Molecular Biology Tutorials

Karyotype and Idiogram: Definition and Importance of Karyotype Test (Karyotyping) in Human


what is karyotyping

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Karyotype, Karyotyping and Preparation of Idiogram

What is a Karyotype?

All species are characterized by a set of chromosomes to carry their genetic information. The chromosomal composition of each species has a number of characteristics. The Karyotype is a set of characteristics that identifies and describes a particular set of chromosome. These characteristics which are described by a karyotype are:-

(1).  The chromosome number

(2).  Relative size of different chromosomes

(3).  Position of centromere and length of chromosomal arms

(4).  Presence of secondary constrictions and satellites

(5).  Banding pattern of the chromosome

(6).  Features of sex chromosomes

What is Karyotyping? How to Prepare the Karyotype of Human?

Ø  The process of preparation of the karyotype of a species is called Karyotyping.

Ø  Karyotyping is now most commonly used in clinical diagnosis and clinical genetics.

Ø  Karyotype is prepared from the microphotographs of metaphase chromosomes.

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Molecular Biology Tutorials

Classification of Chromosomes based on Position of Centromere and Length of Chromosomal Arms


how chromosomes are classified

Classification of Chromosomes Based on Position of Centromere and Length of Arms

Ø  The size and shape of the chromosomes are variable in the different phases of cell cycle.

Ø  Chromosomes in the interphase of cell appear as thin, coiled, elastic and thread-like structures.

Ø  This thread-like stainable interphase chromosome is called chromatin.

Ø  During the mitotic or meiotic cell division, the chromatin materials become thicker in their width and shorter in their length.

Ø  Chromosomes in the metaphase stage of cell division show maximum condensation.

Ø  Each metaphase chromosome contains a centromere (primary constriction).

Ø  The centromere divides the chromosome into two parts called chromosomal arms.

Ø  The small arm of the chromosome is denoted as ‘p’ – arm, whereas the large arm is denoted as the ‘q’ – arm.

Ø  When chromosomes are represented as a karyotype or ideogram, each chromosome is arranged in such a way that the ‘p’ arm is positioned above the centromere and the q arm is represented below the centromere.

Ø  The position of centromere and the relative size of chromosomal arms are used as a criterion for a morphological classification of chromosomes.

Ø  This morphological classification is an important karyotypic feature of an organism.

Classification of chromosome

Ø  Based on the position of centromere and length of chromosomal arms, the chromosomes are classified into 4 groups:

(1).      Telocentric chromosomes

(2).      Acrocentric chromosomes

(3).      Sub-metacentric chromosomes

(4).      Metacentric chromosomes

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mcq biology

DBT BET JRF Exam 2017 Model Questions with Answer Key and Explanations Part 1


dbt bet 2017 free online test

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DBT BET JRF Exam, 2017
Model Question Paper with Answer Key and Explanations

(Biology / Life Sciences MCQ: Multiple Choice Questions)

(1).  _____ can serve as an alternative to ethidium bromide to stain DNA for detection on gels

a.       Mitomycin C
b.      Acridine orange
c.       SYBR Green I
d.      Acriflavine

(2). _____ is a sensitive technique to find out the number of template molecules originally present in a PCR reaction.

a.       Hot start PCR
b.      Real time PCR
c.       AP PCR
d.      Reverse Transcriptase PCR

(3).  Using __________ it is possible to generate fluorescence in quantitative PCR reactions

a.       TaqMan probes
b.      Molecular beacons
c.       Scorpion probes
d.      All of the above

(4). For whole genome amplification, creating very long DNA products ________ method can be employed with great success

a.       MDA
b.      PEP
c.       iPEP
d.      DOP

(5).  ________ polymerase has the ability to add ~70,000 nucleotides every time it binds to primer and has a very low error rate.

a.       Taq polymerase
b.      Tli polymerase
c.       Pfu polymerase
d.      Bacteriophage ϕ 29 polymerase

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Botany lecture notes

Kerala PSC Botany Lecturer Exam 2017 Model Question Paper 3/3


psc botany lecture questions

Kerala PSC Botany Lecturer / Assistant Professor Model Question Paper 2017 Part 3/3

Model/Sample Question Paper of Kerala PSC Botany Lecturer/Assistant Professor Recruitment Examination to be conducted by Kerala Public Service Commission Question for the appointment of Botany Lecturer/Assistant Professor in Government Colleges of Kerala under the Directorate of Collegiate Education, Trivandrum, Kerala. Questions are in MCQ (Multiple Choice Questions) format.

Botany Lecturer Test: Model Questions Set – 3/3

(1). The concept of raising the profile of a particular species to successfully leverage more support for biodiversity conservation of biodiversity is denoted as:

a.       Keystone species concept
b.      Flagship species concept
c.       Umbrella species concept
d.      Indicator species concept

(2). Gelatinous fibres are:

a.       Long sclerenchymatous cells with highly lignified secondary wall
b.      Short sclerenchymatous cells with slightly lignified secondary wall
c.       Fibres with cellulosic secondary cell wall
d.      Fibres with hemicellulosic secondary cell wall

(3). Which of the following is a C3 plant?

a.       Maize
b.      Sugarcane
c.       Sorghum
d.      Rice

(4). The wrong rejection of a true null hypothesis is denoted as:

a.       Type I error
b.      Type II error
c.       Type III error
d.      Type IV error

(5). Carl Woese is best known for his contribution in:

a.       Gene mapping
b.      Three domain system of classification
c.       Genetic engineering
d.      Shotgun sequencing

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Botany lecture notes

Botany Lecturer Recruitment Test 2017 by Kerala PSC: Model Question Paper 2/3


botany college lecturer exam by kpsc

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Kerala PSC Botany Lecturer / Assistant Professor Model Question Paper 2017 (Set 2/3)

Model/Sample Question Paper of Kerala PSC Botany Lecturer/Assistant Professor Recruitment Examination to be conducted by Kerala Public Service Commission Question for the appointment of Botany Lecturer/Assistant Professor in Government Colleges of Kerala under the Directorate of Collegiate Education, Trivandrum, Kerala. Questions are in MCQ (Multiple Choice Questions) format.

Botany Lecturer Test: Model Questions Set – 2/3

(1). The common intermediate in the synthesis of both adenine and guanine (purines) is

a.       IMP
b.      UMP
c.       AMP
d.      GMP

(2). What is Dobson?

a.       The unit of measure of ozone in the atmosphere
b.      The unit of the measure of thickness of ozone layer
c.       The unit of measure of concentration of CFC to destroy 1 mm of ozone layer
d.      The unit to measure the ozone hole

(3). The metabolite that bridges the gap between Glycolysis and the Kreb’s cycle is

a.       Oxaloacetate
b.      Pyruvate
c.       Acetyl Co-A
d.      Citrate

(4). Which of the following statement correctly describe the internal structure of a monocot root?

a.       Vascular bundles numerous, radial, with endarch xylem
b.      Vascular bundles numerous, radial with exarch xylem
c.       Vascular bundles limited in number, radial with endarch xylem
d.      Vascular bundles limited in number, radial with exarch xylem

(5). Which of the following is NOT a characteristic of K-selected species?

a.       Large number of progenies
b.      Parental care
c.       Delayed reproductive maturity
d.      Limited number of progenies

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