54898.Where does this evidence come from? – crossing over takes place at a four-stranded stage and not at two stranded stages of chromosomes.
studies on linkage maps of chromosomes in Drosophila
studies of meiosis in maize
4:4 organization of ascospores in Neurospora
2:2:2:2 organization of ascospores in Neurospora
54900.Crossing-over takes place in the
Diakinesis stage
Anaphase stage
Pachytene stage
Leptotene stage
54901.If the percentage of crossing over between two genes is 10, then the distance between two genes will be
5 morganoid
10 morgan
20 centimorgans
40 map units
54903.Network of microfilaments and microtubules is classified as
cytoskeleton
active skeleton
vertebral skeleton
endoplasmic skeleton
54905.Alleles of different genes that are on the same chromosome can occasionally be separated by a phenomenon called
crossing over
continuous variation
epistasis
pleiotropy
54906.Cell lining of the lumen of the fallopian tube is involved in ciliary action to transport the egg from the ovary to the uterus. The cytoskeleton structure responsible for this movement is
flagella
microfilaments
microtubules
intermediate filaments
54907.The cytoskeleton is a structure maintaining the shape and internal organization of the cell, thereby rendering mechanical support. It is a network of fibers forming the eukaryotic cells, prokaryotic cells and archaeans. These fibers in the eukaryotic cells contain a complex mesh of protein filaments and motor proteins that help in cell movement. A cytoskeleton structure comprises the following types of fibers: Microfilaments, Microtubules and Intermediate Filaments. The cytoskeleton is composed of some motor proteins – dyneins, kinesin and myosin.This statement is true
microtubules are composed of tubulins
microfilaments are composed of actin
intermediate filaments are resistant to cytochalasin-B and colchicine
all the above
54908.In a linear chromosome map distance between 4 loci is as follows a-b is 10%, a-d is 3%, b-c is 4% and a-c is 6%. The crossover frequency between c and d is
4-12%
3-6%
9%
3%
54909.If gene frequency between genes a and c is 2%; b and c is 13%; b and d 4%; a and b 15%; c and d 17 and a and d 19%. The sequence of genes in a chromosome is
a,d,b,c
d,b,a,c
a,b,c,d
a,c,b,d
54910.Percentage of crossing over is more when
genes are located in a different cell
genes are not linked
linked genes are located close to each other
linked genes are located far apart from each other
54911.This cell lacks cytoskeleton
prokaryotic bacterial cells
eukaryotic plant cell
both (a) and (b)
prokaryotic and eukaryotic animal cells
54912.This is the reason why Mendel did not recognize linkage phenomenon in his experiments
he studied only pure plants
he did not have a powerful microscope
characters he studied were situated on different chromosomes
many chromosomes to handle
54913.This is the most heterogenous type of cytoskeleton filament
intermediate filaments
microfilaments
microtubules
none of the above
54915.Malformation of these cytoskeleton structures can be linked to an inability to contract muscle
microfilaments
microtubules
centrioles
intermediate filaments
54916.There are 4 pairs of chromosomes in a Drosophila. The linkage groups present in it are
one more than the pair of chromosomes
one less than the pair of chromosomes
four
eight
54937.The intermediate filament found in hair and nail is a type I IF protein composed of
tubulins
keratins
vimentins
lamins