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.
A blacksmith hammers a hot piece of iron while making a tool. How does the force due to hammering affect the piece of iron?
Describe how coal is formed from dead vegetation. What is this process called?
Name the largest planet of the solar system.
Draw sketches to show the relative positions of prominent stars in
(a) Ursa Major and (b) Orion
Explain how the use of CNG in automobiles has reduced pollution in our cities.
Two mirrors meet at right angles. A ray of light is incident on one at an angle of 30° as shown in Fig. 16.19. Draw the reflected ray from the second mirror.
Select the correct word from the following list and fill in the blanks.
float, water, crop, nutrients, preparation
(a) The same kind of plants grown and cultivated on a large scale at a place is called _____________.
(b) The first step before growing crops is _____________ of the soil.
(c) Damaged seeds would _____________ on top of water.
(d) For growing a crop, sufficient sunlight and _____________ and _____________ from the soil are essential.
In case of a fire, before the firemen use the water hoses, they shut off the main electrical supply for the area. Explain why they do this.
Name three liquids, which when tested in the manner shown in Fig.14.9, may cause the magnetic needle to deflect.
List conditions under which combustion can take place.