Biology Exams 4 U

Biology Exam Preparation Portal. Preparing with U 4 ur exams...

Ecology 10 percent rule Raymond Lindeman’s law of trophic efficiency (Law of 10% Energy Transfer)

Raymond Lindeman’s law of energy transfer or Law of 10 %
Ecosystem refers to the interactions of organisms with one another and with their environment in which they occur. It is a “Life supporting system”

The sustenance of ecosystem is dependent on two major processes namely energy flow and the nutrient cycling. The orderly step by step  transfer of energy from one trophic level to another  or in other words from producers to decomposers is called Energy flow.

Energy flow is always unidirectional and non- cyclic. Some amount of energy is lost at each trophic level either as heat, or used for metabolism, excretion and decomposition.

Lindeman was the first one to study the trophic efficiencies

Study area: Trophic efficiencies at the various trophic levels in two lakes; lake Mendota, Minnesota and Cedar Bog lake.
Raymond Lindeman’s law of trophic efficiency (Law of 10 percent)

 According to Lindeman’s Law of 10%, the efficiency of energy transfer from one trophic level to the next is about 10%. 
Only 10% of the net primary productivity of producers ends up as herbivores and so on  to the next trophic levels.
Many recent studies suggests that the generalization of trophic efficiency to 10% may not be always true. Trophic efficiency vary greatly and primarily depend on the behavior and physiology of the organisms concerned than on their position in a food web or a food chain
Read More

Glossary of Bioinformatics Terms - BLAST BLOSUM E value KEGG FASTA RasMol Tcoffee upgma


Alignment: Representation of two or more protein or nucleotide sequences where homologous amino acids or nucleotides are in the same columns while missing aminoacids or nucucleotides are replaced by gaps

BankIt: A computer programs developed by NCBI ( national)for submitting your own sequences to GenBank.

BLAST(Basic Local Alignment Search Tool): Homology search programs. Program for comparing a sequence with all the sequences contained in the database.
BLAST(Basic Local Alignment Search Tool)

BLOSUM (Block Scoring Matrix), a popular substitution  matrix for aligning protein sequences. 
Biological Databases:
Biological Databases

Clade: Group of related species and their common ancestors.

Cladogram: Phylogenetic tree showing the relationship between the species. 

Clustal W : Multiple sequence alignment program

DALI: Structure database search program.

DDBJ : DNA Data Bank of Japan

Dendrogram: Phylogenetic tree. The clustal W guide tree is often referred to as a dendrogram. It is a file with a .dnd extension.

Dot plot: Method for representing the similarity between two sequences without using an alignment.

EBI: European Bioinformatics Institute. The European homologue of NCBI in US.

EMBL: European Molecular Biology Laboratory. This acronym often refers to the nucleotide database the laboratory maintains.
EMBL: European Molecular Biology Laboratory

ENTREZ: The NCBI database querying system that’s similar to to SRS at the EBI. Best known in the context of the PubMed or Medline bibliographical databases.

Ensembl: Human /mouse genome databse.

E VALUE: Expectation value. Given a database and the score of a hit, the E value tells you how many times you could expected such a result just by chance. In sequence analysis, good E value must be very low.

ExPasy: A server maintained by the Swiss Institute of Bioinformatics. Expasy is the home of SWISS PORT, the annonated protein database.

Fasta: One of the first popular programs for searching databases. By extension, FASTA has become the name of the sequence format used by the FATA program.

GenBank: The main nucleotide database, which is co maintained by NCBI, the EMBL, and DDBJ.

GenScan: Gene prediction software program.

Gibbs sampler.: Local multiple sequence alignment method that uses a stochastic algorithm.

Global alignment: An alignment of two sequences where no aminoacid or nucleotide is discarded. They are all either aligned with other amino aids/ nucleotides or aligned with gaps.

KEGG: Kyoto Encyclopedia of Genes and Genomes. A world famous Japanese database on genomes and biochemical pathways.Metabolic pathways databases

InterPro: Protein domain database.

Lalign: A popular tool for finding ten or more best local alignments between two sequences.

Medline: a collection of bibliographic references maintained by the NCBI.

Mfold: RNA structure prediction software program.

Multiple Alignment: An alignment of more than two sequences.

 Pairwise alignment and Multiple Sequence alignment

NCBI: National Center for Biotechnological Information. A component of the U S National institute of Health dedicated to bioinformatic research, software development, and the service and maintemce of leading public resources such as the GenBank (sequences) and PubMed (bibliograpgy) databases. The United states homologue of the EBI in Europe.

Nj: Neighbor Joining. It is the most popular method for reconstructing phylogenetic trees.

Nucleotide Sequence Databases: GenBank, EMBL, DDBJ

ORF: Open Reading Frame. A part of DNA sequences without stop codons.

OMIM: Genetic disease database.

Pairwise alignment: Alignment of two ( a pair of )sequences.

PAM (Point Accepted mutation). A popular substitution matrix for aligning proteins.

Parismony : A technique for reconstructing phylogenetic trees.

PDB: Protein Data Bank. A database that contains every available three dimensional structure. It contains mostly proteins but also a few DNA and RNA structures.

Pfam: Protein family, a collection of profiles for detecting domains and proteins families.
Phylip: Everything on phylogeny. A powerful package for building phylogenetic trees.

PIR: Protein information Resources. An annotated protein database similar to SWISS PORT. It is the name of a sequences format similar to FASTA.

PROSITE: A popular collection of protein domains and patterns.

PuBMed: NCBI’S efficient implementation of Medline bibliographical database produces by us National Library of Medicine.

Query: Question asked when searching a database.

RasMol: Popular software package for visualizing three dimensional structures.

SRS: Sequence retrieval system. The system used at the EBI to search databases with keywords. It is similar to Entrez at NCBI.

SWISS PORT: One of the most extensive annotated protein databases available.

Tcoffee: A package for computing, evaluating and combining multiple sequence alignment.

TrEMBL: Traslated EMBL, which  contains all the putative protein sequences contained in the nucleotide databases.

UPGMA: Unweighted Pair Group Method with arithmetic mean. A method for reconstructing  phylogenetic trees.
Read More

Number of chromosomes and chromatids in each stage of Mitosis and Meiosis PDF

Number of chromosomes and chromatids in each stage of mitosis and meiosis
Mitosis and Meiosis chromosome number chart
This chart helps you to understand the number of chromosomes and DNA molecules at different stages of mitosis  and meiosis at a glance. (Download PDF)
Number of chromosomes and chromatids in each stage of Mitosis and Meiosis
Read More

ICMR JRF 2017: Exam Pattern, Model Questions and Previous Questions

Exam: ICMR JRF 2017 (life science) Date of test: July 16, 2017 (Sunday) 
1. Fluorescence microscope is type of
a)  electron microscope
b) compound microscope
c)  optical microscope
d) none of these                        (See also: Microscope Resolution Different Types SEM vs TEM)

2. Which of the following does not occur with in mitochondria?
a) Krebs cycle
b) ETS
c)ATP synthesis
d) glycolysis                 

3. The meiotic stage during which crossing over occur is
a) interphase
b) prophase I
c) prophase II
d) anaphase I

4. A synonym for a microtubule for a microtubule organizing center (MTOC) at a polar region of an animal cell
a) kinetochore
b) centrosome

5. The substance that is the general biosynthetic precursor of sex hormones and hormones of the adrenal cortex is
a) lecithin
d)phosphatidyl choline

6. Penicillin acts as an antibiotic in susceptible bacteria by interfering with
a) cell wall formation
b) electron transport chain (ETC)
c) formation of protein
d)Synthesis of DNA

7. The number of turns of the Calvin Benson cycle required to synthesis a molecule of glucose is
a) 1

8. What is found in a nucleolus?
a) rRNA
b) 5.8S, 18S and 28s rRNA
c) 45S rRNA
d)All of these

9. The kind of nucleic acid that is represented by a clover laf model is
a) mitochondrial DNA
b) tRNA

10. Amino acid that has a secondary amine and disrupts alpha helix formation is

ICMR JRF 2017 Exam Pattern Model Questions and Previous Questions
1. c)  optical microscope 
2. d) glycolysis 
3. b)prophase I 
4. b) centrosome
5. b)cholestrol
6. a) cell wall formation
7. d)6
8. d)All of these
9. b) tRNA
10. b)proline
Read More

GATE questions on Food Technology

1. Bread staling is caused by (GATE, 2016)
a) carmelisation
b) Aggregation
c) Retrogradation
d) Gelaninisation
GATE questions on Food Technology

2. The oil, which experiences flavour reversion even at the lower peroxide value is (GATE, 2016)

3. The gradation of tea in the increasing order of their leaf size are ---, --- and ---. (GATE, 2016)
Tea leaf grading

a) Souchang, pekoe and orange pekoe
b) Orange pekoe, pekoe and Souchang  
c) Souchang, orange pekoe and pekoe

d) pekoe, Souchang  and orange pekoe

4. The enzyme that hydrolyzes starch to maltose is (GATE, 2015)
a)alpha amylase
b)beta amylase
d)cyclodextrin glcanotransferase

5. Among the following animal foods, the fat content is least in (GATE, 2015)
a) beef
b)chicken meat
d)lamb flesh

6. Which one of the following is not enriched in endosperm during parboiling of paddy? (GATE, 2015)

7. Standard pasteurization protocol or milk is adequate for destroying (GATE, 2015)
a) Clostridium sporogenes
b) Bacillus cereuss
c) Clostridium boutulinum
d)Listeria monocytogenes

8. How many fold would the g number of a centrifuge increase by doubling both the spinning speed and bowl diameter? (GATE, 2015)

9. Which of the following is not a component of an evaporator? (GATE, 2015)
a)heat exchanger
b)vaccum separator
d)cyclone separator

10. Prolonged fermentation of cocoa seeds lead to off taste due to the release of (GATE, 2015)
b)short chain fatty acids
c)carbon dioxide
Learn more: 
1. c) Retrogradation
2. b)soybean 
3. a)Souchang, pekoe and orange pekoe
4. b)beta amylase
5. b)chicken meat
6. b)fat
7. d)Listeria monocytogenes
8. c)8
9. d)cyclone separator
10. b)short chain fatty acids
Read More

Multiple Choice Questions on Horticulture

1. Most commonly used vegetative propagation method in Rose
a) Layering
c) Budding
d)Tissue culture

2. Propagation of onion is done by

3. The most suitable medium for Orchid cultivation
a)Soil + sand
b)soil + broken bricks
c)coir pith + Broken bricks
d)Wooden chips + Broken chips

4. To control damage by earthworms and termites in lawn which method of the following can be used?

5. Which is not a garden style?
a) English

6. Japanese method of flower arrangement is known as


7. Yellowing of lawn grass indicates deficiency of which nutrients

8. Which of the following green house styles is recommended for hilly areas?
a) even span
b) uneven span
c) lean to
d)Ridge and furrow

9. Which irrigation method is most suitable for lawns/turfs?
a) Furrow

10. Zen garden are also known as
a)Italian garden
b)Mughal garden
c)English garden
d)Japanese garden
1.c) Budding
2. d)separation
3. d)Wooden chips + Broken chips
4. b)rolling
5. b)American
6. a)Ikebana
7. a)Nitrogen
8. d)Ridge and furrow
9. d)Sprinkler
10. d)Japanese garden
Read More

MCQ on Plant Physiology, Biostatistics and Biophysics (Lecturer in Botany Questions)

56. Cells which are involved in the lateral transport of solutes
a) parenchyma cells
b) leaf traces
c) foliar trace
d)transfer cells
Ans: d)transfer cells

57. If respiratory substrate is fat and oil, what will be the RQ?
a) 0.7
d) infinite
Ans: a) 0.7

58. Biosynthesis of ethylene from
MCQ on Plant Physiology

a) methionine
b)mevalonic acid
d) cysteine
Ans: a) methionine

59. Water in non cyclic photophosphorylation is used for
 a) excitation of chlorophyll
b) Hydrolysis of ATP
c)Oxidation of NADPH
d)Reduction of chlorophyll
Ans:  d)Reduction of chlorophyll

60. The first TEM was designed by
b) Smith
c)Knoll and Ruska
Ans: c)Knoll and Ruska
61. A graph which containing frequencies in the form of vertical rectangles?
a) frequency curve
b) frequency polygon
c) histogram
d) both a and b

Ans: c) histogram
(Questions from Kerala PSC -Lecturer in Botany Category code 278/2016)
Read More

MCQ on Plant Anatomy and MIcrotechnique (Lecturer in Botany Questions)

50. A layer which helps in the opening of anther
MCQ on Plant Anatomy
a) Tapetum
b)middle layer
c)epidermal cell
d) endothecium
Ans: d) endothecium
51. The following one sclereid s is found in the seed coats of Pisum sativum
b) Brachysclerids
c) Osteosclereids
Ans: c) Osteosclereids
52. Secondary cortex is
a) Phellogen
b) Phellum
c) phelloderm
d) complementary cells
Ans: c) phelloderm
53. The pollen tubes enters through the nucellus by a process
a) porogamy
b) chalazogamy
c) mesogamy
Ans: c) mesogamy
54. DPX stands for
a) Dilute  Primary xylol
b) Distrene Prime Xylene
c) Destrine Plasticiser Xylene
d) Dilute Plastic xylol
Ans: c) Destrine Plasticiser Xylene
55. Haematoxylin belongs to which category?
a) Acidic stains
b) Neutral stains
c) Basic stains
d) All of these

Ans: c) Basic stains
(Questions from Kerala PSC -Lecturer in Botany Category code 278/2016)
Read More

© Biology Exams 4 U, AllRightsReserved.***Best viewed in Google Chrome and Mozilla firefox***

Maintained by