Consider a single locus with 2 alleles which are at Hardy-weinber

Subject

Life Sciences

Class

CNET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

1.

Which one of the following statements is true? 

  • The specific rotation of enantiomers will be identical 

  • The rate constant of a first order reaction has only time but no concentration units

  • The value of pH + pOH depends on temperature 

  • The bond disassociation energy (kJ/mol) of –C–C– will be greater than –C ≡C– 


2.

Which one of the following statements on protein conformation is NOT true?

  • Dihedral angles of side-chains in amino acids are depicted in the Ramachandran plot

  • Infrared spectroscopy can be used to deduce hydrogen bonding in peptides

  • Three dimensional structures of protein composed of ~100 amino acids can be obtained by nuclear magnetic resonance spectroscopy

  • Globular proteins have α-helical and β-sheet components. 


3.

Choose the correct answer from the following statements on biosynthesis

  • In the biosynthesis of palmitate, all the carbon atoms are derived from activated malonate 

  • The amino acids Met, Thr, Lys, Ile, Val and Leu are biosynthesized from oxaloacetate and pyruvate in most bacteria 

  • Alanine is a major precursor for the biosynthesis of porphyrin

  • Tryptophan is converted to L-DOPA in the biosynthesis of epinephrine 


4.

Which one of the following statements on nucleic acids is NOT true? 

  • The conformation of ribose in DNA is α-2'-deoxy-D-ribofuranose

  • Hydrolysis of RNA takes place under alkaline conditions unlike DNA, as the 2'-hydroxyl in RNA acts as a nucleophile in an intramolecular displacement

  • DNA can occur in different three-dimensional forms 

  • In DNA, deamination of cytosine to uracil can occur in a non-enzymatic manner 


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5.

A rectangular photo frame of size 30cm× 40cm has a photograph mounted at the centre leaving a 5cm border all around. The area of the border is

  • 600 cm2

  • 350 cm2

  • 400 cm2

  • 700 cm2


6.

At birthday, every child gets 2 chocolates, every mother gets 1 chocolates, while no fathers gets a chocolate. In total 69 persons get 70 chocolates. If the number of children is half of the total number of mothers and fathers put together, then how many fathers are there?

  • 22

  • 23

  • 24

  • 69


7.

Following are statements on β-turns:

(a) all the 20 coded amino acids have equal propensity to form β-turns.

(b) Pro cannot occur in β-turns

(c)Pro-Gly sequence strongly favours β-turns.

(d) In Asn-Gly β-turns, Asn can have positive Φ, Ψ values.

  • (b), (d)

  • (a), (c)

  • (a), (d)

  • (c), (d)


8.

What is the significance of upwelling zone for marine ecosystems?

  • It is responsible for uniformity of temperature in ocean to support the marine life

  • It brings nutrients from deeper zones to relatively nutrient poor oceans surface thus increasing marine producity.

  • It is responsible for uniform oxygenation of marine waters thus increasing marine productivity

  • It helps in circulating decomposers from the bottom of ocean to surface for proper decomposition of dead material on the surface


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9.

Given below in column A are schematic representation of three types of pairwise species interaction and the name of some interaction are in column B

Select the best match for interaction between column A and B in each schematic figure.

  • A-(iii), B-(ii), C-(iv)

  • A-(iv), B-(ii), C-(iii)

  • A-(ii), B-(iv), C-(i)

  • A-(iii), B-(i), C-(ii)


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10.

Consider a single locus with 2 alleles which are at Hardy-weinberg equilbrium. If the frequency of one the homozygous genotypes is 0.64, what is the frequency of heterzygotes in the population?

  • 0.16

  • 0.20

  • 0.32

  • 0.36


C.

0.32

Consider the case of a gene with alleles, A and a. The frequency of the A allele is p, and the frequency of the a allele is q.

We know that p+q=1, beacuse only these two alleles are present, so the sum of the fraction must be 1. We the know that q=1-p, and p=1-q, by simple math. A homozygous dominant individuals, AA, has two alleles, both A and a. If we go through each member of the population and count all of the A allel and a alleles, then the fraction of A alleles give p, and the fraction of the a alleles give q.

If a population is in a hardy-weinberg equilibrium, knowing the value of either p or q allow us to determine the fraction of individulas who are homozygous and heterozygous in the population.

For instance, if p= 0.8, then q= 1-p= 0.2

Therefore, p2= 0.64 and q2= 0.04 the frequency of heterozygotes in the population is 2pq= 2 × 0.2= 0.32, 0r 32%.


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