Down's syndrome is an example of
monosomy
trisomy
triploidy
polyploidy
Correct Answer :
B. trisomy
Related Questions
Dyad is
a pair of homologous chromosomes
a pair of non-homologous chromosomes
a pair of sister chromosomes
a pair of non-sister chromosomes
A child is bom with an extra chromosome in each of its cells. This is usually the result of
nondisjunction
crossing over
segregation
hybridization
If an individual does not breed true for its characters, it is called
homozygote
allelomorph
hybrid
ecotype
Chromosomes exhibit minimum coiling during
prophase
metaphase
interphase
telophase
Mutations which are not dominant are not lost by a gene pooL This is known as
Survival of the dominant
Survival of the recessive
Hardly-Weinberg law
None of these
The genetic constitution of an organism is known as
Genome
Genepool
Genotype
Phenotype
Linked genes may be separated by the process of
gene mutation
segregation
crossing over
polyploidy
Which one of the following chemical characteristics is not common to all living beings ?
Similar triplet codes for amino acids
Energy is stored by high energy rich phosphate bonds
Types of protein present in the body.
Ribosomes act at sites of protein synthesis
The first person to induce mutations was
Hugo de Vries
T.H. Morgan
Sturtevant
H.J. Muller
Down's syndrome is an example of
monosomy
trisomy
triploidy
polyploidy
Klinefelter's syndrome is developed when the chromosome in male is
XXY
XXXY
XXYY
All of these
A person meets with an accident and great loss of blood has occurred. There is no time to analyse his blood group. It is safe to transfuse blood of
An offspring of two homozygous parents different from one another by alleles at only one gene locus is known as
monohybrid
dihybrid
trihybrid
backcross
The chromosomal theroy of heredity implies that
chromosomes are composed of DNA and protein
genes are composed of chromosomes
organism cannot live withoutchromosomes
genes are located on the chromosomes and are transmitted to the next generation through them.
How many meiosis will be required to produce 102 pollen-grains ?
25
25.6
26
26.5
In a monohybrid cross the Fi ratio of a backcross is
1:1
3:1
1:2:1
9:3:3:3
Reverse transcription was discovered by
Watson
Crick
Temin
Porter
Lethal genes are those which
cause the death of the organism in which they are present
cause the death of the homozygous infant being formed
cause the death of heterozygous infant being formed
all of the above
Exhibition of superiority by a hybrid over both of its parents is called
heterosis
hybridization
hypostasis
dominance
The best method to determine whether an individual is homozygous or heterozygous is
inbreeding
cross-breeding
back-crossing
self-fertilization
Some people experience PTC paper on tongue as bitter, others as tasteless. This character is hereditary in nature. Suppose T stands for dominant gene and t for recessive gene, the genetic make up of a person who cannot taste is
TT
Tt
tt
None of these
The science dealing with study of inheritance and variation is
Genetics
Evolution
Morphology
Cytology
A giant chromosome having many chromo-nemata lying side by side all along their length is called
megachromosome
heterosome
polytene chromosome
super numerary chromosome
In humans, an example of sex-linked trait is
Curly hair
Sickle-cell anaemia
Colour-blindness
Down's syndrome
Which disease results from the genetic inability to synthesize a single enzyme ?
Diabetes
Phenylketonuria
Colour-blindness
Down's syndrome
A chemical mutagen is
X-rays
UV-rays
-rays
5-Bromo-Uracil
The term 'meiosis' was coined bv
Herting and Van Beneden
Sutton and Boveri
Hofmeister and Waldeyer
Farmer and Moore
Linkage is
directly related to crossing over
same as translocation
inversely related to crossing over
opposite to segregation
The scientists who rediscovered the Mendel's laws are
Mast and Pantin
Watson and Crick
Corren, Tschermark and Hugo de Vries
Khorana and Nirenberg
Colour blindness is caused due to
deficiency of vitamic C
sex-linked abnormality
absence of rods in retina
absence of visual purple in retina