Genetics and Evolution MCQ Quiz in मल्याळम - Objective Question with Answer for Genetics and Evolution - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

The correct answer is Option 1 i.e. Genetics.

Explanation-

Genetics is a branch of biology that is concerned with understanding how characteristics are transmitted from parents to offspring. This includes studying genes, heredity, and genetic variation in living organisms. Genetics also explains how traits and characteristics are influenced by genes and how they change over time in a population.

Microbiology is the study of microorganisms, including bacteria, viruses, fungi, and protozoa. This field encompasses multiple sub-disciplines:

Bacteriology: Study of bacteria.
Virology: Study of viruses.
Mycology: Study of fungi.
Parasitology: Study of parasites.
Immunology: Study of the immune system
Microbiologists primarily aim to understand how these tiny organisms live, grow, and interact with their environments - whether that environment be a pond, a human gut, or a deep-sea hydrothermal vent. 

Cytology is the study of cells – the basic building blocks of life. This field focuses on the structure and function of single cells and their components (like the nucleus, mitochondria, ribosomes, and so on), and cellular processes like energy production, gene expression, cell signaling, and cell division.

Conclusion-  The correct answer is Genetics.

The correct answer is option 3.

Solution

Concept:

• Hardy Weinberg Equilibrium is a model of the relation between alleles and genotype frequencies.
• It states that allele frequencies in a population are stable and constant, they are passed on from generation to generation.
• It is based on assumptions that there are no mutations, no selection, random mating, no migration, and the population size is infinite.

Explanation:

Natural selection is a process in which organisms better adapted to the environment have more chances of survival and reproduction. Natural selection can affect Hardy Weinberg equilibrium and can lead to the following:

• Stabilization is a type of natural selection in which genetic diversity decreases as the population stabilizes on a particular trait value. More individuals acquire mean character value. 
• Directional Change is a mode of natural selection in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype. 
• In this many individuals acquire character value other than the mean value.
• Disruptive change:
• This type of natural selection occurs when selective pressures are working in favor of the two extremes and against the intermediate trait.

In this more individuals acquire peripheral character value which is at the end of the distribution curve.

• (a) Directional change          (b)  Stabilization               (c) Disruptive change

So, the correct answer is option 3.

Concept:

• A test cross is done to find out the genotype of an individual whose genotype is unknown.
• It is usually done to find the kind alleles of a gene present in the genome of an individual for only one or two characters.
• In a test cross, one of the individuals is the one whose genotype for the character is unknown.
• For example, we want to know the genotype for height, which is expressed by one gene with two alleles, T and t.
• The recessive phenotype is expressed only in homozygous condition.
• But dominant phenotype may be homozygous or heterozygous.
• Thus, test cross helps in determining the unknown genotype of the dominant individual.
• There can be two scenarios: the individual with an unknown genotype can be
  1. TT (homozygous dominant)
  2. Tt (heterozygous)
• The individual with an unknown genotype will be crossed with one with a homozygous recessive genotype, i.e., tt.

Explanation

• In scenario 1 where the individual with an unknown genotype is homozygous dominant with genotype TT, all the progeny will be tall.
• The phenotype of all the progeny is tall.

​

• In scenario 2 where the individual with an unknown genotype is heterozygous with genotype Tt, half of the progeny are tall and half are dwarf.
• The phenotypic ratio is 2:2, 50% of the progeny is tall and 50% is short.

• This clear identification is because the use of a homozygous recessive individual in a test cross allows the expression of the unknown genotype.
• The recessive allele will not express until another allele also expresses dwarfism, so, it is easy to identify.

The correct answer is homologous. 

Concept:

• Organic evolution: Evolution is the very gradual process of development of living beings from single-celled organisms to organisms with complex structured organs performing different metabolic processes.
• The discovery of analogous organs and homologous organs are evidence for the process of evolution. 

Analogous organs:

• These are defined as the organs of different animals having different structures but perform the same functions.
• Examples:
  • Wings of insects and birds. 
  • Sweet potatoes and potatoes.
  • The tailfin of a lobster and the flukes of a whale.

Homologous organs:

• These are defined as the organs of different animals having similar structures but differ in their functions.
• Examples:
  • Forelimbs of frog, man, and the flippers of the whale.
  • The arm of a human and the leg of dogs, bulls.
  • A bat's wing and a whale's flipper.
  • The leg of a dog and the flipper of a dolphin or whale.

​

​These similarities in the organs laid down the formation of the theory of evolution. 

Explanation:

• The wings of the bat and flippers of whales are having similar structures. 
• But bats use it for flying while whales use it for swimming in the sea. 
• This change happens due to their different habitat and environment. 
• The organs get evolved according to the need. 
• But, the common structure in organs can clearly be seen.

So, the correct option is homologous. 

The correct answer is option 4.

Solution

Concept:

• The changes in the heritable characteristics of organisms over successive generations is called evolution.
• Evolution relies on the theory of natural selection. This theory is observed as the survival of the fittest.
• The genetic combinations of the stronger ones are carried forward while the weaker ones are eliminated.

Explanation:

Let us see the options:

• Industrial melanism
  • It is a phenomenon in which organisms developed melanism to adapt to environmental changes caused due to pollution.
  • Ex. In 1850s England before industrialization set in, the population of white-winged moths was more than dark-colored moths.
  • But post-industrialization, the population reversed. The tree trunks became dark due to smoke and soot from the industry as a result the white-winged moths were easily spotted by the predators.
  • Only the dark-winged moth survived and their population increased as a result of industrial melanism.
• ​ Natural selection
  • This theory was proposed by Charles Darwin often described as the survival of the fittest.
  • According to this theory, genetic combinations of organisms that are better adapted to their environment survive and produce new generations.
  • Ex. origin of the Giraffe's long neck, in order to eat leaves on the tree the giraffe adapted by the elongation of its neck. 
• Adaptive radiation
  • The process of evolution of different species in a geographical area starting from a point and then radiating to another habitat is called adaptive radiation.
  • Ex. Darwin finches on Galapagos island. Different varieties of finches were found on the same island, the difference was in their beak.
  • There were seed-eating finches, insectivores, and vegetarian finches.
• Convergent evolution
  • It is a phenomenon in which different structures in different organisms have evolved for the same function.
  • Ex. eyes of octopuses and mammals are analogous structures.
  • Another example is the flippers of Dolphins and Penguins; they both are analogous structures. They both help in swimming but are anatomically different. 

So, the correct answer is option 4.

The correct answer is pleiotropy.

Key Points

• The phenomenon in which a single gene may express more than one phenotypic effect is called pleiotropy.
  • Pleiotropy is a genetic condition when a single gene affects two or more distinct phenotypic characteristics or traits, with a single gene affecting multiple traits.
  • Multiple births Polygeny is a type of inheritance when the phenotype of a trait is influenced by more than one gene.

Additional Information

• Incomplete dominance is a form of gene interaction in which both alleles of a gene at a locus are partially expressed, often resulting in an intermediate or distinct phenotype. It is also known as partial dominance.
• Multiple alleles occur when more than two gene variants are present for the same locus.
  • For example, one allele of a gene causing height may be tall, while the other allele may cause dwarfism.
  • It simply indicates that three or more alleles are present in the population for a given gene.
• Codominance, as it relates to genetics, refers to a type of inheritance in which two versions (alleles) of the same gene are expressed differently to produce different traits in an individual.

CONCEPT:

• The Law of Independent Assortment states that when two pairs of traits are combined in a hybrid, the segregation of one pair of characters is independent of the other pair of characters.
• Two pea plants one with round green seeds RRyy and another with wrinkled yellow rrYY seeds produce F₁ progeny that have round, yellow RrYy seeds. When F₁ plants are selfed, the F₂ progeny will have a new combination of characters. It is the dihybrid cross.
• In a dihybrid cross, the phenotypes such as round, yellow; wrinkled yellow; round, green; and wrinkled green appeared in the ratio 9:3:3:1.

EXPLANATION:

• Two pea plants one with round green seeds RRyy and another with wrinkled yellow rrYY seeds produce F1 progeny that have round, yellow RrYy seeds. When F1 plants are selfed, the F2 progeny will have a new combination of characters.
• In this dihybrid cross, a new combination of hybrids comes out, these are round yellow and wrinkled green.
• The cross is in the following,

F₁:                                                  RrYy (Round and yellow)

Selfing of F₁:     RrYy (Round and yellow)   X   RrYy (Round and yellow)

Gametes:                          RY, Ry, rY, ry      X     RY, Ry, rY, ry

F₂:

• In the cross,

  • RRYY, RRYy, RrYY, RrYy, RRYy, RrYy, RrYY, RrYy, RrYy (Round yellow)

  • RRyy, Rryy, Rryy (Round green)

  • rrYY, rrYy, rrYy (Wrinkled yellow)

  • rryy (Wrinkled green)

Hence, the correct option is 2 i and iv.

Concept:

• Stanley Miller conducted an experiment in 1953, which established the chemical theory of evolution as proposed by Oparin and Haldane earlier.
• Chemical evolution - refers to the formation of diverse organic molecules from the existing inorganic molecules.
• It was stated that the first form of life originated from non-living organic molecules, which were in fact formed from inorganic molecules.

Important Points

• During the early years of formation of Earth, the climatic conditions were quite different from what it is in the present.
• Early Earth atmosphere was anoxic i.e., it lacked oxygen.
• Therefore, such conditions had to be created in the laboratory such as - high temperature, volcanic storms and reducing atmosphere with methane (CH₄) and ammonia (NH₃).
• To mimic the conditions, electric discharge was produced in a closed flask that contained CH₄, NH₃, H₂ and water vapour at 800°C.
• Formation of amino acids (organic molecules) were observed from this experiment, which supported the theory of chemical evolution.
• Formation of other organic molecules like sugars, nitrogenous bases, pigments and fats were also observed later by similar experiments.

Key Points

• An allele is an alternative form of the same gene.
• It is a slightly different DNA sequence present at the same locus (position on chromosome) on the homologous chromosomes.
• The gene variants still code for the same trait (e.g. hair color), but they differ in how the trait is expressed (i.e., brown, black, red, blonde hair).

Explanation:

• There are many variations of the same gene called alleles.
• Any diploid individual will have at least two alleles. Another individual can have a different set of alleles.
• But they will have the same location on the chromosome.
  • Any gene has a fixed position on DNA.
• So, the position of all the alleles on the DNA is also fixed.

Therefore, alleles are located on the same locus on homologous chromosomes.

Additional Information

1.  Homologous chromosomes
   • The chromosomes which pair with each other during meiosis.
   • They are made up of chromosome pairs of the same length, centromere position, and staining pattern.
   • They have the same genes with the same corresponding loci.
   • A pair of homologous chromosomes is formed by each homologue coming from each of the parent.
2. Non-homologous chromosome
   • They do not pair during meiosis.
   • They have different lengths, different centromere positions, and staining pattern.
   • They mostly have different sets of genes.