Practice paper · Kolkata region

Foetal ejection reflex inhuman female is induced by

1. ARelease of oxytocin pituitary
2. BFully developed foetus and placenta
3. CDifferentiation of mammary gland
4. DPressure exerted by amniotic fluid

If a cross between two individuals produces offspring with 50% dominant character(A) and 50% recessive character (a) the genotype of parents is

1. AWw x Ww
2. BWw x ww
3. Cww x ww
4. DWW x Ww

Polygenic inheritance occurs in

1. AHuman eye colour and sickle cell anaemia
2. BHair pigment in Mouse and tongue rolling in humans
3. CHuman height and skin colour
4. DABO blood group in human and flower colour in Mirabilis jalapa

A cell is exposed to a chemical inhibitor that specifically blocks the activity of RNA polymerase II in eukaryotes. What will be the immediate effect of this inhibition on the cell?

1. AOnly the transcription of rRNA will be affected.
2. BTranscription of mRNA will stop, affecting protein synthesis.
3. CTranscription of all types of RNA will stop, including rRNA and tRNA.
4. DTranscription will continue unaffected, as the inhibitor targets a different RNA polymerase.

In a couple where both parents are carriers of the autosomal recessive disorder thalassemia, they are considering starting a family. Using your understanding of inheritance patterns, what is the probability that their child will be affected by thalassemia, and how would you explain the genetic basis behind this outcome?

1. A0% chance, as carriers cannot pass the disease to their children.
2. B25% chance, because both parents have a 50% chance of passing on the defective gene, leading to one quarter of their offspring being affected.
3. C50% chance, since the child will inherit one mutated gene from each parent.
4. D75% chance, as both parents are carriers, increasing the likelihood of the child inheriting the disorder.

The idea of natural selection depends on all the following except:

1. AVariation in traits within a population.
2. BOverproduction of offspring.
3. CSurvival and reproduction of individuals with advantageous traits.
4. DIntentional choices made by individuals to evolve.

Raj is studying certain organisms and found its base composition to be A=22%, T=28%, G=20%and C=30%. What will be his conclusion regarding its genetic material?

1. Asingle stranded RNA
2. Bsingle stranded DNA
3. Cdouble stranded RNA
4. Ddouble stranded DNA

Assertion: The tapetum is responsible for nourishing developing pollen grains during microsporogenesis. Reason: Tapetal cells are multinucleate and provide essential nutrients and enzymes required for pollen wall formation.

1. ABoth A and R are true and R is the correct explanation of A.
2. BBoth A and R are true and R is not the correct explanation of A.
3. CA is true but R is false.
4. DBoth Assertion and Reason are false.