Indicate whether the following statements are True (T) or False (F).
(a) Unicellular organisms have one-celled body. (T/F)
(b) Muscle cells are branched. (T/F)
(c) The basic living unit of an organism is an organ. (T/F)
(d) Amoeba has irregular shape. (T/F)
(a) True
This statement is true because unicellular organism have one cell present in their body, in unicellular organisms, all functions are performed by a single cell.
(b) False
This statement is false because the muscle cells are striated cells. These are not branched.
(c) False
This statement is false because the basic unit of living organisms is cell. Group of tissues are called as organ.
(d) True
This statement is true because amoeba is irregular in shape. It has pseudopodia. Amoeba is single celled organism.
Make sketches of animal and plant cells. State three differences between them.
Complete the crossword with the help of clues given below:
Across
1. This is necessary for photosynthesis.
3. Term for component present in the cytoplasm.
6. The living substance in the cell.
8. Units of inheritance present on the chromosomes.
Down
1. Green plastids.
2. Formed by collection of tissues.
4. It separates the contents of the cell from the surrounding medium.
5. Empty structure in the cytoplasm.
7. A group of cells.
Make a sketch of the human nerve cell. What function do nerve cells perform?
Explain why chloroplasts are found only in plant cells?
Write short notes on the following:
(a) Cytoplasm
(b) Nucleus of a cell
Where are chromosomes found in a cell? State their function.
‘Cells are the basic structural units of living organisms’. Explain.
State the difference between eukaryotes and prokaryotes.
Which part of the cell contains organelles?
Which of the following can be beaten into thin sheets?
(a) Zinc (b) Phosphorus (c) Sulphur (d) Oxygen
Fill in the blanks
(a) Most liquids that conduct electricity are solutions of , ______________ and ______________.
(b) The passage of an electric current through a solution causes ______________ effects.
(c) If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the terminal of the battery.
(d) The process of depositing a layer ofany desired metal on another material by means of electricity is called .
Give two examples each of situations in which you push or pull to change the state of motion of objects.
Fill in the blanks:
(a) Friction opposes the _____________ between the surfaces in contact with each other.
(b) Friction depends on the _____________ of surfaces. (c) Friction produces __________.
(d) Sprinkling of powder on the carrom board ________ friction.
(e) Sliding friction is ___________ than the static friction.
List conditions under which combustion can take place.
Which of the following cannot be charged easily by friction?
(a) A plastic scale
(b) A copper rod
(c) An inflated balloon
(d) A woollen cloth.
Fill in the blanks:
(a) A place where animals are protected in their natural habitat is called .
(b) Species found only in a particular area is known as .
(c) Migratory birds fly to far away places because of changes.
Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room. Explain.
What are the different ways in which water gets contaminated ?
Explain the importance of reproduction in organisms.
Differentiate between regular and diffused reflection. Does diffused reflection mean the failure of the laws of reflection?
Give two examples of each.
(a) Kharif crop
(b) Rabi crop
Fill in the blanks:
(a) Burning of wood and coal causes of air.
(b) A liquid fuel, used in homes is .
(c) Fuel must be heated to its before it starts burning.
(d) Fire produced by oil cannot be controlled by .
If wheat is sown in the kharif season, what would happen? Discuss.
What are antibiotics? What precautions must be taken while taking antibiotics?
Can microorganisms be seen with the naked eye? If not, how can they be seen?
It is difficult to burn a heap of green leaves but dry leaves catch fire easily. Explain.
Categorise the materials of the following products into ‘can be recycled’ and ‘cannot be recycled’:
Telephone instruments, plastic toys, cooker handles, carry bags, ball point pens, plastic bowls, plastic covering on electrical wires, plastic chairs, electrical switches.
Write a short paragraph on the harms caused by microorganisms.
Fill in the blanks:
(a) Microorganisms can be seen with the help of a ____________.
(b) Blue green algae fix __________ directly from air to enhance fertility of soil.
(c) Alcohol is produced with the help of __________.
(d) Cholera is caused by __________.