Assignments in Science Class X (Term I)
1. Every living organism has a need of nutrition as
it is through nutrition that one obtains energy.
2. The process of intake and utilisation of nutrients
(i.e. substances that either release energy or
help in the manufacture of biomolecules) is
known as nutrition.
3. Green plants are autotrophs as they synthesise
their own food using sunlight, chlorophyll,
carbon dioxide and water.
13. Breathing is a physical process which involves
inhalation and exhalation.
14. Respiration is a biochemical process which
includes breathing and oxidation of food.
15. Respiration in the presence of oxygen is known
as aerobic respiration.
16. Respiration that occurs in absence of oxygen is
known as anaerobic respiration.
17. During aerobic respiration, food (glucose) is
completely broken down into carbon dioxide
and oxygen and energy is released in the form
4. Photosynthetic equation
6CO2 + 12H2O
6H2O + 6O2
5. Chlorophyll is a light receiver which can trap
solar energy within its molecule.
18. Aerobic respiration occurs in higher organisms
including human being.
19. Anaerobic respiration occurs in certain bacteria,
yeast and also in our muscles.
6. The site of chlorophyll activity is the special
plant cell organelles called chloroplasts.
20. The muscles of vertebrate animals can continue
working for a minute or two without oxygen.
7. In humans the alimentary canal is basically a
long tube extending from the mouth to the anus.
When we eat something we like, our mouth
‘waters’. This watery fluid is called saliva
secreted by the salivary glands.
21. Micro-organisms such as yeast and certain
bacteria obtain their energy by anaerobic
respiration which is termed fermentation.
22. Common type of fermentation is alcoholic
fermentation which is performed by yeast.
8. The gastric glands present in the stomach wall
of human, release hydrochloric acid, pepsin and
23. Direct respiration is seen in unicellular organisms
like Amoeba, Paramecium, bacteria and
9. Tooth decay or dental carries causes gradual
softening of enamel and dentine. Brushing the
teeth after eating removes the dental plaque.
24. Diffusion is defined as the movement of a
substance from a region of higher concentration
to a region of lower concentration.
10. Factors that affect photosynthesis are (i) Light,
(ii) Temperature, (iii) Water, and (iv) Carbon
25. Rate of respiration in plants is much slower than
11. Animal nutrition shows a very wide range.
Unicellular organisms like Amoeba obtain food
by the process of phagocytosis. The human
digestive system climaxes the evolutionary
development of the digestive system with
numerous glands, digestive juices and organs
working together. The various steps of nutrition
are ingestion, digestion, absorption and
26. In higher plants, the exchange of gases occurs
through stomata and lenticels.
27. Organs of respiration in animals are skin,
trachea, gills, lungs, etc.
28. Thin-walled air sacs called alveoli are present
29. The blood contains a pigment, haemoglobin,
which helps in the transport of carbon dioxide
12. The energy-rich molecule in which energy is
first captured is adenosine triphosphate or ATP.
30. In human beings, four basic processes are
involved in respiration—breathing, gaseous
transport, tissue respiration and cellular
31. In the thoracic cavity, the lungs are bound by a
convex muscular and elastic sheet called
32. Diffusion is a major method by which
transportation of material occurs in single celled
organisms like bacteria.
33. Diffusion is the movement of molecules from a
region of higher concentration to that of lower
concentration resulting in their uniform...
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