SUMMER HOLIDAY HOMEWORK
Session 2013-14
D-II, Vasant Kunj, New Delhi - 110070
Name : _____________________
S.No. : 1
Date : _______/ ______/ _______
Class : VIII
Subject: Science
a)
b)
c)
d)
e)
GENERAL INSTRUCTIONS:
All questions are compulsory.
Diagrams should be neatly drawn and labeled.
Questions should be attempted in a sequential manner and a line to be drawn after each question.
Present your work neatly.
Holiday homework sheet should be stapled or stuck to the notebook.
Q1. Add two examples for each of these preserving methods
Method
How it works
Pickling
The food is put in vinegar. The acid
vinegar stops microbial growth.
Drying
Microbes cannot grow without water and
drying dehydrates the food i.e remove
water
Preservatives
Canning
Preserving
Radiation
Salting
Example (give two)
Preservatives are chemicals that kill
microbes or stop them from growing.
Food is cooked and then sealed so that
air does not get in and its contents
remain locked
Food is cooked in sugar. The sugar is too
concentrated for microbes and hence
prevents microbial growth and also
removes excess water
Radiation kills microbes.
Microbes cannot grow in salt. It is too
concentrated and also it dehydrates the
food.
Q2. Answer the questions below IN YOUR REGISTERS.
1. What kinds of niches do you think bacteria might occupy in the ecosystem?
2. Why do you think bacteria are so successful at living almost anywhere on Earth?
3. In what type of ecosystem are zooplankton found?
4. What role do they play in such ecosystems?
5. Name two human diseases caused by protozoa.
6. List three factors that can trigger cyst formation in protozoa.
7. Why are there no free-living protozoa in environments that are dry year-round?
8. Q6. COMPLETE THE GIVEN FLOW CHART
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Q3. COMPLETE THE GIVEN FLOW CHART
Q4. ANSWER THE FOLLOWING:
(a) Food that astronauts take into space has been dried to remove air and water. Write true or false
based on this information and also explain your answer in each case.
(i) dried weighs more______________
(ii) it decays slowly___________________
(iii) microbial growth is less.______________
(b) making bread
Ram is making bread . this is how he does it
Ram wants to find out why yeast is used to make some types of bread. He carries out a test. He makes
one loaf of bread with yeast and one without yeast
Study the picture of the Ram’s test and explain the effect of yeast in bread making.
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ACTIVITY:1
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Q5. BACTERIA QUIZ Circle the correct answer(s). Some questions have more than one answer.
1. Which type of bacteria cannot thrive in oxygen?
a) cyanobacteria
b) aerobic
c) anaerobic d) antibiotic
2. To which group do bacteria belong?
a) eukaryotes b) prokaryotes
c) protists
d) algae
3. What color are gram-positive bacteria?
a) red b) green
c) white
d) purple
4. What is the whip-like appendage called on some bacteria?
a) flagellum
b) chlorophyll
c) ribosome
5. How do most bacteria reproduce?
a) DNA transfer
b) binary fission
d) filament
c) conjugation
d) translocation
6. What is the small DNA segment in a bacterium called?
a) nucleoid
b) capsule
c) peptidoglycan
d) plasmid
7. Where in the human body will you find E. coli?
a) mouth
b) heart
c) gut
d) blood
8. Which of these products does not involve a bacterial process?
a) yogurt
b) wine
c) vitamin C
d) sourdough bread
9. What are rod-shaped bacteria called?
a) cocci
b) spirilla
c) eubacteria
d) bacilli
10. How do heterotrophic bacteria get their energy?
a) transduction b) from sunlight
c) oxidation
d) feed on organisms
11. What is the jelly-like substance in which the bacteria’s DNA is suspended?
a) membrane b) cytoplasm
c) endospore
d) cosmid
12. What does a bacteriophage do?
a) infects bacteria
b) destroys viruses
c) makes antibodies d) invades human cells
13. What bacteria caused the infamous Black Plague of the 14th century?
a) lactobacilli b) Vibrio cholerae c) Y. pestis
d) A. Escherichia coli
Q6. Choose the correct answers:
1. Mycorrhyzal fungi
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2. In Italy truffles are collected from
A Kill trees
B Break down dead wood
C Help trees grow
D Cause disease in sheep
3. The strands that make up a fungus are
called
A Strings
B Hyphae
C Fronds
D Feathers
5. What is a Lichen?
A Fungus
B Alga
C Plant made of Fungus and Alga
D Moss
underground using
A Pigs
B Birds
C Dogs
D Foxes
4. A person who studies fungi is called a
A Taxonomist
B Fungologist
C Taxidermist
D Mycologist
PROBLEM SOLVING ASSESSMENT BASED QUESTIONS:
I) Mahima lives in Chennai in a sea-facing house. While going to her friend‟s house, she turns to
her right. After moving to 70 mtr. in that direction, she again turns to her right. Which
direction is she facing now?
a) North
b) West
c) East
d) South
II) Which pair will come next?
ZX
AC
VT
EG
a) IK
b) NL
c) HI
d) RP
__?
III) Note:- Read the passage and the conclusion carefully and mark the correct option.
It has been observed that educated parents expanse / invest more on education of their children
because
by their experience they know the value or importance of education.
Conclusion – I : Illiterate parents do not understand the value or importance of education.
Conclusion – II: Educated parents understand the value or importance of education
a) Only conclusion I is correct.
b) Only conclusion II is correct
c) Both conclusion I & II are correct
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d) Neither conclusion I nor II is correct
IV) The term „ Global Warming‟ means
a) Quick melting of polar ice sheets.
b) Depletion of Ozone layer.
c) High temperature in Torrid Zone.
d) General rise in temperature due to CO2
(V) These days yellow lamps are frequently used as street light. Which one of following is used in
the lamp:a) Sodium
b) Neon
c) Hydrogen
d) Nitrogen
(VI)Find out from amongst the four alternatives as to how the pattern would appear when the
transparent sheet is folded at the dotted line.
(X)
(1)
(2)
(3)
A.
1
B.
2
C.
3
D.
4
(4)
One day you wake with a sore throat and a runny nose. Your doctor takes a swab from your
throat, sends it to a lab, and telephones you the next day to say that antibiotic will not help
you get better. Which of the following is the most likely reason for the doctor's statement?
A.Having waited a day, it is too late to take an antibiotic
B. You need an antiseptic, not an antibiotic
C. You need to be vaccinated instead of taking an antibiotic
D.You are infected by a virus
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Select the alternative which represents three out of the five alternative figures which when fitted into each
other would form a complete square.
A.
123
B.
345
C.
245
D.
234
Choose the box that is similar to the box formed from the given sheet of paper (X).
A.
1 only
B.
2 only
C.
3 only
D.
4 only
Most abundant tissues of our body are
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A.
muscular
B.
connective
C.
epithelial
D.
nervous
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Nymph is the name of young one of
A.
butterfly
B.
beetle
C.
housefly
D.
cockroach
Mycobacterium leprae causes leprosy, Corynebacterium diphtheria causes diphtheria and Vibrio
comma causes
A.
tetanus
B.
influenza
C.
cholera
D.
typhoid
Phloem is a tissue found in
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A.
reproductive organs of animals
B.
plants
C.
insects
D.
mammals
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