CYTOGEN 3RD TRINAL Flashcards

1
Q
  • diff varieties of chromosomes
A

VARIATION

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2
Q
  • division of normal chromosome
    structure
A

MUTATION

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3
Q
  • Change in the sequence structure of genetic
    material
A

MUTATION

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4
Q

2 TYPES OF MUTAGENS

A
  1. PHYSICAL MUTAGENS
  2. CHEMICAL MUTAGENS
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5
Q

e.g., X-rays, UV rays

A

Physical Mutagens

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6
Q
  • leads to cancer
    e.g., mustard gas, nicotine, benzene
A

Chemical Mutagens

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7
Q

ORIGIN OF MUTATION

A

1) HEREDITARY/GERMLINE MUTATION
2) ACQUIRED/SOMATIC MUTATION

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8
Q
  • runs in the family
  • de-novo mutation = new (no previous
    history, first time to experience)
A

HEREDITARY/GERMLINE MUTATION

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9
Q
    • occurs in body cells
  • Not hereditary
  • e.g., cancer
A

ACQUIRED/SOMATIC MUTATION

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10
Q

TYPES OF MUTATION
On basis of HOW

A
  1. SPONTANEOUS
  2. INDUCED -
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11
Q

TYPES OF MUTATION
On basis of HOW that naturally occurs (internal
factors)

A

SPONTANEOUS

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12
Q

TYPES OF MUTATION
On basis of HOW is an external factors (mutagens)
——>Euploidy (tri, tetra, so on)

A

INDUCED

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13
Q

TYPES OF MUTATION
On basis of WHERE

A
  1. DNA or gene mutation-
  2. Chromosomal aberration -
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14
Q

TYPES OF MUTATION
On basis of WHERE that changes in
structure/number

A

Chromosomal aberration

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15
Q

TYPES OF MUTATION
On basis of WHERE that is a point mutation

A

DNA or gene mutation

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16
Q

causative agent of mutation

A

mutagens

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17
Q

2 copies of each chromosome
somatic non sex cells
composed of first 22 copies of chromosome

A

diploid organism

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18
Q

sex cells,
one copy of each chromosome (gametes)
last chromosome (X,Y)

A

haploid

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19
Q
  • equational division takes place in
    somatic cells
A

mitosis

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20
Q

process of mitosis

A

interphase
prophase
metaphase
anaphase
telophase

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21
Q

last step in the process of mitosis and is a divison of 2 new cells

A

cytokenesis

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22
Q
  • normal chromosome
    -No. of sets of chromosomes in a biological
    cell.
A

PLOIDY

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23
Q
  • abnormal chromosome
  • is the state of a cell or organism having an
    integral multiple of monoploid number
A

EUPLOIDY

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24
Q
  • Refers to number of basic chromosome sets
A

PLOIDY

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25
- A diploid has ____ sets where as a hexaploidy has ____ sets
2 6
26
The basic chromosome number x, also called the ____________ is the number of different chromosomes that make up a single complete set
monoploid number
27
gene containing chromosomes that are multiple of basic single set
EUPLOIDY
28
the variation in the chromosome number that occurs due to increase or decrease of full set of chromosomes
EUPLOIDY
29
the condition of an organism having complete set of chromosomes or multiples of the basic set is euploidy and the cell is said to be euploid
EUPLOIDY
30
is lethal in most animal species, but often tolerated in plants, where it has played a role in specification and diversification
euploidy
31
same species/ same individual
autoploidy
32
same species/different individual
allploidy
33
- This is a condition where the chromosome number is not an exact multiple of the normal diploid number, with either fewer or more than the normal number of chromosomes in the cell
ANEUPLOIDY
34
- can result when either round of meiotic division lacks cytokinesis, or when meiotic nondisjunction occurs for all chromosomes -did not separate
Monoploidy and polyploidy
35
A gamete with 2 sets of chromosomes fused with a normal gamete produces a
triploid (3N) zygote
36
Complete nondisjunction at meiosis produce ____________ with the normal chromosomes, and ________________
½ gametes ½ with no chromosome
37
Fusion of 2 gametes that each have 2 sets of chromosomes produces a
tetraploid (4N) zygote
38
can result from mitotic nondisjunction of complete chromosome sets
Polyploidy of somatic cells
39
An individual that contains ½ the normal number of chromosomes is a ____________ and exhibits ___________
monoploid monoploidy
40
Some species such as bee, ants and male bees are normally _____________ because they developed from unfertilized eggs. Consequently, these individuals will be sterile
monoploid
41
are very rare in nature because recessive lethal mutations become unmasked, and thus they die before they are detected
Monoploids
42
These alleles normally are not a problem in diploids because their effects are masked by dominant alleles in the genome
MONOPLOIDY
43
- Occurs in cells and organisms when there are more than 2 homologous sets of chromosomes - Very common in plants
POLYPLOIDY
44
- polyploids as a result of duplications in the SAME species
AUTOPOLYPLOIDS
45
- polyploid formed by the hybridization BETWEEN TWO species.
ALLOPLOIDS
46
A ___________________. is derived from hybridization from two or more diploid species with chromosome doubling following the hybridization
typica allopolyploid spp.
47
A human cell has ________chromosomes, which is an integral multiple of the monoploid number, 23
46
48
> MONOSOMY (2n-1) > NULLISOMY (2n-2)
HYPOPLOIDY
49
> TRISOMY (2n+1) > TETRASOMY (2n+2)
HYPERPLOIDY
50
- second most common condition - there are 45 chromosomes in each cell of the body instead of the usual 46
Monosomy
51
- most common condition - this means they have 47 chromosomes instead of 46. ex. down syndrome
Trisomy
52
are abnormal structural and numerical changes
Chromosomal changes
53
- Chromosomal changes are abnormal structural and numerical changes - They are also called chromosomal mutations
chromosomal aberrations
54
Gross structural changes of chromosomes are called
structural aberrations or chromosome re-arrangements
55
Numerical changes are called
ploidy changes or numerical aberrations
56
are chromosomes involve in the gain, loss or relocation of chromosome segments and genes
Structural changes
57
STRUCTURAL CHANGES are
o Intrachromosomal aberrations (homosomal aberration) o Interchromosomal aberrations
58
Chromosomal aberration are of 4 basic types
1. Deficiency or deletion 2. Duplication 3. Inversion 4. Translocation
59
▪ Loss of a chromosome segment, together with the genes contains in it
DEFICIENCY OR DELETION
60
- loss of a terminal segment, with a single break in the chromosomes - end part
Terminal deletion
61
- loss of an intercalary segment, with 2 breaks - center
Intercalary deletion
62
- a segment is lost from both the chromosomes of a homologous pair
Homozygous deletion
63
- a segment is lot only from 1 of the 2 homologues
Heterozygous deletion
64
involves the loss of genes so they have deleterious effect on organisms
Deletion
65
If the lost genes are crucial for viability, ___________________________ may result
sterile gametes or nonfunctional somatic cells
66
- deletion of long arm of chromosome 21 - 9 part is lost
Granulocytic leukemia
67
- heterozygous deletion in the short arm of chromosome 5
Cri-du-chat syndrome
68
is the doubling or repetition of chromosome segment during chromosome __________
Duplication
69
a set of genes gets doubles or repeated
Duplication
70
The extra set of genes in duplication is generally called
“repeat”
71
3 types of duplication
1. Tandem Duplication 2. Reverse Tandem Duplication 3. Displaced duplication
72
- the extra segment and the parent segment are next to each other and have the same order of genes - repeated
Tandem Duplication
73
- the extra segment lies next to parent segment with reversed gene sequence - nagbaliktad
Reverse Tandem Duplication
74
- the duplicate segment lies some distance away from the parent segment - away
Displaced duplication
75
are more frequent and less deleterious than deletions
Duplications
76
are believed to be important raw materials of organic evolution
Duplications
77
affect the regulation of gene activity and there by causes phenotypic alterations which in turn promotes speciation and evolution
Large duplications
78
* the reversal of the linear order of a chromosome segment and its gene sequence
Inversion
79
Believed to be occur in intercalary segments-
intercalary inversion
80
involves the breakage of a chromosome segment an its subsequent re-insertion into the same location in a reversed orientation
Intercalary inversion
81
in this case 2 breaks occur in a chromosome-
inversion points
82
- the rotation (180) and reinsertion of an acentric segment
paracentric inversion
83
- the rotation (180) and reinsertion of a centric segment
pericentric inversion
84
paracentric inversion is of two types
(i) Intraradial or homobranchial inversion (ii) Interradial or heterobranchial inversion
85
- single inversion in one arm
Intraradial or homobranchial inversion
86
- 2 inversions 1 in each arm
Interradial or heterobranchial inversion
87
inversion that does not include centromere
paracentric inversion
88
inversion that includes centromere
pericentric inversion
89
- only 1 segment is inverted
Single inversions
90
- more than 1 segment would be inverted
Complex inversions
91
- both the homologues are inverted
Homozygous inversion
92
- 2 homologue is un-inverted and its companion is inverted
heterozygous inversion
93
COMPLEX INVERSIONS
* Independent inversions * Direct tandem inversions * Reversed tandem inversions * Included inversions * Overlapping inversions
94
- Inversions occur in diff. regions of the chromosome and they are separated from 1 another by un-inverted (normal) segment
independent inversions
95
- There are 2 or more inverted segments which are directly adjacent to each other, i.e., the inverted regions are not separated by normal regions
Direct tandem inversions
96
- The 2 inverted segments are adjancent to each other but their positions are mutually interchanged i.e., g. the first segment lies in place of the 2nd an vice versa
Reversed tandem inversions
97
- 1 inversion is confined with another inversion, i.e., a segment within an inverted segment is inverted again; as a result, the 2nd inverted segment possesses the normal gene sequence for the concerned segment
Included inversions
98
- Such inversions have a common segment, i.e., a part of an inverted chromosome segment is inverted again together with an adjacent segment which was not included in the 1st inverted segment
Overlapping inversions
99
* Helps to retain the original gene combination by reducing the crossing over frequency
INVERSION
100
enhances the position effect & there by produces phenotypic changes
Inversion
101
causes chromosome polymorphism with in a population leading to karyotype evolution
Inversion
102
produces balanced gene complexes (super genes) though reduction of crossing over, which in turn confers greater biological fitness and adaptability & increases the evolutionary potentiality.
Inversion
103
is the re-organization of chromosomes through the transfer or change in position of chromosome segments without gain or loss of genes.
Translocation
104
– change in position of a segment within a chromosome, either from one arm to the other or from one location to another in the same arm.
Intrachromosomal Translocation (Chromosomal shift)
105
Intrachromosomal Translocation (Chromosomal shift) –
o Intraradial o Extraradial – o Interchromosomal Translocation o Transpositional Translocation o Reciprocal Translocation
106
– translocation from one location to another in the same arm
Intraradial
107
– translocation from one arm to the other.
Extraradial
108
–Transfer of a segment from one chromosome to other.
Interchromosomal Translocation
109
– one way transfer of a chromosome segment from one portion to another in the same chromosome.
Transpositional Translocation
110
– mutual exchange of segments between two chromosomes.
Reciprocal Translocation
111
– Mutual exchange between homologous chromosomes
Fraternal Translocation
112
– Mutual exchange between non-homologous chromosomes
External Translocation
113
–intercalary incorporation of a chromosome segment by transposition.
Intercalation or Insertional translocation
114
– Exchanged segments are asymmetrical, produces a dicentric & an acentric chromosome
Asymmetrical or Aneucentric Translocation
115
–Exchanged segments are symmetrical, produces two monocentric chromosomes.
Symmetrical or Eucentric Translocation
116
a segment from the orange (donor) chromosome is transferred to the purple (recipient) chromosome without any reciprocal exchange.
insertional translocation
117
* Translocation which involves the transfer of a whole chromosome arm.
WHOLE ARM TRANSLOCATION
118
– Two breaks in two acrocentric chromosomes. One break is in the short arm of a chromosome and the other one is in the long arm of the other chromosome. Their subsequent fusion results in a metacentric chromosome.
Centric Fusion
119
– It is the reverse process in which a metacentric chromosome and a sub metacentric chromosome give rise to two acrocentric chromosomes.
Dissociation
120
– It is the end-to-end fusion between an acrocentric chromosome and a metacentric chromosome with the loss of a centric segment. It produces a double length acrocentric chromosome.
Tandem fusion
121
change the linkage relationships of the genes involved in the affected segments
Translocations & Inversions
122
results in unusual linkage, reduced meiotic recombination, low viability of chromosomes, familial patterns of trisomy
Translocation
123
is an unbranched structural abnormality in which the arms of the chromosome are mirror images of each other
ISOCHROMOSOME
124
is a structural rearranged chromosome generated either by a rearrangement involving two or more chromosomes or by multiple aberrations within a single chromosome
derivative chromosome
125
- is a chromosome whose arms are fused together to form a ring - A structurally abnormal chromosome in which the end of ach chromosome arm has been lost and the broken arms have been reunited to form a ring.
ring chromosome