Tuesday, March 13, 2012

NUCLEIC ACIDS AND CELL DIVISION

1 [A]: DNA and RNA are acidic in nature
[R]: They have pentose sugars





Ans:Both A and R are true but R is not the correct explanation of A
2 The nitrogen base Cytosine is




Ans:Monocyclic, Heterocyclic
3 In a given nucleotide




Ans:Phosphate is attached to 5th carbon and Nitrogen base to the 1st carbon of Pentose sugar
4 These components of DNA are 5-Carbon substances
I. Sugar
II. Adenine
III. Guanine
IV. Cytosine
V. Thymine





Ans:All except IV
5 DNA replication is initiated with the catalytic activity of




Ans:Helicase
6 A given DNA has 4 spirals with the following condition in its different spirals
I. A spiral with 28 hydrogen bonds
II. A spiral with 6 Guanine bases
III. Spiral with 25 hydrogen bonds
IV. Spiral with 6 Adenine bases
Arrange the above 4 different spirals in a sequence of gradual increase in the number of methylated nitrogen bases





Ans:I, II, III, IV
7 In a B-DNA molecule, there are 300 hydrogen bonds, These hydrogen bonds are formed in 3:2 ratio between GC and AT. Then the ratio between number of Adenine and Cytosine bases in the DNA is




Ans:1:1
8 The most common nitrogen base seen in various non-sense codons and initiating codons is




Ans:Uracil
9 Match the following





Ans:A - V, B - I, C- II, D - III
10 Study the following table and choose the correct combination





Ans:II and III
11 Guanine and Cytosine exist in 1:1 ratio but not Adenine and Thymine in




Ans:Reovirus
12 The following nucleic acid always ends with Adenine nucleotide




Ans:tRNA
13 rRNA is mainly transcribed on the DNA of chromosomes which must have




Ans:Secondary constriction I
14 Cell inheritance theory was proposed by




Ans:Virchow
15 [A]: During G1 stage of Cell Cycle, the cell is metabolically inactive
[R]: DNA replication does not occur during the period between M and S stages





Ans: A is false but R is true
16 Arrange the following cells of an angiosperm in a sequence of gradual increase in the amount of DNA
I. Primary endosperm nucleus in G1 stage
II. Stem apical meristem cell in Prophase
III. Generative cell in G2 stage
III. Polar nucleus





Ans:IV, III, I, II
17 If the amount of DNA and number of chromosomes in a cell nucleus are respectively 2C and 2n, then the amount of DNA and number of chromosomes in the cell during G2 stage would be respectively




Ans:4C, 2n
18 There is no S stage in the interphase present between




Ans:Meiosis I and Meiosis II
19 The ATP formed in G2 stage of cell cycle are mainly used for
I. Organisation of nuclear envelope
II. Organisation of Spindle
III. Movement of chromosomes
IV. Cohesion of sister chromatids





Ans:II and III
20 There is increase in the number of all cell organelles in G2 stage except




Ans:The cell organelle with linear DNA
21 In a Dicot plant growth divisions occur in
I. Vascular cambium
II. Cork cambium
III. Procambium
IV. Intercalary meristem





Ans:I, II,III, IV
22 [A]: Chromosomal size is determined in Metaphse
[R]: The chromatids of chromosomes are clearly seen in Prophase





Ans:Both A and R are true but R is not the correct explanation of A
23 Mitosis in plants was discovered by a person who also discovered




Ans:Embryosac and Syngamy
24 Arrange the following events of cell cycle in Correct sequence
I. Visibility of 2 chromatids of chromosomes
II. Replication of DNA
III. Attachment of spindle fibres to Kinetochores
IV. Disruption of Nuclear envelope





Ans:II, I, IV, III
25 Chromosomes do not show any movement at




Ans:Late Metaphase
26 The total number of chromosomal fibres that can be seen in metaphasic metacentric cells of Gossypium is




Ans:104
27 The total number of chromosomes seen in mid-anaphase of a meristematic cell of Oryza is




Ans:48
28 [A]:During mitotic anaphase, the chromosomes are divided into two daughter chromosomes due to pull mechanism
[R]: In the third stage of Karyokinesis, the continuous spindle fibres play a major role in dragging the chromosomes to respective poles





Ans:A is true but R is false
29 Chromosomal identity of chromatin is lost during




Ans:Telophase
30 The ratio between number of chromatids, telomeres, chromosomal arms and kinetochores of a metacentric chromosome of mitotic anaphase is




Ans:1:2:2:1
31 Phragmoplast is made of




Ans:Microtubules
32 Arrange the following events of Mitotic karyokinesis in sequence
I. Total disappearance of Kinetochore spindle fibres
II. Phragmoplast organization
III. Division of centromere
IV. Cell plate formation





Ans:III, I, II, IV
33 How many mitotic divisions have to occur for the formation of 2000 cells from 50 cells




Ans:1950
34 A meristem has 200 cells. Upon every generation of divisions in the tissue 25% of cells show differentiation. After 3 generations of divisions in the meristem, what is the total number of cells formed.




Ans:1150
35 This is not the significance of mitosis




Ans:Exchang of genetic material between sister chromatids
36 Mitotic divisions are not shown by




Ans:Zygospore of Spirogyra
37 Plasmosomes are organized during




Ans:Phase reversal to Prophase
38 Cytokinesis of plants is best described as




Ans:Centrifugal, Cell plate method
39 Match the following





Ans:A- II, B - IV, C - I, D - III
40 If the amount of DNA in a Meiocyte in G1 stage is 2C, the amount of DNA in the nucleus of Telophase I is




Ans:2C
41 Separation of a homologues of a bivalent during Meiosis is initiated at




Ans:Diplotene
42 Sister chromatids of Chromosomes are always genetically identical in
I. Zygotene
II. Diplotene
III. Metaphase
IV. Metaphase I





Ans:I and III
43 The principle of the following meiotic event is exploited in genetic engineering




Ans:Crossing over
44 The ratio between the number of nuclear envelops disappeared to the total number new nuclear envelops formed in a meiotic division is




Ans:1:2
45 Chromosomes move as Bivalents in
I. Anaphase I
II. Diakenesis
III. Anaphase II
IV. Metaphase





Ans:II and IV
46 Polypeptides play a role during
I. Synapsis
II. Crossing Over
III. Disjunction





Ans:I, II, III
47 [A]: The number of crossing overs in a bivalent are easily counted in Diplotene
[R]: Synaptonemal complex is dissolved in a stage of Meiosis interpolated between Pachytene and Diakinesis





Ans:Both A and R are true and R is the correct explanation of A
48 Stage of Prophase I with high intensity of Chromosomal condensation is




Ans:Diplotene
49 Arrange the following events of Meiosis I in correct sequence
I. Increase in the length of Chromosomes
II. Increase in the size of Nucleus
III. Increase in the size of Cell
IV. Increase in the size of Nucleolus





Ans:III, II, IV, I

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ASTHRA JUNIOR COLLEGE , VIJAYAWADA