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What are Carbohydrates? How are they Classified? with simple video

Definition: Carbohydrates are bio molecules which are polyhydroxy aldehydes or ketones made  up of Carbon C, Hydrogen H and Oxygen O in the ratio (1:2:1)
Classification of Carbohydrates
This is a simplified 8 minute video on different classification of carbohydrates
A. Based on No. of Carbohydrate Units
1. Monosaccharides
  • Simplest carbohydrate unit or monomer
  •  that cannot be hydrolysed further
  • General formula (CH2O)n
  • Minimum no of Carbon atom is 3
  • Example: glucose, fructose
2. Disaccharides:
Two monosaccharide units joined by glycosidic bond
Example: Glucose + Glucose=Maltose (Disaccharide)
                   Glucose + fructose= Sucrose
3. Oligosaccharides
Carbohydrates usually made up of 3-10 monosaccharide units joined by glycosydic bond
Eg: Raffinose
4. Polysaccharides
  • Complex Carbohydrates made up of hundreds of monosaccharide unit s joined by glycosydic bond
  • Structural Polysaccharides like Cellulose in plants
  • Storage Polysaccharides like starch in plants and glycogen in animals
B. Based on functional group
  • Aldoses: Carbohydrates with aldehyde(-CHO) functional group Eg: Glucose
  • Ketoses: Carbohydrates with ketone (=C=O) functional group Eg: Fructose
C. Based on no. of carbon atoms
  • Simplest monosaccharide has 3 carbon atom called as Triose. Eg: Glyceraldehyde
  • Tetrose: Monosaccharide with 4 carbon atom Eg: erythrose
  • Pentose: 5 carbon atom Eg: pentose
  • Hexose: 6 carbon atom Eg: Glucose
  • Heptose: 7 carbon atoms Eg: sedoheptulose
D. Based on Rotation (Dextro and Levo)
  • Based on stereochemistry of the highest numbered chiral carbon of the Fischer projection.
  • If the hydroxyl group of the highest numbered chiral carbon is pointing to the right, the sugar is designated as D (Dextro: Latin for on the right side). 
  • If the hydroxyl group is pointing to the left, the sugar is  Levo (Levo: Latin for on the left)
  • Most naturally occurring carbohydrates are of the D-configuration.
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ICMR JRF 2018 Life Science Questions and Answers (Download PDF)

The test will consist of one paper of 2 hours duration. The paper will consist of 2 Sections.
The Aptitude Section (Section A) will have 50 questions on
(i) scientific phenomenon in everyday life;
(ii) general knowledge in sciences; and
(iii) common statistics.
All these questions would be compulsory with each question carrying 1 mark. The subject Specific Section (Section B & C) would pertain to (B) Life Sciences and (C) Social Science. 
ICMR JRF 2018 Life Science Questions and Answers (Download PDF)
The candidate may attempt questions in either of the two areas. Each area of section B & C would have 100 questions and the candidate may attempt any 75 questions in the predesigned area of Section B or C. Each question carries one mark. Negative marking @ 0.25 
ICMR JRF 2018 Questions and Answers - Section I- AptitudeICMR JRF 2018 Life Science Questions and Answers

ICMR JRF 2018 Life Science Questions and Answers

ICMR JRF 2018 Life Science Questions and Answers

ICMR JRF 2018 Life Science Questions and Answers

ICMR JRF 2018 Life Science Questions and Answers

ICMR JRF 2018 Life Science Questions and Answers

ICMR JRF 2018 Life Science Questions and Answers
Download pdf
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ICMR JRF 2018 Questions and Answers - Section I- Aptitude

The test will consist of one paper of 2 hours duration. The paper will consist of 2 Sections.
The Aptitude Section (Section A) will have 50 questions on
(i) scientific phenomenon in everyday life;
(ii) general knowledge in sciences; and
(iii) common statistics.
ICMR JRF 2018 Questions and Answers - Section I- Aptitude
All these questions would be compulsory with each question carrying 1 mark. The subject Specific Section (Section B & C) would pertain to (B) Life Sciences and (C) Social Science. 
The candidate may attempt questions in either of the two areas. Each area of section B & C would have 100 questions and the candidate may attempt any 75 questions in the predesigned area of Section B or C.

Candidates are required to indicate the option for Section B or C in the application form too.
Each question carries one mark. Negative marking @ 0.25 .




Download pdf
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Multiple Choice Questions on Ecological Succession


1. Ecological  succession on sand is
A)xerosere
B) psammosere
C)hydrosere
D)halosere

2. Lichen is the pioneer vegetation on which succession?
A)Hydrosere
B)Lithosere
C)Psammosere
D)None of these

3. Last stable community in succession dependent on climate is
A)seral community
B)climax community
C)both a and b
D)none of these
Multiple Choice Questions on Ecological Succession

4. Both hydrarch and xerarch succession lead to
A)highly dry conditions
B) xeric conditions
C)excessive wet conditions
D)medium water conditions

5.  Reed swamp state is seen in
A)Xerosere
B)Psammosere
C)Hydrosere
D)Lithosere

6. A climax community
A)is self-sustaining
B)is never changing
C)show growth proceeding in a predictable pattern
D)is not likely to be disturbed by localized climatic changes

7. Which of the following is  a characteristic of an early seral community
A)Narrow niche specialization
B)high species diversity
C)low community production
D)open mineral cycling

8. The type of plant succession in which lichens form a component is
A)Hydrosere
B)Psamosere
C)Halosere
D)Lithosere

9. The several stages of hydrosere along with suitable examples are given. Indicate  the correct matches for them
I. Plank stage- Diatoms
II. Woodland stage- Juncus
III. Floating stage- Nymphaea
iv. Submerged stage- Hydrilla
v.Reed swamp stage- Sagittaria

A) I, II, III, and IV
B) I, III, IV and V
C) I, II, IV and V
D)  I, II, III and V
 10. Match the following and select the correct option.
A
EartVhworm
i
Pioneer species
B
Succession
ii
Detritovore
C
Ecosystem service
Iii
Natality
D
Population growth
iv
Pollination

A) A –i, B-ii, C-iii, D-iv
B) A –iv, B-ii, C-iii, D-ii
C) A –iii, B-ii, C-iv, D-i
D) A –ii, B-i, C-iv, D-iii
Answers:
1. B) psammosere
2. B)Lithosere
3. B)climax community
4. D)medium water conditions
5. C)Hydrosere
6. B)is never changing
7. D)open mineral cycling
8. D)Lithosere
9.  B)I, III, IV and V
10. D) A –ii, B-i, C-iv, D-iii
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What are the Major Differences Between Prokaryotic and Eukaryotic Cell?

Prokaryotic vs Eukaryotic Cell, 5 major differences.

This is a simplified 5-minute video on the difference between the prokaryotic cell and eukaryotic cell.

  • Definition of Prokaryotic vs Eukaryotic Cell
  • Cell wall of Prokaryotic vs Eukaryotic Cell
  • DNA of Prokaryotic vs Eukaryotic Cell
  • Cell division of Prokaryotic vs Eukaryotic Cell
  • Cell surface appendages of Prokaryotic vs Eukaryotic Cell

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Handshake Problem Simple Formula and Practice Problem

"Hand Shake Problem" is a very common question in many competitive exams such as CSIR in the Aptitude part questions. Here we are discussing a simple formula for answering this question.
Watch this two minute video or refer the questions below
Practice Problems
1. In a group of 11 persons, each shakes hand with every other once and only once. What is the total number of such handshakes? (CSIR DEC, 2018)
This is the formula

Handshake Problem Simple Formula









Answer: Total No of hand shakes (T)= n(n-1)/2
                                No of persons n=11
N=11 (11-1)/2
=11x10/2=110/2
Answer: 55 handshakes

2. If there are 10 football teams in a tournament, how many games must be played in order for each team to play every other team exactly once? (same pattern question in a different context)
Answer: No of games= n(n-1)/2
N=10 (10-1)/2
=10x9/2=90/2=45 games
Use this formula for answering any questions of this pattern
Thank you so much and best wishes for your exam
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CSIR UGC NET Life Sciences June 2019 Exam Paper Pattern Part A, B and C Questions

The csirhrdg has announced the notification of Exam to be held on June 2019.
Here biologyexams4u team prepares a 10 minute short video on exam pattern with a solved sample question from part A, B and C. Get familiar with the question pattern and also sharing some tips and tricks for answering questions from my experience. 
Best Wishes for your exam
"Don't stop when you are tired, stop when you are done"
Thank you so much for your support. Send your comments to make our free resources better. Definitely, we are preparing with you in chasing your dream. 
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CSIR UGC NET Life Sciences December 2018 cut off marks and Result

The csirhrdg has announced the cutoff marks of Exam held in December 2018. See the figure
For Results Click this link CSIR UGC NET LIfe sciences result Dec 2018.

CSIR UGC NET Life Sciences December 2018 cut off marks
Best wishes for everyone
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