development

Back 69

TRUE

Front 70

the only human autosomal trisomy in which a significant # of individuals survive longer than a year past birth

Back 70

down syndrome

Front 71

what is the designation for down syndrome?

Back 71

trisomy 21
47, 21+
an extra chrom, called chromosome 21

Front 72

how many births result in down syndrome

Back 72

approximately 1 in 800 live births (6,000 children a year)

Front 73

what are some phenotypical results of down syndrome (trisomy 21)

Back 73

1)fold in corner of each eye
2)flat face
3)round head
4)short
5)protruding tongues
6)short hands
7)physical psychomotor and mental retardation
8)short life expectancy
9)prone to respiratory disease
10)heart malformations
11)leukemia

Front 74

___% of people affected by down syndrome are expected to live to the age of 50

Back 74

50%, over 50 they teend to develop many problems

Front 75

what would be the designation of a BOY with down syndrome?

Back 75

(47, XY, 21+)

Front 76

what would be the designation of a girl with down syndrome?

Back 76

(47, XX, +21)

Front 77

the _______ is the source of the extra chromosome in 95% of down syndrome cases

Back 77

ovum

Front 78

t/f the female is more than likely responsible for the extra chromosome present in down syndrome children

Back 78

TRUE

Front 79

t/f the female is more than likely responsible for the deleted portion of chrom 5 in the cru du chat syndrome-

Back 79

FALSE, 80% of the cases, the deleted chrom 5 portion is paternal in origin

Front 80

at the age of 30 how many births would likely be affected by down syndrome?

Back 80

1 in 1,000

Front 81

at the age of 40 how many births would likely be affected by down syndrome?

Back 81

1 in 100

Front 82

why are older women more likely to have a child w/ DS?

Back 82

the primary oocytes that undergo complete meiosis I and enter into meiosis II in a 40 yr old woman are older than the oocyte that went through the same process 10 years ago

Front 83

what is the mean maternal age for those giving birth to down syndrome children

Back 83

32

Front 84

t/f maternal nondisjunction during the 2nd meiotic division is the cause of trisomy 21

Back 84

F, nondisjunction during the 1st meiotic division is the most common cause of DS

Front 85

what is the most common cause of DS?

Back 85

maternal nondisjunction of the 1st meiotic division

Front 86

what is the designation of Patau Syndrome?

Back 86

(47, +13)

Front 87

___ in _______ live births result in Patau Syndrome

Back 87

1 in 19,000

Front 88

what is the avg survival rate of someone w/ Patau syndrome

Back 88

3 months (1 in 20 will live longer than 6 months)

Front 89

this syndrome is addition of a chromosome to the 13th genome, results in death due to cardiopulmonary arres, congenital heart disease and pneumonia

Back 89

Patau Syndrome

Front 90

this syndrome is related to partial monosomy

Back 90

Cru du chat

Front 91

this syndrome is trisomy 13

Back 91

Patau syndrome

Front 92

this syndrome is trisomy 18

Back 92

Edwards Syndrome

Front 93

this syndrome is trisomy 21

Back 93

Downs Syndrome

Front 94

this is a test used to detect partial monosomy

Back 94

fluorescent in situ hybridization (FISH)

Front 95

it is estimated that ______% of all conceptions are terminated by spontaneous abortion

Back 95

15-20%

Front 96

t/f a significant number of spontaneous abortuses are trisomic

Back 96

TRUE

Front 97

t/f trisomies for every chromosome have been detected

Back 97

TRUE

Front 98

_________ aberrations for every chromosome have been detected

Back 98

trisomic

Front 99

_____ abberations are rarely found

Back 99

monosomic

Front 100

what 3 organisms have been commonly used to study modes of sexual differentiation by studying the lifecycle

Back 100

1)Clamaydomonas (green algae)
2) Zea Mays (corn)
3) C. elegans (nematodes)

Front 101

C elegans have ___ autosomal chrom's

Back 101

5

Front 102

what are the genotypes of female and male nematodes?

Back 102

female XX
male XO (they lack the Y chromosome)

Front 103

how do you determine the sex of a nematode?

Back 103

the ratio of X chromosomes to the number of autosomal chromosomes

Front 104

a ratio of ____ in nematodes results in hermaphrodites, and a ratio of ____ results in males-

Back 104

1, 0.5

Front 105

who used the hermipteran insect Lugaeus turicus to study XX/XY mode of sex determination

Back 105

Edmund Wilson

Front 106

females produce similar gametes and are referred to as being the ________ sex

Back 106

homogametic

Front 107

t/f females are the heterogametic sex

Back 107

F, homogametic (XX)

Front 108

t/f males are the heterogametic sex

Back 108

T, (XY)

Front 109

Edmund Wilson used _______ to begin to understand how sex is determined

Back 109

Protenor

Front 110

in 1920 ______ discovered the Y chromosome

Back 110

Painter discovered the Y chromosome

Front 111

what did Painter discover?

Back 111

Y chromosome

Front 112

when was it determined that the diploid number is 46

Back 112

1956

Front 113

this syndrome involves abnormal sexual development such as male genitalia and internal ducts, but testes fail to produce sperm, enlargment of breasts and rounded hips, below normal intelligence

Back 113

Klinefelter syndrome

Front 114

what are some symptoms of Klinefelter syndrome?

Back 114

1) male genitalia and internal ducts, but failure to produce sperm
2) enlargement of breasts and rounded hips
3) below avg intelligence
4) long arms, legs, large feet and hands

Front 115

what is the designation for Klinefelter syndrome?

Back 115

(47, XXY) 44 autosomes and the XXY chromosomes

can also be 48,XXXY; 48,XXYY; 49,XXXXY; 49,XXXYY

Front 116

how many males will have the klinefelter syndrome?

Back 116

2 in every 1,000

Front 117

what are treatment options for klinefelter syndrome?

Back 117

1) testosterone replacement for correction of the androgen deficiency
2) tailoring school curricula to address learning difficulties

Front 118

syndrome involving female external genitalia and internal ducts, but the ovaries are rudimentary

Back 118

turner syndrome

Front 119

this phenotype would indicate what genetic disorder?
short stature, skin flaps on the back of neck, underdeveloped breasts, but normal intelligence-

Back 119

turner syndrome

Front 120

t/f someone with turners syndrome would be LESS susceptible to disorders such as osteoperosis, hypothyroidism, and diabetes

Back 120

FALSE, they would be MORE susceptible

Front 121

what is a viable treatment for turners syndrome?

Back 121

hormone treatment (estrogen)

Front 122

what is the designation of turners syndrome?

Back 122

(45, X) 44 autosomes and one X chromosome

Front 123

how many females will develop turner syndrome?

Back 123

1 in 2,000 (most 45,X embryos die in utero)

Front 124

when a mitotic error during development occurs such as (45,X)/(46,XY) and (45,X)/(46,XX)

Back 124

mosaic

Front 125

t/f turner syndrome is an example of a mosaic genetic disorder

Back 125

T, mosaic is a mitotic error during early development

Front 126

which syndrome is a good example of a mosaic disorder?

Back 126

Turner Syndrome

Front 127

term for an error during cell division in which the homologous chrom's fail to seperate and migrate to opposite poles

Back 127

nondisjunction

Front 128

this syndrome is a result of nondisjunction that results in monosomic gametes

Back 128

Turner syndrome

Front 129

this syndrome is a result of nondisjunction where trisomic gametes form

Back 129

Kleinfelder

Front 130

this designation occurs 1 in 1200 births, can appear normal or can have underdeveloped secondary sex characteristics, sterility and mental retardation

Back 130

47,XXX

Front 131

this sex linked disorder will result in above avg height and subnormal intelligence

Back 131

47,XXY
no consistent correlation b/t the extra Y chrom and the predisposition of males to behavioral problems

Front 132

region of the human Y chrom that contains genes

Back 132

euchromatin

Front 133

region of the human Y chrom that lacks genes

Back 133

heterochromatin

Front 134

region of the Y chrom that has some genes that are homologous to the X and some that aren't

Back 134

NRY-non recombining region

Front 135

region of the human Y chrom that shares homology w/ the X chrom

Back 135

PAR (psuedoautosomal region)

Front 136

region of the human Y chrom that encodes a gene product that signals undifferentiated gonadal tissue of the embryo to form testes (the testis determining factor)

Back 136

SRY region (sex determining region Y)

Front 137

this region of the Y chromosome is NOT in female chromosomes

Back 137

SRY (sex determining region Y) region

Front 138

t/f the SRY region is present in ALL male mammals

Back 138

TRUE

Front 139

how can a human male have the sexual genotype XX?

Back 139

if the SRY region is present on one of the X chrom's

Front 140

how can human females have the sexual genotype XY?

Back 140

if the SRY region is missing from the Y chromsome

Front 141

explain the transgenic mice experiment-

Back 141

eggs that are XX are injected with SRY DNA and the offspring develop into males thus proving that SRY gene is the primary signal for male development

Front 142

t/f because females have 2 X chromosomes more genes are expressed in females

Back 142

F, only a SINLGE active X chromosome exists in each cell, no more genes are expressed in females than males

Front 143

this is a term to describe a mechanism that regulates the level of gene products at a certain loci on the X chrom such that the males nad females have equal amnts of gene product

Back 143

dosage compensation

Front 144

the dark staining body in interphase cells of females is referred to as-

Back 144

barr bodies

Front 145

t/f the study of sex chromosome syndromes have shown that regardless of how many X chromosomes exist, all but one is inactivated

Back 145

TRUE, no matter how many X chromosomes exist, all but one is inactivated

Front 146

if all but one X chrom is inactivated why aren't individuals w/ Turner or Kleinfelder syndrome 'normal'?

Back 146

-perhaps inactivation doesn't occur during early stages of development
-maybe not ALL of the genes are inactive

Front 147

this is the idea that inactivation of the X chrom occurs randomly-

Back 147

Lyon Hypothesis (Mary Lyon and Liane Russell)

Front 148

the mosaic pattern of orange or black in Calico cats is an example of -

Back 148

the Lyon Hypothesis
-in rare cases there are male calicos (1 in 3,000)

Front 149

Pigmentation gene on the ______ chromosome allows calico cats to have one allele that will give rise to black color and another allele that gives rise to the orange color

Back 149

X chromosome

Front 150

the allelic forms of Glucose-6-Phosphate dehydrogenase in which fibroblasts taken from females and G6PD isoforms were analyzed is evidence for -

Back 150

Lyon Hypothesis

Front 151

give an example of a phenotype of an X-linked disorder in females-

Back 151

the retinas of female carriers are composed of mosaic patches of colorblind and normal areas

Front 152

how are almost all genes on an entire X chrom inactivated?

Back 152

there is a region on the X chrom, called the X Inactivation Center (XiC) 1Mb or 10^6 base prs

Front 153

this is the region of the X chromosome that is responsible for the inactivation of almost all genes on an entire X chrom

Back 153

X Inactivation Center (XiC)

Front 154

in the X inactivation center what gene is transcribed (RNA made) that is involved in inactivating the X chrom

Back 154

Xist gene

Front 155

what experiment proved that the XIC region inactivated the genes on the extra X chromosome

Back 155

an experiment that deleted that region resulted in the X chromosome no longer being inactivated thus proving that the XIC region was responsible for inactivating the genes on the extra X chrom

Front 156

who first showed in 1916 that in flies the Y chrom doesn't determine maleness?

Back 156

Calvin Bridges

Front 157

what did Calvin bridges propose about the drosophila sex determination?

Back 157

he proposed that both the X chrom's and the autosomes play a role in sex determination

Front 158

t/f if a fly displays the sex genotype XXY it will be male-

Back 158

F, XXY flies were normal females, thus proving that Y chromosomes did not cause maleness

Front 159

what is the genotype of sterile drosophila males?

Back 159

XO

Front 160

what is the role of the Y chromosome in flies-

Back 160

the Y chromosome in flies lacks male determining factors, but Y does contain some genes important for male fertility

Front 161

what determines sex in flies?

Back 161

the ratio of X chroms to the number of haploid sets of autosomes

Front 162

what characteristics would indicate a triploid female drosophila?

Back 162

heavy set bodies, course bristles, course eyes, and they may be fertile

Front 163

how do triploid drosophila females originate?

Back 163

from diploid eggs fertilized by normal haploid sperm

Front 164

what kind of gametes are produced by triploid drosophila females?

Back 164

gametes that display a wide range of chrom complements, thus giving rise to offspring w/ a variety of abnormal chromosomal constituents

Front 165

this involves the sex-determining system of flies in which sexual phenotype is controlled by a balance b/t genes on the X chrom and genes on the autosomes

Back 165

Genic Balance Theory

Front 166

this sex determining factor of flies involves the X:A ratio at 1:2, where the presence of an additional X chrom alters the balance and results in female differentiation

Back 166

threshold for maleness

Front 167

t/f mutants have been identified that are involved w/ sex determination in flies

Back 167

TRUE

Front 168

this is the autosomal gene causing maleness even if the sex genotype is XX

Back 168

transomer (tra) tra/tra
XX tra/tra are male

Front 169

this X linked gene is known as the 'master switch' in which if females of XX have it they will die, but if XY males with the gene have it, they are fine-

Back 169

Sex lethal (sxl)
XX sxl/sxl-females die
XY sxl males- are fine

Front 170

t/f in both mammals and flies x-linked genes are transcribed at twice the level of the genes in females

Back 170

FALSE, only in drosophila (flies)

Front 171

term that describes the expression of a recessive allele on one homolog as caused by the deletion of the dominant allele on the other homolog

Back 171

psuedodominance

Front 172

describe psuedodominance

Back 172

expression of a recessive allele on one homolog as caused by the deletion of the dominant allele on the other homolog

Front 173

what is the inheritance pattern of chrom duplication?

Back 173

semidominance

Front 174

how do new genes arise?

Back 174

duplications of an essential genes and an extra copy of the gene can get mutations and thus give rise to a new gene

Front 175

t/f in general an essential gene doesn't accumulate mutations

Back 175

TRUE, duplications of essential genes, and extra copies can get mutations

Front 176

this describes a segment of the chrom that is turned around 180 degrees

Back 176

inversion

Front 177

t/f the inverted sequence may or may not include the centromere

Back 177

TRUE, doesn't necessarily involve the centromere

Front 178

in this type of inversion the arm ratio remains unchanged

Back 178

paracentric inversion

Front 179

in this type of inverstion the arm ratio is changed

Back 179

pericentric inversion

Front 180

what are the consequences of inversions during gamete formation?

Back 180

normal linear synapsis during meiosis is not possible
an inversion loop will form and crossing over doesn't occur

Front 181

in this type of inversion the centromere is not part of the rearranged chromosome segment

Back 181

paracentric inversion

Front 182

what happens when a single crossover occurs w/i an inversion loop?

Back 182

the inversion loop can produce abnormal chromatids

Front 183

when a single crossover occurs, this type of inversion doesn't involve centromere's as part of the rearranged chrom segment

Back 183

paracentric

Front 184

when a single crossover occurs, this type of inversion involves the centromere as part of the rearranged chrom segment

Back 184

pericentric inversion

Front 185

this is the movement of a chromosomal segment to a new location in the genome

Back 185

translocation

Front 186

the exchange that occurs in translocation occurs b/t 2 ___________ chromosomes

Back 186

nonhomologous

Front 187

breaks occur w/i the ___________ region on 2 nonhomologous chromosomes

Back 187

centromeric

Front 188

this syndrome involves sensitive sites along chrom X, results in mental retardation

Back 188

Fragile X syndrome

Front 189

fragile X syndrome affects ___________ males and ___________ females

Back 189

1 in 4000 males and 1 in 8000 females

Front 190

what gene on the X chromosome accounts for the Fragile X syndrome?

Back 190

FMR1 gene encodes an RNA binding protein, and thus a trinucleotide repeat of CGG occurs

Front 191

what reasons are bacteria good research organisms?

Back 191

1) short reproductive cycles
2) grow fast
3) haploid
4) spontaneous mutations

Front 192

this is considered the primary source of genetic variation

Back 192

spontaneous mutation

Front 193

why is it advantageous for bacteria to be haploid-

Back 193

b/c all mutations will be expressed DIRECTLY in the descendants of mutant cells

Front 194

type of medium where the nutrient components of the growth medium are very simple and consist only of an organic carbon source-

Back 194

minimal medium

Front 195

wild type bacteria for all growth reuqirements and can grow on minimal medium

Back 195

prototroph

Front 196

a bacterium that is unable to synthesize one or more organic compounds-

Back 196

auxotroph

Front 197

an auxotroph that loses its ability to make histidine would be disignated as-

Back 197

his-

Front 198

what 2 bacteriologists were involved in conjugation studies

Back 198

lederburg, tatum

Front 199

process where the genetic info from one bacterium is transferred and recombined w/ that another bacterium

Back 199

conjugation

Front 200

genetic info is transferred from one chrom to another, resulting in an altered genotype

Back 200

genetic recombination

Front 201

describe tatum and lederburgs experiment that implied genetic recombination-

Back 201

they plate 2 auxotrophic strains (A and B) on minimal medium and discovered NO GROWTH, but after mixing the 2 (both containing components the other didn't have) they found that plating would produce prototrophs, and growth occurred on the minimal medium through genetic recombination

Front 202

cells that serve as donors of parts of their chrom's

Back 202

F+ cells (f for fertility)

Front 203

recipient bacteria that receive the donor chrom material (DNA) and recombine it w/ part of their own chrom

Back 203

F- cells

Front 204

who designed the U tube in which to grow F+ and F- cells

Back 204

Davis

Front 205

physcial interaction is the initial stage of the process of conjugation and is mediated through a conjugation tubed called the ______

Back 205

F or sex pilus

Front 206

F+ cells contain a __________ that confers the ability to donate part of their chrom during conjugation

Back 206

F factor (fertility factor)

Front 207

following conjugation and genetic recombination- recipient cells always become ___

Back 207

F+

Front 208

a gene of the F factor that is involved in the transfer of genetic info

Back 208

tra genes

Front 209

t/f the F factor has been shown to consist of a circular dbl stranded DNA mx, making up about 2% of the bacterial chrom

Back 209

TRUE

Front 210

t/f the F factor is AKA a plasmid

Back 210

T

Front 211

process in which a separation of 2 strands of the dbl helix of DNA occurs, one moving by way of a sex pilus into a recipient cell (F-) and the other remaining in the donor cell (F+), both replicating which results in both cells becoming F+

Back 211

conjugation

Front 212

cells that behave as chrom donors, a special calls of F+ cells that demonstrate an elevated frequency of recombination

Back 212

Hfr (high frequency recombination)

Front 213

t/f when Hfr comes into contact with F- cells, the F-cells become Hfr

Back 213

FALSE, they remain F- cells

Front 214

t/f when F+ cells come into contact w/ F- cells, the recipient becomes F+

Back 214

TRUE

Front 215

technique in which Hfr and F- cells come into contact but are put in a blender to separate conjugation, then grown on medium containing the antibiotic to ensure recovery of only recipient F- cells

Back 215

interrupted mating technique

Front 216

what experiment proved that Hfr bacterium was transferred linearly and gene order and distance between genes, as measure in minutes could be predicted

Back 216

interrupted mating technique- by interrupting the conjugation of Hfr and F- cells at different pts in time, one could see which genes were transferred at a faster rate and before others

Front 217

t/f minutes are equivalent in bacterium to mu's in eukaryotes

Back 217

TRUE

Front 218

t/f E.coli chrom is circular (no free ends) w/ a point of origin (O) that varies from strain to strain

Back 218

T

Front 219

What determines the O site of E.coli Chrom-

Back 219

the F factor intergrates into the chrom at different pts and its position determies the O site

Front 220

the use of _________________ w/ different Hfr strains allowed researchers to map the entire E. coli chrom

Back 220

interrupted mating technique

Front 221

Hfr underwent a comination at a rate of ______ times more frequently than F+ strain

Back 221

1,000

Front 222

Alderberg discovered that the F factor could lose its integrated status, causing the cell to revert to the F+ state known as

Back 222

F'-> Hfr

Front 223

F' cells initiate conjugation w/ F- cells, much like F+ cells do; the f factor is transferred to the F- cell, and then duplicate w/i the recipient cell, b/c the recipient still has a complete chrom- this creates a partially diploid calle called a

Back 223

merozygote

Front 224

t/f the transfer of DNA b/t bacteria is unidirectional

Back 224

T

Front 225

this is an enzyme consisting of polypeptide subunits encoded by 3 rec genes (recb, recc, and recd)

Back 225

RecBCD protein

Front 226

extrachromosomal, circular piece of dsDNA that replicates independent of the chromosome

Back 226

plasmid

Front 227

what are the 2 components of R plasmids

Back 227

1)RTF-resistance transfer factor
2) r-determinants

Front 228

this component of the R plasmid encodes genetic info essential to transfer the plasmid b/t bacteria

Back 228

RTF factor

Front 229

this component of the R plasmid are genes conferring resistance to antibiotics

Back 229

r-determinants

Front 230

what would happen if a bacteria contained r-determinant plasmids but not RTF plasmids?

Back 230

the bacterial cell would still be resistant however it would not be able to transfer the genetic material for resistance to recipient cells

Front 231

_______ derived from E.coli, encodes for one or more proteins that are highly toxic to bacterial strains that don't harbor the same plasmid

Back 231

Col plasmid- not usually transmissable to other cells, whereas the R plasmid is easily trasmissable

Front 232

proteins, called ______, encoded for by the Col plasmid kill neighboring bacteria

Back 232

colicins

Front 233

process in which small peices of extracellular DNA are taken up by a living bacterium, leading to a stable genetic change in the recipient cell

Back 233

transformation

Front 234

what are the 2 main categories of transformation

Back 234

1)entry of DNA into a recipient cell
2)recombination of the donor DNA w/ its homologous region in the recipient chrom

Front 235

t/f only competent bacterial cells will take up DNA in transformation

Back 235

T

Front 236

the recombinant region in transformation that contains one host strand and one mutant strand

Back 236

heteroduplex

Front 237

after the first round of cell division following transformation what is produced-

Back 237

1 cell containing the original nontransformed chrom and the other containing the transformed chrom.

Front 238

these are referred to as bacterial viruses

Back 238

bacteriophages

Front 239

these are viruses that have bacteria as their host

Back 239

bacteriophages/phages

Front 240

bacteriophage that includes an icosahedral head filled w/ DNA, a tail consisting of a collar, tube, sheath, base plate and tail fibers-

Back 240

bacteriophage T4

Front 241

what are the 3 processes in assembly of a mature virus structure-

Back 241

1)DNA packaging as viral heads are assembled
2)tail assembly
3)tail fiber assembly

Front 242

a cleared area where bacteria is absent

Back 242

plaque

Front 243

______ occur wherever a single virus has intially infected one bacterium in the lawn that as grown up during incubation

Back 243

plaques

Front 244

virally mediated gene transfer from one bacterium to another

Back 244

transduction

Front 245

when approximately _____ viruses are constructed w/i a bacteria, the cell lyses and the mature phages are released to infect other bacterial cells

Back 245

~200 viruses

Front 246

process in which viral DNA enters a bacterial cell and instead of replicating in the bacterial cytoplasm, its integrated into the bacterial chrom

Back 246

lysogeny

Front 247

t/f in lysogeny- no new viruses are produced and no lysis of the bacterial cell will occur

Back 247

TRUE, unless introduced to certain stimuli that would induce viral DNA to lose its integrated status and initiate replication, phage reproduction, and lysis of the bacterium

Front 248

viral DNA integrated into the bacterial chromosome

Back 248

prophage

Front 249

ciruses that can either lyse the cell or behave as a prophage

Back 249

temperate

Front 250

viruses that can only lyse the call are referred to as-

Back 250

virulent

Front 251

bacterium harboring a prophage has been ___________ and is said to be ________

Back 251

lysogneized, lysogenic

Front 252

bacterium that is capable of being lysed as a result of induced viral reproduction

Back 252

lysogenic

Front 253

viral DNA, that can replicate either in the bacterial cytoplasm or as part of the bacterial chrom is classified as an-

Back 253

episome

Front 254

virus mediate bacterial DNA transfer

Back 254

transduction

Front 255

who discovered transduction

Back 255

Zinder and Lederberg

Front 256

describe the Zinder-Lederberg experiment using Salmonella-

Back 256

using the Davis U tube, they placed 2 auxotrophic strains of Salmonell LA-2 and LA 22 on either side of the filter, when plated independently the LA 22 side produced prototrophs

Front 257

this type of inheritance is exhibites when intermeidate phenoypic expression fo a trait occurs in an organism that is heterozygours for 2 alleles

Back 257

incomplete dominance

Front 258

inheritance where 2 distinctive effects of 2 alleles occur simultaneously in a heterozygous organism

Back 258

codominance

Front 259

chromosomes consist of very lg numbers of genes that are part of the same chrom and are said to be __________

Back 259

linked

Front 260

the _________ is the unit of transmission during meiosis

Back 260

chromosome (NOT THE GENE)

Front 261

-the reshuffling or recombination of the alleles b/t homologs
-a physical breaking and rejoining process that occurs during meiosis

Back 261

crossing over

Front 262

the degree of crossing over b/t any 2 loci on a single chrom is proportional to the distance b/t them known as-

Back 262

interlocus distance

Front 263

these indicate the relative locations of genes on the chrom

Back 263

chromosome maps

Front 264

type of linkage resulting in only parental or noncrossover gametes

Back 264

complete linkage (seldom occurs)

Front 265

t/f the frequency w/ which crossing over occurs b/t any 2 linked genes is proportional to the distance seperating the respecitve loci along the chrom-

Back 265

TRUE

Front 266

as the distance b/t 2 genes increases the proportion of _______ gametes increases and that of __________ gametes decreases

Back 266

recombinant, parental

Front 267

t/f the number of recombinant gametes approaches but will not exceed 50%

Back 267

TRUE

Front 268

what ratio is characteristic of complete linkage?

Back 268

1:2:1

Front 269

_________ is observed only when 2 genes are located very close together and the # of progeny is relativiely small

Back 269

complete linkage

Front 270

who was the first to discover X-linkage

Back 270

Morgan

Front 271

these are known as points of genetic exchange

Back 271

chiasmata

Front 272

t/f if linked genes exist in a linear order along the chrom, then a variable amount of exchange occurs b/t any 2 genes

Back 272

TRUE

Front 273

the physical exchange of genetic info leading to recombination

Back 273

crossing over

Front 274

t/f linkage and crossing over are restricted to X-linked genes

Back 274

F, thy could also be demonstrated w/ autosomal genes

Front 275

in flies crossing over only occurs in-

Back 275

females

Front 276

what is the chromosomal theory of inheritance-

Back 276

chromosomes contain genes in a linear order and these genes are equivalent to Mendel's unit factors

Front 277

the closer 2 loci reside on the axis of the chrom, the less likely that any ____________ event will occur b/t them

Back 277

single crossover

Front 278

when 2 loci are far apart, crossover will occur in an area of the chrom b/t them, this seperates them, yielding-

Back 278

recombinant gametes

Front 279

the chromatids that are not involved in the exchange of material during cross over

Back 279

non cross over gametes

Front 280

in a single crossover-the %age of tetrads involved in an exchange b/t 2 genes is twice as great as the percentage of __________

Back 280

recombinant gametes produced

Front 281

what is the theoretical limit of recombination due to crossing over?

Back 281

50%

Front 282

double exchanges of genetic material result from -

Back 282

DCOs (double cross overs)

Front 283

in the case of a ____________, 2 seperate and independant events or exchanges must occur simultaneously

Back 283

double crossover

Front 284

if 3 genes are relatively close together along one chrom, the expected frequency of dbl crossover gametes is
a)extremely high
b)extremely low

Back 284

extremely LOW

Front 285

the 3 criteria for a successful mapping cross-

Back 285

1) genotype of the organism producing the crossoer games must be heterozygoes at all loci under consideration
2)crross must be constructed so that genotypes of all gametes can be accurately determined by observing the phenotypes of offspring
3)a sufficient # of offspring must be produced in the mapping experiment to recover a representative sample of all crossover classes

Front 286

phenotypes that complement one another (i.e. one wild, other mutant)

Back 286

reciprocal classes

Front 287

these phenotypes generally occur in the greateast proportion of offspring

Back 287

noncrossover phenotype

Front 288

phenotype, because of their probability of occurence, must be present in the least numbers

Back 288

double crossover phenotype

Front 289

when a crossover event in one region of the chrom inhibits a 2nd event in nearby regions

Back 289

interference

Front 290

_________ decreases as the genes in question are located father apart

Back 290

interference

Front 291

this type of exchange of genetic material takes place in Drosophila as well as certain Fungi

Back 291

mitotic recombination

Front 292

a statistical method used to determine if 2 genes are linked or unlinked

Back 292

LOD score method

Front 293

technique that aids in assigning human genes to their respective chrom's that relies on the fact that 2 cells in culture can be induced to fuse into a single hybrid cell

Back 293

somatic cell hybridization

Front 294

when 2 cells from different organisms are induced to fuse together they produce a__________, containing 2 nuclei in a common cytoplasm-

Back 294

heterokaryon

Front 295

when the 2 nuclei of a heterokaryon eventually fuse together they form a-

Back 295

synkaryon

Front 296

result of fragments of a particular chrom become transferred to another chrom

Back 296

translocation

Front 297

_______ ensures genetic constancy within members of the same species

Back 297

meiosis

Front 298

chromosomes such as XY, often characterize one sex or the other

Back 298

heteromorphic chrom's/ sex chrom's

Front 299

_______ rather than _________ ultimately serve as the underlying basis of sex determination

Back 299

genes rather than chrom's

Front 300

differentiation involving the gonads where gametes are produced

Back 300

primary sexual differentiation

Front 301

differention that involves the overall appearance of the organism, IE differences in such organs as mammary glands, external genetalia

Back 301

secondary sexual differentiation

Front 302

an individual containing ONLY male or ONLY female reproductive organs-

Back 302

unisexual, dioecious, gonochoric

Front 303

individuals containing both male AND female reproductive organs

Back 303

bisexual, monoecious, hermaphroditic

Front 304

individuals of intermediate sexual differentiation, who are most often sterile

Back 304

intersex

Front 305

green alga Chalmydomonas spend most of their lives in the _______ phase, asexually producing daughter cells by mitotic division

Back 305

haploid

Front 306

this organism spends most of its life in the haploid phase, reproducing asexually

Back 306

Chlamydomonas

Front 307

this organism has an alternating life cycle b/t the diploid sporophyte stage and the haploid gametophyte stage, that are linked by the processes of meiosis and fertilization

Back 307

Zea mays

Front 308

what are the 2 sexual phenotypes of C. elegans-

Back 308

hermaphroditic-both testes and ovaries and males with only testes

Front 309

approximately how many male C. elegans would be produced after self fertilization?

Back 309

less than 1%, the rest hermaphrodite

Front 310

what percentage of male vs hermaphrodite would result in the cross fertilization of a male and a hermaphrodite C. elegans

Back 310

50% male, 50% hermaphrodite

Front 311

t/f C. elegans lacks a Y chromosome completely

Back 311

T, maleness is determined by genes located on both the X chrom and autosomes

Front 312

what determines the sex of C. elegans?

Back 312

the ratio of X chromosomes to the number of sets of autosomes

Front 313

who demonstrated that females have 2 X chromosomes whereas males only have 1, by examining Protenor (with 14 chrom's)

Back 313

Wilson

Front 314

fertilization by X bearing sperm resultes in ______ offspring, and fertilization by X deficient sperm results in ________ offspring

Back 314

female, male

Front 315

ratio of offspring depending on the random distribution of the X chrom into 1/2 male gamets during segregation

Back 315

XX/XO sex determination or Protenor mode of sex determination

Front 316

what 2 organisms did Wilson study to better understand sex determining chromosomes

Back 316

Protenor and Lygaeus turicus

Front 317

Wilson discovered that males of the Lygaeus turicus species have a single X and a smaller heterochromosome called a

Back 317

Y chrom

Front 318

mode of sex determination following random fertilization, equal numbers of male and female progeny will be produced w/ distinct chrom complements-

Back 318

XX/XY sex determination

Front 319

In Protenor and Lygaeus insects, males produce unlike gametes and are thus described as-

Back 319

heterogametic sex

Front 320

females who have 'like' sex chroms are the________ producing uniform gametes w/ regard to chrom numbers and types

Back 320

homogametic sex

Front 321

t/f the male is always the heterogametic sex

Back 321

FALSE

Front 322

who discovered the Y chrom in human males

Back 322

Painter

Front 323

when was the diploid number of human chromosomes finally clarified?

Back 323

1956

Front 324

t/f the Y chrom determines maleness in humans

Back 324

TRUE

Front 325

syndrome where genetalia and internal ducts are usually male, but testes are rudimentary and fail to produce sperm

Back 325

Klinefelter syndrom

Front 326

syndrome where affected individ'l has female external genetalia and internal ducts, but ovaries are rudimentary

Back 326

Turner syndrome

Front 327

t/f in Klinefelter syndrome intelligence is not affected

Back 327

FALSE, its usually below normal

Front 328

t/f in Turner syndrome intelligence is not affected

Back 328

TRUE

Front 329

what is the designation of Klinefelter syndrome?

Back 329

(47, XXY)

Front 330

what is the designation of Turner syndrome?

Back 330

(45,X)

Front 331

both turner and klinefelter syndrome result from __________, the failure of the X chrom to segregate properly during meiosis

Back 331

nondisjunction

Front 332

individuals called _____ whose somatic cells display 2 different genetic cell lines, each exhibiting a different karyoype

Back 332

mosaics
(IE 45,X/46,XY or 45,X/46,XX)

Front 333

t/f most 45,X fetuses die in utero and are aborted spontaneously

Back 333

TRUE, making Klinefelters more frequent than Turner syndrome

Front 334

syndrome that occurs every 1 in 1200 births, varies highly in expression, some women are normal and other are underdeveloped secondary sex charactersitcs, sterility, retardation

Back 334

47, XXX syndrome

Front 335

present on both ends of the Y chrom are ______ that share homology w/ the X chrom and synampse and recombine during meiosis

Back 335

PARS

Front 336

gene that controls male sexual development, encodes a gene product that triggers the undifferentiated gonadal tissue of an embryo to form testes-

Back 336

SRY (sex determining region Y)

Front 337

t/f the SRY gene on the Y chrom provides the primary signal for male development

Back 337

TRUE

Front 338

the critical factor in determining sex of drosophila is the ratio of X chrom's to the number of haploid sets of _________

Back 338

autosomes