• In a fertilized ovule of an angiosperm:
– n (haploid): Found in antipodal cells.
– 2n (diploid): Found in the zygote formed by fertilization.
– 3n (triploid): Found in the endosperm formed by double fertilization.
• This distribution of ploidy levels is characteristic of the angiosperm reproductive process.

• Ovum: The unfertilized egg cell (B) as shown in the diagram.
• Morula: A solid ball of cells (D) resulting from the early cleavage stages post-fertilization.
• Blastocyst: A hollow structure (G) formed in the early development of mammals, which implants in the uterine wall.

• A – The pill: Works by inhibiting ovulation (III).
• B – Condom: Prevents sperm from reaching the cervix (I).
• C – Vasectomy: Involves cutting/tying vas deferens, resulting in semen containing no sperm (IV).
• D – Copper-T: Prevents implantation of the fertilized egg in the uterus (II).

Step 1: Analyze the Pedigree Chart.
- Both males and females are affected, indicating autosomal inheritance.
- The disorder appears in siblings but not in the parents, which is characteristic of a recessive trait.
Final Answer: The genetic disorder depicted is autosomal recessive.

Step 1: Recall the Human Genome Project.
- Chromosome 1 was the last human chromosome to be fully sequenced due to its size and complexity. It contains the largest number of genes and a high number of repetitive sequences, making sequencing particularly challenging.
Final Answer: The last chromosome to be completely sequenced was Chromosome 1.

Step 1: Interpret the Anther Diagram.
- Connective tissue joins the two lobes of the anther.
- Endothecium forms the outer wall of the pollen sac.
- Pollen grains are present inside the pollen sac.
Final Answer: The correct identification is A – Connective, B – Endothecium, C – Pollen grain.

Step 1: Understand Turner’s Syndrome.
- Turner’s syndrome is a chromosomal disorder caused by the presence of a single X chromosome (45, XO) instead of two sex chromosomes.
- This is a form of aneuploidy, which refers to the loss or gain of chromosomes.
Final Answer: Turner’s syndrome is caused by aneuploidy.

Step 1: Recall the Central Dogma.
- Transcription (P): DNA to mRNA.
- mRNA (Q): Carries genetic information.
- Translation (R): mRNA to protein.
Final Answer: P – Transcription, Q – mRNA, R – Translation.

Step 1: Recall Evolutionary Theories.
- Hugo de Vries proposed the mutation theory, which states that evolution occurs through sudden, heritable changes in an organism’s genetic material.
- These mutations serve as raw material for natural selection.
Final Answer: The mutation theory was proposed by Hugo de Vries.

Step 1: Match Bioactive Substances to Their Actions.
- Statin: Lowers blood cholesterol (III).
- Cyclosporin A: Acts as an immuno-suppressive agent (IV).
- Streptokinase: Removes clots from blood vessels (II).
- Lipase: Removes oil stains (I).
Final Answer: A – III, B – IV, C – II, D – I.

Step 1: Understand Restriction Enzymes.
- Restriction enzymes, also known as molecular scissors, cut DNA at specific sequences.
- These enzymes are extensively used in genetic engineering and molecular biology.
Final Answer: Restriction enzymes are referred to as molecular scissors.

• ELISA (Enzyme-Linked Immunosorbent Assay) works on the principle of antigen-antibody binding to detect specific proteins or antibodies in a sample.
• The reaction between an enzyme-labeled antibody and its antigen is measured through color development, indicating the presence of the antigen.

• Fig and wasp share a mutualistic relationship where each depends on the other for survival and reproduction.
• Wasps pollinate fig flowers while laying eggs, ensuring mutual benefit.

• Plasmids are indeed circular DNA molecules capable of autonomous replication, but they are commonly found in prokaryotic cells like bacteria, not eukaryotes.

• Patents are legal rights granted to inventors for exclusive use of their inventions.
• The purpose of patents is to prevent unauthorized commercial use and ensure the protection of intellectual property, which directly explains the reason provided.

• Inverted biomass pyramids occur in aquatic ecosystems where the biomass of primary consumers exceeds that of producers.
• The energy transfer efficiency in trophic levels determines biomass, not the amount of energy required by higher trophic levels, which makes the reason valid but not explanatory for the assertion.

• The graph shows:
– Woman ‘X’: Normal thickening of the uterine wall due to regular hormonal activity.
– Woman ‘Y’: Lack of thickening indicates a hormonal imbalance or insufficient estrogen/progesterone secretion.

• Lactational amenorrhea prevents ovulation during intense lactation.
• Prolactin, the hormone responsible for milk production, suppresses gonadotropin release.

• To prevent misuse and ensure MTP is conducted only for genuine medical or legal reasons.
• Protects the health and rights of women.

• Source: Pancreas of pigs and cows.
• Reason: Animal insulin caused allergic reactions in some patients due to structural differences from human insulin.

• Human insulin is produced as proinsulin and requires processing to remove C-peptide.
• Eli Lilly produces ready-to-use recombinant insulin without requiring further processing.

• Grazing food chain: Begins with producers consumed by herbivores. (e.g., Grass → Deer → Lion)
• Detritus food chain: Begins with decomposers breaking down organic matter. (e.g., Dead leaves → Fungi → Earthworm)

• Brood parasitism: A reproductive strategy where one species lays eggs in the nest of another species.
• Example: Cuckoo lays eggs in crow nests; cuckoo chicks outcompete crow chicks for food.

• Biodiversity hotspots are regions rich in endemic species but threatened by habitat loss.
• Protecting hotspots helps conserve numerous species, ensuring ecosystem stability and reducing extinction rates.

• Western Ghats.
• Indo-Burma region.

Functions:
• Generative cell: Divides to form two male gametes.
• Tube cell: Grows into a pollen tube to facilitate fertilization.

Father’s Genotype: I^Ai
Mother’s Genotype: I^AI^B
Punnett Square:
[Insert Punnett Square Image/Text Here - Example below]
| | I^A | I^B |
|---|---|---|
| I^A | I^AI^A | I^AI^B |
| i | I^Ai | I^Bi |
Children’s Blood Groups:
• Blood Group A: I^AI^A, I^Ai
• Blood Group B: I^Bi
• Blood Group AB: I^AI^B

The ABO blood grouping is based on:
• The presence or absence of antigens (A and B) on the surface of red blood cells.
• The presence of antibodies (anti-A and anti-B) in the plasma.

• Skull A: Homo sapiens
• Skull B: Neanderthals
• Skull C: Australopithecus
• Skulls A and B are more similar to each other.

• (i) Australopithecus (ape-like)
• (ii) Homo erectus (man-like)

Steroids.

These drugs are consumed orally, injected, or applied topically.

Liver.

[Insert Antibody Diagram Here]
• Antibodies are Y-shaped molecules produced by B-lymphocytes.
• Chemical Nature: Proteins made of light and heavy polypeptide chains.

• Flocs: Aggregates of bacteria and fungi used in the secondary treatment to degrade organic matter in sewage.
• Anaerobic sludge digester: Breaks down organic matter into methane, CO₂, and water during the anaerobic digestion of sludge.

• A: Denaturation of DNA at high temperatures.
• D: Amplification of DNA after 30 cycles.

Primer annealing.

• C: Taq DNA polymerase.
• Source: Thermus aquaticus.

• Used in Polymerase Chain Reaction (PCR) to amplify DNA for genetic testing, disease diagnosis, and forensic analysis.

• Transgenic animals are engineered to produce important biological products like proteins and hormones.
• Example: Transgenic cows producing human lactoferrin, which has therapeutic applications.

• Transgenic animals are used as models to study human diseases and their progression.
• Example: Transgenic mice are commonly used to study cancer, diabetes, and Alzheimer’s disease.

• Transgenic animals are used to test the safety of chemicals and drugs before they are approved for human use.
• Example: Transgenic mice are used to assess the toxicity of new pharmaceutical compounds.

• Curve ‘A’: Exponential growth curve.
• Curve ‘B’: Logistic growth curve.
• Explanation: Exponential growth occurs under unlimited resources, showing a J-shaped curve. Logistic growth accounts for environmental constraints and levels off at the carrying capacity (K), forming an S-shaped curve.

• The dotted line represents the carrying capacity (K).
• Importance: Carrying capacity is the maximum population size that an environment can sustain indefinitely. It is determined by resource availability and environmental factors.

• Curve ‘B’ (logistic growth) differs from curve ‘A’ (exponential growth) because it incorporates the concept of limited resources and environmental resistance.
• Logistic growth considers population stabilization when reaching the carrying capacity, making it more realistic.

• Curve ‘B’ (logistic growth) is more realistic because populations are subject to resource limitations, predation, and environmental constraints.
• Curve ‘A’ (exponential growth) assumes unlimited resources, which is rarely the case in natural ecosystems.

• The exponential growth curve (Curve ‘A’) is more relevant because the human population continues to grow at a rapid rate, often exceeding the carrying capacity temporarily.
• However, environmental resistance like resource depletion and climate change will eventually necessitate stabilization, transitioning to a logistic growth model.

• The RNA product is mRNA (messenger RNA).
• Enzyme responsible: RNA polymerase II.

• Process: Splicing.
• Explanation: During splicing, non-coding regions (introns) are removed from the pre-mRNA, leaving only coding regions (exons) to form mature mRNA. This ensures the correct sequence for translating into a 400 amino acid polypeptide.

• Prokaryotes: One RNA polymerase is involved in transcription.
• Eukaryotes: Three RNA polymerases (RNA polymerase I, II, and III) are involved in transcription.

• Prokaryotes: Transcription occurs in the cytoplasm.
• Eukaryotes: Transcription occurs in the nucleus.

• Process: Spermatogenesis.
• Description: Spermatogenesis is the process of formation of sperm cells (spermatozoa) from the spermatogonial cells in the seminiferous tubules of the testes. It includes the following stages:
– Multiplication Phase: Mitotic division of spermatogonia to produce primary spermatocytes.
– Growth Phase: Enlargement of primary spermatocytes.
– Maturation Phase: Meiosis to produce haploid spermatids from secondary spermatocytes.
– Differentiation Phase: Spermatids transform into spermatozoa.

• The cell is the Sertoli cell.
• Function: Sertoli cells provide nourishment and structural support to the developing sperm cells. They also secrete inhibin, which regulates spermatogenesis.

• ‘A’: Chasmogamous flower.
• ‘B’: Cleistogamous flower.

• Characteristic feature:
– Chasmogamous flowers: Open flowers, reproductive parts exposed.
– Cleistogamous flowers: Closed flowers, reproductive parts not exposed.
• Modes of pollination:
– Chasmogamous flowers: Cross-pollination facilitated by agents like wind, insects, or water.
– Cleistogamous flowers: Self-pollination occurs as flowers never open.

• Outbreeding devices:
– Self-incompatibility.
– Production of unisexual flowers.
• Explanation: These devices prevent self-pollination and promote cross-pollination, which enhances genetic diversity and adaptation.

• Polarity: 5’ to 3’ direction.
• Number of additional amino acids: Depends on the number of codons left untranslated on the mRNA.
• Reason: Each codon corresponds to one amino acid, and translation stops when a stop codon is encountered.

• Initiating codon: AUG.
• Anticodon: UAC.
• Amino acid: Methionine.

• Charging of tRNA: Aminoacyl-tRNA synthetase attaches a specific amino acid to its corresponding tRNA, forming aminoacyl-tRNA.
• Importance: Charged tRNA ensures accurate addition of amino acids to the growing polypeptide chain during translation.

• The disorder causes red blood cells to assume a sickle shape under low oxygen conditions, leading to its name.

• It is caused by a point mutation in the β-globin gene, where glutamic acid is replaced by valine at the sixth position of the haemoglobin protein.
• The mutated haemoglobin (HbS) polymerizes under low oxygen conditions, leading to cell deformation.

[Insert Punnett Square Here]
• When both parents are carriers (HbA HbS), the offspring have a 25% chance of inheriting two sickle-cell alleles (HbS HbS), causing the disorder.

• Entry: HIV enters host cells (CD4+ T-cells) via surface receptors.
• Reverse transcription: Viral RNA is converted into DNA by reverse transcriptase.
• Integration: Viral DNA integrates into the host genome via integrase enzyme.
• Replication: Host machinery synthesizes viral components.
• Assembly and release: New viral particles are assembled and released, infecting other cells.
• Progression to AIDS: Gradual destruction of CD4+ cells leads to weakened immunity and opportunistic infections, culminating in AIDS.

• Symptoms:
– High fever with chills.
– Sweating and headache.
– Nausea and vomiting.
• Cause: The symptoms are caused by the rupture of red blood cells during the release of merozoites and the immune response to parasitic toxins.

• Gametocytes develop in human blood and are taken up by a mosquito during a blood meal.
• Fertilization occurs in the mosquito’s gut, forming a zygote.
• The zygote develops into an ookinete and then an oocyst.
• Sporozoites are released from the oocyst and migrate to the salivary glands, ready to infect another human.