MH-CET 2014

Notes on Excretion and Osmoregulation

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1.       Urinary bladder is provided with transitional epithelium and detrusor muscles.


i. Transitional epithelium helps in the expansion of the urinary bladder.

ii. The detrusor muscles are smooth muscles which help in making the wall of urinary bladder though and thick.

iii. Since in the urinary bladder, about half to one litre of urine is stored temporarily, it needs to be expandable and tough.

iv. Urinary bladder is provided with such transitional epithelium and detrusor muscles as they help in this function.

2.       EFP is crated in the glomerulus.


i. EFP or effective filtration pressure is a hydrostatic pressure.

ii. It is created because the blood enters the glomerulus at a faster rate than the rate by which it leaves.

iii. This is because the diameter of afferent renal arteriole is larger than the diameter of efferent renal arteriole.

iv. The glomerular capillaries therefore create glomerular hydrostatic pressure called EFP in the glomerulus.

3.       Distal convoluted tubule is important for homeostatic regulation of acidity of blood.


i. During the last phase of urine formation, i.e. during tubular secretion, some nitrogenous waste substances which have eventually entered the blood circulation through peritubular capillaries are secreted back into the DCT.

ii. The substances routinely secreted back are creatinine, potassium and hydrogen ions.

iii. The secretion of hydrogen ions occurs chiefly in DCT and collecting tubule.

iv. This regulates the acidity of the blood through homeostasis. Therefore, distal convoluted tubule is said to be important for homeostatic regulation  of the acidity of blood.

4.       Osmoregulation and excretion go hand in hand.


i. Kidneys are the organs of excretion and osmoregulation.

ii. The water is removed by the kidney as per the requirement of the body.

iii. While doing so the solute concentration is also maintained to a constancy by osmoregulation.

iv. Hormones like ADH which maintain osmoregulation act on renal tubules in kidney. Similarly aldosterone, parathormone, etc. also maintain ionic balance in kidney. Thus, osmoregulation and excretion go hand in hand.

5.       Low secretion of ADH causes diabetes insipidus.


i. Diabetes insipidus is a disorder in which excessive urine is produced with constant thirst.

ii. Polydipsia and polyuria are due to lack of sufficient ADH secretion.

iii. ADH causes antidiuretic effect. When ADH is in more amount every drop of water is reabsorbed through the loop of Henle. Due to this hypertonic urine is produced.

iv. But when ADH level is low water reabsorption is suppressed. This produces hypotonic urine.

v. When ADH secretion is low then person concerned produces excessive urine due to faulty reabsorption of water leading to diabetes insipidus.

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-Team Ednexa

Use of plasmids as vectors in genetic Engineering.

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Plasmids used in genetic engineering are called vectors.

Plasmids serve as important tools in genetics and biotechnology labs, where they are commonly used to multiply (make many copies of) or express particular genes.

Many plasmids are commercially available for such uses.

The gene to be replicated is inserted into copies of a plasmid containing genes that make cells resistant to particular antibiotics and a multiple cloning site(MCS or polylinker), which is short region containing serveral commonly used restriction sites allowing the easy insertion of DNA fragments at this location.

Then the plasmids are inserted into bacteria by a process called transformation.

The bacteria are the exposed to the particular antibiotics. Only bacteria that take up copies of the plasmid survive, since the plasmid makes them resistant. In particular, the protecting genes are expressed (used to make a protein) and the expressed protein breaks down the antibiotics. In this way, the antibiotics act as a filter to select only the modified bacteria. Now these bacteria can be grown in large amounts, harvested and lysed (often using the alkaline lysis method) to isolate the plasmid of interest.

Another major use of plasmids is to make large amounts of proteins. In this case, researchers grow bacteria containing a plasmid harbouring the gene of interest. Just as the bacterium produces proteins to confer its antibiotic resistance, it can also be induced to produce larger amounts of proteins from the inserted gene. This is a cheap and easy way of mass – production of a gene or the protein, e.g., the gene insulin or even antibiotics.

However, a plasmid can contain inserts of only about 1- 10kbp. To clone longer lengths of DNA, lambda phage without lysogeny genes, cosmids, bacterial artificial chromosomes or yeast artificial chromosomes are used.

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Notes for Biology and Human Welfare

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Notes for Biology and Human Welfare for MH-CET 2014


5 tips to Get rid of Exam Stress

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5 tips to get rid of exam,

Feeling prepared and in control is the best gift you can give yourself as you get ready for your exams. No matter how much we do to prevent it, exams are almost always going to be accompanied by stress. Therefore, the best thing to do is to manage the stress and make sure that it does not break down your physical, mental or emotional health.

Here are some ideas for what you may want to include in your plan Read here

MH-CET 2014 application details announced!

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The long awaited news has come. Official notification for application to MH-CET 2014 has been announced.

This is first time students are supposed to fill the form online only. They have to create a login Id on MH-CET website and follow the instructions mentioned.

This link provides all the procedure in details. The start date of form submission is 5th March and the last date is 31st March.

Admit card could be downloaded from 25th April to 7th May 2014.

Exam timing 8th May, 10:00 am to 01:00 pm.

Results will be declared by 30th, May 2014.

We will welcome any query call from you related to registration procedure.

Ednexa wishes all the best to all the aspiring candidates for the best results!

Call us on 9011041155/ 9011031155 if you need any help related to form submission and exam preparation.

Human Reproduction (Distinguishing Factors) – MH-CET 2014

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Human Reproduction (Distinguishing Factors) – MH-CET 2014


1. Blastula and Gastrula.




1. Blastula has a blastocoel.

2. Blastula is produced by the process of blastulation.

3. Blastula undergoes implantation followed by gastrulation.

1. Gastrula has a gastrocoel or archenteron.

2. Gastrula is produced by the process of gastrulation.

3. Gastrula undergoes morphogenesis and then forms germ layers.


2. Spermatogenesis and Oogenesis.




1. Spermatogenesis takes place in testis in mature and fertile males.

2. From one Spermatogonium four haploid sperms are formed during Spermatogenesis.

3. Spermatid developed undergoes metamorphosis in the process of Spermatogenesis.

4. Spermatid development takes place which later becomes a functional sperm.

5. Spermatogonia,primary and secondary spermatocytes and spermatid are the stages of sperms formed during spermatogenesis.

1. Oogenesis takes place in ovaries in mature and fertile females.

2. From one oogonium one haploid ovum and a polar body is formed during oogenesis.

3. There is no such process of metamorphosis in oogenesis

4. Ootid development does not take place during oogenesis. It develops only after fertilization.

5. Oogonia, primary and secondary oocytes are the stages formed during oogenesis. Ootid formation occurs only after fertilization.


3.  Morula and Blastula.




1. Morula is the embryonic stage formed after the completion of cleavage.

2. Morula is formed 4 to 6 days after the fertilization.

3. Morula consists of 16 cells.

4. Morula is solid ball of cells.

5. Morula stage is passed in fallopian tube, once it reaches uterus, it starts developing into the next stage.

6. Morula does not have any dis-tinction of its inner cell structure.

1. Blastula is the embryonic stage formed after the completion of blastulation.

2. Blastula is formed  4 to 6 days after the fertilization.

3. Blastula consists of more than 64 cells.

4. Blastula is a hollow ball of cells.

5. Blastula after reaching the uterus is implanted on the wall of uterus.

6. Blastula has a blastocoel, trophoblast and inner cell mass.


4. Zona pellucida and Corona radiata.


Zone pellucida

Corona radiata.

1. Zona pellucida is inner, thin and transparent layer surrounding the secondary oocyte.

2. Zona pellucida is a non – cellular layer.

3. Zona pellucida is secreted by the ovum itself.

4. Zona pellucida is retained for more time after fertilization till the ovum gets implanted in the uterus.

5. Zona pellucida is digested by zona lysine or acrosin at the time of fertilization.

1. Corona radiata is the outer thick layer surrounding the secondary oocyte.

2. Corona radiata is a cellular layer.

3. Corona radiata is formed by follicular cells which are glued together by hyaluronic acid.

4. Corona radiata is retained till the ovum gets fertilized.

5. Corona radiata is digested by hyaluronidase enzyme at the time of fertilization.


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Team Ednexa

Computer Chemists win Nobel prize

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Three molecular chemists won the Nobel Prize for Chemistry today for devising computer simulations that are used to understand and predict chemical processes, the jury said.
Martin Karplus, a US-Austrian citizen, Michael Levitt, a US-British citizen, and Arieh Warshel of the US and Israel, were honored “for the development of multiscale models for complex chemical systems,” the jury said.
Their prize winning work has helped develop computer models mirroring real life, “which have become crucial for most advances made in chemistry today.”
As a result, powerful computer programmes can be used to predict complex chemical processes, providing pharmaceutical engineers and manufacturing chemists with a fast-track way to solve problems.
These processes can take place in a fraction of a millisecond, defeating conventional algorithms that try to map them step by step.
The contribution of the three was to combine classical physics with quantum physics in their model.
This hugely boosts the number of permutations for calculation, although it also requires enormous computer power to crunch the data.
“The strength of the methods that Martin Karplus, Michael Levitt and Arieh Warshel have developed is that they are universal,” the Nobel panel said.
“They can be used to study all kinds of chemistry; from the molecules of life to industrial chemical processes. Scientists can optimize solar cells, catalysts in motor vehicles or even drugs, to take but a few examples.”
The trio will share the prize sum of eight million Swedish kronor (USD 1.25 million), reduced because of the economic crisis last year from the 10 million kronor awarded since 2001.
In line with tradition, the laureates will receive their prize at a formal ceremony in Stockholm on December 10, the anniversary of prize founder Alfred Nobel’s death in 1896.
Last year, the honor went to Robert Lefkowitz and Brian Kobilka of the United States for identifying a class of cell receptor, yielding vital insights into how the body works at the molecular level.
Stay with us for latest updates.
- Team Ednexa