mcq biology

Biology MCQ-01: ICMR JRF Entrance Exam Model Question Paper-1 with Answer & Explanations

Biology MCQ (Multiple Choice Questions in Life Science)
(Sample/Model/Practice Questions for JRF/NET Life Science Examination, ICMR JRF, DBT JRF, GATE, ICAR NET, PG Entrance)

ICMR JRF Model Question Paper
INDIAN COUNCIL OF MEDICAL RESEARCH


 Model Question Paper 01 (MCQ 01)


New: NET Life Sciences Dec 2015 Question Paper with Detailed Answer key

1. The average size of 70S ribosomes of prokaryotes are:

a.      ~ 200 Å
b.      ~ 250 Å
c.      ~ 290 Å
d.      ~ 303 Å

2. Which of the following is an example for chemolithotroph?

a.       Acidithiobacillus ferrooxidans
b.       Nitrosomonas

c.       Nitrobacter
d.      All of the above

3. Which of the following is an example for denitrifying bacteria?

a.       Nitrosomonas
b.       Nitrobacter

c.       Pseudomonads
d.      All of the above

4. Who introduced the group Archaea for a group of prokaryotes on the basis of phylogenetic analysis of 16S rRNA?

a.       Roger Stanier
b.       Carl Woese

c.       C. B. van Niel
d.      Theodor Escherich

5. Who discovered endoplasmic reticulum?

a.      Keith porter
b.      Konstantin Mereschkowsky

c.      Camillo Golgi
d.      George Emil Palade

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Notification of CSIR JRF NET, Life Science Examination

ICMR JRF Entrance Exam: 2015: Life Sciences: Notification

ICMR (Indian Council of Medical Research) in collaboration with PGIMER, Chandigarh will conduct a national level examination for the award of JRF (Junior Research Fellowship) in Life Sciences/Social Sciences stream on Sunday, July 19 2015 (19/07/2015) at 12 selected centers all over India (Bhopal, Bhubaneswar, Chandigarh, Chennai, Delhi, Kolkata, Mumbai, Hyderabad, Guwahati, Srinagar, Bengaluru and Varanasi).

A total of 150 Fellowships would be awarded among which 120 Fellowships would be awarded for work in the field of bio-medical sciences with emphasis on Life Sciences (microbiology, physiology, molecular biology, genetics, human biology, bioinformatics, biotechnology, biochemistry, biophysics, immunology, Pharmacology, zoology, Environment Science, botany, veterinary sciences, bio-informatics etc.). Thirty Fellowships would be awarded for work with emphasis on Social sciences like psychology, sociology, home science, statistics, anthropology, social work and Health Economics.

Another 100 candidates will be selected for consideration for positions of JRF under various research schemes of ICMR for the duration of that scheme. These JRFs would also be permitted to complete Ph.D. while working in the scheme, if enrolled.  The validity of result will be two years for placement in ICMR funded projects.

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Biotechnology Lecture Notes

Enzyme Immobilization Methods and Applications (Biotechnology Lecture Notes)

Methods & Applications of Enzyme & Whole Cell Immobilization
(Advantages and Disadvantages of Enzyme Immobilization; Matrix/Supports Used in Enzyme Immobilization)


What is enzyme immobilization?

Immobilization is defined as the imprisonment of cell or enzyme in a distinct support or matrix. The support or matrix on which the enzymes are immobilized allows the exchange of medium containing substrate or effector or inhibitor molecules. The practice of immobilization of cells is very old and the first immobilized enzyme was amino acylase of Aspergillus oryzae for the production of L-amino acids in Japan. 

Advantages of immobilized enzymes:

(1).   Increased functional efficiency of enzyme

(2).   Enhanced reproducibility of the process they are undertaking

(3).   Reuse of enzyme

(4).   Continuous use of enzyme

(5).   Less labour input in the processes

(6).   Saving in capital cost and investment of the process

(7).   Minimum reaction time

(8).   Less chance of contamination in products

(9).   More stability of products

(10). Stable supply of products in the market

(11). Improved process control

(12). High enzyme substrate ratio

Disadvantages of enzyme immobilization:

(1).  Even though there are many advantages of immobilized enzymes, there are some disadvantages also.

(2).  High cost for the isolation, purification and recovery of active enzyme (most important disadvantage)

(3).  Industrial applications are limited and only very few industries are using immobilized enzymes or immobilized whole cells.

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easybiologyclass, csir jrf net life sciences

CSIR UGC JRF NET December 2014 Results Life Sciences

Results of CSIR-UGC-JRF-NET Examination December 2014 has been announced.

You can check the results from here (CSIR-JRF NET Life Sciences December 2014 Results)

In the category of Life Sciences a total of ~ 520 JRFs and ~ 680 NETs were awarded this time.

So far the CSIR has not mentioned the details of cut-off marks this time.

And the answer keys of December 2014 Examination have not been released yet.

Congratulations from EBC to all who qualified the examination
Regards
easybiologyclass

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biological chemistry

Biochemistry of Plasma Membrane Lipids: Properties, Structure and Classification (Biochemistry Lecture Notes)

PLASMA MEMBRANE LIPIDS
Biochemistry, Properties, Structure and Classification of Lipids of Plasma Membrane

 “Good fences make good neighbors”
Robert Frost, “Mending Wall”, 1914


Biological membrane system: Biological membranes are highly dynamic two layers thick sheath like structures formed by the non-covalent assemblage of lipids, proteins and carbohydrates. They form closed boundaries between different compartments of the cells such as separation of nucleoplasm from the cytoplasm by nuclear membrane in all eukaryotes. They act as barriers to the passage of polar molecules and ions. The thickness of membrane varies among different classes of organisms and the average width ranges from 60 Å (6 nm) to 100 Å (10 nm) in most of the cases.

Even though membrane contains carbohydrates and proteins, the major structural components of bio-membrane are a special class of lipids called membrane lipids. In storage lipids (triglycerides) the three –OH groups of glycerol moieties are esterified by three fatty acids and thus they are completely non-polar. However in membrane lipids, the hydroxyl group at C1 and C2 are esterified with fatty acids and the remaining third –OH group (at C3) will combine to a polar molecule. Thus membrane lipids are amphipathic because they have hydrophilic head (polar) at one end and hydrophobic tail (nonpolar) at the other end. The long hydrocarbon chain of fatty acids forms the hydrophobic part. The hydrophilic moieties of membrane lipids are of different types and which may be as simple as –OH or may be much complex like carbohydrates or amino acids or their derivatives. We commonly call the polar part of membrane lipid as ‘Head’ group and the nonpolar part as ‘Tail’ group.

easybiologyclass, membrane lipid: polar head and non-polar tail group

easybiologyclass, plasma membrane structure and organization, lipid bi-layer of plasma membrane.

The hydrophobic interactions of the nonpolar parts among themselves and the hydrophilic interaction with water are responsible for the packing of lipids in the membrane. These hydrophilic and hydrophobic interactions are also responsible for the bilayer organization of membranes in the cells.

Classification of membrane lipids:

Membrane lipids are classified based on the properties of ‘Head’ group. The membrane lipids of Prokaryotes, Eukaryotes and Archaebacteria are grouped into four major categories:

.

1.   Phospholipids

2.   Glycolipids

3.   Sterols

4.   Archaebacterial ether lipids

 easybiologyclass, mind map membrane lipid classification chart

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