Genetics and Evolution MCQ Quiz - Objective Question with Answer for Genetics and Evolution - Download Free PDF

The correct answer is Hydrogen bonding potential based on base specificity.

Key Points

• The term "complementary" in DNA refers to the ability of nucleotide bases to pair specifically through hydrogen bonding, ensuring accurate replication and transcription.
• Adenine (A) pairs with Thymine (T) via two hydrogen bonds, while Cytosine (C) pairs with Guanine (G) via three hydrogen bonds.
• Complementary base pairing is guided by Chargaff's Rule, which states that the amount of A equals T, and the amount of C equals G in double-stranded DNA.
• This property is essential for the double-helix structure of DNA, where the two strands run antiparallel to each other.
• Complementary base pairing ensures genetic fidelity, allowing DNA to serve as a template for replication and RNA synthesis.

Additional Information

• Nucleotide Structure: Each nucleotide consists of three components: a phosphate group, a sugar molecule (deoxyribose in DNA), and a nitrogenous base (A, T, C, G).
• Antiparallel Orientation: DNA strands run in opposite directions, 5' to 3' and 3' to 5', allowing complementary base pairing.
• Hydrogen Bonding: These weak bonds stabilize the double-helix structure while allowing strand separation during replication and transcription.
• Chargaff's Rule: This rule provides the foundation for complementary base pairing, ensuring equal proportions of A-T and C-G pairs in double-stranded DNA.
• DNA Replication: Complementary base pairing enables each strand of DNA to act as a template for the synthesis of a new strand, ensuring accurate genetic transfer.

The correct answer is option 3.

Key Points

• Human insulin was the first hormone to be produced using recombinant DNA technology. Hence, option 3 is correct.
• It was developed by Genentech and Eli Lilly in the early 1980s, marking a major breakthrough in biotechnology and medicine.
• This synthetic insulin is called "Humulin", and it is produced by inserting the human insulin gene into E. coli bacteria, which then synthesize insulin.

Answer:
Correct Answer: B) Gregor Johann Mendel

Key Points

• Mendel conducted hybridization experiments on pea plants.
• He discovered that traits are inherited in specific ratios. 
• His work laid the foundation for modern genetics.
• He was an Austrian monk and scientist.
• His contributions were initially overlooked but later became the basis of classical genetics.

Additional Information

• Charles Darwin is known for the theory of evolution.
• Watson and Crick discovered the double-helix structure of DNA in 1953.
• Lamarck proposed an early theory of evolution based on the inheritance of acquired characteristics, which was later disproven.

Answer:
B) Adenine, Guanine, Uracil, Cytosine

Key PointsRNA (Ribonucleic Acid) is made up of four nitrogenous bases:

• Adenine (A)
• Guanine (G)
• Cytosine (C)
• Uracil (U)

In RNA, Uracil (U) replaces Thymine (T), which is found in DNA.

RNA is typically single-stranded, unlike DNA, which is double-stranded.

Important PointsBase Pairing in RNA:

• Adenine (A) pairs with Uracil (U)
• Guanine (G) pairs with Cytosine (C)

Key Points

Discoverers:

• James Watson (American biologist)
• Francis Crick (British physicist)
• Proposed the double helix model of DNA in 1953.

Model:

• DNA consists of two strands twisted into a double helix.
• The strands are held together by complementary base pairs:
• Adenine (A) pairs with Thymine (T)
• Cytosine (C) pairs with Guanine (G)

Nobel Prize:

• In 1962, the Nobel Prize in Physiology or Medicine was awarded to:
• James Watson, Francis Crick, and Maurice Wilkins
• Rosalind Franklin's crucial contributions were not recognized at the time due to her early death in 1958.

Concept:

• Analogy is the study of organisms with structures that are not anatomically similar but perform similar functions. There is no common ancestor between the two organisms. They are actually a product of convergent evolution. Example of analogy includes the structure of wings of a butterfly and of birds that are not looking anatomically similar but they perform similar functions.
• Homology is the study of organisms with similar anatomical structures.  Homologous organs evolved from the common ancestor. Homologous structures are a result of divergent evolution which explains that the same structures are developed along with different directions due to adaptations to different needs. An example includes the pattern of bones of forelimbs of frogs, lizards, birds, and humans that share similarities in their structures but performs different functions according to their needs in these animals.

Explanation:

• Homologous and analogous structures are often confused, Homologous organs have the same origin but perform different functions while analogous organs have different origins but perform the same functions 

• Somatic Mutation is not hereditary.
• Somatic Mutation is defined as the alteration in DNA that occurs after conception.
• It can occur in any of the cell body except the germ cells and therefore is not hereditary.

The correct answer is A, B, and AB.

Key Points

• Blood is a body fluid.
• ABO blood grouping was given by Karl Landsteiner.
• The parent's blood group is AB.
• The blood group proteins are present in the 'I ' gene.
• The genotype of a parent is IA IB.

• From the punnet square, we can see that,
• The Blood group can be A, AB, and B.
• The blood group shows codominance interaction.
• A and B are codominant over the O blood group.
• IAIA = A blood group as here only A  allele is present on the I gene.
• IAIB= AB blood group as here A and B allele is present on the I gene.
• IBIB=B blood group as here B allele is present on the I gene.
• If the blood group of both parents is AB, then the possible blood group of their children will be A, B, and AB.

Additional Information

Concept:

• Sex determination is the mechanism which determines the biological sex of an individual.
• Henking (1891) had observed a nuclear structure throughout the spermatogenesis process in few insects and named it X-body.
• He also observed that after spermatogenesis, half of the sperms received this X-body and half of them did not.
• It was later found that this X-body was a chromosome and hence it became the X-chromosome.
• As the X-chromosome is involved in the sex determination process, it is termed as a sex chromosome.
• The other chromosomes that are not involved in sex determination are known as autosomes.

Important Points

Sex Determination Types -

• Male Heterogamety -
  • Males produce 2 different types of gametes, while the female produces a single type of gamete.
  • This can again be of 2 types -
  1. XX/XY type - The females possess a pair of X-chromosomes, while the males possess one X-chromosome and one Y-chromosome. E.g.- Man, Drosophila.
  2. XX/XO type - The females possess a pair of X-chromosomes, but the males posses only one X-chromosome, thus having one less chromosome than the females. E.g.- Grasshopper.
• Female Heterogamety -
  • In this type, the females produce 2 different types of gametes, while the males produce a single type of gamete.
  • This is observed in some birds.
  • Here, the sex chromosomes are denoted as ZZ and ZW in males and females respectively.
  • Therefore, the sex determination type is known as ZW/ZZ type.

The correct answer is Golden age of Fishes.

Important Points

• The Devonian is a period of the Paleozoic Period.
• Fish reached substantial diversity during this time, leading the Devonian and thus called as "Age of Fish".
• The first ray-finned and lobe-finned bony fish appeared and placoderms began dominating almost every known aquatic environment in this period and thus called as the golden age of fishes. 

So, the Devonian period is also known as the Golden age of Fishes.

• Males have a single X and a single Y chromosome.
• Females can have only XX.
• Females will have defects related to the only X chromosome.
• Turner syndrome: Either X is missing or defected and XXX where extra is present. Males have a mix in XY present with excess Y added.

The correct answer is metamorphosis.

Key Points

• Metamorphosis process: The transformation of the larva into an adult through drastic changes is called metamorphosis. It is a biological process that involves sudden and abrupt changes in the body structure of the animal by cell growth and differentiation. It is generally observed in amphibians and insects. Examples: frogs and butterflies.

Important Points

• Metamorphosis of a butterfly
  • There are four stages in the process of the Metamorphosis of a butterfly.
  • The first stage is the egg.
  • The Butterfly eggs are laid on the plants by the female Butterfly.
  • The second stage is the larva stage in which the butterfly exists in the form of a caterpillar.
  • The Third stage is Pupa which is the transitional phase in which the Caterpillar changes into Butterfly.
  • The fourth stage is the Adult stage in which a full-grown adult butterfly comes out of the pupa.

Additional Information

• Complete metamorphosis is seen in butterflies. 
• Complete metamorphosis consists of a very active, ravenously eating larval stage and an inactive pupa stage while the incomplete metamorphosis has a nymph, which very closely resembles the adult
• Examples of insects showing Complete metamorphosis -  wasps, ants, butterflies, and fleas  
• Examples of insects showing Incomplete metamorphosis - are termites, praying mantis, and cockroaches

• Each human cell contains 23 pairs of chromosomes which mean 46 individual chromosomes.
• A chromosome is a threadlike structure that carries genetic information, they are made from DNA.
• Each human has 22 identical pairs of chromosomes and the 23rd pair decides the gender and are known as sex chromosomes.

The correct answer is Meiosis and fertilization.

Key Points

• Meiosis and fertilization:
  • Meiosis is a type of cell division that occurs in the formation of gametes (sperm and egg cells).
  • During meiosis, the chromosome number is reduced by half, leading to genetic diversity among the resulting gametes.
  • Fertilization then involves the fusion of these gametes, combining genetic material from two different individuals.
  • The combination of meiosis and fertilization results in offspring with unique combinations of genes, contributing significantly to genetic diversity.
  • Meiosis and fertilization are the two important features of sexual reproduction in higher organisms that create genetic diversity in offspring.

Additional Information

• Mitosis and fertilization:
  • Mitosis is a process of cell division that results in two daughter cells with the same genetic information as the parent cell.
  • While mitosis plays a crucial role in the growth and repair of tissues, it does not contribute to genetic diversity.
  • Fertilization, on the other hand, involves the fusion of gametes (sperm and egg cells) and brings together genetic material from two parents.
  • However, since mitosis does not involve the creation of genetically diverse offspring.
• Mitosis and binary fission:
  • Mitosis, as mentioned earlier, is a process of cell division that results in genetically identical daughter cells.
  • Binary fission is a method of asexual reproduction observed in prokaryotic organisms, where a single cell divides into two identical daughter cells.
  • Both mitosis and binary fission do not directly contribute to genetic diversity in offspring.
• Meiosis and conjugation:
  • ​Conjugation is a process of genetic exchange in some single-celled organisms, such as bacteria.
  • While it involves the transfer of genetic material, it is not a feature of sexual reproduction in higher organisms.
  • Meiosis, on the other hand, is a key process in the formation of gametes, contributing to genetic diversity when followed by fertilization.

The correct answer is 23.

Key Points

• Chromosomes reside inside the nucleus of cells.
• These are threadlike structures made of protein and a single molecule of DNA.
• It serves the purpose to carry the genomic information from cell to cell.
• A chromosome is a long DNA molecule with part or all of the genetic material of an organism.
• Most eukaryotic chromosomes include packaging proteins called histones which are aided by chaperone proteins.
• Together they bind and condense the DNA molecule to maintain its integrity.

Additional Information

• In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46.
• 22 of these pairs are known as autosomes having identical looks in both males and females.
• 23rd pair, the sex chromosomes, differ between males and females.
  • Females have two copies of the X chromosome while males have one X and one Y chromosome.