Structure And Development Of Seed And Fruit

The graph depicts Directional Selection, which occurs when one extreme phenotype is favored over others due to environmental pressures. Key points:
Definition: Directional selection shifts population traits toward one extreme, favoring individuals with advantageous traits.
Example: During industrial melanism, darker moths had better camouflage in polluted environments, increasing survival and reproduction rates.
Impact: Over time, populations evolve, favoring traits that enhance adaptability to specific environments.
Directional selection contrasts with:
Stabilizing Selection: Maintains traits within a specific range.
Disruptive Selection: Favors extreme phenotypes over intermediate ones.

Mosquito: Aedes aegypti.
Disease: Dengue or Zika virus.

The sporozoites take time to multiply in liver cells and then infect red blood cells, leading to symptoms.
Symptoms like fever, chills, and sweating appear after the parasites rupture red blood cells.

(1) Sporozoite – The infective stage that enters the human body.
(2) Gametocytes – The stage that enters the mosquito during a blood meal.

Bioactive molecules have diverse medical and industrial uses. Statins from {Monascus purpureus} lower cholesterol, reducing cardiovascular risks. Cyclosporin A from {Trichoderma polysporum} suppresses immune responses, vital for organ transplants.
Penicillin, an antibiotic from {Penicillium notatum}, combats bacterial infections.
Citric acid from {Aspergillus niger} serves as a food preservative and additive. Lactic acid from {Lactobacillus} aids food preservation.
These microorganisms' bioactive molecules highlight their significance in medicine, agriculture, and industry.

Advantage: Amniocentesis detects genetic or chromosomal disorders during pregnancy, helping in early diagnosis and medical intervention.
Disadvantage: Misuse for sex determination risks female feticide, raising ethical concerns. Regulatory measures are crucial to prevent such exploitation of this diagnostic tool.

Farmers use apomictic seeds because they are genetically identical to the parent plant, ensuring trait stability. These seeds eliminate the need for annual purchases, reducing costs while preserving desirable traits across generations without genetic variability.

Adenine pairs with thymine (31% each), totaling 62\%. Cytosine and guanine share the remaining 38%. Therefore, cytosine is 19%, following Chargaff’s rule, where purines (adenine, guanine) always pair with pyrimidines (thymine, cytosine).

X: Slurry tank stores organic waste mixed with water.
Y: Gas outlet releases methane-rich biogas.
Z: Digester uses anaerobic bacteria to decompose organic material, producing biogas and nutrient-rich slurry for agricultural purposes.

A probe is a labeled DNA or RNA strand used to identify specific sequences in molecular diagnostics.
It hybridizes with its complementary DNA, supporting Reason (R) as the explanation for Assertion (A).

Species-rich communities show greater stability as they buffer against environmental fluctuations.
Reason (R) explains Assertion (A), as a higher number of species ensures resource utilization efficiency and ecological balance, minimizing biomass variation.

The disorder is autosomal recessive based on the following observations:
The trait skips generations, as unaffected parents can pass the recessive allele to their offspring.
Both males and females are equally affected, indicating autosomal inheritance.
The condition appears only in individuals inheriting two copies of the recessive allele, one from each parent.
This pattern eliminates options for X-linked or dominant inheritance, confirming autosomal recessive inheritance.

In the fertilized embryo sac: A represents degenerating synergids as they are no longer needed post-fertilization.
B is the zygote, formed after the fusion of male and female gametes.
C is the Primary Endosperm Nucleus (PEN), which divides to form the endosperm, a nutritive tissue.
D shows degenerating antipodal cells that play no role after fertilization.

Humus is an amorphous, colloidal, dark-coloured substance.
It is resistant to microbial action and contributes to soil fertility.
Light-coloured humus is not a characteristic feature.

During sewage treatment, bacteria and fungal filaments aggregate to form flocs.
Flocs help in the breakdown of organic matter and are an essential part of biological treatment.

Fungal cells have a cell wall made of chitin.
Chitinase is the enzyme that breaks down chitin, allowing the release of DNA and other macromolecules.

The lac operon includes the following genes and their products:
'i' gene: Produces the repressor protein (iii).
'z' gene: Produces -galactosidase (i), which breaks down lactose.
'a' gene: Produces transacetylase (iv).
'y' gene: Produces lac permease (ii), which facilitates lactose entry into the cell.

- AIDS (Acquired Immunodeficiency Syndrome) is caused by the Human Immunodeficiency Virus (HIV), making (A) true.
- However, HIV is a retrovirus with RNA as its genetic material, not DNA, making (R) false.

Source of Smack.
Smack is a common name for heroin, a derivative of morphine.
Morphine is extracted from the latex of Papaver somniferum, commonly known as the opium poppy.

Identifying the labeled parts of the fertilized embryo sac.
- A represents degenerating synergids, which are no longer functional after fertilization.
- B is the zygote, formed by the fusion of male and female gametes.
- C is the Primary Endosperm Nucleus (PEN), which develops into endosperm to nourish the embryo.
- D represents degenerating antipodal cells, which have no role post-fertilization.

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.

The pBR322 vector is a widely used plasmid in genetic engineering. Key features include:
- BamHI site: A restriction site for inserting foreign DNA.
- Ampicillin resistance gene: Enables selection of transformed cells that can grow in the presence of ampicillin.
- Ori (Origin of replication): Ensures plasmid replication within the host cells.
- Rop gene: Regulates plasmid copy number for stable cloning. These components make pBR322 an efficient and versatile vector for molecular cloning, simplifying the process of inserting and propagating foreign DNA in host cells.

The diagram depicts Intracytoplasmic Sperm Injection (ICSI).
Sperm is directly injected into the egg's cytoplasm using a fine needle.
This method is used in cases of male infertility or low sperm count.

Trisomy of chromosome 21 results in Down syndrome.
Symptoms include furrowed tongue (i) and characteristic palm crease (ii). Other features vary and may include developmental delays.

In transcription, the coding strand's sequence directly determines the mRNA sequence, but with uracil (U) replacing thymine (T).
Coding strand: 5'–ATGAATG–3' \item mRNA transcript: 5'–AUGAAUG–3'