Biology Sample Question Paper Sheet - Class Xii, Central Board Of Secondary Education, 2010 Page 25
ADVERTISEMENT
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
3927.
Genetic engineering/Recombinant DNA technology; segment of DNA removed from human cell
and DNA segmant incorporated into bacterial plasmid ; Plasmid taken up into bacterial cell which
makes protein directed by human DNA.
(1 + 1 + 1) = 3
28.
(i)
Page 211 production of insulin to cure Diabetes mellitus or gene therapy for cure of ADA
(ii)
Page 209 - using Agrobacterium vectors to introduce nematode specific genes or RNAi
(iii)
Page 213- generating transgenic cow such as Rosie.
(1 x 5) = 5
Ethical standards required as genetically manipulated organisms may harm other organisms/results
unpredicatable.
OR
Cloning vectors - (i) plasmids, (ii) bacteriophages (iii) YACS, (iv) BACS (any two)
1
Features required to facilitate cloning into a vector are
(1 x 4 ) = 4
(a)
Origin of replication (ori) - Sequence where replication starts and any piece of DNA when
linked to this sequence can be made to replicate within host cells.
(b)
Selectable marker - Helps in identifying and eliminating non transformants and selectively
permitting the growth of the transformants.
(c)
Cloning sites : Few or single recognition sites are preferable
(d)
Vectors for cloning genes in plants and animals. eg genetically modified Agrobacterium
tumifaciens and retroviruses.
29.
(i)
CO
2
(ii)
Fuels burnt in vehicles emit CO
which goes into atmosphere
2
(iii)
Causes global warming
(iv)
Long summer/ Himalayan caps melting/floods etc.
(v)
Plant more trees/Afforestation/ car pool/ any other (any two)
1 x 4 + ½ x 2 = 5
30.
-
Genetic code degenerate i.e more than one code for one amino acid.
-
Both GAG, GAA code for glutamic acid.
-
Mutation of third base/ nucleotide- no change in phenotype in mutation A/Wobble hypothesis
nd
-
In case of change on 2
codon of triplet code as in Mutation B, codon stands for a different
amino acid valine.
-
Hb becomes different / normal Hb becomes Hbs/Structure of protein changed. (1 x 5 ) = 5
OR
DNA is packaged in the cell in the following manner:
(a)
As Nucleosomes consists of Histone octamer around which the positively charged DNA is
wrapped around to form a nucleosome. A typical nucleosome contains 200bp of DNA helix.
(b)
Repeated units of nucleosomes then form chromatin (in a nucleus). The nuceleosomes represent
the “Beads on String” structure” as seen in electron microscopic picture.
(c)
These are then further coiled and condensed at metaphase stage to form chromosomes.
(d)
For packaging of chromatin at higher level, non histone proteins are required.
5
25
ADVERTISEMENT
0 votes
Related Articles
Related forms
Related Categories
Parent category: Education