GENETICS-PRELIM

NOTES KEY CONCEPTS/TERMS

CHAPTER 1.

1. Overview of Genetics

• Genetics in the 21st Century: Built on a rich history of discovery and experimentation, genetics has evolved from ancient theories to modern molecular biology.

• Transmission Genetics: The process by which traits controlled by genes are passed through gametes from one generation to the next.

• Molecular Genetics: The Watson-Crick model of DNA structure explains how genetic information is stored and expressed.

• Recombinant DNA Technology: Revolutionized genetics, enabling the Human Genome Project and the creation of genetically modified organisms (GMOs).

• Biotechnology: Applications in agriculture, medicine, and industry, including the use of model organisms to study human diseases.

• Ethical Concerns: Genetic technology is advancing faster than the policies and laws governing its use.

2. CRISPR-Cas: A Breakthrough in Genetic Technology

• CRISPR-Cas System: A molecular mechanism in bacteria that allows precise editing of DNA sequences in any organism.

• Mechanism: CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) produces RNA that binds to viral DNA, and Cas (CRISPR-associated) is a nuclease that cuts the DNA.

• Applications:

  • Human Genetic Disorders: Used to repair mutations in diseases like cystic fibrosis, Huntington’s disease, and sickle-cell anemia.

  • Agriculture: Editing genes in mosquitoes to prevent malaria, increasing biofuel production in algae, and creating disease-resistant crops.

• Ethical Concerns: Potential for editing human embryos, raising questions about the long-term impact on future generations.

3. Historical Development of Genetics

• Early Theories:

  • Aristotle (350 B.C.): Proposed that "humors" carried hereditary traits.

  • William Harvey (1600s): Proposed the theory of epigenesis, stating that organisms develop from a fertilized egg through a series of developmental events.

  • Preformationism: The idea that a fertilized egg contains a miniature adult (homunculus).

• Cell Theory (1830s): Proposed by Schleiden and Schwann, stating that all organisms are composed of cells derived from preexisting cells.

• Darwin and Mendel:

  • Charles Darwin (1859): Published On the Origin of Species, introducing the theory of natural selection.

  • Gregor Mendel (1866): Discovered the principles of inheritance through experiments with pea plants, laying the foundation for modern genetics.

4. Chromosome Theory of Inheritance

• Chromosomes: Identified in the late 19th century, chromosomes were found to carry genetic information.

• Mitosis and Meiosis: Processes of cell division that ensure the transmission of genetic material.

  • Mitosis: Produces identical diploid cells.

  • Meiosis: Produces haploid gametes, ensuring genetic diversity.

• Sutton and Boveri (Early 20th Century): Proposed that genes are located on chromosomes, unifying Mendel’s laws with chromosome behavior during meiosis.

5. DNA as the Genetic Material

• Avery, MacLeod, and McCarty (1944): Demonstrated that DNA, not protein, carries genetic information.

• Hershey and Chase (1952): Confirmed DNA as the genetic material using bacteriophages.

• Watson and Crick (1953): Discovered the double-helix structure of DNA, explaining how genetic information is stored and replicated.

6. Gene Expression: From DNA to Phenotype

• Central Dogma: DNA is transcribed into RNA, which is translated into proteins.

  • Transcription: DNA is used as a template to produce mRNA.

  • Translation: mRNA directs the synthesis of proteins using tRNA and ribosomes.

• Proteins: The end products of gene expression, responsible for the diversity of biological functions.

• Sickle-Cell Anemia: A single nucleotide change in the β-globin gene leads to a change in one amino acid, causing the disease. This demonstrates the link between genotype and phenotype.

7. Recombinant DNA Technology

• Restriction Enzymes: Used to cut DNA at specific sequences, enabling the creation of recombinant DNA molecules.

• Cloning: DNA fragments are inserted into vectors and replicated in bacterial cells, allowing for the production of large quantities of specific DNA sequences.

• Genomic Libraries: Collections of DNA clones representing an organism’s entire genome.

8. Impact of Biotechnology

• Agriculture: Genetically modified crops (e.g., herbicide-resistant corn and soybeans) have revolutionized farming.

• Medicine: Transgenic animals produce therapeutic proteins, and cloning technology has applications in both agriculture and medicine.

• Genetic Testing: Allows for the diagnosis of genetic disorders and the identification of carriers, raising ethical concerns about privacy and discrimination.

9. Genomics, Proteomics, and Bioinformatics

• Genomics: The study of genomes, including their structure, function, and evolution.

• Proteomics: The study of the complete set of proteins in a cell and their functions.

• Bioinformatics: The use of computational tools to analyze and manage large datasets generated by genomics and proteomics.

10. Model Organisms in Genetics

• Early Model Organisms: Fruit fly (Drosophila melanogaster) and mouse (Mus musculus) were used to study basic genetic principles.

• Modern Model Organisms: Roundworm (Caenorhabditis elegans), zebrafish (Danio rerio), and mustard plant (Arabidopsis thaliana) are used to study development and disease.

• Human Disease Models: Model organisms are used to study human diseases, such as cancer, diabetes, and neurodegenerative disorders, by transferring human genes into these organisms.

11. Ethical and Social Implications of Genetics

• Nobel Prizes in Genetics: Many Nobel Prizes have been awarded for discoveries in genetics, reflecting the field’s rapid advancement.

• Ethical Dilemmas: Issues such as genetic privacy, discrimination, and the ethics of gene editing (e.g., CRISPR-Cas) are ongoing concerns.

• Future Challenges: As genetic technology continues to advance, society must grapple with the ethical and legal implications of these discoveries.

12. Key Concepts and Questions

• Mendel’s Laws: Traits are passed from parents to offspring through genes, which segregate during gamete formation.

• Chromosome Theory: Genes are located on chromosomes, which are transmitted through gametes.

• DNA Structure: The double-helix structure of DNA explains how genetic information is stored and replicated.

• Central Dogma: DNA → RNA → Protein is the basis of gene expression.

• Biotechnology: Recombinant DNA technology has revolutionized agriculture, medicine, and industry.

• Ethics: The rapid advancement of genetic technology raises important ethical questions about its use and regulation.

13. Summary

• Genetics has evolved from Mendel’s experiments with pea plants to the modern era of genomics and biotechnology.

• The discovery of DNA as the genetic material and the development of recombinant DNA technology have transformed our understanding of biology.

• Model organisms play a crucial role in studying human diseases and understanding genetic mechanisms.

• Ethical concerns surrounding genetic technology, such as gene editing and genetic testing, are becoming increasingly important as the field advances.

CHAPTER 2

Chapter 2: Mitosis and Meiosis

Key Concepts

1. Genetic Continuity:

   • Mitosis ensures genetic continuity between generations of cells.

   • Meiosis ensures genetic continuity between generations of sexually reproducing organisms.

   • Both processes involve the distribution of chromosomes into progeny cells.

2. Chromosomes:

   • Eukaryotic cells contain pairs of homologous chromosomes (one from each parent).

   • Chromosomes are visible during mitosis and meiosis but are in a diffuse state (chromatin) during interphase.

3. Mitosis:

   • Converts a diploid cell into two diploid daughter cells.

   • Ensures each daughter cell has the same number of chromosomes as the parent cell.

4. Meiosis:

   • Reduces the diploid chromosome number to haploid.

   • Generates genetic variability by distributing different combinations of maternal and paternal chromosomes into gametes or spores.

2.1 Cell Structure and Genetic Function

• Cell Components:

  • Plasma Membrane: Controls movement of materials in and out of the cell.

  • Cell Wall (in plants): Made of cellulose.

  • Glycocalyx (in animals): A glycoprotein and polysaccharide layer that provides biochemical identity to cells (e.g., blood group antigens).

• Eukaryotic vs. Prokaryotic Cells:

  • Eukaryotes: Have a nucleus and membranous organelles.

  • Prokaryotes: Lack a nucleus and membranous organelles; DNA is in a nucleoid region.

• Cytoplasm:

  • Contains organelles like the endoplasmic reticulum (ER), ribosomes, mitochondria, and chloroplasts.

  • Cytoskeleton: Provides structural support and facilitates cell movement.

2.2 Chromosomes in Diploid Organisms

• Homologous Chromosomes:

  • Exist in pairs in diploid organisms.

  • Each pair has one chromosome from the maternal parent and one from the paternal parent.

  • Locus: The specific location of a gene on a chromosome.

• Chromosome Structure:

  • Centromere: Constricted region that determines chromosome shape.

  • Arms: Shorter arm (p) and longer arm (q).

  • Chromosomes are classified based on centromere position:

    • Metacentric: Centromere in the middle.

    • Submetacentric: Centromere slightly off-center.

    • Acrocentric: Centromere near one end.

    • Telocentric: Centromere at the end.

• Karyotype:

  • A display of chromosomes arranged by size, shape, and centromere position.

  • Humans have 46 chromosomes (23 pairs).

• Haploid vs. Diploid:

  • Haploid (n): One set of chromosomes (e.g., gametes).

  • Diploid (2n): Two sets of chromosomes (e.g., somatic cells).

2.3 Mitosis

• Purpose:

  • Ensures each daughter cell receives an identical set of chromosomes.

  • Critical for growth, development, and cell replacement.

• Cell Cycle:

  • Interphase:

    • G1: Cell growth and normal function.

    • S: DNA replication.

    • G2: Preparation for mitosis.

  • Mitosis (M): Division of the nucleus (karyokinesis) and cytoplasm (cytokinesis).

• Stages of Mitosis:

  1. Prophase:

     • Chromosomes condense.

     • Centrioles migrate to opposite poles.

     • Nuclear envelope breaks down.

  2. Prometaphase:

     • Chromosomes attach to spindle fibers via kinetochores.

  3. Metaphase:

     • Chromosomes align at the metaphase plate.

  4. Anaphase:

     • Sister chromatids separate and move to opposite poles.

  5. Telophase:

     • Chromosomes de-condense.

     • Nuclear envelope re-forms.

     • Cytokinesis divides the cytoplasm.

• Cytokinesis:

  • In animal cells: Cleavage furrow forms.

  • In plant cells: Cell plate forms.

2.4 Meiosis

• Purpose:

  • Produces haploid gametes or spores.

  • Generates genetic variation through:

    • Independent assortment of chromosomes.

    • Crossing over between homologous chromosomes.

• Meiosis I:

  • Prophase I:

    • Homologous chromosomes pair up (synapsis) to form bivalents.

    • Crossing over occurs, creating chiasmata.

  • Metaphase I:

    • Bivalents align at the metaphase plate.

  • Anaphase I:

    • Homologous chromosomes separate (disjunction).

  • Telophase I:

    • Two haploid cells are formed, each with duplicated chromosomes.

• Meiosis II:

  • Similar to mitosis but without DNA replication.

  • Anaphase II:

    • Sister chromatids separate.

  • Telophase II:

    • Four haploid gametes or spores are produced.

2.5 Gametogenesis

• Spermatogenesis:

  • Occurs in the testes.

  • Produces four haploid sperm cells from one diploid spermatogonium.

  • Cytoplasm is equally divided.

• Oogenesis:

  • Occurs in the ovaries.

  • Produces one haploid ovum and two or three polar bodies.

  • Cytoplasm is unequally divided to provide nutrients for the embryo.

2.6 Meiosis in Sexual Reproduction

• Genetic Variation:

  • Crossing over and independent assortment create unique combinations of maternal and paternal chromosomes.

  • Essential for evolution and adaptation.

• Life Cycles:

  • In fungi: Haploid cells dominate the life cycle.

  • In plants: Alternation between diploid sporophyte and haploid gametophyte stages.

2.7 Chromosome Structure

• Chromatin:

  • Uncoiled DNA-protein complex during interphase.

• Mitotic Chromosomes:

  • Formed by coiling and folding of chromatin fibers.

  • Visible during cell division.

Key Terms

• Homologous Chromosomes: Chromosome pairs with the same genes but potentially different alleles.

• Sister Chromatids: Identical copies of a chromosome connected by a centromere.

• Crossing Over: Exchange of genetic material between homologous chromosomes during meiosis.

• Karyotype: A visual representation of an organism's chromosomes.

• Haploid (n): A single set of chromosomes.

• Diploid (2n): Two sets of chromosomes.

Summary

• Mitosis ensures genetic continuity in somatic cells, producing two identical diploid daughter cells.

• Meiosis reduces the chromosome number to haploid, producing gametes or spores with genetic variation.

• Gametogenesis differs between males (spermatogenesis) and females (oogenesis), with oogenesis producing fewer, but larger, gametes.

• Crossing over and independent assortment during meiosis are key sources of genetic diversity.
  

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Chapter 3

1. Introduction to Mendelian Genetics

• Gregor Mendel: Often referred to as the "father of genetics," Mendel conducted experiments with garden peas (Pisum sativum) in the mid-19th century. His work laid the foundation for the field of genetics, though it was largely ignored until the early 20th century.

• Key Concepts:

  • Genes: Discrete units of inheritance that control traits.

  • Chromosomes: Structures that carry genes and are passed from parents to offspring.

  • Diploid Organisms: Organisms with two sets of chromosomes, one from each parent.

  • Mendel's Postulates: Principles that describe how traits are inherited, including segregation and independent assortment.

2. Mendel's Experimental Approach

• Model Organism: Mendel chose the garden pea because it was easy to grow, had a short life cycle, and could be easily cross-bred.

• Seven Traits: Mendel studied seven contrasting traits in pea plants, such as seed shape (round vs. wrinkled), seed color (yellow vs. green), and stem height (tall vs. dwarf).

• True-Breeding Strains: Mendel used plants that consistently produced the same traits when self-fertilized, ensuring purity in his experiments.

3. Monohybrid Cross

• Definition: A cross between two parents that differ in only one trait.

• Example: Crossing tall (TT) and dwarf (tt) pea plants.

• F1 Generation: All offspring were tall, indicating that tallness is dominant over dwarfness.

• F2 Generation: When F1 plants were self-fertilized, the offspring showed a 3:1 ratio of tall to dwarf plants, demonstrating Mendel's principle of segregation.

• Mendel's Postulates:

  1. Unit Factors in Pairs: Traits are controlled by pairs of unit factors (genes).

  2. Dominance/Recessiveness: One allele can mask the expression of another (dominant vs. recessive).

  3. Segregation: During gamete formation, the two alleles for a trait separate, so each gamete carries only one allele.

4. Modern Genetic Terminology

• Phenotype: The physical expression of a trait (e.g., tall or dwarf).

• Genotype: The genetic makeup of an organism (e.g., TT, Tt, or tt).

• Alleles: Different forms of a gene (e.g., T for tall and t for dwarf).

• Homozygous: Having two identical alleles (e.g., TT or tt).

• Heterozygous: Having two different alleles (e.g., Tt).

5. Punnett Squares

• Purpose: A diagram used to predict the genotype and phenotype ratios of offspring from a genetic cross.

• Example: A Punnett square for a monohybrid cross between two heterozygous tall plants (Tt x Tt) predicts a 3:1 phenotypic ratio (3 tall : 1 dwarf) and a 1:2:1 genotypic ratio (1 TT : 2 Tt : 1 tt).

6. Testcross

• Purpose: Used to determine the genotype of an organism with a dominant phenotype.

• Method: Cross the organism with a homozygous recessive individual.

• Outcome:

  • If all offspring show the dominant trait, the unknown genotype is homozygous dominant.

  • If the offspring show a 1:1 ratio of dominant to recessive traits, the unknown genotype is heterozygous.

7. Dihybrid Cross

• Definition: A cross between two parents that differ in two traits.

• Example: Crossing pea plants with yellow, round seeds (YYRR) and green, wrinkled seeds (yyrr).

• F1 Generation: All offspring were yellow and round, indicating that yellow and round are dominant traits.

• F2 Generation: When F1 plants were self-fertilized, the offspring showed a 9:3:3:1 ratio (9 yellow/round : 3 yellow/wrinkled : 3 green/round : 1 green/wrinkled), demonstrating Mendel's principle of independent assortment.

• Mendel's Fourth Postulate: Independent Assortment - Alleles for different traits segregate independently during gamete formation.

8. Trihybrid Cross

• Definition: A cross between two parents that differ in three traits.

• Example: Crossing plants with alleles AABBCC and aabbcc.

• F1 Generation: All offspring are heterozygous for all three traits (AaBbCc).

• F2 Generation: The offspring show a 27:9:9:9:3:3:3:1 ratio, which can be predicted using the forked-line method (branch diagram).

9. Rediscovery of Mendel's Work

• Early 20th Century: Mendel's work was rediscovered by scientists like Hugo de Vries, Carl Correns, and Erich Tschermak.

• Chromosome Theory of Inheritance: Walter Sutton and Theodor Boveri linked Mendel's principles to the behavior of chromosomes during meiosis, establishing that genes are located on chromosomes.

10. Genetic Variation and Probability

• Independent Assortment: Leads to extensive genetic variation because each pair of homologous chromosomes segregates independently.

• Probability Laws:

  • Product Law: The probability of two independent events occurring together is the product of their individual probabilities.

  • Sum Law: The probability of an event that can occur in multiple ways is the sum of the probabilities of each way.

11. Chi-Square Analysis

• Purpose: Used to determine if observed genetic ratios deviate significantly from expected ratios due to chance.

• Null Hypothesis (H₀): Assumes no real difference between observed and expected ratios.

• Chi-Square Formula:

  χ2=∑(o−e)2eχ2=∑e(o−e)2​

  where oo is the observed value and ee is the expected value.

• Degrees of Freedom (df): The number of categories minus one.

• Interpretation: If the p-value is less than 0.05, the null hypothesis is rejected, indicating that the deviation is not due to chance.

12. Pedigree Analysis

• Purpose: Used to study the inheritance of traits in humans, where controlled matings are not possible.

• Pedigree Symbols:

  • Circles represent females, squares represent males.

  • Shaded symbols indicate individuals expressing the trait.

  • Unshaded symbols indicate individuals not expressing the trait.

• Patterns of Inheritance:

  • Autosomal Recessive: Traits appear in offspring of unaffected parents (e.g., Tay-Sachs disease).

  • Autosomal Dominant: Traits appear in every generation (e.g., Huntington disease).

13. Case Study: Tay-Sachs Disease

• Molecular Basis: Caused by a deficiency of the enzyme hexosaminidase A (Hex-A), leading to the accumulation of gangliosides in nerve cells.

• Inheritance: Autosomal recessive; carriers (heterozygotes) show no symptoms but can pass the mutation to their offspring.

14. Online Mendelian Inheritance in Man (OMIM)

• Purpose: A database that catalogs human genes and genetic disorders.

• Example: Sickle-cell anemia, an autosomal recessive disorder caused by a mutation in the HBB gene.

15. Ethical Considerations in Genetic Testing

• Case Study: Huntington disease, an autosomal dominant disorder, raises ethical questions about genetic testing and informing family members.

• Issues: The psychological impact of knowing one's genetic risk, the right to privacy, and the decision to test children.

16. Problem-Solving in Genetics

• Example: Solving a dihybrid cross problem involving pea plants with different seed shapes and colors.

• Approach: Use Punnett squares and the forked-line method to predict genotypic and phenotypic ratios.

PRACTICE QUESTIONS

Sample Multiple Choice Questions

Sure! Here is the full, neatly arranged version of your multiple-choice questions from 1 to 50:

Genetics and Cell Biology Quiz

Basic Genetics

1. What is the basic unit of inheritance according to Mendel?

   • A) Chromosome

   • B) DNA

   • C) Gene ✅

   • D) Trait

2. Who is considered the father of genetics?

   • A) Charles Darwin

   • B) Gregor Mendel ✅

   • C) Watson and Crick

   • D) Avery, MacLeod, and McCarty

3. What do you call the alternative forms of a gene?

   • A) Loci

   • B) Alleles ✅

   • C) Chromatids

   • D) Phenotypes

4. What is the term for the specific location of a gene on a chromosome?

   • A) Chromatid

   • B) Locus ✅

   • C) Allele

   • D) Karyotype

5. Which Mendelian postulate states that alleles for different traits segregate independently?

   • A) Unit Factors

   • B) Dominance

   • C) Segregation

   • D) Independent Assortment ✅

Cell Division & Chromosomes

6. Which process ensures genetic continuity in somatic cells?

   • A) Mitosis ✅

   • B) Meiosis

   • C) Cellular Respiration

   • D) DNA Replication

7. What is the result of meiosis?

   • A) Two identical diploid cells

   • B) Four haploid gametes ✅

   • C) One diploid cell

   • D) Two haploid cells

8. Which process generates genetic variation through crossing over?

   • A) Mitosis

   • B) Meiosis ✅

   • C) Transcription

   • D) Replication

9. What type of chromosome consists of two identical chromatids?

   • A) Homologous chromosomes

   • B) Sister chromatids ✅

   • C) Autosomes

   • D) Sex chromosomes

10. How many chromosomes do humans have?

• A) 23

• B) 46 ✅

• C) 36

• D) 48

11. Which phase of mitosis involves the separation of sister chromatids?

• A) Prophase

• B) Metaphase

• C) Anaphase ✅

• D) Telophase

12. Which phase of meiosis involves homologous chromosomes pairing up?

• A) Prophase I ✅

• B) Metaphase I

• C) Anaphase I

• D) Telophase I

13. Which phase of meiosis is characterized by the separation of homologous chromosomes?

• A) Prophase II

• B) Anaphase I ✅

• C) Telophase II

• D) Metaphase II

14. During which stage of the cell cycle does DNA replication occur?

• A) G1 phase

• B) G2 phase

• C) S phase ✅

• D) M phase

15. What structure forms during cytokinesis in plant cells?

• A) Cleavage furrow

• B) Zygote

• C) Cell plate ✅

• D) Nucleus

Genetic Crosses & Ratios

16. What type of cross involves parents differing in two traits?

• A) Monohybrid Cross

• B) Dihybrid Cross ✅

• C) Test Cross

• D) Trihybrid Cross

17. What is the expected phenotypic ratio in the F2 generation of a monohybrid cross?

• A) 1:1

• B) 3:1 ✅

• C) 9:3:3:1

• D) 1:2:1

18. What is the expected genotypic ratio from a monohybrid cross of two heterozygous parents?

• A) 1:1

• B) 3:1

• C) 1:2:1 ✅

• D) 9:3:3:1

19. How many distinct phenotypes are produced in the F2 generation of a dihybrid cross?

• A) 2

• B) 3

• C) 4 ✅

• D) 16

20. What is the expected phenotypic ratio in the F2 generation of a dihybrid cross?

• A) 3:1

• B) 9:3:3:1 ✅

• C) 1:1

• D) 2:1

Molecular Biology & Biotechnology

21. What kind of RNA is produced during transcription?

• A) tRNA

• B) mRNA ✅

• C) rRNA

• D) hRNA

22. Which type of RNA carries amino acids to the ribosome during protein synthesis?

• A) rRNA

• B) mRNA

• C) tRNA ✅

• D) cRNA

23. The central dogma of molecular biology describes the process of:

• A) DNA → RNA → Protein ✅

• B) RNA → DNA → Protein

• C) Protein → DNA → RNA

• D) DNA → Protein → RNA

24. What is the role of a restriction enzyme in recombinant DNA technology?

• A) Cut DNA at specific sequences ✅

• B) Amplify DNA

• C) Sequence DNA

• D) Modify proteins

25. What is a key ethical concern surrounding CRISPR technology?

• A) The cost of implementation

• B) The speed of research

• C) Editing human embryos ✅

• D) Availability of resources

Here is the continuation of your neatly arranged quiz questions from 26 to 50:

Genetic Disorders & Applications

26. Which of the following traits follows autosomal recessive inheritance?

• A) Huntington's disease

• B) Tay-Sachs disease ✅

• C) Ocular Albinism

• D) Sickle-cell anemia

27. What genetic disorder is linked to a mutation in the HBB gene?

• A) Huntington's disease

• B) Tay-Sachs disease

• C) Sickle-cell anemia ✅

• D) Cystic fibrosis

28. What is the medical significance of transgenic organisms?

• A) They produce only healthy offspring

• B) They can be used for drug production ✅

• C) They do not cause diseases

• D) They are easy to breed

29. What is a karyotype?

• A) Measurement of genetic diversity

• B) A visual representation of an organism's chromosomes ✅

• C) The process of chromosome replication

• D) A method of genetic mapping

30. Which term describes the arrangement of chromosomes in an organism's cell?

• A) Chromatin

• B) Karyotype ✅

• C) DNA sequence

• D) Chromatid

DNA & Genetic Mutations

31. Which of the following ensures accurate cell division in eukaryotic cells?

• A) Cytokinesis

• B) DNA replication

• C) Chromosome alignment

• D) All of the above ✅

32. Which step in recombinant DNA technology creates many copies of a DNA sequence?

• A) Cloning ✅

• B) Transformation

• C) Sequencing

• D) Editing

33. Which major discovery is attributed to Watson and Crick?

• A) Chromosome Theory of Inheritance

• B) The structure of Proteins

• C) The structure of DNA ✅

• D) The process of Genetic Mutation

34. A genetic disorder caused by a single nucleotide change is known as what type of mutation?

• A) Deletion

• B) Substitution ✅

• C) Insertion

• D) Duplication

35. What is the fundamental difference between meiosis and mitosis?

• A) Resulting cell types

• B) Occurrence of DNA replication

• C) Number of divisions

• D) All of the above ✅

Genetic Principles & Probability

36. The probability of an offspring exhibiting a recessive trait is determined by which inheritance law?

• A) Product Law

• B) Sum Law

• C) Independent Assortment

• D) Law of Segregation ✅

37. What is the outcome of a testcross?

• A) Determining the sex of offspring

• B) Identifying the genotype of an organism with a dominant phenotype ✅

• C) Measuring gene expression

• D) Predicting genetic disorders

38. What is the expected phenotypic ratio in the F2 generation of a dihybrid cross?

• A) 3:1

• B) 9:3:3:1 ✅

• C) 1:1

• D) 2:1

39. Which of the following processes is NOT involved in genetic diversity?

• A) Crossing over

• B) Independent assortment

• C) Mitosis ✅

• D) Genetic mutation

40. What process describes the formation of gametes from diploid cells?

• A) Mitosis

• B) Meiosis ✅

• C) Binary fission

• D) Budding

Molecular Genetics & Gene Expression

41. What refers to the collection of all DNA sequences from an organism?

• A) Proteome

• B) Genome ✅

• C) Transcriptome

• D) Metabolome

42. The study of proteins expressed in a cell is known as what?

• A) Genomics

• B) Proteomics ✅

• C) Bioinformatics

• D) Transcriptome

43. Which type of RNA carries amino acids to the ribosome during protein synthesis?

• A) rRNA

• B) mRNA

• C) tRNA ✅

• D) cRNA

44. What is the main advantage of using model organisms in genetic research?

• A) Ease of manipulation

• B) Similarity to humans

• C) Short generation time

• D) All of the above ✅

45. What is the process of generating new sequences of DNA by combining sequences from different sources?

• A) Cloning

• B) Gene editing

• C) Genetic recombination ✅

• D) Sequencing

Genetic Engineering & CRISPR

46. Which phase of meiosis is characterized by the separation of homologous chromosomes?

• A) Prophase II

• B) Anaphase I ✅

• C) Telophase II

• D) Metaphase II

47. What is a key ethical concern surrounding CRISPR technology?

• A) The cost of implementation

• B) The speed of research

• C) Editing human embryos ✅

• D) Availability of resources

48. Which of the following reflects the correct name for the double-stranded helical structure of DNA?

• A) Nucleotide chain

• B) mRNA complex

• C) Ribosome

• D) Double helix ✅

49. Which step in recombinant DNA technology creates many copies of a DNA sequence?

• A) Cloning ✅

• B) Transformation

• C) Sequencing

• D) Editing

50. Which inheritance law states that alleles segregate independently?

• A) Product Law

• B) Sum Law

• C) Law of Segregation

• D) Independent Assortment ✅