Organisms and populations (BOTANY PART 1)

Ecology:The branch of biology that deals with the study of relationships of living organisms with the abiotic and biotic components of their environment.
Ecosystem ecology:The branch of ecology which deals with the study of ecosystems.
Global ecology:The study of climatic change,biodiversity conservation and ecological sustainability.
Species ecology:The study of an individual organism in relation to its environment.
Community ecology:The study of a group of organisms in relation to their environment.
Population:A group of individuals of a plant or animal species,inhabiting a given area.
Community:An assemblage of the populations of organisms that live under a given area and interact with one another.
Biome:A large regional unit characterized by a major vegetative type and associated fauna found in a specific climatic zone.
Biosphere:All terrestrial biomes and aquatic systems of the earth on the global level.
Habitat:The specific place where an organism lives.
Niche:The habitat together with the functions.
Euryhaline:Organisms which can tolerate wide ranges in salinity.
Stenohaline:Organisms which can live within a narrow ranges of salinity.
Auroral:Animals which are active at dawn only.
Vesporal:Animals which are active at dusk only.
Edaphic factors:The factors which relate to the structure and composition of the soil.
Conformers:The organisms which cannot maintain a constant internal environment.
Ephemerals:Plants which complete their life cycle within a short period.
Succulents:Xerophytes which have the capacity to absorb and store water.
Acclimatization:The gradual physiological adjustment to slowly changing new environment conditions.

Radioactive dating(Uranium)

Uranium is a radioactive element so it decays into an isotope of another element at a fixed rate. Uranium 238 is an isotope of uranium and it has a half life time of about 4.5 billion years.In the case of Uranium ,it finally forms lead 206.Scientists know the rate of transformation of uranium 238 to lead 206,they can determine the age of the rock containing lead 206.
Scientists calculate radioactive dating of rocks by taking the ratio of uranium 238 to lead 206.

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Principles of inheritance and variation (NOTES PART 1)

Genetics: Study of heredity and variation.

Heredity: Inheritance of characters transmitted from parents to offsprings.

Variation: Degree by which progeny differ from their parents.

Father of genetics- Gregor Johann Mendel.
He conducted experiments in garden pea(Pisum sativam)

Reasons for selecting garden pea,
1.Bisexual flower.
2.Self and cross pollination takes place.
3.Contrasting pairs of characters.
4.Short life span.

There is a particular gene for a particular character.
For indicating a gene ,there are two alleles.


1.True breeding
(Producing same character from same plants by producing them for 3-4 generation,made them pure for that specific character)
By self pollination,he created two pure breeding Tall and a pure breeding dwarf.
A character has two forms a dominant and a recessive form.
For example Height has two forms one is Tall and the other is dwarf.
2.A pure breeding Tall is crossed with a pure breeding dwarf.
At the time of gamete formation,the two factors separate or segregate.
The next generation is known as F1 generation or first filial generation.
In F1 generation, Dominant character T is expressed.
And T is completely dominant over t -- complete dominance.
Thus it expresses tallness.
This observable character is called phenotype.The genetic constitution is called genotype.

3.Then the F1 generation is self polinated.
At gamete formation,both alleles segregate,
TT Tt Tt tt are formed
Phenotype - 3 tall and 1 short is formed.

Genotype - 3genotype TT Tt tt

Phenotypic ratio-3:1
Genotypic ratio-1:2:1
Monohybrid cross-The character of one is crossed.

Reginald C Punnett brought a square called Punnett square or check board for easily finding the phenotype and genotype.

Biotechnology(PREVIOUS YEAR QNS Kerala)


A restriction enzyme called EcoRI from E.coli is expected to cleave the DNA at the following sequence:

ANDI is the cloned:

The enzyme used to cut the DNA molecule is:
Restriction endonucleases.(2003)

The enzyme DNA polymerase was discovered by:

Restriction endonuclease,an enzyme used in genetic engineering is employed for:
Cutting double stranded DNA.(2004)

Molecular scissors, which cut DNA at specific site:
Restriction endonucleases.(2004)

The technique used for separating molecules by passing electric fent:
Electrophoresis. ( 2004)

Who discovered recombinant DNA technology?:
Stanley Cohen and Herbert Boyer.(2007)

The enzyme used to join DNA fragments is:
DNA ligase.(2009)

Ti  plasmid used in genetic engineering is obtained from:
Agrobacterium tumefaciens.(2009)


A cybrid is a hybrid carrying:
Cytoplasms of two different plants and genome of one plant.(2004)

What does Bt stand for in the popular crop Bt-cotton :
Bacillus thuringiensis.(2004)

SCID is caused by the defective gene coding for the enzyme called:
Adenosine deaminase.(2006)

The construction of the first rDNA was done by using the native plasmid of :
Salmonella typhimurium

Refer textbook for clarifications and other references.

Best of luck friends....


Chromosome map-A linear graphic representation of the sequence and relative distances of the various genes present in the chromosome.
Chromosome mapping-The method of preparing maps of a species.
Mutation-The sudden heritable change in the genotype of an organism.
Mutants-The individuals showing mutations.
Muton-The smallest segment of DNA which can undergo mutation.
Chromosomal aberrations-The structural changes in a chromosome.
Point mutation-Mutation which arises due to change in a single base pair of DNA.
Mutagens-The physical and chemical factors which bring about mutations.
Pedigree analysis-An analysis of traits in several generations of s family.
Pedigree-The ancestral history in an individual.
Proband-The person from whom case history of the pedigree starts.
Proposity-Male pro band.
Proposita-Female pro band
Mendelian disorders-Genetic disorders caused due to alteration or mutation in single gene.
Phenylpyruvic idiots-Persons with phenylketonuria.
Chromosomal disorders-Genetic disorders caused due to absence or excess or abnormal arrangement of one or more chromosomes.
Ploidy-The numerical changes of chromosomes.
Polyploidy-Occurence of more than two genomes.
Euploidy-The numerical changes of chromosomes in genome level.
Aneuploidy-The numerical changes of chromosomes at an individual level.
Trisomy-2n+1 condition