Holiday Homework
Session 2013 – 2014
Name : _____________________
S.No. : ______________
Date : _______/ ______/ _______
Class : XII____________
D-II, Vasant Kunj, New Delhi - 110070
Subject : Bio______________
General Instructions:
1.
Do the Home Work in the Biology Notebook and stick the Question sheet in your notebook.
2.
Draw the neat and labeled figures wherever it is required.
3.
Do the questions in a serial manner.
Topics:
Q1
Q2
Q3
Q4
Q5
Q6
Q7
Q8
Q9
Q10
1.Principles of Inheritance and variation
2. Molecular basis of Inheritance
Section A
In a cross between a black and a white guinea pigs, all F1 members are black. But F2 generation
raised by crossing two such F1 consists of approximately ¾ black and ¼ white guinea pigs.
a) What are the possible genotypes at each level?
b) What will be the offsprings be like if two F2 whites are mated?
What is a test cross? Give its utility?
A plant with red flowers was crossed with another plant of same species with white flowers. The
offspring, thus, produced comprised of 60 plants, all of which had pink flowers. On selfing, these
plants produced 240 plants, of which 60 had red flowers, 120 had pink flowers and 60 had white
flowers. Explain the principle of genetics behind these results?
A man with blue eyes and black hair (homozygous for both characters) marries a woman with
black eyes and red hair. Black eyes (E) are dominant over blue eyes (e) and black hair (H) is
dominant over red hair (h). Work out the probabilities of phenotypes of the children of this
couple using punnett square method.
a) List the three different allelic forms of gene ‘I’ in humans. Explain the different phenotypic
expressions, controlled by these three forms.
b) A woman with blood group ‘A’ marries a man with blood group ‘O’. Discuss the possibilities
of the inheritance of the blood groups in the following starting with ‘yes’ or ‘no’ for each:
1) They produce children with blood group “A” only.
2) They produce children some with “O” blood group and some with “A” blood group.
What is the inheritance pattern observed in the size of starch grains and the seed shape of
Pisum sativum? Workout the monohybrid cross showing the above traits. How does this pattern of
inheritance deviate from that of Mendelian law of dominance?
In a test cross AaBb x aabb, 90% of the progeny are like parents. Determine:
1) The progeny type for the rest of the population?
2) Are the genes linked?
3) Is there any crossing over between the genes?
What will be the kind of children born to a normal father and carrier mother for the trait of
haemophilia? Show it with the help of the punnett square.
Name a few human disorders that are caused by recessive genes present on autosomes and
recessive genes present on X-chromosomes.
If the base sequence of one strand of DNA is CAT,TAG,TAC,GAC, what will be the base sequence.
a) of complementary DNA strand
b) of its complementary RNA strand
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The Heritage School, Vasant Kunj
Anjali Bhat
Q11
Q12
Q13
If one strand of double stranded DNA has the following sequence:
5’ AGC ATTCG 3’
What would be the sequence of the opposite strand in its 5’ to 3’ direction?
Mention the dual purposes of deoxyribonucleoside triphosphate?
Q14
Label A,B,C and D in the given diagrams
Q15
Match the following experiments & conclusions with respective worker.
a. Transforming Principle
i) Messelson & Stahl
b. DNA is genetic material
ii) Watson & Crick
c. Semi conservative mode of DNA replication
iii) Fredrick Griffth
d. Proof of semi conservative replication
iv) Hershey & Chase
Q16
Assume that no new mutations have arisen in the family.
Q17
Answer each question with either ‘Yes’ or ‘No’
i) Could this be inherited as recessive trait?
ii) Could this be inherited as dominant trait?
The map distance between A & B genes is 18 unit; between B & C is 20
unit and C & A is 2 unit.
(a)What is the order of genes on a linkage group?
(b) Write the unit of map distance.
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The Heritage School, Vasant Kunj
Anjali Bhat
Q18
Pedigree analysis:
a) What do the symbols used in this pedigree mean?
Q19
b) What is the inheritance pattern of the above pedigree analysis.
c) Mention 3 clues by which you can detect this type of inheritance.
Identify the structural units of the transcription unit?
B
A
C
D
3’
5’
E
5’
3’
Q20
Q21
State aim and describe Messelson and Sthal’s experiment?
Describe an experiment with the names of the scientists who proved that DNA is the genetic
Material.
Section B
Investigatory project:
The vacations would be the best time to prepare an investigatory project on the topic of your choice.
The project is a mandatory part of your board practical examination which the external examiner is
going to assess at the time of practical examination. So, complete it well in advance and submit the first
draft in July. It will be read and critically evaluated for the feedback so that necessary changes could
be made before the final draft.
So, first lets discuss the procedures of the investigatory project.
First of all, remember that it carries 5 marks which is inclusive of viva. So, it is strongly suggested to
everyone not to copy the project from anywhere, because it would be counterproductive. You should
know your project in and out, so that no matter what the examiner asks you, you should be able to
answer him/her pretty well.
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Anjali Bhat
The most important thing, your project should include is a case study because it not only makes your
project more readable, but also shows that you took out time to prepare it. The case study
should be as detailed as possible.
Now, where can you get a Case Study? Just go into any hospital and ask for a case study of a
particular disease and get it photocopied. If possible, also seek out a doctor in your city who is a
specialist in that disease and get his opinion/notes on the subject. Let me acquaint you with the meaning
of investigatory research projects.
Investigatory projects are meant to be a pleasure-cum-work-cum-knowledge gathering exercise and it is
a type of experimental exercise performed with a scientific attitude by the students.
1. Selection of topic: For this, you need to work and read different chapters of your syllabus and
also consults scientific literature, magazines, newspapers, use search engines of internet, etc. Then
select the topic of your interest.
2. Planning of the project: Collect all possible available information about the topic. Prepare a rough
outline of the experimental work of the project.
3. Experimentation for the project: Plan and conduct the experimental work with precision so that
you are sure to get correct results.
Following points should be kept in mind while performing the experiments for the project work.
i. Collect data with honesty and utmost care.
ii. Record only your observations and data.
iii. Repeat the experiment several times and take average of the results of all the experiments.
iv. Compare your results with those available in the reference books.
v. Discuss your results in the light of available information about the project and draw out
meaningful conclusion.
vi. Make use of histograms, graphs, photographs, diagrams or models, case studies to support your
observations
and conclusions.
vii. Give a list of books, magazines/journals and internet sites you have consulted during the
course of your project.
viii. Acknowledge the guidance, help and assistance rendered by your teachers, parents,
neighbours and friends by expressing sincere gratitude and thanks to them in the beginning.
4. How to write: Students are required to get their project report typed on bond paper sheets and to
represent it in the best possible manner. The project report should be written in the following
sequence:
Title / Aim – Name of the project.
Introduction – Information collected from various sources related to the topic.
Requirements – Materials required for experimental work.
Procedure – Write details of the experimental work you have performed.
Observations – Record your observations / data in the form of tables, histograms, graphs,
photographs, etc.
Results / Conclusion – Give analysis of the data and compare your results with those available in
the literature and draw conclusions.
References – Give the list of books, internet websites, magazines or journals you have consulted,
for the project work.
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Anjali Bhat
Here are a few topics to give you an idea
If you are preparing the project on a disease write about its prevention, medication and cure too.
1. A study on HIV Aids – Talk about the disease, the virus – go in details. Include a Case
study.
2. How Hair Colors and Dyes Affect your hair – Conduct experiments on how different hair
colors and dyes affect hair. Point out the difference between ammonia included and
ammonia free hair dyes.
3. Cigarettes are harmful – Do tests on various tobacco products and list out
their harmful effects. Do a Case Study.
4. Cancer – Do a general overview first, then choose a particular cancer and write in detail.
do a Case Study.
5. Pulmonary Tuberculosis – Explain the disease. Do a Case Study.
6. Noise Pollution and its effect on ears – Study and show how ears react to different
decibels of sound. What sound levels are acceptable? Do a case study, if possible.
7. Eye Cataract – Explain the disease and do a case study.
8. Ovarian Cyst – Explain the disease and do a case study.
9. Blood - Explain the different components in detail. Pick a disease related to it and do a
case study.
10. Tea leaves/Coffee addiction – Explain how tea leaves/coffee beans cause addiction and
their effects. Do a filter test. If possible, do a case study.
11. DNA Fragments used in forensics – Explain how DNA fragments help solving crime. Do a
case study. Study apical dominance in potato and coleus
12. Study of pollen structure and calculation of pollen viability.
13. To study dispersal of seeds by various agencies.
14. Study the effect of avenue trees on temperature under canopy and outside.
15. Study of coaguable and non-coaguable milk proteins.
16. Study of pollination in sunflower and legume.
Here are a few more tips to secure the extra marks  Please make sure you write the project yourself (this fetches you extra marks),
rather than a print out.
 A good project (including case study) should consist of 20+ pages.
 Paste as many graphs, pie charts , diagrams and photographs regarding the topic as
possible. Make it look appealing.
 Make sure that you understand the project really well, because you will need to score good
on the viva too. A great project and a poor viva will spoil the show.
 Think 5-10 questions about your project, which you think the examiner can ask you
and prepare them well.
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The Heritage School, Vasant Kunj
Anjali Bhat