Biogas Plant

The biomass pyramid will always remain upright in terrestrial ecosystems, where primary producers (plants) have the highest biomass. This occurs because plants form the largest biomass base, which supports consumers at higher trophic levels.

Plant breeders are interested in artificial hybridisation because it allows them to combine desirable traits from two different plant varieties into a single variety. This helps improve crop yield, resistance to diseases, and adaptability to environmental conditions. It is also a method to develop new plant varieties with enhanced traits. The process of artificial hybridisation involves the following steps: - Emasculation: Anthers are removed from the flower of the female parent to prevent self-pollination. - Bagging: The emasculated flower is covered to avoid contamination by unwanted pollen. - Pollination: Pollen from the desired male parent is manually transferred to the stigma of the emasculated flower. - Re-bagging: The pollinated flower is covered again to ensure successful fertilisation.

\begin{figure}[H] \centering \includegraphics[width=0.7\textwidth]{Screenshot 2025-01-16 182923.png} % Replace 'path_to_image' with the actual path to your image file \caption{Development of a megaspore mother cell into a mature embryo sac.} \label{fig:embryo_sac_development} \end{figure} The development involves the differentiation of a diploid megaspore mother cell (MMC) within the ovule. It undergoes meiosis to form four haploid megaspores, of which only one survives. The surviving megaspore undergoes three mitotic divisions, forming an eight-nucleate, seven-celled embryo sac. % Quick tip

\begin{itemize} \item Phase: Luteal phase (Day 15–28). \item Reason: The endometrium is thick and rich in blood supply during this phase, suitable for embryo implantation and nourishment. \end{itemize}

Curve \u2018B\u2019 (logistic growth) is more realistic because populations are subject to resource limitations, predation, and environmental constraints. Curve \u2018A\u2019 (exponential growth) assumes unlimited resources, which is rarely the case in natural ecosystems.

Curve \u2018B\u2019 (logistic growth) differs from curve \u2018A\u2019 (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.

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.

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.

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

Primer annealing.
(c) Write what is ‘C’? Name its source organism.
Solution: C: Taq DNA polymerase. Source: Thermus aquaticus. (d) Mention the use of this technique in molecular diagnostics.
Solution: Used in Polymerase Chain Reaction (PCR) to amplify DNA for genetic testing, disease diagnosis, and forensic analysis.

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, CO , and water during the anaerobic digestion of sludge.

Antibodies are Yshaped molecules produced by Blymphocytes. Chemical Nature: Proteins made of light and heavy polypeptide chains.

(i) Australopithecus (apelike) (ii) Homo erectus (manlike)

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

The diagram of a male gametophyte/microspore of an angiosperm should include: \begin{figure}[H] \centering \includegraphics[width=0.7\textwidth]{Screenshot 20250121 123807.png} % Replace 'path_to_image/male_gametophyte_diagram.jpg' with the path to your image \caption{Sectional view of a male gametophyte of an angiosperm. Labelled parts include: Exine, Intine, Vegetative Cell, and Generative Cell.} \label{fig:male_gametophyte} \end{figure} Functions: Generative cell: Divides to form two male gametes. Tube cell: Grows into a pollen tube to facilitate fertilization.

Western Ghats. IndoBurma region.

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.

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.

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)

Lactational amenorrhea prevents ovulation during intense lactation. Prolactin, the hormone responsible for milk production, suppresses gonadotropin release. (b) Why has our government intentionally imposed strict conditions for MTP (Medical Termination of Pregnancy)?
% Solution Solution: To prevent misuse and ensure MTP is conducted only for genuine medical or legal reasons. Protects the health and rights of women.

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.

The endosperm contains 30 chromosomes (3n, triploid), while the zygote has 20 chromosomes (2n, diploid). These are formed through double fertilization, unique to angiosperms. One sperm nucleus fertilizes the egg cell, forming the diploid zygote. Simultaneously, another sperm nucleus fuses with two polar nuclei, forming the triploid endosperm. This process ensures both the development of the embryo and the formation of a nutrient-rich tissue (endosperm) for seed nourishment, vital for seed germination and plant growth. % Quick tip

In an angiosperm, the cells with , , and ploidy levels are: (haploid): Antipodals, synergids, and egg cells. (diploid): Zygote, formed by the fusion of one sperm cell with the egg. (triploid): Endosperm, formed by the fusion of the second sperm cell with two polar nuclei in the embryo sac.

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.

When both parents are carriers (HbA HbS), the offspring have a 25\% chance of inheriting two sicklecell alleles (HbS HbS), causing the disorder.

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

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.

Out breeding devices: Selfincompatibility. Production of unisexual flowers. Explanation: These devices prevent selfpollination and promote crosspollination, which enhances genetic diversity and adaptation.

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

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.

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.

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

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.

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

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.

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

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.

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: 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: 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.

Transgenic tobacco plants produce double-stranded RNA (dsRNA) that targets essential genes in nematodes. Key Mechanisms: \begin{itemize} \item RNA Interference (RNAi): The dsRNA produced by the plant is absorbed by the nematode, where it triggers RNAi, silencing critical genes required for survival and reproduction. \item Gene Silencing: Without the expression of vital genes, the nematode cannot perform necessary cellular processes, leading to its death. \item Eco-friendly Approach: Unlike chemical pesticides, this method is specific to nematodes, leaving beneficial soil organisms unharmed. \end{itemize} Advantages: \begin{itemize} \item Protects crops effectively. \item Reduces reliance on chemical pesticides. \item Promotes sustainable agriculture. \end{itemize} % Quick tip

The vector used is Agrobacterium tumefaciens. Key Features: \begin{itemize} \item Ti Plasmid: The bacterium contains a tumor-inducing (Ti) plasmid, modified to include nematode-specific genes for safe transfer. \item RNAi Technology: The introduced genes produce double-stranded RNA, which triggers RNA interference (RNAi) to silence critical nematode genes. \item Eco-friendly Protection: Transgenic tobacco plants resist nematode infestation without the need for chemical pesticides. \end{itemize} Applications: \begin{itemize} \item Agrobacterium-mediated gene transfer is widely used to create transgenic plants with improved traits, such as pest and disease resistance. \end{itemize} % Quick tip

The nematode is Meloidogyne incognita, commonly known as the root-knot nematode. Key Details: \begin{itemize} \item It infects the roots of tobacco plants, causing the formation of characteristic root knots or galls. \item These galls disrupt the root structure, leading to reduced water and nutrient absorption. \item Infected plants exhibit stunted growth, wilting, and significantly reduced yields. \end{itemize} Management Practices: \begin{itemize} \item Crop rotation with non-host plants to break the nematode life cycle. \item Application of nematicides to control nematode populations. \item Development and use of nematode-resistant plant varieties. \end{itemize} % Quick tip

The hypothesis of the origin of life according to early Greek philosophers is referred to as Panspermia. It suggests that life arrived on Earth in the form of spores or microscopic life forms from outer space.