CYTOGEN 3RD TRINAL Flashcards
- diff varieties of chromosomes
VARIATION
- division of normal chromosome
structure
MUTATION
- Change in the sequence structure of genetic
material
MUTATION
2 TYPES OF MUTAGENS
- PHYSICAL MUTAGENS
- CHEMICAL MUTAGENS
e.g., X-rays, UV rays
Physical Mutagens
- leads to cancer
e.g., mustard gas, nicotine, benzene
Chemical Mutagens
ORIGIN OF MUTATION
1) HEREDITARY/GERMLINE MUTATION
2) ACQUIRED/SOMATIC MUTATION
- runs in the family
- de-novo mutation = new (no previous
history, first time to experience)
HEREDITARY/GERMLINE MUTATION
- occurs in body cells
- Not hereditary
- e.g., cancer
ACQUIRED/SOMATIC MUTATION
TYPES OF MUTATION
On basis of HOW
- SPONTANEOUS
- INDUCED -
TYPES OF MUTATION
On basis of HOW that naturally occurs (internal
factors)
SPONTANEOUS
TYPES OF MUTATION
On basis of HOW is an external factors (mutagens)
——>Euploidy (tri, tetra, so on)
INDUCED
TYPES OF MUTATION
On basis of WHERE
- DNA or gene mutation-
- Chromosomal aberration -
TYPES OF MUTATION
On basis of WHERE that changes in
structure/number
Chromosomal aberration
TYPES OF MUTATION
On basis of WHERE that is a point mutation
DNA or gene mutation
causative agent of mutation
mutagens
2 copies of each chromosome
somatic non sex cells
composed of first 22 copies of chromosome
diploid organism
sex cells,
one copy of each chromosome (gametes)
last chromosome (X,Y)
haploid
- equational division takes place in
somatic cells
mitosis
process of mitosis
interphase
prophase
metaphase
anaphase
telophase
last step in the process of mitosis and is a divison of 2 new cells
cytokenesis
- normal chromosome
-No. of sets of chromosomes in a biological
cell.
PLOIDY
- abnormal chromosome
- is the state of a cell or organism having an
integral multiple of monoploid number
EUPLOIDY
- Refers to number of basic chromosome sets
PLOIDY
- A diploid has ____ sets where as a hexaploidy
has ____ sets
2
6
The basic chromosome number x, also
called the ____________ is the number
of different chromosomes that make up a
single complete set
monoploid number
gene containing chromosomes that are
multiple of basic single set
EUPLOIDY
the variation in the chromosome number that
occurs due to increase or decrease of full
set of chromosomes
EUPLOIDY
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
is lethal in most animal species, but
often tolerated in plants, where it has played
a role in specification and diversification
euploidy
same species/ same individual
autoploidy
same species/different individual
allploidy
- 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
- can result when either round of meiotic division lacks cytokinesis, or when meiotic
nondisjunction occurs for all chromosomes
-did not separate
Monoploidy and polyploidy
A gamete with 2 sets of chromosomes fused
with a normal gamete produces a
triploid (3N) zygote
Complete nondisjunction at meiosis produce
____________ with the normal chromosomes, and ________________
½ gametes
½ with no chromosome
Fusion of 2 gametes that each have 2 sets of
chromosomes produces a
tetraploid (4N) zygote
can result from mitotic nondisjunction of complete chromosome sets
Polyploidy of somatic cells
An individual that contains ½ the normal
number of chromosomes is a ____________
and exhibits ___________
monoploid
monoploidy
Some species such as bee, ants and male
bees are normally _____________ because they
developed from unfertilized eggs.
Consequently, these individuals will be
sterile
monoploid
are very rare in nature because
recessive lethal mutations become
unmasked, and thus they die before they are
detected
Monoploids
These alleles normally are not a problem in
diploids because their effects are masked by
dominant alleles in the genome
MONOPLOIDY
- Occurs in cells and organisms when there
are more than 2 homologous sets of
chromosomes - Very common in plants
POLYPLOIDY
- polyploids as a result of
duplications in the SAME species
AUTOPOLYPLOIDS
- polyploid formed by the
hybridization BETWEEN TWO species.
ALLOPLOIDS
A ___________________. is derived from
hybridization from two or more diploid species
with chromosome doubling following the
hybridization
typica allopolyploid spp.
A human cell has ________chromosomes, which is an integral multiple of the monoploid number, 23
46
> MONOSOMY (2n-1)
NULLISOMY (2n-2)
HYPOPLOIDY
> TRISOMY (2n+1)
TETRASOMY (2n+2)
HYPERPLOIDY
- second most common condition
- there are 45 chromosomes in each cell of the body instead of the usual 46
Monosomy