CBSE Questions for Class 12 Medical Biology Evolution Quiz 3 - MCQExams.com

• The Hardy-Weinberg principle states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences. 
• It operates in the absence of mutation, natural selection, and recombination.

• The heterotrophic hypothesis, also known as the Haldane-Oparin hypothesis after two scientists who independently proposed it, stats that life (organic molecules) could have formed from inorganic molecules. 
• In other words, life could have formed without requiring a 'divine nudge' and without having to come from another planet. 
• Much research has been conducted to explain how life could spontaneously form. The general theme is that components of the earth's atmosphere could form into complex organic molecules, which could then assemble into more complex groupings, which eventually would become life. 
• So, the heterotroph hypothesis assumes that a complex organism originated in simple surroundings.

• The heterotrophic hypothesis, also known as the Haldane-Oparin hypothesis after two scientists who independently proposed it, posits that life (organic molecules) could have formed from inorganic molecules.
• In other words, life could have formed without requiring a 'divine nudge' and without having to come from another planet.
• Much research has been conducted to explain how life could spontaneously form. 
• The general theme is that components of the earth's atmosphere could form into complex organic molecules, which could then assemble into more complex groupings, which eventually would become life.
• Heterotrophic hypothesis helps us to understand the definition of the term life, differences between the living and nonliving and increasing complexity moving from the atom to the simple molecule to complex proteins, to living organisms, populations, societies and communities.
  
  Thus, option D is correct.

• A protocell is a self-organized spherical body made up of a fatty acid membrane. 
• It is considered the first life found in marine water. It is also called protovirus or eobiont or protobiont by Oparin. 
• They did not have a definite nucleus. They were anaerobes and chemoheterotrophs.

Abiogenesis of primitive polypeptides, the pro-proteins, in primitive sea was followed by formation of large spherical colloidal aggregates of proteins that remain suspended as droplets in sea water. It was driven by dehydration/opposite charge attraction. The hydrophilic amino acids attracted water molecules and led to formation of a water envelop around each aggregate. Aggregation of fat/lipid molecules formed a coating membrane around each aggregate to hold the colloidal particles together thereby facilitating chemical reactions among them. A protobiont/eobiont/protocell is defined as aggregate of abiotically produced organic molecules surrounded by non-unit membrane. Thus, the above mentioned colloidal aggregate is protobiont/eobiont/protocell. It is called so because of its role as progenitor of first life form, the prokaryotic bacteria like cell. Thus, the correct answer is option D.

• The gene is autosomal recessive lethal, the heterozygous individuals carrying one copy of the affected allele and one of wild type allele will serve as carriers. 
• If the genotype of homozygous individuals for the recessive lethal gene is $$qq$$ and that of homozygous individuals for wild-type gene is $$pp$$ then the genotype of heterozygous individuals will be $$pq$$. 
• According to the question, the frequency of a recessive lethal allele is (q =  0.4). Frequency of wild-type allele : $$p = 1 - q, i.e., 1 - 0.4 = 0.6$$ 
• Hardy Weinberg law states that the sum of all genotype frequencies is represented as the binomial expansion of the square of the sum of p and q. This sum is equal to one.  $$(p + q)^2$$ = $$p^2$$ + $$2pq$$ + $$q^2$$ = $$1$$.
• Hence, the frequency of carrier genotype in total population $$(2pq)$$ =  $$2$$ X $$0.6$$ X $$0.4$$ = $$0.48$$. 
• And the number of carriers in the population of 200 is = $$0.48$$ X $$200$$ = $$96$$.