Q1. Indicate whether the following statements are True (T) or False (F).
(a) Unicellular organisms have a one-celled body. ( )
(b) Muscle cells are branched. ( )
(c) The basic living unit of an organism is an organ. ( )
(d) Amoeba has an irregular shape. ( )
(a) Unicellular organisms have a one-celled body. (True)
(b) Muscle cells are branched. (True)
(c) The basic living unit of an organism is an organ. (False)
(d) Amoeba has an irregular shape. (True)
Q2. Make a sketch of the human nerve cell. What function do nerve cells perform?
Nerve cells carry nerve signals from the brain to different organs and from different organs to the brain.
Q3. Write short notes on the following:
(b) Nucleus of a cell
(b) Nucleus of a Cell
Q4. Which part of the cell contains organelles?
Ans: The cytoplasm contains cell organelles.
Q5. Make sketches of animal and plant cells. State three differences between them.
Q6. State the difference between eukaryotes and prokaryotes.
Q7. Where are chromosomes found in a cell? State their function.
Q8. ‘Cells are the basic structural units of living organisms’. Explain.
Ans: Cells are the smallest units from which a living organism is made. A cell contains all the necessary structures which are required to carry out various biological processes. A group of cells makes a tissue which further makes organs and finally an organism. Thus, cells are called the basic structural unit of living organisms.
Q9. Explain why chloroplasts are found only in plant cells?
Ans: Chloroplasts are a type of plastids that contain chlorophyll. Chlorophyll is a green colour pigment that plays important role in photosynthesis. Since green plants need to prepare their food, hence chloroplast is present in them.Structure of Chloroplast
Q10. Complete the crossword with the help of clues given below:
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.
1. Green plastids.
2. Formed by a 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.