VELAMMAL BODHI CAMPUS –KOLAPAKKAM
UNIT-IX
BIOLOGY –WORK SHEET
STD-XII
Q. No Question Marks
Multiple Choice Questions
Q.1 There are two statements given below marked as Assertion (A) and Reason 1
(R). Read the statements and choose the correct option.
Assertion: RNA interference (RNAi) is used to protect plants against
nematode infestation.
Reason: RNAi method involves silencing of a specific mRNA by a
complementary dsRNA molecule that binds to and prevents translation of the
mRNA.
A. A is true but R is false.
B. A is false but R is true.
C. Both A and R are true and R is the correct explanation of A.
D. Both A and R are true and R is not the correct explanation of A.
Q.2 Given below are steps involved in the gene therapy of a patient with adenosine 1
deaminase (ADA) deficiency.
P) Lymphocytes are grown in a culture outside the human body.
Q) Lymphocytes are altered with a functional ADA cDNA.
R) Lymphocytes are collected from the blood of the patients.
S) The genetically modified lymphocytes are infused back into the patient.
Which of the following show the correct order in which these steps must
occur?
A. Q --> P --> R --> S
B. R --> S --> Q --> P
C. R --> P --> Q --> S
D. S --> R --> P --> Q
Q.3
Given below is an image of the process involved in recombinant DNA
technology.
LacZ is a gene that codes of β-galactosidase. When plated on an appropriate
medium, cells that produce β-galactosidase form blue colonies whereas those
that do not produce it form white colonies.
Answer the Questions from Q5-Q8
Q.4 Which of the following chemicals will be involved in a step that would come 1
before step 1?
lysozyme, ethanol, ribonuclease, cellulase, protease
A. only lysozyme and ethanol
B. only cellulase, lysozyme and ethanol
C. only lysozyme, ribonuclease, protease, and ethanol
D. all - lysozyme, ethanol, ribonuclease, cellulase, protease
Q.5 Which of the following will help one detect cells containing the recombinant 1
DNA?
A. A
B. B
C. C
D. D
Q.6 At which step will DNA ligase be required? 1
A. step 2
B. step 3
C. step 4
D. (DNA ligase is not required in this process)
Q.7 What would be the colour of the colonies formed by variant P? 1
A. only blue colonies
B. only white colonies
C. a mix of blue and white colonies
D. (They will not form any colonies.)
Q.8 Polymerase chain reaction (PCR) mimics which of the following natural 1
processes?
A. ligation
B. translation
C. replication
D. transformation
Q.9 Which of the following correctly states the purpose of steam in a bio- 1
processor?
A. helps organisms grow faster
B. adds to the water content
C. maintains sterility
D. (Steam is not required in a bio-processing unit.)
Q.10 Similar to sexual reproduction, rDNA technology contributes to . 1
P) genetic mutation
Q) faster replication
R) genetic variation
S) DNA ligation
A. only R
B. only P and R
C. only P, Q and R
D. all - P, Q, R and S
Q.11 In which of the following natural processes is recombinant DNA made? 1
A. prophase in mitosis
B. prophase 1 in meiosis
C. prophase 2 in meiosis
D. (Recombinant DNA cannot be made naturally).
Q.12 Two statements are given below - one labelled Assertion (A) and the other 1
labelled Reason (R).
Assertion (A): Sexual reproduction is similar to rDNA technology because it
results in variations.
Reason (R): Variation is impossible through asexual reproduction.
Which of the following is correct?
A. Both A and R are true, and R is the correct explanation for A.
B. Both A and R are true, but R is not the correct explanation for A.
C. A is true, but R is false.
D. A is false, but R is true.
Q.13 Two statements are given - one labelled Assertion (A) and the other labelled 1
Reason (R).
Assertion (A): Gene therapy is a method of treating a disorder but cannot cure
it.
Reason (R): In gene therapy, cells are drawn from a patient and the functional
gene is introduced into these cells and transferred back to the patient.
Which of the following is correct?
A. Both A and R are true, and R is the correct explanation for A.
B. Both A and R are true, but R is not the correct explanation for A.
C. A is true, but R is false.
D. A is false, but R is true.
Q.14 Given below are two statements about polymerase chain reactions. 1
P) It mimics DNA replication that happens in a cell.
Q) It cannot be used to amplify RNA
molecules. Which of these is/are TRUE?
A. only P
B. only Q
C. both P and Q
D. neither P nor Q
Free Response Question/ Subjective Question
Q.15 X is the first restriction enzyme isolated from strain H of Bacillus 3
amyloliquefaciens. This enzyme cuts between two guanine bases of the
following palindromic sequence:
5’-G G A T C C-3’
3’-C C T A G G-5’
(a) Name the restriction enzyme X. Explain how you arrived at this name.
(b) Draw the DNA fragments produced due to the action of enzyme X on the
palindromic sequence shown above.
Q.16 In 1997, an American company obtained patent rights on Basmati rice, 3
allowing them to market a 'new' strain of Basmati rice in the United States
and overseas. This 'new' Basmati strain was really derived from Indian
farmer's varieties.
(a) What is this unauthorised act called? Define it.
(b) State TWO ways in which Indian farmers are set to lose due to this
unauthorised act.
(c) State TWO measures that different countries are taking to prevent such
unauthorised exploitation of their bio-resources.
Q.17 (a) What are transgenic animals? 2
(b) To produce transgenic animals, the gene of interest is introduced into
embryonic stem cells. These stem cells are undifferentiated and the preferred
target in the process of developing any transgenic animal. Give a reason why.
Q.18 CRISPR is a gene editing technique for which the developers won the Nobel 2
Prize. Indian scientists are in the process of developing resilient and high-yield
varieties of rice using this technology and providing these to Indian farmers by
2024, once approved.
(a) Which organisation would be responsible for approving such varieties?
(b) What is the purpose of establishing the organisation identified in (a)?
Q.19 Kavya and David needed to cut out a 200 base-pair (bp) long DNA fragment 3
from a 650 bp long vector. Enzyme A cuts at 350 bp and at 550 bp whereas
enzyme B does not cut the vector. They followed the given steps to do this:
Step David Kavya
1 Take 3 micrograms of the vector Take 3 micrograms of the vector
2 Add 2 microlitres of enzyme A Add 2 microlitres of enzyme B
3 Incubate at 37°C for 2 hours Incubate at 37°C for 2 hours
4 Run the sample on an agarose gel Run the sample on an agarose gel
Given below is an image of the gel that was run with the samples.
(a) What is the purpose of the marker?
(b) Which of these shows the samples run by David and Kavya? Justify your
answer.
Q.20 Given below is a diagram of a bio-reactor with some of its parts labelled P and 3
Q.
(a) Which type of organisms can MOST likely be used if part P is not made a
part of the bio-reactor? Why?
(b) Identify the name and purpose of part Q.
(c) How does the thermal jacket help in the process?
Q.21 (a) Give a reason why, although a toxin, Bt toxins are deadly for insects but 3
not for plants producing them.
(b) Describe the steps in which Bt toxins act on insects.
Q.22 Plants of a region in India are constantly infested by the corn borer. 2
(a) What components are required in a recombinant plasmid that can
produce modified plants which are resistant to the corn borer? State the
purpose of each component.
(b) Give an example of a plasmid that can be used for (a).
Q.23 Identify if the following statement is true or false. 2
Between formation of the dsRNA and silencing of mRNA, the dsRNA needs to
undergo an additional step.
Justify if true, and rewrite the correct statement, if false.
Q.24 Hormones are broadly categorised as steroid hormones and protein 2
hormones. Patients with type 2 diabetes, generally, have to take insulin
externally. Researchers across the world believe that if insulin can be given
orally it would be ideal as it would closely mimic the movement of natural
insulin. Yet, injectable insulin is commonly prescribed by doctors.
What type of a hormone is insulin and why can't it be administered orally?
Q.25 (a) What causes adenosine deaminase (ADA) deficiency? 3
(b) What are the THREE methods that are currently used for the treatment of
ADA?
(c) What is the problem with the methods described in (b)? How can this
problem be overcome?
Q.26 Give a reason why: 2
(a) Transgenic animals are used for the production of biological components
of medicines over synthetic industrial production.
(b) In the process of testing for effects of chemicals, transgenic animals are
used rather than non-transgenic ones.
Q.27 Naturally growing potatoes show bruises (black discolouration) when they get 5
damaged. Bruising occurs when the tissue is crushed and cells rupture,
releasing enzymes that produce a black discolouration. A gene has been
identified which codes for this enzyme. A company wants to produce potatoes
that do not show these bruises.
(a) Describe the steps in which they can produce such potatoes that do not
show bruises.
(b) What is the process called?
Step Anita Di
Q.28 pti
(a) What is a disadvantage of the traditional hybridisation procedure? 2
(b)
1 How has
usedrDNA technology
a restriction overcome
enzyme to the disadvantage identified
used a restriction in (a)?
enzyme
obtain gene of interest to obtain gene of interest
Q.29 Anita
2 andmade
Diptimultiple
followedcopies
the steps mentioned
of the gene below
ligatedtothe
introduce
gene oftheir gene of
interest 2
interest into the target
of interest organism.
using PCR with a cloning vector
3 introduced the amplified genes in introduced the vector
the cell prepared in step 2 in the cell
Of these, whose experiment is more likely to succeed and why?
Q.30 Golden rice is a variety of rice that has been genetically modified to produce a 5
compound called β-carotene, which gets converted to Vitamin A when
metabolised in the human body. This was done by introducing the genes
coding for three enzymes - 'psy' and 'LCYB' from daffodil and 'crtI' from the
soil bacterium Erwinia uredovora.
(a) With the help of a diagram, describe the process by which golden rice can
be made.
(b) Name the vector used in the process.
(c) Give a reason why the vector identified in (b) should be used.
Q.31 Karan wanted to cut a DNA fragment which was 800 base-pairs long from a 2
vector. He followed each step of the protocol correctly and ran the resultant
sample on an agarose gel. In an earlier attempt in extracting DNA from onion
cells, he had seen DNA form a thread like precipitate in ethanol. Given below
is an image of the gel after he finished running his sample in it.
(a) Why does he not see the same thread like precipitate in the gel?
(b) How can he ensure he has obtained the desired result?
Q.32 Papaya is a widely cultivated crop in several regions. However, its production 5
was limited by papaya ringspot disease which is caused by the Papaya
ringspot virus (PRSV). Papaya plants infected by PRSV show symptoms of
yellowing, discolouration of leaves and 'ringspots' on the fruit. PRSV belongs
to the genus Potyvirus which has a single-stranded RNA as its genetic
material.
(a) Explain the step-by-step process to inhibit the viral RNA from surviving in
the papaya plants thus creating disease-resistance varieties of papaya.
(b) Name the biotechnological process described in (a) and give a reason why
it is the appropriate process to be used in this case.
Q.33 Growth hormone injection treatment is prescribed for children who have 5
been diagnosed with growth hormone (GH) deficiency and other conditions
causing short stature and insufficient growth. This hormone is produced by
the pituitary gland in humans so the gene for this hormone was isolated from
the pituitary gland and introduced into phGH407 vectors for production.
However, a problem with this was that the protein so produced was 26 amino
acids longer than the active growth hormone (24 amino acids long) and so this
method could not be used.
(a) Given that the amino acid sequence of the active growth hormone was
known, use a diagram to explain how human growth hormone could be
produced outside the body.
(b) The vector consists of a lac gene which codes for the enzyme β-
galactosidase. Describe how this gene can help with the selection of colonies
containing the transgene.
Q.34 Given below is the step-by-step process in the formation of yoghurt (curd) in a 3
bioreactor.
(a) Why does the pH start decreasing a while after the mixture is incubated at
37-44 °C?
(b) From the flowchart, identify two systems that the bioreactor would have.
Give a reason to support your answer.
Q.35 Nidhi performed gel electrophoresis after treating one vector with restriction 2
enzymes. She added one mixture in well Q and another mixture in well R.
Given below is an image of the results.
(a) What can be concluded about the mixtures loaded in wells P and Q?
(b) What is the likely reason that the fragments in wells Q and R are different?
36 What components of a disease can be detected using ELISA?
Describe the components that can be checked if one wants to identify
whether an individual is allergic to pollen or not.
Given below is an image of an ELISA test result with two of its cells marked P
and Q. A coloured cell indicates a positive result whereas an uncoloured cell is
a negative result.
(c) The colour of P is darker than the colour of Q. What could this possibly
indicate?
Q.37 Explain why vectors that have restriction site/s within a marker gene are 2
preferred, for recombinant DNA technology.
