Wednesday, 17 August 2016


Chromosomes are the hereditary vehicles that carry characteristic features from parents to offspring. They are proteinaceous capsules with DNA inside. They are absent both in viruses and prokaryotes. They are the bearer of genes to encode specific traits in future generations.

Now read the following questions and answers and suggest some more questions for the aspirants for competitive exams. Please help us rectify the mistakes and improve the content.


1) Who first observed chromosomes in the pollen grains of Tradescantia?
A) Hoffmeister
2) Who gave the name chromosome?
A) Waldeyer
3) Who ascribed chromosomes as hereditary vectors?
A) Theodor Boveri
4) Who discovered the role of chromosomes in hereditary process?
A) TH Morgan
5) Which organism has the least number of chromosomes?
A) Ascaris megalocephala (2)
6) Which organism has the maximum number of chromosomes?
A) Aulocantha (1600)
7) How is the rod shaped chromosome with an apical  centromere described?
A) Telocentric chromosome
8) How is the rod shaped chromosome with a sub-apical centromere described?
A) Acrocentric chromosome
9) How is the v-shaped chromosome with sub-central centromere described?
A) Sub-metacentric chromosome
10) How is the v-shaped chromosome with central centromere described?
A) Metacentric chromosome
11) What is the outer covering of the chromosomes?
A) Pellicle
12) What is the jelly like substance in the chromosome?
A) Matrix
13) What are the intertwined thread like structures floating in chromosomal matrix?
A) Chromonemata
14) What are the gene carrying knots on chromonemata?
A) Chromomeres or nucleosomes
15) What is the colourful granule on the chromosome?
A) Centromere
16) What is the bulb like structure on the chromosome?
A) Satellite
17) What are the giant chromosomes?
A) Polytene and lampbrush chromosomes
18) What are the giant chromosomes in chivanomous larvae?
A) Polytene chromosome
19) What are the giant chromosomes in vertebral oocytes?
A) Lampbrush chromosomes
20) What are the DNA-protein complexes inside chromosomes?
A) Nucleosomes
21) What are proteins that bind DNA?
A) Histones
22) What is the number of chromosomes in the human somatic cell?
A) 46
23) When does chromosomal replication occur?
A) S-phase of cell cycle
24) What is the shape of a metaphase chromosome?
A) X-shaped
25) How are original and replicated chromosomal segments of a metaphase chromosome called?
A) Sister Chromatids
26) What is the protein junction of two sister Chromatids in a chromosome called?
A) Centromere
27) At what stage of a cell cycle chromosomes are visible under compound microscope?
A) During mitosis
28) What kind of human cells do not contain chromosomes?
29) What kind of cells have DNA without histone proteins?
A) Prokaryotes
30) Who coined the term chromatin?
A) Walther Fleming
31) What were the factors of Mendel?
A) Chromosomes
32) Who gave the chromosomal theory of heredity?
A) Sutton & Boveri
33) Who gave the human chromosomal number as 46?
A) Joe Hin Tjio
34) What is the condensed form of chromatin?
A) Chromosome
35) What are the somatic chromosomes?
A) Autosomes
36) What are the sex chromosomes?
A) Allosomes
37) How many pairs of autosomes are present in a human cell?
A) 22 pairs
38) What are the allosomes?
A) X-chromosomes & Y-chromosomes  (sex chromosomes )
39) How do you call the cell with two sets of chromosomes?
A) Diploid cell
40) How do you call the cell with only one set of chromosomes?
A) Haploid cell
41) What are the haploid cells in human beings?
A) Gametes (sperms and eggs)
42) How the existence of more than two sets of chromosomes in a cell described?
A) Polyploidy
43) How is the characteristic chromosomal complement of a cell described?
A) Karyotype
44) What is the pictorial representation of a Karyotype?
A) Karyogram
45) What are genosomes?
A) Allosomes or sex chromosomes
46) Which is the best cell phase to study karyogram or Karyotype?
A) Metaphase
47) What are the closest relatives of human beings with 48 chromosomes?
A) Chimpanzees
48) How is the abnormality of chromosomal sets described?
A) Aneuploidy
49) Which genetic disease is caused due to the deletion of a part of chromosome 5 in humans?
A) Chri do chat
50) Which is the most common trisomy 21 in human beings?
A) Down's syndrome
51) What is the trisomy 18?
A) Edwards Syndrome
52) What is the terminal 11q  deletion disorder?
A) Jacobsen syndrome
53) What is XXY syndrome?
A) Klinefelter Syndrome
54) What is trisomy 13?
A) Patau syndrome or D-Syndrome
55) What is X0 syndrome?
A) Turner's syndrome
56) What is the cause of sperm aneuploidy?
A) Air pollution, smoking, benzene,  insecticides,  perfluorinated compounds
57) Which chromosome is the sex determiner in male human beings?
A) Y-Chromosome
58) What kind of human gametes have all X-chromosomes?
A) Female gametes
59) What kind of human gametes have either X or Y chromosomes?
A) Malegametes
60) Which sex chromosome possesses dominant genes?
A) X chromosome
61) What are are the bundles of tightly coiled DNA?
A) Chromosomes
62) What are the steps in DNA coiling to form chromosomes?
A) Nucleosomes - chromatin loops - chromosomes
63) What are the protective caps at the ends of chromosomal arms against DNA replication?
A) Telomeres
64) What is a protein structure on chromatids where the spindle fibers attach during cell division?
A) Kinetochore
65) What are the two stages of mitosis during which the chromosomes are distinct enough to study?
A) Metaphase & Anaphase
66) Which nutrient element has its marked effect of the size and structure of chromosomes?
A) Phosphorus
67) Whether animals have larger chromosomes or plants?
A) Plants
68) Whether decot plants  have larger chromosomes or monocots?
A) Monocots
69) What are the spirally coiled threads in a chromatids?
A) Chromonemata
70) Who discovered chromonemata?
A) Baranetzky
71) Who coined the term chromonemata?
A) Vejdovsky
72) What are the loosely intertwined and easily separable coils of chromonemal fibrils?
A) Paranemic coils
73) What are the closely intertwined and inseparable coils of chromonemal fibrils?
A) Plectonemic coils
74) What are the bead-like structuresof the chromonema?
A) Chromomeres
75) What is the primary constriction on a chromosome?
A) Centromere,  kinetomere or Kinetochore
76) How is called the chromosome with a single centromere?
A) Monocentric chromosome
77) How is called a chromosome with a two centromeres?
A) Dicentric chromosome
78) How is called a chromosome with many centromeres?
A) Polycentric  chromosome
79) What is the other name for the secondary constriction on the chromosome?
A) Nucleolar organiser
80) What is the structure beyond secondary constriction in the chromosome?
A) Satellite
81) How is called a chromosome with a satellite?
A) SAT-chromosome
82) What is meant by SAT in SAT-chromosome?
A) "Sine Acid Thymonucleionico" without thymonucleic acid or DNA
83) Which cell organelle is homologous to the centromere?
A) Centriole
84) What is the terminal part of a chromosome?
A) Telomere
85) What is the peculiar staining method applied for chromosomes?
A) Chromomeral Banding
86) What is the smallest unit of the chromosome with 2 double DNA helices?
A) Fibril
87) How many double DNA helices present per a half Chromatid?
A) 8
88) How many double DNA helices present per a chromatid?
A) 16
87) How many double DNA helices present per a chromosome ?
A) 32
88) Who coined the term nucleosome?
A) Oudet et al
89) Who discovered salivary gland chromosomes or Polytene chromosomes in the Chironomus larva?
A) Balbiani
90) Which group of insects have polytene chromosomes?
A) Diptera
91) What is the point at which all the centromeres of the polytene  chromosomes meet?
A) Chromocenter
92) What kind of chromosomes contain Balbiani rings?
A) Polytene chromosomes

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