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CBSE Class 12 Chemistry Chapter 16 Revision Notes

Industrial Chemistry

CBSE Class 12 Chemistry Chapter 15 Revision Notes

Organic Chemistry

CBSE Class 12 Chemistry Chapter 14 Revision Notes

Biochemistry

CBSE Class 12 Chemistry Chapter 13 Revision Notes

CBSE Class 12 Chemistry Chapter 12 Revision Notes

CBSE Class 12 Chemistry Chapter 11 Revision Notes

CBSE Class 12 Chemistry Chapter 10 Revision Notes

CBSE Class 12 Chemistry Chapter 9 Revision Notes

Inorganic Chemistry

CBSE Class 12 Chemistry Chapter 8 Revision Notes

CBSE Class 12 Chemistry Chapter 7 Revision Notes

CBSE Class 12 Chemistry Chapter 6 Revision Notes

CBSE Class 12 Chemistry Chapter 5 Revision Notes

Physical Chemistry

CBSE Class 12 Chemistry Chapter 4 Revision Notes

CBSE Class 12 Chemistry Chapter 3 Revision Notes

Electrochemistry

CBSE Class 12 Chemistry Chapter 2 Revision Notes

CBSE Class 12 Chemistry Chapter 1 Revision Notes

Analytical Chemistry

CBSE Class 12 Physics Chapter 15 Revision Notes

Modern Physics

CBSE Class 12 Physics Chapter 14 Revision Notes

Electricity and Electronics

CBSE Class 12 Physics Chapter 13 Revision Notes

Nuclear Physics

CBSE Class 12 Physics Chapter 12 Revision Notes

CBSE Class 12 Physics Chapter 11 Revision Notes

CBSE Class 12 Physics Chapter 10 Revision Notes

Optics

CBSE Class 12 Physics Chapter 9 Revision Notes

CBSE Class 12 Physics Chapter 8 Revision Notes

Magnetism

CBSE Class 12 Physics Chapter 7 Revision Notes

CBSE Class 12 Physics Chapter 6 Revision Notes

CBSE Class 12 Physics Chapter 5 Revision Notes

CBSE Class 12 Physics Chapter 4 Revision Notes

CBSE Class 12 Physics Chapter 3 Revision Notes

CBSE Class 12 Physics Chapter 2 Revision Notes

CBSE Class 12 Physics Chapter 1 Revision Notes

# Chapter 3: Human Reproduction
__[3D Model Library](https://www.inspiritvr.com/search?resource=model3d)__

## __The Male Reproductive System__
![male reproductive system](//images.ctfassets.net/4yflszkpcwkt/3umghiT8jggL8wb6ZTp6Cs/ffe3b455c78273b37f97f0add2e7b9ec/male-anatomy-en.svg)
- The __male reproductive system__ consists of a pair of __testes and accessory glands, ducts, and external genitalia__ and is located in the pelvic area. 
- The testes are positioned just outside the abdominal cavity and encased in a sac-like structure known as the __scrotum__. 
- The __rete testis, vasa differentia, epididymis, and vas deferens__ are the male sex accessory ducts. 
- The urethra connects the __urethral meatus__ to the outside environment. 
- The __penis__, the male external genitalia, is enveloped with foreskin, a loose flap of skin. 
- The __urethra__, which originates in the urine bladder and extends through the penis towards its external entrance, the urethral meatus, __stores and transports sperm__ from the testes to the outside. 
- The paired __seminal vesicles, prostate__, and paired __bulbourethral glands__ are all-male accessory glands. 
- The __seminal plasma__, which includes __fructose, calcium, and enzymes__, is formed by the secretion of these glands. 

## __The Female Reproductive System__
![Female Reproductive System](//images.ctfassets.net/4yflszkpcwkt/2D8otuZyr5hjzLQiB3IjZD/9ac40c973d8879d07755f6cc9a05080e/The-female-reproductive-system-Created-by-PhotoroyaltyFreepikcomus.png)
- The female reproductive system's internal and external sex organs include a pair of __ovaries and oviducts, cervix, uterus, vagina__, and external genitalia located in the pelvic area. 
- Along with the __mammary glands__, these female reproductive organs are physically and functionally united to support the whole reproductive process, comprising __ovulation, fertilization, pregnancy, and childbirth__. 
- The __oviducts(fallopian tube), vagina, and uterus__ make up the female __accessory ducts__.
- __Mons pubis, labia minora, labia majora, clitoris, and hymen__ are the parts of the female external genitalia. 

## __Menstrual Cycle__

- For females menstruation begins at puberty and is known as __menarche__. 
- It lasts till the female attains the age of 50 and the end of the cycle is called __menopause__.
- During the follicular stage of this cycle, the __primary follicles__ in the ovary grow and mature into __graafian follicles__. 
- Simultaneously the __endometrium__ (lining of the uterus) regenerates through proliferation.
- The secretion of __gonadotropin__ increases during the follicular phase. This stimulates the __follicular development__ and also the secretion of __estrogen__.
- __LH and FSH__ attain their peak in the middle of the cycle. (On the 14th day for a female who has a 28 day cycle.)
- The surge in LH induces rapture of the graafian follicle and the __ovum__ is released.
- The endometrium is maintained by __progesterone__ which is secreted in large amounts by the corpus luteum. 
- The __reproductive phase__ in a human female extends from __menarch to menopause__.

## __Process of Human Reproduction__

__Gametogenesis__
__Oogenesis__: is the term used to describe the process of formation of __mature female gametes__.
- The gametes __mother cells__ begin to divide and enter __prophase-I__ of meiotic division, where they are temporarily arrested and referred to as __primary oocytes__.
- The __primary follicle__ has a layer of __granulosa cells__ that surrounds each primary oocyte.
- The __secondary follicle__, surrounded by several layers of granulosa cells, transforms into a __tertiary follicle__ with a fluid-filled cavity called the __antrum__.
- The tertiary follicles then mature into the __Graafian follicle__, which ruptures to release __secondary oocytes (ovum)__ from the ovary during the __ovulation__ process.
__Spermatogenesis__: spermatogenesis, which begins at __puberty__, produces sperm in the testes.
- The __spermatogonia__ (immature germ cells) on __seminiferous tubules__’ inner surface grow and increase in quantity by mitotic division.
- Spermatogonia produces __spermatocytes__ that divide during meiosis to create __secondary spermatocytes__.
- __Spermiogenesis__ is the process through which __spermatids__ are converted into __spermatozoa__. 
- The sperm heads stay in __Sertoli cells__ and are discharged from seminiferous tubules during the __spermiation process__.
- __Sperm__ are tiny structures with a __head, neck, middle portion, and tail__. 
- The sperm head has an extended __haploid nucleus__ with a cap-like structure called an __acrosome__ covering the front half.

## __Fertilization__
Fertilization is the process of sperm and ovum fusing.
![Fertilization](//images.ctfassets.net/4yflszkpcwkt/5kH8k7gxH6fN8Jopyy83CG/0140d1970560d6386f8de7900cec49c2/sperm-cell-changes-layers-contact-prominence-spermatozoa.jpg)
- __Semen__ is discharged into the __vaginal canal__ during __coitus__ (copulation). 
- The __motile sperms__ swim quickly to reach the __isthmus and ampulla__ of the __fallopian tube's junction__. 
- The __ovum__ also makes its way there, and __gametes fuse__ at the __ampullary-isthmic junction__.
- The sperm acrosome performs an __acrosomal reaction__, releasing __sperm lysins__ that break down the egg envelopes locally and open the way for sperm entry.
- These sperm lysins contain __hyaluronidase__, a lysing enzyme that dissolves the __hyaluronic acid polymers__ in the intercellular spaces that hold the granulosa cells of the __corona radiata__ together.
- It also contains corona penetrating enzyme (which dissolves the corona radiata), and __acrosin__, a lysing enzyme that dissolves the hyaluronic acid polymers in the intercellular (which dissolves the zona pellucida). 
- The zona pellucida is then dissolved.

## __Embryonic Development__ 
- __Chorionic villi__ are finger-like extensions on the __trophoblast__ after implantation.
- These along with the uterine wall, constitute a functional unit between the growing embryo and the mother body termed the __placenta__. 
- An __umbilical cord__ connects the __placenta to the fetus__, transporting __nourishment and oxygen__ to the __embryo__.
![Embryonic Development](//images.ctfassets.net/4yflszkpcwkt/6L819o4NxFm9FFAU8qqIFJ/a4a00e3802eb64e277ea6391a9be2481/diagram-showing-human-embryonic-foetal-260nw-604738178.jpg)
- The placenta produces the hormones __hCG (human chorionic gonadotropin), hPL (human placental lactogen), and relaxin__ in women exclusively during pregnancy.
- After implantation, the __inner cell mass__ (embryo) divides into two layers: __ectoderm__ on the outside and __endoderm__ on the inside. 
- Between the ectoderm and the endoderm appears a __mesoderm__. 
- These three layers give birth to all tissues (organs) in adults. 
- An __embryo's heart__ in a human is created after __one month__ of pregnancy. 
- Legs and fingers are established at the end of the second month. 
- In 5 months, the fetus makes its first movement. 
- The body is coated with fine hair by the end of 24 weeks, and eyelids and eyeless have developed. 
- The __fetus__ is completely formed at __9 months__. 

## __Parturition and lactation__ 
- __Parturition__ refers to the process of delivering a __fully formed fetus__. 
- The fully grown fetus and __placenta__ send out __parturition signals__, which cause moderate uterine contractions known as the __Fetal ejection reflex__. 
- It causes the __maternal pituitary__ to produce __oxytocin__. 
- __Lactation__ is the process through which a woman's __mammary glands__ begin __producing milk__ and continue to do so until the pregnancy is over. - __Colostrum__ is the milk produced during the first few days of breastfeeding and contains many __antibodies__. 

## Questions
1. Which of these is a lytic enzyme released by the sperm? 
2. A human primary spermatocyte has autosomes.
3. In a human female ovulation normally takes place phase of the menstrual cycle.
4. The ovum receive the sperm at the 
5. Which part of the sperm penetrates the ovum? 
6. Which of these is contained in the umbilical cord? 
7. helps human sperm move.
8. Cryptorchidism is a condition where one or both testes fail to descend into the scrotum. 
9. Bidder’s canal receives .
10. Post ovulation, the mammalian egg is covered by .
11. Which of these hormones is released from the testes? 
12. Another name for Wolffian duct .
13. Acrosome contains .
14. Which of these is a temporary organ that connects a mammalian mother to its fetus? 
15. The sperm is responsible for carrying to the egg.

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Our CBSE study guides are structured to mimic your chapter-wise, detailed, revision notes! We’ve ensured to structure our guides around crucial concepts that you’ll need to ace your exams, while being quick and easy to understand. Make sure to also check out the supporting VR-based classrooms and study sessions on the Inspirit App!

CBSE Class 12 Biology Chapter 3 Revision Notes

Human Biology

# Chapter 4: Reproductive Health Revision Notes

__[3D Model Library](https://www.inspiritvr.com/search?resource=model3d)__

## Multiple Choice Questions

1. is not a copper releasing IUD.

2. MTP stands for 

3. is a widely accepted method of contraception in India.

4. Which part of the female reproductive system remains blocked after tubectomy? 

5. Amniocentesis is a process used to 

6. A couple suffering from infertility can still have a baby through process.

* **Reproductive health** refers to the healthy and proper/normal functioning of all reproductive organs, which includes all elements of reproduction. 
* India was one of the first countries to use **family planning policies and programs** to achieve overall reproductive health as a societal aim. 
* It was established at the national level in 1951 to raise knowledge about all reproduction elements by providing facilities and assistance to create a **reproductively healthy community**. 

Both governmental and non-governmental entities have taken numerous initiatives to raise citizen knowledge of reproduction-related issues to carry out these programs successfully, including: 

* **Family planning** is becoming more popular. 
* **Sex education** is being implemented in schools. 
* To raise awareness, printed materials were distributed. 
* **Reproductive Health** Powerpoint Slides with Audio and Video 
* Complete information about reproductive organs, puberty, safe and sanitary sexual activities, sexually transmitted illnesses, birth control techniques, mother and newborn child care, and so on. 

## Amniocentesis

![amniocentesis](//images.ctfassets.net/4yflszkpcwkt/4ASHUrTDewpIi4KWdMxwBH/3e0fca7a69686e666de85e8ccbf5f2ca/Amniocentesis.jpg)

__Source: [Amniocentesis](https://www.scientificanimations.com/what-is-amniocentesis/)__

* **Amniocentesis** is a method that uses amniotic fluid to detect **chromosomal abnormalities** such as **down syndrome, sickle cell anemia,** in a growing fetus. 
* It's also been utilized to confirm **fetal sex** based on the chromosomal pattern in the amniotic fluid around the growing embryo. 

## Population stabilization and birth control

* Causes such as a quick drop in the **death rate, infant mortality rate, maternal mortality rate,** and a significant rise in the reproductive age are contributing factors to an exponential rise in the population from the moment of independence until May 2011. 
* As a consequence of the worrisome growth rate that has resulted in a scarcity of necessities, the government has been compelled to take drastic steps. 
* The essential way to slow population increase is to encourage smaller families by using different **contraceptives**. 
* Other initiatives included **familiarizing slogans** (Hum do Hamare do), mandatory **increasing of both male and female marriageable ages**, and **incentives for couples with fewer kids**, among others. 
* **Natural/traditional techniques** (periodic abstinence), **IUDs, barriers** (diaphragms, condoms, cervical caps, vaults), **oral contraceptives** (pills), **implants, surgical procedures** (sterilization), **injectables**, and so on are all examples of contraceptive methods. 

## Methods of contraception

* **Natural approaches** function on the idea of preventing ovum and sperm from colliding.
* It entails **periodic abstinence** – couples avoid coitus from days 10 to 17 of the menstrual cycle since the chances of fertilization are highest during this time, known as the fertile period. 
* **Withdrawal or coitus interruptus** — to avoid conception, the male partner withdraws his penis from the vaginal canal shortly before ejaculation. 
* **Lactational Amenorrhea** - lack of menstruation after parturition, and owing to intensive milk feeding and no ovulation at this time, chances of fertilization are slim to none. 
* **Barrier techniques** use a barrier to prevent ovum and sperm from physically meeting.
* **Condoms** are used by men, and women use a barrier made of rubber or latex sheet to cover their penis, vagina, and cervix. It also protects against STDs. 
* **Intrauterine Devices (IUDs)** are medical devices put into the female uterus through the vaginal canal by a doctor or a trained nurse. 
* **Non-medicated IUDs** (e.g., Lippes loop), **copper-releasing IUDs** (CuT, Cu7, Multiload 375), and **hormone-releasing IUDs** are all examples of IUCDs (Progestasert, LNG-20) 
* **Copper reduces sperm motility** and reproductive capability, while **IUCDs promote sperm phagocytosis** in the uterus. 
* **IUDs** that **release hormones** render the uterus unsuitable for implantation and the cervix unfriendly to sperm. 
* It is good for women who desire to **postpone pregnancy** and space their children out. 
* Females take **oral pills** containing progesterone or a progesterone-estrogen combo. 
* They **limit or delay sperm entrance** by inhibiting ovulation and implantation and altering the quality of cervical mucus. 
* The **surgical approach** is also known as **sterilizing**. 
* It is used as a **last-resort technique** of contraception in both men and women to avoid conception. 

## Medical termination of pregnancy (MTP)

* In India, **MTP, or induced abortion**, was permitted in 1971 under tight restrictions to prevent abuse. 
* It refers to the **voluntary or purposeful termination** of a pregnancy before the full term has been reached. 
* It is regarded as **safe until the first trimester**, after which the odds of being in a dangerous situation grow. 

## Infertility

* **Infertility** is defined as the inability to create offspring despite sexual contact. 
* It can be caused by various causes, including **hereditary, physical, pharmacological, psychological, and immunological**. 
* There are specialist treatments to help such couples - **ART** (assisted reproductive technologies), which includes **IVF** (in-vitro fertilization) and **ET** (electronic fertilization) (Embryo transfer)

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CBSE Class 12 Biology Chapter 4 Revision Notes

# Chapter 8: Human Health and Diseases Revision Notes Part 1

__[3D Model Library](https://www.inspiritvr.com/search?resource=model3d)__

## Multiple Choice Questions

1. During an allergic response antibody is generated.

2. Which of these is an example of a congenital disease? 

3. is a primary lymphoid organ.

4. is used to make the Hepatitis B vaccine.

5. An infection disease spread from one person to another is also known as 

## Reproductive Health
* Health entails **disease-free living and physical fitness**. 
* Health is dependent on a few factors, and some of them are listed below: 

 i. **Genetic diseases** that are inherited often affect an individual’s potential health
 ii. **Microbes** or other creatures that cause disease
 iii. **Lifestyle choices** - includes the foods and beverages we consume, physical activity levels, and sleep patterns

## Disease types

There are two sorts of diseases: **infectious and non-infectious**. 

### Congenital diseases

* Genetic disorders present at birth are known as **congenital diseases**. 
* This might result from a **gene mutation, chromosomal abnormality, or environmental factors**. 
* Defects in the chromosome and genes are passed on to the following generation. 
* **Haemophilia, color blindness, Down syndrome, Turner's syndrome**, and other conditions are examples. 

### Acquired diseases

Diseases acquired during a lifetime are acquired diseases. 

1. **Communicable**: An infectious sickness is spread from one person to another. 
1. **Non-communicable:** Illness does not spread by infection. 
1. **Deficiency disease: Anemia, kwashiorkor, beriberi, diabetes**, and other deficiencies are caused by a lack of a key vitamin, enzyme, or hormone. 
1. **Allergies:** are a type of hypersensitivity to external particles such as pollen and dust. 

## Immunity and Related Disorders

* Immunity refers to the **body's ability to defend itself** against pathogens and other objects. 
* The immune system **protects** our bodies against infection. 

Immunity can be divided into different categories: 

### Innate immunity

The immunity that is present from **birth** is known as innate immunity. There are four sorts of barriers in the human body's defense mechanism. 

* **Skin and mucous** covering of respiratory, gastrointestinal, and urinary tract epithelial linings are **physical barriers**. 
* **Saliva, tears, or stomach acid** act as **physiological barriers**. 
* **Neutrophils, monocytes**, and natural killer lymphocytes are **cellular barriers**. 
* **Interferons** released by virus-infected cells form **cytokine barriers**. 

### Acquired immunity

Acquired immunity is **pathogen-specific immunity** that we develop throughout our lives. 

* After the **initial interaction** with a virus, the low-intensity primary reaction kicks in. 
* Due to the **memory** of the initial reaction, a recurrent infection causes a substantially increased **secondary response or anamnestic response**. 
* **B-lymphocytes** produce **antibodies** in response to foreign **antigens**. 
* **Antibodies (H2L2)** are **Y-shaped protein molecules** with two light and two heavy peptide strands. 

![Antibodies](//images.ctfassets.net/4yflszkpcwkt/5aTKVmJgoUQTUxryfgN7rc/0bc36b6abc049836c5b586bcb98855ba/chains-structure-antibody-immunoglobulin-molecule-light-unit.jpg)

__Source: [Antibodies](https://www.britannica.com/science/antibody)__

* Humans have five different forms of antibodies or **immunoglobulins**: **IgG, IgM, IgD, IgA, and IgE**. 
* **IgG** is the most prevalent antibody in the **blood**, and it defends a fetus while its immunity builds. 
* **IgA** is plentiful in **breast milk and colostrum**, the yellowish fluid released at the beginning of breastfeeding. 
* **IgE** has a role in **allergic reactions**. 
* The **humoral immune response** is an **antibody-mediated** reaction. 
* **Cell-mediated response**, or CMI, is regulated by **T-lymphocytes**. 
* After **transplantation**, the **cell-mediated response** is crucial for discriminating among **self and non-self** and graft rejection. 

### Active immunity

* **Antibodies** are created in the **host’s body** in response to **antigen**, and it takes time to respond effectively. 
* **Vaccination**, which involves injecting an **attenuated pathogen**, is an example of active immunity. 

![Types of Immunity](//images.ctfassets.net/4yflszkpcwkt/3Taom5B7mfi6p0y326Ij80/621190b0d2d6027e749bb7b78b937877/Types_of_Immunity.png)

__[Source](https://ib.bioninja.com.au/higher-level/topic-11-animal-physiology/111-antibody-production-and/types-of-immunity.html)__

### Passive immunity

* Passive immunity is defined as providing **pre-made antibodies** to elicit a rapid response against a disease. 
* Passive immunization is achieved by injecting **antitoxin** for snakebite, including antibodies against the venom. 
* The use of **recombinant DNA technology** has aided in large-scale manufacturing vaccines. For example, yeast is used to make the hepatitis B vaccine. 

### Allergies

* **Pollens, dust, mites**, and other environmental antigens elicit an exaggerated **immunological response**. 
* During an allergic response, the **IgE antibody** is generated. 
* During an allergic response, the **mast cell produces histamine and serotonin**. 
* **Antihistamines, adrenaline, and steroids** all help to alleviate allergy symptoms. 

![Allergies](//images.ctfassets.net/4yflszkpcwkt/7l7UWw69gCQkQXJpgQS9eq/5ef9c031cd26ce695599d997ccbfcc53/19150.jpg)

__[Source](https://medlineplus.gov/ency/article/000812.htm)__

### Auto-immunity

* Auto-immune illness occurs when the **body attacks its own cells**. 
* **Rheumatoid arthritis** is an autoimmune disease that affects the body's immune system. 

![Autoimmune Diseases](//images.ctfassets.net/4yflszkpcwkt/AkeDLhcAONkhSBBIxmFs0/41846ae9427c67c104ac2271bca9d3f5/autoimmune_disease.jpg)

[__Source](https://www.niehs.nih.gov/health/topics/conditions/autoimmune/index.cfm)__

## Immune system: Lymphoid organs 

* The **lymphoid organs, cells, and antibodies** make up the human immune system. 
* **Bone marrow and thymus** are the primary lymphoid organs. 
* **Lymphocytes** grow, mature, and differentiate into antigen-specific lymphocytes in this area. 
* **Spleen, lymph nodes, tonsils, Peyer's patches** in the small intestine, and **appendix** are secondary lymphoid organs. 
* These are the **antigen-reaction sites**, and following proliferation, they become effector cells. 
* The **spleen** functions as a **blood filter**. **Lymphocytes and phagocytes** are present, as well as a considerable number of **erythrocytes**. 
* **Antigens** in the lymph or tissue fluid are trapped in **lymph nodes**. 
* **MALT** (mucosa-associated lymphoid tissue): the mucosal lining of the respiratory, urinary, and digestive tracts accounts for half of all lymphoid tissues in the body. 

![Lymphatic System](//images.ctfassets.net/4yflszkpcwkt/1A75kjpwfaGfrHLlanWT6g/157609e968322bc85e3f830780b3c10b/Fig-1-The-major-components-of-the-lymphatic-system-1024x856.jpg)

__Source: [Lymphatic system](https://byjus.com/neet/important-notes-of-biology-for-neet-human-health-and-disease/)__

__[__SciWordle__: a daily word game for science lovers](https://www.inspiritvr.com/sciwordle)__

CBSE Class 12 Biology Chapter 8 Revision Notes Part 1

# Chapter 8: Human Health and Diseases Revision Notes Part 2

__[3D Model Library](https://www.inspiritvr.com/search?resource=model3d)__

## Multiple Choice Questions

1. Which type of tumors can invade adjacent tissues and cause harm? 

2. Plasmodium, the parasite that causes malaria, is spread from person to person by the bite of the female Anopheles mosquito. 

3. The HIV virus uses to generate viral DNA in the host.

4. Which of these impacts the cardiovascular system? 

5. Ringworm is caused by .

## Human Health and Disease

* A state of complete **physical, mental, and social** well-being is characterized as health.
* A **pathogen** is a disease-causing organism, such as bacteria, viruses, protozoans, fungus, or worms. 
* A pathogen can enter our bodies in a variety of ways. 

### Pathogen-related Disease

**Typhoid**: caused by a bacteria, Salmonella typhi. 
* One can contract this disease through **contaminated food and water**. 
* Symptoms include **high fever, headache, constipation, and loss of appetite**. 
* This disease can be diagnosed by performing a **Widal test**, and intestinal perforations can be seen In some extreme cases. 

**Pneumonia**: a lung infection that causes the **air sacs** in one or both lungs to become **inflamed**.
* **Cough with phlegm or pus, fever, chills, and trouble breathing** can occur when the air sacs fill with fluid or pus (purulent material). 
* **Streptococcus pneumoniae** is the most prevalent cause of **bacterial pneumonia**.
* This form of pneumonia can develop independently or as a result of a cold or virus. 

**Ascariasis**: a parasitic illness of the small intestine.
* Caused by the roundworm **Ascaris lumbricoides**. 
* Roundworms are **parasitic worms**, and Roundworm infections are rather frequent. 
* The most prevalent roundworm infection is __ascariasis__. 

__Ringworm__: A fungus causes ringworm, which is a common skin illness. 
* Because it can create a **circular rash** (formed like a ring) that is generally **red and itchy**, it's nicknamed "ringworm." 
* Ringworms may affect anyone. 

**Malaria:** Malaria is an infectious illness spread by mosquitoes that affect people and other animals. 
* Malaria is characterized by **fever, exhaustion, vomiting, and headaches**. 
* In extreme cases, it can cause **yellow skin, convulsions**, coma in extreme cases, or death. 

* __Lifecycle of Plasmodium__
 * **Plasmodium** is spread from person to person by **female Anopheles mosquito** bites.
 * **Sporozoites**, which are formed by female anopheles saliva after they bite, are the **infectious form**.
 * Before attacking RBCs, it **replicates in liver cells**, leading RBCs to explode.
 * **Haemozoin**, a harmful toxin, is secreted.
 * The infected person's **gametocyte** is transferred to the mosquito whenever a mosquito bites an infected person.
 * Macro and micro gametocytes get fertilized, converted, and **sporogenesis** happens in the mosquito's stomach, culminating in the formation of sporozoites.
 * The cycle is restarted when sporozoites reach a **mosquito's salivary gland**.
 * Plasmodium sp. **needs both humans and female Anopheles mosquitoes** to finish its life cycle.

![Plasmodium lifecycle ](//images.ctfassets.net/4yflszkpcwkt/720ugybHkElrhi6dLStlKU/226455f635c548cf6aabfcc18dd9b2d5/life-cycle-of-the-malarial-parasite-plasmodium.jpeg) 

__Source: [Plasmodium lifecycle](https://byjus.com/neet/important-notes-of-biology-for-neet-human-health-and-disease/)__

## AIDS (Acquired Immunodeficiency Syndrome) 

* Caused by **HIV** (Human Immunodeficiency Virus) 
* The virus uses the **reverse transcriptase enzyme** to generate viral DNA in the host. 
* The viral DNA is integrated into the **host genome**, resulting in numerous copies of the virus. 
* The virus targets **helper T-cells**, where it replicates and multiplies, resulting in a significant **reduction in T lymphocyte** numbers. 
* After the virus targets T-helper cells, the infected person develops __immunodeficiency__. 
* AIDS patients are vulnerable to infections such as **mycobacterium, toxoplasma, fungal, and viral infections**. 
* The **ELISA test** is a commonly used AIDS diagnostic test. 
* AIDS can be passed down from **mother to fetus** through the placenta, **contaminated blood transfusions**, or using an **infected syringe**. 

![HIV Replication Cycle](//images.ctfassets.net/4yflszkpcwkt/6dEzt0WYY2RdStLljI8e0o/48a72b4376c09864041f712b0cfa3ebf/hivReplicationCycle2.jpg)

__Source: [HIV](https://byjus.com/neet/important-notes-of-biology-for-neet-human-health-and-disease/)__

## Cancer

* Cancer is caused by **unregulated cell division**, which results in tumor development. 

![Tumors](//images.ctfassets.net/4yflszkpcwkt/NUiihqtmYI3zEBOHMg4g2/9db2610505353f781e3d039b3217a3f1/cancer-101-s2-tumors-benign-malignant.jpg)

* Cancerous cells cannot stop future **cell proliferation** when they touch other cells. 
* Non-invading **benign tumors** stay in their original position and **do not spread**. 
* **Malignant tumors** can invade adjacent tissues and cause harm. 
* **Metastasis** is a feature of malignant tumors in which sloughed-off cells travel to distant areas and establish tumors in various sections of the body. 
* Cancer is caused by **DNA damage or genetic mutations** that result in improper cell cycle control. 
* Under some conditions, cancer can also be triggered by the activation of **proto-oncogenes** found in normal cells. 
* **Ionizing radiation** (e.g., X-rays, gamma rays), **non-ionizing radiation** (UV rays), **chemical agents** (e.g., tobacco), viral oncogenes of oncogenic viruses are all examples of carcinogens. 
* A **CT scan, MRI, X-ray, PET scan**, or histological investigations of tissue and blood can all be used to identify cancer. 
* Molecular biology approaches can also diagnose cancer by identifying inherited **cancer-prone genes**. 
* **Surgery, transplantation, immunotherapy, and radiation therapy** are all options for cancer treatment. 
* **𝛂 -interferon** acts as a biological response modifier, activating the immune system and causing it to attack the tumor. 

### Alcohol and Drug Abuse

Commonly misused drugs include **opioids, cannabinoids, and coca alkaloids**. 

* **Opioids** bind to **opioid receptors** in our **central nervous system and gastrointestinal tract.**
* **Diacetylmorphine** is sometimes known as smack or heroin.
* It's made from the latex of the **Papaver somniferum poppy plant**, and the acetylation of morphine produces it. 
* **Cannabinoids** interact with the brain's cannabinoid receptors, and they have an impact on the **cardiovascular system**. 
* Cannabis, hashish, charas, ganja, and other cannabinoids are extracted from the plant's flower tops, leaves, and resins, **Cannabis sativa**. 
* **Cocaine**, also known as coca alkaloid, is derived from the **Erythroxylum coca plant**. 
* Cocaine works by interfering with **dopamine transport**, a neurotransmitter. 
* Cannabinoids are also used by athletes to improve their performance, **muscle relaxation, and anxiety reduction**. 
* **Morphine** is a **sedative** and a pain reliever. 
* Depression, sleeplessness, and other mental illnesses are treated with **barbiturates, amphetamines, and benzodiazepines**, among other drugs. 
* **Tobacco's nicotine** (alkaloid) promotes the adrenal gland's secretion of **adrenalin and nor-adrenalin hormones**. It raises **blood pressure and heart rate**. 
* Smoking causes **oxygen deficit** by raising carbon monoxide levels in the blood, lowering the concentration of oxygen bound to hemoglobin. 
* Excessive drug and alcohol use harms the **nervous system** and leads to **liver cirrhosis**. 

__[__SciWordle__: a daily word game for science lovers](https://www.inspiritvr.com/sciwordle)__

CBSE Class 12 Biology Chapter 8 Revision Notes Part 2

# Chapter 9: Strategies for Enhancement in Food Production Revision Notes Part 1

__[3D Model Library](https://www.inspiritvr.com/search?resource=model3d)__

## Multiple Choice Questions

1. The process of crossing done between different species is known as .

2. Control breeding is done with the help of .

3. Which of these is an example of a marine fish? 

4. is another name for beekeeping.

5. A mule is a cross between .

## Strategies for Enhancement in Food Production

* **Food** is necessary for the **development and survival** of all living things. 
* To meet the needs of a growing population, we need to **increase food production**.
* State-of-the-art technologies such as **plant breeding, animal breeding, tissue culture, genetic engineering, and embryo transfer** have increased yields many times. 

__Animal Husbandry__ 
* It is a practice to **raise and breed** livestock (buffalo, cow, sheep, cow, etc.). 
* This includes **poultry farming and fishing**. 
* Dairy farm management and poultry farm management are necessary to select excellent breeds with **high yield potential and disease-resistant breeds**. 

![animal husbandry](//images.ctfassets.net/4yflszkpcwkt/3OYicTIOZJG1P6CkdoKGO/c6488c3c28033da205985bb964a6269f/1589565650-1045.jpg)

__Source: [Animal husbandry](https://www.business-standard.com/article/economy-policy/govt-to-avail-kcc-to-more-livestock-dairy-farmers-animal-husbandry-secy-121020401961_1.html)__

## Animal Breeding

Breeds are a group of animals of the same species related to their ancestors and share common characteristics and appearance. There are two types of breeding: **inbreeding and outbreeding**. 

![inbreeding](//images.ctfassets.net/4yflszkpcwkt/6RAKpeOtIpX7kouZbe40wc/7aad4746fd7da74e08992a3c47e85b97/75350_evo_resources_resource_image_430_original.gif)

[Source](https://evolution.berkeley.edu/teach-resources/inbreeding-depression/)

### Inbreeding

* It refers to **four to six generations** of breeding between males and females of the same breed. 
* **Superior males and females** are chosen and matched for this reason. 
* Inbreeding encourages **homozygosity** and is necessary for the evolution of pure lines or genuine breeding species, as in Mendel's experiment. 
* Inbreeding **eliminates undesired genes** while increasing the number of **excellent genes**.
* Continuous inbreeding causes **inbreeding depression**. 
* Here, **production and fertility decline** but may be restored by mating with superior animals who are unrelated. 

### Outbreeding

It refers to the **mating of animals** who are **not related**. There are three varieties of this: 

* **Out-crossing:** is the mating of animals of the **same breed** who haven't shared an ancestor in a few generations. This aids in the **treatment of depression** caused by inbreeding. 
* **Cross-breeding**: It allows **two breeds**' excellent qualities to be combined. Superior males of one breed are mated with superior females of another breed for this reason. 

**Hisardale** is a new breed of sheep that has been established in Punjab as a result of **crossbreeding** of **Marino rams** (males) and **Bikaneri ewes** (females). 

* **Interspecific hybridization** is the **cross-breeding** of **two related but not identical species**. 

**Mule**- A mule is a cross between a **male donkey and a female horse**. 

**Controlled breeding studies** are carried out to address several issues that arise during regular mating. 

Control breeding is accomplished using **artificial insemination**, and semen can be utilized right away or frozen and transferred for later use. 

### MOET

![moet](//images.ctfassets.net/4yflszkpcwkt/hcIpS9l3UqB5oNWZla32l/269328e13b11dbea35e52a33fed77add/Embryo-Transfer-credit-BBC.gif)

[Source](https://tunza.eco-generation.org/ambassadorReportView.jsp?viewID=45946)

* **Multiple Ovulation Embryo Transfer Technology:** Improves the odds of successful hybridization. 
* To encourage **follicular maturation**, the cow is administered hormones equivalent to FSH (Follicle-stimulating hormone). 
* Compared to a typical cycle, this leads to **more (6-8) eggs**. 
* The **fertilized eggs** (at the stage of 8-32 cells) are transferred to **surrogate moms** after mating or artificial insemination with the sperm of an elite bull. 

## **Fisheries**

![fisheries](//images.ctfassets.net/4yflszkpcwkt/7BwtvQ9qzLTX8kj2YGcfzt/a296478f7f224c5a5ca66dd7c0a7c932/1sofia-PO_TUR_20200316_018.jpg)

**Source: [Fisheries](https://www.fao.org/fileadmin/user_upload/newsroom/photos/1sofia-PO_TUR_20200316_018.jpg)**

* Fishery refers to **capturing, processing, and selling** fish, shellfish, and other aquatic creatures. 
* **Catla, rohu, and common carp** are the most prevalent **freshwater fish**. 
* **Hilsa, sardines, mackerel, and pomfrets** are all common **marine fish**. 
* **Aquaculture and pisciculture** are two approaches that have been used to boost productivity. 
* The growth in fish and other aquatic creatures is linked to the **Blue Revolution**. 
* **Aquaculture** is the practice of commercially **breeding and producing aquatic flora** (fish, mollusks, crustaceans) **and fauna** (aquatic plants and algae). 
* Intensive aquaculture occurs in ponds and tanks, whereas extensive aquaculture takes place in seas, rivers, or lakes. 
* **Pisciculture** is the **growing of fish** to produce **edible fish and fish products**. 
* Different fishes are cultivated together in **polyculture**, and different species are cultivated separately in **monoculture**. 

## **Bee-keeping (Apiculture)**

![beekeeping](//images.ctfassets.net/4yflszkpcwkt/5bPudkdYGnvBzVCd6tPU0O/10181ff32f0e8c8c6f395a8a9b0d0ebe/beekeeper.jpg)

[Source](https://www.uaex.uada.edu/farm-ranch/special-programs/beekeeping/)

* **Beekeeping**, also known as **apiculture**, is the practice of keeping honeybee colonies in order to produce honey. 
* **Honey** is a **nutrient-dense food** that is also used in traditional medicine, and **Beeswax** is also produced. 
* **Apis indica** is the most prevalent honey bee species. The following considerations are critical for beekeeping success: 
* **Understanding the nature and habits** of bees is essential. 
* **Choosing an appropriate place** for the beehives 
* **Swarm catching** and hiving
* **Managing beehives** at different times of the year 
* Honey and beeswax **handling and gathering** 
* Maintaining beehives in agriculture fields boosts **pollination efficiency** and productivity during the flowering season. 

__[__SciWordle__: a daily word game for science lovers](https://www.inspiritvr.com/sciwordle)__

CBSE Class 12 Biology Chapter 9 Revision Notes Part 1

Genetics

# Chapter 9: Strategies for Enhancement in Food Production Revision Notes Part 2

__[3D Model Library](https://www.inspiritvr.com/search?resource=model3d)__

## Multiple Choice Questions

1. The process of breeding nutrient dense crops is known as .

2. The semi-dwarf rice variety cultivated in India is .

3. The first step in the process of plant breeding is .

4. Ratna is a high-yielding and disease-resistant wheat cultivated in India. 

5. Single celled proteins can be obtained from on an industrial scale.

## Strategies for Enhancement in Food Production

* **Plant breeding** is the deliberate modification of plant species to produce desirable plant kinds that are more suited for cultivation, **higher yields, and disease-resistant**. 
* Increased food production to fulfill population demands is called the **Green Revolution**.
* **M. S. Swaminathan** was the driving force behind India's green revolution. 
* **Fertilizers, insecticides, high-yielding crops, irrigation infrastructure**, and other modern procedures and technology are employed for this purpose. 
* **Wheat and rice cultivators** with high yields have made a significant contribution to the expansion in food grain output. 

## Plant breeding

Plant breeding enhances **production, quality, tolerance** to environmental stress, and p**est and disease resistance**. 

The government and private enterprises undertake plant breeding programs all around the world. The following are the stages involved in creating a new plant genetic variety: 

* **Collection of variability** refers to collecting all the different varieties of a certain crop. All of a plant's alleles for its genes are gathered, and **Germplasm collection** is the term for it. 
* **Selection of parents**: The germplasm is tested for the desired characteristic, and parents are chosen based on the results. 
* **Cross hybridization** occurs when two desirable characteristics are united, such as disease resistance and high protein content. 
* **Selection and testing of better recombinants**: Hybrids with desirable traits are chosen and self-pollinated over several generations to achieve **homozygosity**. This prevents character segregation in the following generation. 
* **Commercializing new cultivars**: entails a thorough quality inspection for productivity and other characteristics such as disease resistance. The crop is cultivated in a controlled environment in a research area for this purpose. 

Following the evaluation, **three seasons of testing** in farmer's fields across the country are conducted. 

## High-yielding Variety of Hybrid Indian Crop

![chickpea](//images.ctfassets.net/4yflszkpcwkt/2IjWvYkI4gvIjt41GbpZS5/982599bcc8bbead1c6868b2b5c06c32c/crop_science5.jpg)

__Source: [Crop improvement](https://www.iari.res.in/index.php?option=com_content&view=article&id=550&Itemid=171)__

**Wheat:** In Mexico, Norman E Borlaug produced **semi-dwarf** wheat types. Wheat production has increased from 11 million to 75 million tonnes. 

High-yielding and disease-resistant wheat types cultivated in India are **Sonalika and Kalyan Sona**. 

**Rice**: **IR-8** (created in the Philippines) and **Taichung Native-1** were used to create semi-dwarf rice cultivars (Taiwan). 

Semi-dwarf rice cultivators **Jaya and Ratna** were created in India. 

**Cane sugar:** **Saccharum Barberi** (north Indian sugarcane) and sugar-rich **Saccharum officinarum** (south Indian sugarcane with thick stems) were successfully cross-bred to produce high yield, sugar content, and thick stems that can be cultivated in North India as well. 

The traditional approach (hybridization and selection) or the mutation method creates disease-resistant variants. Disease-resistant varieties are also obtained by **genetic engineering** and selection among somaclonal variations. 

### Mutational Breeding

When a gene is mutated, the sequence of the gene changes. Mutation can be purposely produced to get a characteristic that was not present previously. 

* For example, a novel Mung bean variety resistant to **powdery mildew disease** and the **yellow mosaic virus** has been generated through mutation. 
* It is critical to have **disease resistance** and a high producing capacity. 
* To achieve this combination, **disease-resistant genes** are introduced to **high-yielding** types via **sexual hybridization**. 
* **Parbhani Kranti** is a new type of **bhindi** that has been designed to be resistant to the **yellow mosaic virus**. The disease resistance gene was inherited from a wild animal. 

## Plant breeding for improved food quality

* Aside from disease resistance, pest resistance, and high yield, the **higher nutritional value** is also vital for eradicating nutrient-deficient disorders. 
* We can promote public health by growing nutrient-dense foods with **lower fat, greater protein, and more vitamins and minerals**. 

## Biofortification

![biofortification](//images.ctfassets.net/4yflszkpcwkt/4WIaLKlw4W0evB88Aa3NNf/fd133c223220f059b81e1710d422ed95/List-of-biofortified-crops.jpg)

__Source: [Biofortification ](http://www.krishisewa.com/articles/miscellaneous/1045-role-of-biofortification-through-crop-improvement.html)__

* **Biofortification** is the process of **breeding nutrient-dense crops**. 
* Crops with higher nutritional value have more **protein, oil, vitamin, micronutrient, mineral content, and higher quality**. 
* The **Indian Agricultural Research Institute (IARI)** in New Delhi has published several vitamins and mineral-rich vegetable cultivators. 

## Single-cell Protein

* **Single-cell protein** is one of the protein sources that can fulfill the ever-increasing human and animal population's nutritional needs 
* **Microbes** are cultured on an industrial scale to get SCP. 
* **Spirulina**, a kind of **blue-green algae**, is a good source of nutrients and may be easily cultivated on **sewage, potato processing plant effluent, animal dung, and straw molasses**. 

**Tissue culture:** Tissue culture and **somatic hybridization techniques** have enormous promise for manipulating plants in vitro to create novel types.

__[__SciWordle__: a daily word game for science lovers](https://www.inspiritvr.com/sciwordle)__

CBSE Class 12 Biology Chapter 9 Revision Notes Part 2

# Chapter 10: Microbes in Human Welfare Revision Notes

__[3D Model Library](https://www.inspiritvr.com/search?resource=model3d)__

* **Microbes** may be found in the most **severe environments**, where no other life could live. 
* Viruses, bacteria, protozoa, fungus, viroids, prions, and other tiny organisms are among them. 
* They may be **pathogenic**, yet they serve a crucial function in **human health**. 

![microbes](//images.ctfassets.net/4yflszkpcwkt/wmy6DGBN9N3SAZiyNvXFd/af3c7f76508045a1adaf35fd2231e158/istock-924923870.jpg)

* Microbes may be easily produced in labs or on a large scale to conduct research and manufacture various valuable goods. 
* **Microbes benefit humans **and the environment in a variety of ways: 

## Household products

* The microorganisms found in curd _Lactobacillus_ generate **lactic acid**, which causes the **milk protein** to **coagulate** and be partially digested and boost **vitamin B12** levels. 
* These bacteria can also be found in the **stomach**, where they **inhibit the development** of other bacteria. 
* Idli and dosa are south Indian dishes made from fermented dough. Because **bacteria** **produce CO2**, the **dough ferments**. 
* **Yeast** is used in the creation of **bread**. 
* Saccharomyces cerevisiae is a kind of yeast. 
* **Toddy** is prepared from **palm sap** that has been **fermented**. 

![Fermented food](//images.ctfassets.net/4yflszkpcwkt/4KJ4oqB7qy0gKR3x1XRKIZ/84441f8820040dc753e69bdf3eca7c5d/Image_02X01.jpg)

## **Fermented beverages**

* Since ancient times, **Brewer's yeast** (Saccharomyces cerevisiae) has been used to make **alcoholic drinks** from malted grains and fruit juices. 
* Various drinks are generated depending on the raw material and fermentation procedures utilized, such as wine and beer without distillation and whiskey, rum, and brandy too. 

![fermentation products](//images.ctfassets.net/4yflszkpcwkt/61i5Cs6f5a7nShHCSSY4kA/23900060a3e3604086fda7934d0a8f0a/fermentation-products.png)

## **Vaccines**

* **Vaccines** are made from **disease-causing bacteria**, their surface proteins, or poisons that have been weakened or attenuated. 
* **Edward Jenner** was the first to design a **smallpox vaccine**. 
* **Polio, DPT, Measles, Hepatitis-A and B, Pneumococcal, Influenza**, and other viral illnesses have all been the subject of vaccine development. 

## **Enzymes and Chemicals**

* Streptococcus generates **streptokinase**, a clot-busting enzyme that has been genetically engineered and is used to **remove clots** from blood arteries. 
* **Lipases** are enzymes found in detergents and help **remove greasy stains**. 
* **Pectinases and proteases** are enzymes that are used to **clear bottled juices**. 
* **Bioactive compounds** are made and utilized for a variety of applications. 
* Trichoderma polysporum produces **cyclosporin A.** (fungus). It's an **immune system suppressant** that's utilized in **organ transplant patients**. 
* Monascus purpureus produces **statins (yeast)**. It **decreases cholesterol** levels in the blood by preventing cholesterol production. 

## **Sewage Treatment**

* **Sewage treatment facilities (STPs)** process sewage to make it less polluting. 
* The **heterotrophic microorganisms** naturally present in the sewage treat the wastewater.

**Biogas: **Biogas is a **combination of gases** (mostly methane) created by microbial activity that may be utilized as a source of energy.

### **Biocontrol of Pests and Diseases**

* **Dragonflies and ladybugs** control mosquitoes and aphids. 
* Caterpillars and insect larvae are controlled by Bacillus thuringiensis. 
* The gene coding for the toxin has been inserted into the plant genome in certain genetically engineered plants, and Bt-cotton, for example, is **pest-resistant**. 
* Trichoderma (a fungus) is a **biocontrol agent** for various plant infections. In most cases, the fungus may be found in the roots. 
* Baculoviruses belonging to the genus Nucleopolyhedroviral are powerful biocontrol agents. Although they only attack arthropods, they are hazardous to plants and other creatures such as birds, fish, and mammals. 

### Biofertilizers 

![biofertilizer](//images.ctfassets.net/4yflszkpcwkt/72NFd3zuFdFNjxzhva1Zgq/e130802700c299b538f90468817eed7b/Algal-Biofertilizers.png)

* Fungi, bacteria, and cyanobacteria mostly produce **biofertilizers**. 
* Leguminous plants have Rhizobium in their root nodules, and it is capable of **removing nitrogen** from the atmosphere. 
* On the other hand, Leguminous plants help **increase the nitrogen concentration** of the soil. 
* Free-living nitrogen-fixing bacteria such as Azotobacter and Azospirillum can be found in the soil. 
* The mycorrhizal fungus **enhances the nutritional content** of the soil as well.
* Glomus fungi are responsible for** absorbing phosphorus** for the plant. 
* These **symbiotic relationships** benefit not only by **boosting nutritional content** but also by providing **disease resistance and drought and salinity tolerance**. 
* Nostoc, Anabaena, Oscillatoria, and other cyanobacteria may fix atmospheric nitrogen. 
* Cyanobacteria are widely employed as a **biofertilizer** in paddy fields. 
* Blue-green algae are autotrophic and may be found in aquatic and terrestrial environments. By contributing organic matter to the soil, they improve its fertility. 

__Multiple Choice Questions__

1.The big holes we see in Swiss cheese are made by a .

2. Microbes are used during stages of purification of water.

3. In the preparation of which of these is Streptococcus used? 

4. A high BOD(Biochemical Oxygen Demand)value, indicates .

5. Which of these is a good producer of citric acid? 

6. Which of these is not an example of performing biological control of diseases/pests using microbes? 

7. Azoila and have a symbiotic relationship.

8. is a free living anaerobic nitrogen fixing bacterium.

9. Usnic acid is an antibiotic obtained from . 

10. is produced by the activity of anaerobic bacteria on sewage.

11. Nif gene is found in .

12. The most common substrate used in distilleries for the production of ethanol is .

13. is not a biofertilizer.

14. In the process of Lactate fermentation Carbon dioxide is not released.

15. Who used the term antibiotic for the first time? 

[__SciWordle__: a daily word game for science lovers](https://www.inspiritvr.com/sciwordle)

 CBSE Class 12 Biology Chapter 10 Revision Notes

Microbiology

# Chapter 12: Biotechnology and Its Applications

__[3D Model Library](https://www.inspiritvr.com/search?resource=model3d)__

## **Definition of biotechnology**

* **Biotechnology** is an applied discipline of science that produces goods and processes from biological agents and their derivatives. 
* These materials and techniques are used in **medicine, pharmaceuticals, bioenergy, and environmental protection.**

![Biotechnology](//images.ctfassets.net/4yflszkpcwkt/11Z9AuoDobmhg9vv7YhL0M/98e5f4cbb0390b7e122e287aa7fa2133/EDUSA_Biotechnology-and-Bio-Engineering-How-to-Choose-P.Usha-Sri-Hema-G.jpg)

## **Types of biotechnology**

__Medical biotechnology__: This field uses **live cells** to create technologies that benefit human health. Medical biotechnology has assisted in the development of **vaccines and antibiotics.**

**Agricultural biotechnology:** This field is associated with the synthesis of genetically engineered plants by integrating the desired gene into the plant. This, in turn, contributes to **increased agricultural output.**

## **Methods that utilize biotechnology**

The three most important **biotechnology approaches** are:

* **Recombinant DNA Technology (Genetic Engineering): **This discipline deals with the **manufacturing of artificial genes**, the** repair of genes**, the **mixing of DNA from two organisms** (recombinant DNA), and the** manipulation of artificial genes in conjunction with recombinant DNA** for the betterment of microorganisms, plants, animals, and humans. 
* **Plant Tissue Culture**: A process that allows plants to be **saved from extinction** and develop into full-fledged plants from a cell or a tiny plant portion. This process is known as tissue culture. Plants can be **regenerated** in a controlled laboratory environment from plant explants like root and shoot tips, buds, leaf, developing embryos, bud scales, and so on), tissue explants like pith, cortex, etc. epidermis, phloem, nucellus), and plant cells. 
* **Transgenic (Genetically Modified Organisms)**: Transgenics or GMOs are organisms that have been genetically engineered. Transgenic genotypes are those created through the **genetic engineering** method. It can be a plant, an animal, or germs like fungus, bacteria, or viruses.

## **Applications** **of biotechnology**

**Biotechnology** is widely applied to develop helpful goods for human benefit in various disciplines such as **medicine, agriculture, food processing**, and so on. The primary **biotechnology applications** are as follows - 

![ Applications of biotechnology](//images.ctfassets.net/4yflszkpcwkt/10G5QdyiXtU7DU9t9I4kZh/9030c5ad940b3f3af484c75fa15ab879/3-In-Environment.jpg)

### 1. Biotechnology in medicine

* Biotechnology is used to produce **medications** that were otherwise difficult to produce conventionally due to purity problems. 
* Initially **insulin** was extracted from the **pancreas** of cattle and pigs.
* Insulin is made up of 2 short polypeptide chains; __chainA and chainB__ - linked together by **disulphide bridges**.
* In humans, the pro-hormone of insulin contains an extra stretch called __C peptide.__ This is processed before it becomes a mature and functional hormone. 
* In 1983, an American company **made 2 DNA sequences** corresponding to **chain A and chain B** of human insulin.
* This was introduced as **plasmid** in bacterium **E. coli** to produce insulin chains. 
* The first clinical **gene therapy** was given in the year 1990 to treat a 4 year old child for **ADA (adenosine deaminase) deficiency.**
* **ADA** is usually cured by **bone marrow** transplantation, but with the advent of biotechnology, it can now be treated by **enzyme replacement** therapy. 
* A functional **ADA cDNA** is introduced in **lymphocytes** of blood grown cultures via a **retroviral vector.** 
* **PCR and ELISA** are important techniques using **recombinant DNA technology** that help in early diagnosis of diseases. 
* ELISA is based on the principle of **antigen-antibody** interaction. 

## 2. Biotechnology in various industry

* Biotechnology creates **alcohol, detergents, cosmetics**, and other items. 
* Self-healing concrete, plants that change color when they sense an explosion, clothes and footwear made of synthetic spider web, and so on might all be available in the near future.

## 3.Biotechnology in agriculture

* In addition to **genetically engineered foods**, biotechnology has resulted in the development of __crops resistant to droughts__ and certain insects that may prove critical in the **battle against famine**.
* A bacterium called Bacillus thuringiensis produces **Bt toxin**. 
* Some strains of this bacterium produce **proteins** that kill certain **insects**.
* When the insect **ingests the Bt toxin**, the **protoxin** is converted into its **active form** due to the **alkaline pH** of the gut of the insect.
* It binds to the **midgut epithelial cells** and **creates pores**.
* Bt toxin is coded by the gene name **cry.**
* Its proteins are encoded by genes **cryIAc** which controls the **comborer** and **cryIIAb** which control **bollworms**.

### 4. Biotechnology for the environment

* Biotechnology is usually applied in the **generation of energy**. 
* There is a need to seek an alternate source due to the depletion of natural resources.
* Biotechnology tools are used to create such fuels. These are **environmentally friendly** and emit no greenhouse gases. 
* The catabolic characteristics of microbes, fungi, plants, and enzymes are exploited to rehabilitate damaged habitats via **bioremediation processes**, which are extremely beneficial for **ecological recovery**. 

### **5. Applications in Forensic Science**

* Forensic scientists employ biotechnology to gather or analyze trace evidence such as hair, skin, blood, or sperm samples found at crime scenes. Forensic DNA, or genetic markers, is a key part of contemporary forensics.

## __Multiple Choice Questions__

1. links together the two polypeptides of human insulin. 

2. Which of these is commonly used as a vector for introducing a DNA fragment in human lymphocytes? 

3. In Bt Cotton, the Bt toxin present in plant tissue as protoxin is converted into active toxin due to .

4. The first human hormone produced by recombinant DNA technology is .

5. Which of the following Bt crops is being grown in India by the farmers?

6. The first clinical gene therapy was given for treating .

7. Transgenic animals are those which have .

8. Bacillus thuringiensis forms protein crystals which contain insecticidal protein. This protein binds with epithelial cells of midgut of the insect pest ultimately killing it. 

9. Which one of the following is now being commercially produced by biotechnological procedures .

10. The first transgenic plant to be produced is .

[__SciWordle__: a daily word game for science lovers](https://www.inspiritvr.com/sciwordle)

CBSE Class 12 Biology Chapter 12 Revision Notes

CBSE Class 12 Biology Chapter 1 Revision Notes Part 2

Animal Biology

CBSE Class 12 Biology Chapter 1 Revision Notes Part 1

CBSE Class 12 Biology Chapter 2 Revision Notes Part 1

Plant Biology

CBSE Class 12 Biology Chapter 2 Revision Notes Part 2

CBSE Class 12 Biology Chapter 5 Revision Notes Part 1

CBSE Class 12 Biology Chapter 5 Revision Notes Part 2

# Chapter 6: Molecular Basis of Inheritance Revision Notes Part 1

__[3D Model Library](https://www.inspiritvr.com/search?resource=model3d)__

- **DNA** is the genetic material for most organisms, except for viruses which use **RNA** instead
- DNA helps in the synthesis of RNA, which in turn helps in **protein synthesis**, and these proteins **control traits** of individuals.
- **DNA**, **RNA**, and the **genetic code** are responsible for the transmission of genes from parents to progeny.

## ****Molecular Basis of Life****

- At the molecular level, all living organisms are made up of **cells**
- Some organisms are made up of a **single cell**, while others contain **millions of cells** that carry out particular or specialized functions in the organism as a whole

## Nucleotides: ****DNA & RNA****

- The nucleolus of the cell contains **chromatin** which makes **chromosomes**. Chromosomes, in turn, consist of **genes** that are made up of **twisted DNA strands.**
- Living organisms have a fixed number of chromosomes. For example, human beings have **23 chromosome pairs**, amounting to 46 total.
- DNA is responsible for the transfer of traits from one generation to another

![dna packaging](//images.ctfassets.net/4yflszkpcwkt/5to2hwAn2krpNmoQ9GZJM4/055c8f2b137f0bb5a0f23e13e817f2fa/illustration-zimmer-chromatin-eng.jpg.jpg)

[Source](https://research.pasteur.fr/en/news/an-imaging-and-modeling-approach-to-characterize-the-structure-of-dna-in-human-cells/)

- **DNA functions:**
 - genetic material passed from parent to offspring
 - provides all of the required information to direct and regulate the construction of the proteins necessary for a cell to perform all of its functions
- RNA is essential for various biological roles like **coding, decoding, regulation**, and **expression of genes**
- RNA is the genetic material in **viruses**
- **RNA functions:**
 - convert the information stored in DNA into proteins

## DNA and RNA Structure

- DNA and RNA molecules are polymers formed by single units called __n__**ucleotides** (called ribonucleotides for RNA)
- DNA is **double stranded**, whereas RNA is **single stranded**
- Nucleotide components:
 - Pentose Sugar
 - Nitrogenous Bases
 - Phosphate Group

![diff](//images.ctfassets.net/4yflszkpcwkt/2NNaI9WAkX2khaRkMKKyPa/39c116d25a79505e175e1fda107384b7/dna-versus-rna-608191_sketch_Final-54acdd8f8af04c73817e8811c32905fa.png)

[Source](https://www.thoughtco.com/dna-versus-rna-608191)

- Multiple nucleotides joined together form polynucleotides
- The structure of polynucleotide chain is as follows:
 - adenine (A), guanine (G), cytosine (C), or thymine (T) and a phosphate group together make the polynucleotide chain.
 - The phosphate groups are connected by phosphodiester bonds to the subsequent nucleotide's sugar molecule, thus forming the polynucleotide chain.

## DNA: Double Helix Structure

- made up of two polynucleotide chains
- backbone = sugar + phosphate
- interior parts made of nitrogenous bases
- complementary base pairing - only certain bases will pair with the another
- Maintains a uniform distance between these pairs - pairing occurs between one **purine** and one **pyrimidine**

## ****DNA Structure and Packaging****

- Cells make **histone proteins** that bind the DNA to counterbalance negative charge of the double helix

![histone](//images.ctfassets.net/4yflszkpcwkt/29ZIUx2kiJalwxPJ9y52IR/fb37e5092b6f272aa7740c35ac271b44/biobook_dna_graphik_12.png)

[Source](https://www.shmoop.com/study-guides/biology/dna/dna-packaging)

- **DNA Packaging** is the process of folding the DNA molecule into chromatin to fit into the nucleus of a cell
 - required because DNA is around **3 meters** in length, and it needs to be packed into the small nucleus
- DNA strands are helically coiled (right-handed coil)
- **Pitch** of each helix is **3.32 nm** (10 nucleotides per turn)
- A typical strand of DNA is **2.2 meters long**

![packaging](//images.ctfassets.net/4yflszkpcwkt/7KXB7woPTMY9PreS3Tcov8/621d7fbefee1545309ea3f294f572612/biobook_dna_graphik_11.png)

[Source](https://www.shmoop.com/study-guides/biology/dna/dna-packaging)

## ****DNA Replication****

- Replication results in multiple copies of a DNA strand, that takes place in three stages: **initiation**, **elongation**, and **termination**
- Primary enzyme involved in the process: **DNA Polymerase**
- DNA replication occurs after the unwinding of the double strand by **helicase**

![replication DNA](//images.ctfassets.net/4yflszkpcwkt/5T6fUEvnSIv5cEbnBfV4qR/7914325688227b09ad643651f41d860d/dna-replication-summary.jpg)

[Check out our DNA Replication Simulation in 3D!](https://www.dnareplicationsimulation.com/ "DNA replication sim")

## Multiple Choice Questions
1. DNA Polymerase synthesises the new DNA strand in which direction? 

2. Packaging of the DNA is important because 

3. TRUE or FALSE: Chromosomes are made up of wound up RNA and DNA.

4. The different stages of DNA replication are ______, _________, and ________. 

5. The negative charge of the DNA double helix is neutralized by ______ proteins.

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