The "cri-du-chat" syndrome is caused by change in chromosome structure involving
deletion
duplication
inversion
translocation
A.
deletion
Cri du chat is a rare syndrome caused by a deletion on the short arm of chromosome 5. It is a rare genetic disorder due to a missing portion of chromosome 5. It refers to a distinctive cry of children. The cry is mainly caused by abnormal larynx development, which becomes normal within a few weeks of birth. Infants with cri du chat have low birth weight and may have respiratory problems.
Assertion: Polytene chromosomes have a high amount of DNA.
Reason: Polytene chromosomes are formed by repeated replication of chromosomal DNA without separation of chromatids.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Grain colour in wheat is determined by three pairs of polygenes. Following the cross AABBCC (dark colour) x aabbcc (light colour), in F2 generation what proportion of the progeny is likely to resemble either parent?
None
Less than 5 percent
One third
Half
Genes present in the cytoplasm of eukaryotic cells are found in
mitochondria and inherited via egg cytoplasm
lysosomes and peroxisomes
Golgi bodies and smooth endoplasmic reticulum
plastids and inherited via male gamete
In which one of the following sets of three items each belong to the category mentioned against them
Lysine, glycine, thiamine - amino acids
Myosin, oxytocin and gastrin - hormones
Rennin, helicase and hyaluronidase - enzymes
Optic nerve, oculomotor, vagus - sensory nerves
Which one of the following pairs of features is a good example of polygenic inheritance
Human height and skin colour
ABO blood group in humans and flower colour of Mirabilis jalapa
Hair pigment of mouse and tongue rolling in humans
Human eye colour and sickle cell anaemia
Mating of an organism to a double recessive in order to determine whether it is homozygous or heterozygous for a character under consideration is called
reciprocal cross
dihybrid crossn
test cross
back cross
Given below is a highly simplified representation of the human sex chromosomes from a karyotype
The gene a and b could be of
colour blindness and body height
attached ear lobe and Rhesus blood group
haemophilia and red-green colour blindness
phenylketonuria and haemophilia
Given below is a pedigree chart showing the inheritance ofa certain sex-linked trait in humans
The trait traced in the above pedigree chart is
dominant X- linked
recessive X- linked
dominant Y- linked
recessive Y- linked
