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What Causes Inherited Genetic Diseases Having A Predisposition To Cancer?

Several inherited genetic diseases in which there is a predisposition to cancer are caused by mutations in the cellular systems that respond to... View Article

How Might Defective Double-strand Break Repair Lead To Gross Chromosome Rearrangements?

Rearrangements can arise from failures in the repair of double-strand breaks by homologous recombination. As human chromosomes contain so much... View Article

How Harmful Are Non-reciprocal Translocations?

Non-reciprocal translocation could be specifically dangerous if it produces a chromosome with two centromeres (a dicentric chromosome). The two... View Article

Describe Telomeres Briefly.

Telomeres are the tracts of repetitive DNA found at the ends of chromosomes that are packaged in particular, proteins providing a protective cap... View Article

What Is Aneuploidy And Tetraploidy In Cancer Cells?

Usually, human cancer cells have unusual numbers of chromosomes, a condition called aneuploidy. The chromosome number in the later stages of... View Article

What Mainly Causes Tetraploidy?

Tetraploidy is considered mainly to be caused by failures in cytokinesis. In the mammalian cell cycle, progression from mitosis to G1 is not... View Article

Write About The Occurrence Of Tetraploidization.

Tetraploidization occurs at a small but significant rate even in normal cells, perhaps as a response to minor defects in chromosome segregation.... View Article

Can Cancer Tumours Be Cured?

In most cases, Cancer is fatal as it invades tissues and colonizes them, which gradually destroys and disrupts its function. Most of the tumours... View Article

What Goals Must Ideal Cancer Treatment Achieve?

The ideal cancer treatment must achieve two goals. First, the treatment must focus specifically on tumour cells and leave normal cells unscathed.... View Article

In Antirrhinum two plants with pink flowers were hybridized. The F1 plants produced red, pink and white flowers in the proportion of 1 red, 2 pink and 1 white. What could be the genotype of the two plants used for hybridization? Red flower colour is determined by RR, and white by rr genes?

A) RR B) rr C) Rr D) rrrr Answer: C) Rr Explanation: Antirrhinum or snapdragon shows incomplete dominance. In incomplete dominance there... View Article

The genotype of a plant showing the dominant phenotype can be determined by

A) dihybrid cross B) test cross C) back cross D) pedigree analysis Answer: B) test cross Explanation: Test cross involves crossing a plant... View Article

Select the correct statement from the ones given below with respect to dihybrid cross.

A) Genes far apart on the same chromosome show very few recombinations B) Tightly linked genes on the same chromosomes show higher... View Article

Test cross in plants or in Drosophila involves crossing

A) between two F1 hybrids B) between two genotypes with recessive trait C) between two genotypes with dominant trait D) the F1 hybrid with a... View Article

Which one of the following conditions of the zygotic cell would lead to the birth of a normal human female child?

A) Only one Y chromosome B) Two X chromosomes C) One X and one Y chromosome D) Only one X chromosome Answer: B) Two X chromosomes... View Article

Which one of the following conditions correctly describes the manner of determining the sex?

A) XO type of sex chromosomes determine male sex in grasshopper B) Homozygous sex chromosomes (ZZ) determine female sex in birds C) Homozygous... View Article

When two unrelated individuals or lines are crossed, the performance of F1 hybrid is often superior to both its parents. This phenomenon is called

A) transformation B) heterosis C) metamorphosis D) splicing Answer: B) heterosis Explanation: Improved quality or function in the hybrid is... View Article

A test cross is carried out to

A) predict whether two traits are linked B) determine the genotype of a plant at F2 C) determine whether two species or varieties will breed... View Article

F2 generation in a Mendelian cross showed that both genotypic and phenotypic ratios are the same as 1 : 2 : 1. It represents a case of

A) dihybrid cross B) codominance C) monohybrid cross with incomplete dominance D) monohybrid cross with complete dominance Answer: C)... View Article

Down’s syndrome in humans is due to

A) three copies of chromosome 21 B) three ‘X’ chromosomes C) two ‘Y’ chromosomes D) monosomy Answer:A) three... View Article

If two persons with ‘AB’ blood group marry and have sufficiently large number of children, these children could be classified as ‘A’ blood group: ‘AB’ blood group : ‘B’ blood group in 1 : 2 : 1 ratio. Modern technique of protein electrophoresis reveals presence of both ‘A’ and ‘B’ type proteins in ‘AB’ blood group individuals.

A) complete dominance B) partial dominance C) incomplete dominance D) codominance Answer:D) codominance Explanation: It is an example of... View Article

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