Gentics And Evoloution — Part 1 MCQs with Explanations

The correct answer is Option D: Stebbins . This quote explains how living things change and evolve over long periods. Let's break it down: 1. Variations make evolution possible : Imagine a group of plants. Some might be taller, some shorter, some have different colored flowers. These differences are called variations . Evolution, which is the process of life changing over time, can only happen if there are these differences among individuals. 2. Intermediate basis: Genetic Segregation and Recombination : Think of it like shuffling a deck of cards. You're not creating new cards, but you're getting new combinations. Similarly, genetic segregation (when genes separate during reproduction) and recombination (when genes from parents mix to form new combinations in their offspring) create new mixes of existing genetic material. This is a very important way to create diversity, but it's like rearranging what's already there. 3. Ultimate source: Mutation : This is the key! While shuffling cards (recombination) creates new hands, what if a card itself suddenly changed, or a new card appeared in the deck? That's what a mutation is. A mutation is a sudden, permanent change in the genetic material (DNA). It's the only way to introduce truly *new* genetic information into a population. So, mutations are the ultimate source because they create the original raw material for variation, which can then be shuffled around by segregation and recombination. Stebbins (G. Ledyard Stebbins) was a famous evolutionary biologist who was a key figure in developing the "Modern Synthesis" of evolution. This theory combined Charles Darwin's ideas of natural selection with Gregor Mendel's genetics and the understanding of mutations. His work emphasized the crucial role of mutation as the ultimate source of genetic variation upon which evolution acts. So, in simple terms: Mutations create new traits, and then those traits get mixed and matched through genetic segregation and recombination, allowing evolution to happen!

Let's break down this DNA pairing question! Statement 1: Adenine pairs with thymine (A : T) and guanine with cytosine (G : C). This is a fundamental rule of DNA base pairing, so it's TRUE . Statement 2: Adenine and thymine are joined by three hydrogen bonds. This is incorrect . Adenine and thymine are joined by TWO hydrogen bonds. So, it's FALSE . Statement 3: Guanine and cytosine are joined by two hydrogen bonds. This is also incorrect . Guanine and cytosine are joined by THREE hydrogen bonds. So, it's FALSE . Statement 4: The weak hydrogen bonding enables the two strands of the DNA to separate during replication. This is TRUE . The relatively weak hydrogen bonds are essential for DNA replication because they allow the DNA strands to be easily separated so they can be copied. Therefore, only statements 1 and 4 are true. The correct answer is Option D: Only 1 and 4 are true.

Let's break down this question! Statement 1: "DNA is the hereditary material of all living organisms." This is TRUE . DNA carries the genetic instructions for nearly all living things. Statement 2: "All segments of DNA code for synthesis of proteins." This is FALSE . Only specific sections of DNA, called genes , code for proteins. Many other DNA segments have regulatory or structural roles. Statement 3: "Nuclear DNA is double helical with two nucleotide chains which run anti-parallel." This is TRUE . DNA in the nucleus has a double helix shape, and the two strands run in opposite directions (anti-parallel). Statement 4: "DNA is also found in mitochondria." This is TRUE . Mitochondria, the powerhouses of the cell, have their own DNA. So, the correct statements are 1, 3, and 4. Therefore, the answer is Option C: 1, 3 and 4 .

Vector is the correct answer to “A piece of DNA molecule that can serve as a carrier for the gene to be cloned is called as a”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Hemizygous is the correct answer to “A haploid organism contains only one set of chromosomes, and is said to be”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

de Vries - Mutation theory is the correct answer to “Which of the following is the correct pair”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Transitions is the correct answer to “Substitution of a purine by a purine, of a pyrimidine by a pyrimidine, and of a base-pair by another base-pair which retains the original orientation of the purines and pyrimidines belongs to the class known as”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

All of the above is the correct answer to “The kind and amount of fertilizers to be applied to the soil are determined considering which of the following points”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Variable expressivity in addition to incomplete penetrance is the correct answer to “The gene producing chlorophyll deficiency in Lima bean (Phaseolus lunatus) exhibits”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Giovanni Arduino is the correct answer to “The first geological time scale was developed by”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

1, 2, 3 and 4 are true is the correct answer to “Consider the following statements regarding self-assembly and choose the correct answer: 1. Modern self-assembly theory holds that protobiogenesis occurred due to inherent property of chemical molecules of self organization 2. First clear cut demonstration of self-assembly was provided by Schmitt (1956) 3. The combination of proteins and nucleic acids, as in tobacco mosaic virus, is an example of intermacromolecular assembly 4. The modern researches of protobiogenesis by self-assembly challenge the central dogma of molecular biology suggested by Watson (1965)”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Translocation is the correct answer to “When a part of one chromosome is joined to a part of different chromosome, the aberration is called”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

thymine is the correct answer to “DNA differs from RNA in having nitrogenous base”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Observed frequency of double crossovers / Expected frequency of double crossovers is the correct answer to “The formula for 'coincidence' is”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

DNA and proteins is the correct answer to “Chromosomes consist of”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Wobble hypothesis is the correct answer to “According to which hypothesis, only the first two positions of a triplet codon on mRNA have a precise pairing with the bases of the tRNA anticodon”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

None of the above is the correct answer to “Consider the following statements. 1. The smallest RNA is t RNA. 2. The most abundant RNA of cell is r RNA. 3. DNA can be formed over RNA through reverse transcriptase. Which of the statements given above are false”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

None of these is the correct answer to “What is the chromosome number in it human ovum”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Gamow (1954) is the correct answer to “A triplet or three-letter code was first suggested by”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Only 1, 2 and 4 are true is the correct answer to “Consider the following statements regarding evolution and choose the correct answer: 1. The different divisions of algae have evolved from bacterial ancestors, probably from the members of autotrophic bacteria 2. The blue-green algae are the earliest plants known from the fossil record 3. The bryophytes have become differentiated into liverworts, hornworts and mosses which have further developed progressive types of plants 4. The earliest and primitive tracheophytes have succeeded in colonising the land”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

A pentose group is the correct answer to “Each strand of DNA consists of alternating molecules of deoxyribose which is”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Morgan unit is the correct answer to “The distance represented by 100 per cent crossover between two genes is known as”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Transformation is the correct answer to “The introduction of a naked DNA, linear or circularized, into a bacterium has been described as”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

14 - 20 Kb length of insert DNA is the correct answer to “Replacement phage vectors can accommodate”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Langur is the correct answer to “Among the following which one is not an ape”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Pyrophosphates is the correct answer to “The synthesis of RNA chain is energised by expenditure of energy in the form of”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Macrogenesis is the correct answer to “The sudden origin of new species, new higher taxa, or quite generally of new types by some sort of saltation has been termed”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

1, 2, 3 and 4 are true is the correct answer to “Consider the following statements regarding the nonhistone chromosomal proteins and choose the correct answer: 1. Nonhistone chromosomal (NHC) proteins occur in far great variety of forms than histones 2. Different tissues in the same organism differ in their NHC protein pattern 3. NHC proteins have been localized in the active regions of the chromosomes 4. Inhibition of transcription caused by histones is reversed on addition of NHC proteins”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Phytophthora palmivora is the correct answer to “Which of the following is an example of bioherbicide”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

A reciprocal translocation is the correct answer to “If two breaks occur in one chromosome, and one in a non-homologous one, the fragment from the first chromosome may become joined in an intercalary position in the second chromosome. This is a case of”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

phosphate group is the correct answer to “The hydrophilic nature of DNA is due to the presence of”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

SSB proteins is the correct answer to “The DNA strands separated into a fork, at the Ori C are bound by which of the following to keep them rigid and separate”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Watson and Crick is the correct answer to “Who proposed 3-D helical DNA model”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Petrifactions is the correct answer to “Which of the following are the most important among fossils since they show microscopic tissue structure often to the finest details”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Triticum and Secale is the correct answer to “Triticale, the first man made crop was derived by crossing”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

1, 2, 3 and 4 are true is the correct answer to “Consider the following statements regarding the conclusions drawn from fossil records and choose the correct answer: 1. There existed a multitude of diversified animal groups, similar to the animal groups that exist today 2. The most primitive forms of life are found in the oldest rocks 3. None of the past forms of life are exactly like any of those now living 4. All fossils did not appear at a time, but appeared during different great spans of times”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Only 1, 3 and 4 are true is the correct answer to “Consider the following statements regarding the origin of protobionts (protocells) and choose the correct answer: 1. The self-assembly process is internally controlled by selective intermolecular forces 2. The protocells possessed lipids, nucleic acids and had a definite molecular configuration 3. The protocells were heterotrophic 4. The instructions for the behaviour in the protocellular life-cycle were in the protenoids”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Gene is the correct answer to “The unit of DNA responsible for the appearance and inheritance of a character is known as a”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

Gregor Johann Mendel is the correct answer to “Who among the following is called the "Father of genetics"”. This question is standard in competitive examination syllabi for Gentics And Evoloution.

a-3, b-4, c-1, d-2 is the correct answer to “Match the following lists: List-I (Discoverer) List-II (Discovery) a. Jenner 1. Blood grouping b. Watson 2. Penicillin c. Landsteiner 3. Vaccination d. Fleming 4. Double helix”. This question is standard in competitive examination syllabi for Gentics And Evoloution.