Short note

Part I

44th BCS

1. Conjugation (38th)

2. Branchial Basket

3. Egg laying mammals (38th)

4. Tadpole larva

5. Dinosaur

6. Paramecium

43th BCS

7. Tracheal system

8. Liver fluke

9. Proglotid

10. Trochophore larva (41th)

11. Marsupial animals

12. Archaeopteryx (11th)

41th BCS

13. Marsupial animal

14. Polymorphism

15. Species diversity

16. Proglotid

17. Trochophore larva

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38th BCS

17. Canal system

18. Vermicomposting

19. Retrogressive metamorphosis

20. Venomous

Part II

1. Golgi bodies
2. DNA double helix
3. Water pollution
4. Endemic fauna
5. Continental drift
6. Gametogenesis (43rd BCS)
7. Sericulture (38th)
8. Glomerular filtration (38th)
9. Difference DNA and RNA
10. Importance of genetic Engineering in medical Science
11. Blood group (38th)
12. Problems and prospects of shrimp culture in Bd. 38th
13. Chromosome
14. Wildlife sanctuary
15. Cleavage

10. **Importance of Genetic Engineering in Medical Science**

Genetic engineering is the direct manipulation of an organism’s genes

using biotechnology. In **medical science**, it has revolutionized disease
treatment, drug development, and healthcare.

### **1. Disease Treatment & Gene Therapy**

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- **Gene Therapy:** Used to treat genetic disorders like **cystic fibrosis,
sickle cell anemia, and muscular dystrophy** by replacing faulty genes.
- **CRISPR Technology:** Allows precise gene editing to correct mutations
causing diseases.
- **Cancer Treatment:** Genetic engineering helps develop **personalized
cancer therapies** by modifying immune cells (CAR-T cell therapy).

### **2. Production of Medicines & Vaccines**

- **Insulin Production:** Genetically modified bacteria (E. coli) produce
**human insulin** for diabetes treatment.
- **Recombinant Vaccines:** Genetic engineering has led to vaccines like
**Hepatitis B and COVID-19 mRNA vaccines (Pfizer, Moderna)**.
- **Blood Clotting Factors:** Used to treat **hemophilia** using genetically
engineered cells.

### **3. Organ Transplantation (Xenotransplantation)**

- Genetic modification of animal organs (e.g., pigs) reduces rejection in
**human transplants**.
- **CRISPR-based gene editing** is making organ transplantation safer and
more successful.

### **4. Diagnosis of Genetic Disorders**

- **Genetic Screening:** Detects inherited diseases like **Down syndrome,
Huntington’s disease, and BRCA-related cancers**.
- **Personalized Medicine:** Tailors treatments based on a person’s genetic
profile (**pharmacogenomics**).

### **5. Stem Cell Research & Regenerative Medicine**

- Genetic engineering enhances **stem cell therapies** for conditions like
**spinal cord injuries, Parkinson’s disease, and heart disease**.
- Helps in **tissue engineering** for regenerating damaged organs.

### **6. Infertility Treatment & Reproductive Medicine**

- **Gene editing in embryos** may help prevent inherited disorders.

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- **In-vitro fertilization (IVF)** benefits from genetic screening for healthier
embryos.

### **7. Biopharmaceuticals & Drug Development**

- Genetically modified organisms (GMOs) are used to produce **antibiotics,
hormones, and monoclonal antibodies** for diseases like **cancer and
autoimmune disorders**.

### **Conclusion**
Genetic engineering has transformed **medical science**, improving
disease treatment, drug production, and healthcare. With advancements
like **CRISPR and gene therapy**, it holds immense potential for curing
genetic disorders and enhancing human health. However, ethical
considerations and safety regulations remain important in its application.

14**Wildlife Sanctuary**

A **wildlife sanctuary** is a protected area where wildlife is preserved in its

natural habitat. It provides a safe environment for **animals, birds, and
plants**, protecting them from **hunting, poaching, and habitat
destruction**.

### **Features of a Wildlife Sanctuary:**

- **Protection of Wildlife:** Hunting and poaching are strictly prohibited.
- **Limited Human Activity:** Activities like grazing and tourism may be
allowed but regulated.
- **Natural Habitat Conservation:** Ensures the survival of endangered
species.
- **Scientific Research & Education:** Supports ecological studies and
biodiversity awareness.

### **Importance of Wildlife Sanctuaries:**

1. **Biodiversity Conservation:** Helps protect endangered species like
tigers, rhinos, and elephants.
2. **Ecological Balance:** Preserves ecosystems and food chains.

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3. **Prevents Extinction:** Provides breeding grounds for threatened
species.
4. **Eco-Tourism & Economy:** Attracts tourists, creating jobs and revenue.
5. **Climate Regulation:** Maintains forests, which absorb CO₂ and
regulate temperature.

### **Threats to Wildlife Sanctuaries:**

- **Deforestation & Habitat Loss**
- **Illegal Poaching & Hunting**
- **Climate Change & Pollution**
- **Human Encroachment & Urbanization**

### **Famous Wildlife Sanctuaries:**

- **Sundarbans Wildlife Sanctuary (Bangladesh & India)** – Home to the
Royal Bengal Tiger.
- **Kaziranga Wildlife Sanctuary (India)** – Protects the one-horned
rhinoceros.
- **Yellowstone National Park (USA)** – A famous sanctuary for diverse
wildlife.
- **Kruger National Park (South Africa)** – Known for African big game
animals.

### **Conclusion:**
Wildlife sanctuaries play a crucial role in **preserving biodiversity and
protecting endangered species**. Strict conservation efforts and awareness
are necessary to maintain these vital ecosystems for future generations.

13 **Chromosome**

A **chromosome** is a thread-like structure made of **DNA and proteins**

found in the nucleus of cells. It carries genetic information that determines
an organism’s traits and is essential for cell division and inheritance.

### **Structure of a Chromosome:**

- **DNA:** Chromosomes are made of tightly coiled DNA.

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- **Histone Proteins:** Help in DNA packaging and stability.
- **Centromere:** The central region that divides a chromosome into two
arms.
- **Chromatids:** Two identical halves of a duplicated chromosome.
- **Telomeres:** Protective caps at the chromosome ends, preventing DNA
damage.

### **Types of Chromosomes (Based on Centromere Position):**

1. **Metacentric:** Centromere in the middle, arms are equal.
2. **Submetacentric:** Centromere slightly off-center, arms are unequal.
3. **Acrocentric:** Centromere near one end, with very short arms.
4. **Telocentric:** Centromere at the extreme end (not found in humans).

### **Functions of Chromosomes:**

- **Genetic Information Storage:** Carry genes that determine traits.
- **Cell Division:** Play a key role in **mitosis (body cell division)** and
**meiosis (reproductive cell division).**
- **Inheritance:** Pass genetic material from parents to offspring.
- **Protein Synthesis:** Provide the code for making proteins.

### **Human Chromosomes:**

- Humans have **46 chromosomes (23 pairs)** in each cell.
- **22 pairs are autosomes**, and **1 pair are sex chromosomes (XX in
females, XY in males).**

### **Chromosomal Disorders:**

- **Down Syndrome (Trisomy 21):** Extra chromosome 21.
- **Turner Syndrome (45, XO):** Missing an X chromosome in females.
- **Klinefelter Syndrome (47, XXY):** Extra X chromosome in males.

### **Conclusion:**
Chromosomes are vital for genetic inheritance and cell function.
Understanding them helps in medical research, genetics, and disease
diagnosis.

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1. Golgi Bodies (Golgi Apparatus or Golgi Complex)**

The **Golgi bodies**, also known as the **Golgi apparatus** or **Golgi

complex**, are membrane-bound organelles found in the **cytoplasm** of
eukaryotic cells. They play a crucial role in modifying, sorting, and
packaging proteins and lipids for secretion or delivery to other parts of the
cell.

### **Structure of Golgi Bodies:**

- **Cisternae:** The Golgi apparatus consists of stacked, flattened
membrane-bound sacs called **cisternae**.
- **Trans, Medial, and Cis Face:** The Golgi complex has three distinct
regions:
1. **Cis Face:** The side facing the **endoplasmic reticulum (ER)**,
where newly synthesized proteins and lipids enter the Golgi.
2. **Medial Face:** The middle region where further modifications (such
as glycosylation) occur.
3. **Trans Face:** The side where processed proteins and lipids exit,
usually in vesicles.
- **Vesicles:** Small membrane-bound sacs that transport molecules to and
from the Golgi body.

### **Functions of Golgi Bodies:**

1. **Protein Modification:** Modifies proteins by adding sugar molecules
(glycosylation) or phosphate groups, making them functional and ready for
secretion or use in the cell.
2. **Protein Sorting and Packaging:** Sorts proteins and lipids into vesicles
that are transported to their correct destinations, such as the cell
membrane or lysosomes.
3. **Secretion of Substances:** Packages proteins into secretory vesicles
for export outside the cell (exocytosis).
4. **Formation of Lysosomes:** Involved in the creation of **lysosomes**,
which contain digestive enzymes for breaking down waste materials.
5. **Lipids and Steroid Production:** Plays a role in synthesizing lipids,
steroids, and hormones in some cells.

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### **Golgi Bodies in Different Organisms:**
- **In Animal Cells:** Present in the cytoplasm near the nucleus and
endoplasmic reticulum.
- **In Plant Cells:** Golgi bodies are responsible for synthesizing
polysaccharides that form the **cell wall**.
- **In Fungi and Algae:** Golgi apparatus performs similar functions, but its
structure may vary.

### **Conclusion:**
Golgi bodies are essential organelles in cells for modifying, sorting, and
packaging proteins and lipids. Their functions are critical for processes like
secretion, cell communication, and maintaining cellular integrity.
2. DNA Double Helix

The **DNA double helix** is the structure of deoxyribonucleic acid (DNA),

which carries genetic information in living organisms. It was first described
by **James Watson and Francis Crick** in 1953, based on X-ray diffraction
data from **Rosalind Franklin** and **Maurice Wilkins**.

### **Key Features of the DNA Double Helix:**

1. **Two Strands:** DNA consists of two long chains (strands) of
nucleotides twisted around each other, forming a helical shape.
2. **Base Pairing:** The strands are connected by **complementary base
pairing**, where **adenine (A) pairs with thymine (T)** and **cytosine (C)
pairs with guanine (G)** through hydrogen bonds.
3. **Antiparallel Orientation:** The two strands run in opposite
directions—one in the **5' to 3'** direction and the other in the **3' to 5'**
direction.
4. **Sugar-Phosphate Backbone:** The structure is held together by a
backbone made of **deoxyribose sugar and phosphate groups**, giving it
stability.
5. **Major and Minor Grooves:** The twisting of the helix creates grooves
(major and minor), which play a role in protein binding and gene regulation.

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### **Functions of DNA:**
- **Genetic Storage:** DNA stores the genetic blueprint for building and
maintaining organisms.
- **Replication:** It can make identical copies of itself before cell division.
- **Protein Synthesis:** DNA provides instructions for making proteins via
transcription (mRNA synthesis) and translation (protein formation).

The **DNA double helix** is a fundamental discovery in molecular biology,

forming the basis for genetics, biotechnology, and medical research.

12. Problems and prospects of shrimp culture in Bd

Shrimp farming is a major industry in Bangladesh, contributing significantly

to the economy through exports. However, it faces various challenges and
opportunities.

## **Problems of Shrimp Culture in Bangladesh**

### **1. Environmental Issues**

- **Salinity Intrusion:** Excessive shrimp farming increases soil and water
salinity, affecting agriculture and drinking water.
- **Mangrove Destruction:** Expansion of shrimp farms leads to
deforestation of **Sundarbans** and other mangrove areas.
- **Water Pollution:** Use of chemicals, antibiotics, and waste from shrimp
farms pollutes local water bodies.

### **2. Disease Outbreaks**

- Shrimp diseases like **White Spot Syndrome Virus (WSSV)** and **Early
Mortality Syndrome (EMS)** cause massive losses.
- Lack of proper disease management and biosecurity measures.

### **3. Socio-Economic Challenges**

- **Land Conflicts:** Farmers converting rice fields to shrimp farms create
disputes over land use.

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- **Labor Exploitation:** Workers, especially women and children, often
receive low wages and poor working conditions.
- **Middlemen Dominance:** Farmers depend on middlemen, reducing
their profits.

### **4. Climate Change Impact**

- Rising sea levels and cyclones (e.g., **Cyclone Sidr, Aila**) damage
shrimp farms.
- Unpredictable weather affects shrimp growth and production.

### **5. Lack of Technological Advancement**

- Traditional farming methods lead to low productivity.
- Limited access to quality shrimp seed (post-larvae) and advanced farming
techniques.

---

## **Prospects of Shrimp Culture in Bangladesh**

### **1. High Export Potential**

- Shrimp (especially **Black Tiger Shrimp & White Leg Shrimp**) is a major
export commodity.
- **Europe, USA, and Japan** are key markets for Bangladeshi shrimp.

### **2. Government Support & Policies**

- Bangladesh has introduced **Blue Economy policies** to promote
sustainable shrimp farming.
- Incentives and training programs for farmers.

### **3. Expansion of Sustainable and Eco-friendly Farming**

- Adoption of **Integrated Multi-Trophic Aquaculture (IMTA)** and **biofloc
technology** to reduce environmental impact.
- Organic shrimp farming has a growing demand in global markets.

### **4. Employment and Rural Development**

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- Provides jobs to millions, including women and marginalized communities.
- Enhances economic conditions in coastal areas like **Khulna, Bagerhat,
Satkhira, and Cox’s Bazar**.

### **5. Technological Advancements**

- Development of **disease-resistant shrimp varieties**.
- Use of **recirculating aquaculture systems (RAS)** for better water
management.

---

## **Conclusion**
Despite challenges like environmental concerns, diseases, and climate
change, shrimp farming in Bangladesh has **huge potential**. By adopting
**sustainable practices, modern technology, and strong government
policies**, the industry can grow further and contribute more to the
**national economy** and **global seafood market**.

3 Water Pollution

**Water pollution** refers to the contamination of water bodies such as rivers, lakes, oceans,
and groundwater due to harmful substances. It poses serious risks to human health, aquatic life,
and the environment.

### **Causes of Water Pollution:**

1. **Industrial Waste:** Factories discharge toxic chemicals, heavy metals, and pollutants into
water sources.
2. **Sewage and Wastewater:** Untreated or poorly treated sewage introduces harmful
bacteria, viruses, and organic waste.
3. **Agricultural Runoff:** Pesticides, fertilizers, and animal waste from farms wash into water
bodies, causing pollution.
4. **Oil Spills:** Accidental spills from oil tankers and offshore drilling pollute oceans and coastal
areas.
5. **Plastic Waste:** Plastic debris, microplastics, and non-biodegradable materials harm
marine life.
6. **Thermal Pollution:** Industries release heated water, disrupting aquatic ecosystems.
7. **Acid Rain:** Emissions of sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) mix with rain,
making it acidic and harmful to water bodies.

### **Effects of Water Pollution:**

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- **Health Issues:** Contaminated water causes diseases like cholera, typhoid, and dysentery.
- **Loss of Aquatic Life:** Pollutants reduce oxygen levels, leading to fish and marine species
deaths.
- **Eutrophication:** Excess nutrients lead to algal blooms, which deplete oxygen and harm
aquatic ecosystems.
- **Disruption of Food Chains:** Toxic substances accumulate in aquatic organisms, affecting
the entire ecosystem.
- **Economic Losses:** Water pollution affects fisheries, tourism, and agriculture.

### **Prevention and Control Measures:**

- **Proper Waste Treatment:** Industries and households should treat waste before releasing it
into water bodies.
- **Reducing Plastic Use:** Limiting single-use plastics and promoting recycling help reduce
pollution.
- **Eco-friendly Agriculture:** Using organic fertilizers and proper irrigation reduces runoff.
- **Strict Regulations:** Governments should enforce laws to control industrial and domestic
pollution.
- **Public Awareness:** Educating people about the importance of clean water and sustainable
practices.

### **Conclusion:**
Water pollution is a serious environmental issue that requires immediate action. Sustainable
practices, strict regulations, and community efforts can help protect our water resources for
future generations.
7 **Sericulture (Silk Farming)**

**Sericulture** is the process of rearing **silkworms** for the production of **silk fiber**. It is an
important agro-based industry that provides employment and contributes to the textile sector.

### **Stages of Sericulture:**

1. **Silkworm Rearing:**
- The silkworm species **Bombyx mori** is commonly used.
- Silkworms are fed with **mulberry leaves** for growth.

2. **Cocoon Formation:**
- After 25-30 days, silkworms spin silk threads around themselves, forming cocoons.
- Each cocoon contains a **continuous silk thread** of about **300–900 meters**.

3. **Cocoon Harvesting:**
- Cocoons are collected and subjected to **stifling** (exposure to heat) to kill the pupa inside.

4. **Reeling of Silk:**
- Silk fibers are unwound from the cocoons in hot water.
- The extracted silk threads are **twisted and woven** into fabric.

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### **Types of Silk:**
- **Mulberry Silk** – Most common and high-quality silk.
- **Tasar Silk** – Produced by wild silkworms.
- **Eri Silk** – Soft and warm, from **Philosamia ricini** worms.
- **Muga Silk** – Golden yellow silk found in Assam, India.

### **Importance of Sericulture:**

- **Economic Growth:** Provides employment to farmers and artisans.
- **Exports:** Silk products have a high demand in the global market.
- **Sustainable Farming:** Utilizes natural resources efficiently.
- **Cottage Industry:** Encourages small-scale industries in rural areas.

### **Challenges in Sericulture:**

- Diseases affecting silkworms.
- High production costs.
- Environmental factors like temperature and humidity.
- Competition from synthetic fibers.

### **Conclusion:**
Sericulture is a profitable and eco-friendly industry that plays a vital role in the textile sector.
With proper technology and government support, it can boost rural economies and global silk
production.

Difference between DNA and RNA

Features DNA RNA

Structure Double-stranded helix Single-stranded

Sugar Deoxyribose (lacks one oxygen Ribose (has an extra oxygen

atom) atom

Nitrogenous Bases Adenine (A), Thymine (T), Adenine (A), Uracil (U) (instead of
Cytosine (C), Guanine (G Thymine), Cytosine (C), Guanine
(G)

Location Mostly in the nucleus (also in Found in the nucleus and

mitochondria cytoplasm

Function Stores genetic information for Involved in protein synthesis anc

inheritance gene expression

Stability More stable due to the absence Less stable, degrades more
of an extra oxygen atom easily

Types One main type Three main types: mRNA, tRNA,

rRNA

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Replication Self-replicating Synthesized from DNA
(transcription

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