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The lymphatic system is a network of tissues and organs that help rid the body of toxins, waste and other unwanted materials. The primary function of the lymphatic system is to transport lymph, a fluid containing infection-fighting white blood cells, throughout the body.

(a) 

(i) According to the one of the first models proposed for the genetic code by physicist George Gamow, each amino acid in a polypeptide was encoded by three sequential nucleotides. The code words, or codons, for amino acids were nucleotide triplets. 

(ii) In 1968, the Nobel Prize in Physiology or Medicine was awarded jointly to Robert W. Holley, Har Gobind Khorana and Marshall W. Nirenberg for their work on the interpretation of the genetic code and its function in protein synthesis, showing how the order of nucleotides in nucleic acids, which carry the genetic code of the cell, encode the proteins synthesized by the cell . They established the biological language or genetic code common to all living organisms, is spelled out in three-letter words: each set of three nucleotides codes for a specific amino acid. 

(iii) Nirenberg and Mathaei used a synthetic poly (U) RNA and deciphered the genetic code by translating this as polyphenylalanine. 

(iv) Over the course of several years, Marshall Nirenberg, Har Khorana and Severo Ochoa and their colleagues elucidated the genetic code - showing how nucleic acids with their 4-letter alphabet determine the order of the 20 kinds of amino acids in proteins. In 1959, Nobel Prize for the discovery of RNA polymerase was given to Ochoa. 

(b) The genetic code is the set of rules by which information encoded in genetic material (DNA or RNA sequences) is translated into proteins (amino acid sequences) by living cells. 

• They are unambiguous means that one codon specifies only one amino acid and not any other. 

• They are universal means that the genetic code is applicable universally, i.e., a codon specifies the same amino acid from a virus to a tree or human being.

• They are degenerate means some amino acids often have more than one codon. Only methionine and tryptophan have singlet triplet codons. All other amino acids are specified by two to six codons.

Streptococcus pneumoniae.

My School Or College

1. Name and Situation:
The name of my school is C.A.V. Inter College, Allahabad. It is situated in the heart of the city.

2. Building:
It has a very large double-storeyed building. The main building of the school consists of the three blocks. Our classes run in the main building. It has about twenty rooms with a big hall. There are four laboratories for Science and Biology. All the rooms are airy and well-ventilated. Electric light and fans are fitted in every room. The hall of the school is very big. General meetings are held here. The Principal’s Office is in the middle of the building. There are some quarters for the peons. It has well-furnished canteen too.

3. Library:
The main attraction of the college is its library. There are two big rooms. There is a regular issue of books. The strength of the college is about six thousand. The staff members are one hundred and fifty. All students and teachers get books issued from the library. There are two reading rooms, one for the teachers and the other for the students. Newspapers and magazines are put on the tables to read.

4. Play Ground:
We are lucky to have two play grounds. They are well-maintained. Our game superintendent is very expert. He is very careful about the play grounds. We enjoy our games daily in the evening. Some students go to play in the vacant periods.

5. Conclusion:
Our college is a reputed college in the district. Students from rural areas also come to get their admission. We are proud of it.

My Father

1. Introduction:
I am Mukesh Jain. My father is Shri S. K. Jain. He is a doctor. He has a grand personality. He is fifty yet he is smart and active.

2. His Dress and Behaviour:
He is a simple man. He is always neat and clean. He wears white shirt and white pant. His dress is always pressed and well-maintained. In winter, he wears woollen clothes. He is very kind and gentle too. Everybody likes and respects him.

3. His Qualities:
My father is a man of character. He always helps the poor and needy. He is popular among his neighbours. People respect him and come to him for advice. He is religious minded. Every day, he goes to temple and worships there for an hour. Daily Life My father gets up early in the morning. He goes for a walk daily. He gets ready for his daily work. He leaves the house at 10 o’clock and goes to Municipal hospital. He returns from there at 4 o’clock. Then he looks after us.

4. Conclusion:
My father is a gentleman. He is a famous doctor in the district. He is always busy in doing one thing or the other. He hates telling lies and speaking ill of others. I am proud of him. I love him very much.

My Mother

1. Introduction :
I am Meena. I am the daughter of Mrs. Shamo Rani. She is a post graduate retired English teacher. She loves me very much as I am her eldest daughter.

2. Her Nature:
She is fair, active and religious minded. She herself does most of the household work.  She likes cleanliness. She is daring, dashing and brave. She teaches me daily for two hours. She is always busy doing one thing or the other.

3. Her Qualities:
She hates telling lies and speaking ill of others. She is very sweet tempered. She is very honest and intelligent. She believes in simple living and high thinking. She helps the poor. She behaves well and she is never angry.

4. Conclusion:
She is a religious minded lady. She loves each and every member of the family. She is like a goddess on earth. I love my mother very much.

My Visit to A Fair

1. Introduction:
The Ganga is a holy river. In the month of Kartik, Ganga fairs are held at many places. Varanasi is one of them. Once I had a chance to go to this fair with my friends.

2. Scene at the ghats:
We went to the fair by the train take. We went directly to the ghat, where our friends were waiting for us. We went to take bathe in the Ganga. There was a very big crowd on the ghats. Police constables and volunteers were on duty. Boats were moving in the river. After bathing we came back to a hotel.

3. Description of the fair:
In the evening, we went to the fair. There were two lines of shops. They were well-decorated. We made some purchases in the market. When night befell, there was light everywhere. It looked very beautiful, we felt hungry. So we took sweets and tea. Then we went to see the circus. We came back to hotel at 12 O’clock in the night

4. Conclusion:

Fairs are very useful. There we meet many of our friends and relatives. We see many new things. We also learn some new things. We forget our sorrows. We enjoy them much.

My Favourite Book

1. Name of the book and the author:
I am fond of reading books. Reading books is my hobby. I have read so many books. The Ramcharit Manas is one of them. I like it very much. I read it again and again. Its author is Goswami Tulsidas. He was a famous poet.

2. Theme of the book (Description):
There is vivid story of Lord Ram who was the eldest son of Dashratha. Dashratha was the famous king of Ayodhya. Ram was set into forest for fourteen years. Sita who was his wife also went to the forest. His brother Laxman was with him. In the forest Sita was carried off forcibly by Ravan; the king of Lanka. Ram killed Ravan and came back to Ayodhya after fourteen years.

3. Its languages and style:
‘The Ramcharit Manas’ is an epic. It is written in Hindi. Sanskrit is also used in it. It is in verse. Tulsidas has written so many books. All books are written in “Awadhi”, so the Ramcharit Manas is also in Awadhi.

4. Reasons for liking it :
I like the book very much. Its language is musical and simple. It is full of wisdom. It is a store house of ideals which have worthy to be followed: Before us it presents a picture of an ideal society. It points out that the evil is punished and the good prevails in the end.

5. Conclusion:
Due to all the above qualities, the Ramcharit Manas is very popular in India. It is widely read with devotion. The Hindus worship it. It is also known as the “Ramayan’. I like it very much. I read it everyday.

(4) Four pairs of spermathecae are located in 6^th-9^th segments.

My Idea of A Model Village

1. Introduction :
India is a land of villages. About seventy percent people live in villages. The villagers are very poor. It is our duty to improve them.

2. Spreading of education:
The most important thing is education. Most of the villagers cannot read or write. So we should start night schools for them.

3. Arrangements of hospitals:
The villagers do not get medicines when they fall ill. So we should build hospitals for them in villages. There should be well qualified doctors in these hospitals to look after them.

4. Teaching good habits:
The villagers have some very bad habits. They drink and smoke. They spend much money on marriages and other ceremonies. They should be taught that all these things are bad. They should be asked to avoid them to make their lives comfortable.

Correct option is A) I’ll be

Ribosomes are made of two subunits, the small subunit and the large subunit. These subunits are made of ribosomic RNA (rRNA) and proteins. Ribosomes have three binding sites, one for mRNA and two for tRNA.

Each sequence of three nitrogencontaining bases of RNA that codifies one amino acid is called a codon. The codon is the codifier unit of the genetic code. 

In prokaryotes ribosomes are found free in cytoplasm. In eukaryotic cells they can also be found free in cytoplasm and mainly adhered to the external membrane of the karyotheca and of the rough endoplasmic reticulum.

Transcription is the name given to the formation of DNA molecules from an open DNA chain used as a template. Translation is the making of polypeptides (amino acids bound in sequence) and thus of proteins based on information encoded in the mRNA molecule. 

In eukaryotic cells transcription occurs in the nucleus and translation occurs in ribosomes. Transcription precedes translation.

Correct answer is a) Recreational activities 

A nucleic acid having a TAC sequence surely is not tRNA, it is DNA since RNA does not present the nitrogen-containing base thymine. Since it is not RNA it cannot be a codon or an anticodon.

During translation the ribosome always exposes two mRNA codons to be translated by moving along the mRNA. When a peptide bond is made the ribosome moves to expose the next codon. This moving is called ribosomal translocation. (In the rough endoplasmic reticulum ribosomes are attached outside the membrane and mRNA molecules rather moving through them).

Correct answer is iron

(a). Drosophila melanogaster They observed that two genes (located closely on a chromosome) did not segregate independently of each other (F2 ratio deviated significantly from 9 : 3 : 3 : 1) Tightly linked genes tend to show fewer (lesser) recombinant frequency of parental traits / show higher (more) frequency of parental type Loosely linked genes show higher percentage (more) of recombinant frequency of parental traits / lower frequency percentage of parental type Genes present on same chromosome are said to be linked and the recombinant frequency depends on their relative distance on the chromosome 

(b). He used the frequency of recombination between gene pairs on the same chromosome, as a measure of the distance between genes and mapped their position on the chromosome.

Correct answer is TV

Amino acids are brought to ribosomes by RNA molecules known as transfer RNA, or tRNA. One tRNA associated to its specific amino acid binds by a special sequence of three nucleotides to a mRNA codon exposed in the ribosome. This sequence in the tRNA is known as anticodon. The tRNA anticodon must be complementary to the mRNA codon to which it binds, according to the rule AU, CG. The ribosome then slides along the mRNA molecule (a process called translocation) to expose the following codon to the binding of other tRNA. When amino acids corresponding to neighboring codons bind by peptide bond the first tRNa is liberated. 

To make proteins mRNA molecules necessarily associate to ribosomes. Ribosomes have two sites for the binding of two neighboring mRNA codons and where anticodons of tRNA bind by hydrogen bond. Thus ribosomes are the structure responsible for the positioning and exposure of mRNA codons to be translated. In ribosomes the peptide bond between two amino acids brought by tRNA molecules also occurs. The peptide bond happens when tRNAs carrying amino acids are bound to exposed mRNA codons.

Characteristics of organisms depend on chemical reactions that occur in them. These reactions are catalyzed by enzymes, highly specific proteins. Every protein of an organism is made from information contained in RNA molecules that are made according to a template sequence of nucleotides of a DNA chain.

A gene is a DNA polynucleotide sequence that contains information for the production of a protein.

Experimental verification of the chromosomal theory of inheritance was done by Morgan

Correct answer is telephone

Correct answer is kettle

The hereditary molecule that controls the cellular functioning is the DNA (deoxyribonucleic acid). The DNA contains information for protein synthesis in cells. 

Correct answer is dishwasher

Genetic code is the key for the conversion of DNA nucleotide sequences (and thus RNA nucleotide sequences) into amino acids sequences that will compose proteins. 

The pyruvic acid molecules made in the cytosol by glycolysis enter into the mitochondria. 

Within the mitochondria, each pyruvic an acid molecule is converted into one a molecule of acetyl-CoA (acetyl coenzyme A) with the liberation of one carbon dioxide. The Krebs cycle (also known as citric acid cycle), the second stage of aerobic respiration, then begins.

The cell organelles that are specialized in aerobic respiration are the mitochondria.

Molecular oxygen (O₂) consumption has direct relation to the cell metabolic rate in aerobic cells and so to the metabolic rate of the organisms. Cells having higher metabolic activity demand more energy and such energy comes from ATP molecules. As there is need for ATP production, the intensity of aerobic cell respiration is also higher and then more oxygen is consumed.

The general equation of the aerobic respiration is:

C₆H₁₂O₆ + 6 O₂ + 36 ADP + 36 P --> 6 CO₂ + 6 H₂O + 36 ATP

Oxygen enters the aerobic respiration in its final phase, the respiratory chain. It is of fundamental importance because it is responsible for the maintenance of the hydrogen concentration gradient between the spaces separated by the inner mitochondrial membrane. This gradient promotes the functioning of the ATP synthetase and thus the phosphorylation of ADP to form ATP. In the space inside the inner membrane oxygen binds to free hydrogens to form water and this hydrogen consumption keeps the hydrogen gradient and the proton traffic through the ATP synthetase.

The entire aerobic respiration process has the intent to make the ATP synthetase work. Aerobic beings, for example, we humans, need to breathe oxygen to maintain that hydrogen concentration gradient and keep the ATP synthetase working.

After aerobic respiration 38 ATP molecules are made with the consumption of one glucose molecule (but two of this ATP are consumed by glycolysis). The net gain of the process is then 36 ATP molecules per glucose molecule.

Bioremediation is the use of microorganisms, like bacteria, protists and fungi, to degrade noxious substances turning them into non toxic or less toxic substances. Bioremediation employs microorganisms whose metabolism uses contaminants as reagents. 

Bioremediation is used, for example, in the decontamination of environments polluted by oil spills. In this process bacteria that use hydrocarbons as substrate for their cellular respiration are employed.

Anoxia is a situation in which there is no available oxygen in the cell. Whitout oxygen the respiratory chain stops, there is no ATP production, the cell does not obtain energy and dies.

Anoxia can be caused, for example, by pulmonary insufficiency (drowning, extensive pulmonary injuries, etc.), by obstructions, halts and deficiencies in tissue circulation (atherosclerosis of the coronary arteries that irrigate the myocardium, tourniquets, heart arrest), by hemolysis (lysis of red blood cell) or hemoglobin diseases (anemias, fetal erythroblastosis), etc.

Parasitism is an inharmonious interspecific ecological interaction in which individuals of a species (the parasites) explore organs, tissues or cells of individuals of another species (the hosts) causing harm to these.

Inharmonious, or negative, ecological interaction is that in which at least one of the participating beings is harmed.

In the chronic phase of Chagas’ disease, that manifests years after the infection, the trypanosoma infests the muscles of the heart causing insufficient blood pumping, pulmonary edema and increase in the size of the organ (cardiomegaly). This is the cardiac manifestation of Chagas’ disease. The main symptoms that appear are dyspnea, cough and cardiac arrhythmias.

In the digestive form of manifestation of the disease the parasite destroys cells of the autonomic nervous system responsible for the peristaltism of the digestive tube. Since the motility of the esophagus and intestines is reduced the transit of materials inside these organs is impaired and they increase in size (width), conditions respectively known as megaesophagus and megacolon. The main symptoms are dysphagia (impaired swallowing), constipation, flatulence and formation of fecaloma (accumulation of feces inside the bowels).

Trypanosoma cruzi is a heteroxenous parasite, i.e., it has an intermediate host, the triatomine bug, and a definitive host, the human. The triatomine bug becomes infected by sucking the blood of a contaminated person. Within the bug gut the protozoan reproduces itself. When the triatomine bites another person it defecates near the bite site. Generally the bitten person itches the area of the bite and the parasite gains the circulation of the definitive host. Within humans the Trypanosoma cruzi multiply as amastigote form in the cardiac muscle tissue or in the nervous tissue forming pseudocysts. These pseudocysts break releasing flagellate parasites into the circulation and the cycle is repeated.

Prophylaxis are measures taken to prevent diseases. For example, the use of condoms in sexual relations is a prophylaxis against contamination by agents that cause STDs (sexually transmitted diseases).

Chagas’ disease may or may not present an acute phase. When it is present, the incubation period is about 5 to 14 days. The chronic phase, however, can manifest in more than 10 years after the infection.

At the site where the trypanosoma has penetrated the skin or the mucosa becomes swelled: This sign is known as chagoma. Another sign that may appear in up to 20% of cases after the infection is the Romana’s sign, a swelling of one of the eyelids when infection took place through the ocular route. In the acute Chagas’ disease fever, malaise, inflammation and enlargement of lymph nodes may occur. In more severe cases fatal inflammation of the cardiac muscle or of the meninges may happen.

Incubation period is the time interval between the infection by an agent that causes disease and the first signs or symptoms of the disease. 

In the definitive hosts as well as in triatomine bugs (intermediate hosts) the protozoan that causes Chagas’ disease alternates mastigote (flagellate) and amastigote forms and also intermediate forms between these forms. 

The criterion used to classify hosts as intermediate hosts or as definitive hosts is the kind of reproduction of the parasite, sexual or asexual, within the host. The host within which the sexual reproduction stage of the parasite occurs is the definitive host. The host within which the asexual reproduction stage of the parasite occurs is the intermediate host.

Amebiasis is caused by the protozoan Entamoeba histolytica, or simply amoeba.

The transmission of the disease is oralfecal, through contaminated water and food or by insects like cockroaches and flies. The amoeba parasites the intestine of humans generally in an asymptomatic manner, but it can sometimes cause enteritis with diarrhea and severe dysentery, abdominal pain, weight loss and anemia. In rare cases extra-intestinal invasion may occur affecting the liver, skin, genital organs and other organs.