Genetics Chapter 8

Front 1

Chromosomes

Back 1

-Large piece of DNA

-DNA double helix structure

-can have a single chromatid or two sister chromatids

Front 2

Telomeres

Back 2

Stable ends of the chromosomes

Front 3

Centromere

Back 3

Constricted region of the chromosome where the kinetochore forms and the spindle microtubules attach

Front 4

Metacentric

Back 4

the centromere is located approximately in the middle, and so the chromosome has two arms of equal length

Front 5

Submetacentric

Back 5

the centromere is located approximately in the middle, and so the chromosome has two arms of equal length

Front 6

Acrocentric

Back 6

the centromere is near one end, producing a long arm and a knob,or satellite, at the other

Front 7

Telocentric

Back 7

the centromere is at or very near the end of the chromosome

Front 8

Phytohemagglutinin

Back 8

-Mitogen

-Stimulates mitosis

Front 9

Colchicine

Back 9

-Disables the spindles

Front 10

Colchicine

Back 10

-Disables the mitotic spindles

Front 11

Back 11

Q Banding

Quinacrine Mustard

Fluorescent

Front 12

Back 12

C Banding

Centromeric Heterochromatin

Front 13

Back 13

R Banding

GC rich regions

Front 14

Aneuploidy

Back 14

the presence of an abnormal number of chromosomes in a cell, such as having 45 or 47 chromosomes when 46 is expected

Front 15

Polyploidy

Back 15

Cell containing more than two paired (homologous) sets of chromosomes

Front 16

Change in chromosome structure can result in different phenotypes becasue:

Back 16

-changes in gene number (dosage)

-changes in gene position (chromatin)

-disruption of coding sequences

Front 17

In animals, including humans, rearrangements particularly _________ and __________ are often lethal and almost always deleterious.

Back 17

Deletions and duplications

Front 18

Chromosomal rearrangements occur primarily as a result of:

Back 18

Illegitimate recombination or breakage- joining (nonhomologous end joining)

Front 19

Rearrangements can occur in:

Back 19

Both mitosis and meiosis (mitotic can result in mosaics)

Front 20

Chromosomal mutations can arise in _______A________ of ______B_______. In order to be passed on the mutation must be in ______C______.

Back 20

A) in any cell

B) any tissue

C) germinal tissue

Front 21

Duplication

Back 21

Type of mutation. Segment of the chromosome is duplicated.

Front 22

Deletion

Back 22

Type of mutation. Segment of the chromosome is deleted.

Front 23

Inversion

Back 23

Type of mutation. Segment of the chromosome becomes inverted, turned 180°.

Front 24

Translocation

Back 24

Type of mutation. Segment of the chromosome moves from one chromosome to a non-homologous chromosome or to another place on the same chromosome.

Front 25

In an individual heterozygous for a duplication, the duplicated chromosome ____A____ during ___B___ of ____C____ in ____D_____.

Back 25

A) loops out

B) synapsis

C) homologous pairing

D) prophase I

Front 26

The Bar phenotype in Drosophila results from ____A____. Unequal crossing over produces ____B___ and _____C_____ mutations. Chromosomes do not align properly resulting in unequal crossing over: one chromosome has a ____D_____ and the other ______E_____.

Back 26

A) An X-linked duplication

B) Bar

C) double Bar

D) Bar duplication

E) deletion

Front 27

Unbalanced gene dosage leads to developmental abnormalities. Duplications and other chromosome mutations produce ____A____ of ______B_______ which alters the relative amounts (doses) of ______C______. If the amount of one product ____D____ but the other product _____E____ developmental problems occur.

Back 27

A) extra copies

B) some but not all genes

C) interacting gene products

D) increases

E) remains the same

Front 28

Interstitial deletion

Back 28

Chromosomal deletion. Result of two breaks.

Front 29

Terminal deletion

Back 29

Chromosomal deletion. Result of a single break.

Front 30

Intragenic deletion

Back 30

Chromosomal deletion. A small deletion within the gene.

Front 31

Multigenic deletion

Back 31

Chromosomal deletion. Large deletion involving two to several thousand genes.

Front 32

Chromosomal deletions are recognized by:

Back 32

-reduced recombination frequency

-pseudodominance

-recessive lethality

-lack of reverse mutation

-visible deletions

Front 33

Chromosomal deletion result in _____A_____. Phenotypic consequences of a deletion depends on _____B_____. If a deletion includes the ____C____, the chromosome will not segregate in mitosis or meiosis and will usually be lost.

Back 33

A) looping similar to duplication

B) the genes located in the deleted region

C) centromere

Front 34

Many deletions are ____D____ in the homozygous state because all copies of any ____E____ location in the ____F_____ are missing.

Back 34

D) lethal

E) essential genes

F) deleted region

Front 35

Heterozygous individuals for deletions may have multiple defects for 3 reasons: 1) the heterozygous conditions may produce an __A__ in the amount of __B__ similar to the __C__ produced by __D__.

Back 35

A) imbalance

B) gene products

C) imbalance

D) extra gene copies

Front 36

Heterozygous individuals for deletions may have multiple defects for 3 reasons: 2) recessive mutations on the ____E____ lacking the deletion may be expressed when the ____F____ allele has been ____G____ (pseudodominance).

Back 36

E) homologous chromosome

F) wild type

G) deleted

Front 37

Heterozygous individuals for deletions may have multiple defects for 3 reasons: 3) some genes must be present in ___H___ copies for normal function. When a single copy gene is not sufficient to produce a ___I____ (haploinsufficient gene) loss of function mutations in ____J_____ are ____K_____.

Back 37

H) two

I) wild type phenotype

J) haploinsufficient genes

K) dominant

Front 38

The Notch phenotype is produced by a ___A___ that includes the __B__ gene. The Notch locus is __C__.

Back 38

A) chromosomal deletion

B) Notch

C) haploinsufficient

Front 39

A chromosomal inversion occurs where a chromosome segment is __A__. The is believed to happen when chromosome __B__ occur. The __C__ piece may reattach but not necessarily in the same __D__as before.

Back 39

A) inverted (turned 180°)

B) breaks

C) broken

D) orientation

Front 40

Which chromosomes are inverted? Names? ●=centromere

1) AB●CDEFG

2) AB●CFEDG

3) AD●CBEFG

Back 40

1) normal chromosome

2) inverted: paracentric

3) inverted: pericentric

Front 41

In chromosome inversion, no __A__ of genetic material, only order has been __B__. Inversion may break __C__ into 2 parts.

Back 41

A) loss or gain

B) altered

C) gene

Front 42

Position effect

Back 42

The position of many genes on chromosome effects their regulation. Inversion can cause inappropriate expression patterns.

Front 43

In chromosomal inversions the heterozygote has one __A__ chromosome and one chromosome with an __B__ segment. (Paracentric)

Back 43

A) normal

B) inverted

Front 44

In prophase I ofmeiosis, thechromosomes form an ____A____, whichallows the homologoussequences to align. This paracentric loop structure is one way to detect ___B____.

Back 44

A) inversion loop

B) inversions

Front 45

Crossing Over within aParacentric Inversion

The heterozygote possessesone wild-type chromosomeand one chromosome with a ____A___. In prophase I, an ___B___ forms. A single crossover withinthe inverted region resultsin an ___C___ structure.

Back 45

A) paracentric inversion

B) inversion loop

C) unusual

Front 46

Crossing Over within aParacentric Inversion

One of the four chromatidsnow has two ___D___ and one lacks a centromere. The cell then enters ___E___. In anaphase I, the centromeres separate,stretching the ___F___ chromatid, whichbreaks. The chromosome lacking a centrosome is __G__.

Back 46

D) centromeres
E)Anaphase I

F) dicentric

G) lost

Front 47

Crossing Over within aParacentric Inversion

In anaphase II, four __H__ are produced. Two gametes contain wild-type __I__ chromosomes. The other two contain __ J__ chromosomes that are missing somegenes; these gametes will not produceviable offspring.

Back 47

H) gametes

I) nonrecombinant
J) recombinant

Front 48

Crossing Over within aPericentric Inversion

Recombination is also reduced within a pericentricinversion. No __A__ or __B__ areproduced, but recombinant chromosomes have toomany copies of some genes and no copies of others. Gametes that receive __C__ cannot produce viable progeny.

Back 48

A) dicentric bridges

B) acentric fragments
C) recombinant chromosomes

Front 49

Crossing Over within aPericentric Inversion

The heterozygote possessesone __D__ chromosomeand one chromosome with a __E__. In prophase I, an __F__ forms.A single crossover withinthe inverted region resultsin an __G__ structure.

Back 49

D) wild-type

E) pericentric inversion

F) inversion loop

G) unusual

Front 50

Crossing Over within aPericentric Inversion

If crossing over takes place withinthe inverted region, two of theresulting chromatids will have __H__ copies of some genes and __I__ of others. The chromosomes separate in __J__. The chromatids separate in __K__ forming four gametes.

Back 50

H)too many
I) no copies
J) anaphase I
K)anaphase II

Front 51

Inversions

In heterozygotes, inverted region loops out whenhomologous chromosomes __A__ in meiosis I. Can have phenotypic effects– may __B__ in two– may have __C__. Observed recombination is reduced because of theproduction of __D__ gametes.

Back 51

A)pair
B)break genes
C) position effects
D)non-viable

Front 52

Translocation

Back 52

entails the movement of genetic materialbetween nonhomologous chromosomes or within the samechromosome. Should not be confused with crossing over.

Front 53

Crossing Over

Back 53

The exchange of genetic material between homologouschromosomes

Front 54

Nonreciprocal translocation

Back 54

AB-CDEFG and MN-OPQRS----> AB-CDG and MN-OPEFQRS

Front 55

Reciprocal Translocation

Back 55

AB-CDEFG and MN-OPQRS ----->AB-CDQRG and MN-OPEFS