Lakhmir Singh & Manjit Kaur: Cell Structure and Functions- 1 | Lakhmir Singh & Manjit Kaur Solutions: Class 8 Science PDF Download

Q.1. Which instrument was essential for the study of cells? 

A microscope was essential for the study of cells.

Q.2. What is the basic similarity among all the living organisms (plants and animals)? 

The basic similarity among all living organisms is that they all are made up of cells.

Q.3. Name the scientist who observed a thin slice of cork through a microscope and coined the team ‘cell’. 

Robert Hooke in 1665 observed a thin slice of cork through a microscope and coined the term ‘cell’.

Q.4. Name the outermost layer of an animal cell. 

The plasma membrane is the outermost layer of an animal cell.

Q.5. Which part of the cell contains organelles? 

Cell organelles are present in the cytoplasm.

Q.6. Name any two organelles present in a cell. 

Mitochondria and Endoplasmic reticulum.

Q.7. Which part of a cell carries out respiration? 

Mitochondria is the site of respiration.

Q.8. What are the units of inheritance in living organisms? 

Gene is a unit of inheritance in living organisms.

Q.9. Which is the largest floating body generally in the center of a cell? 

The nucleus is the largest floating body generally in the center of a cell.

Q.10. What is the function of the nucleus in a cell? 

The nucleus controls all activities of the cell, hence it is also called the Master or Director of the cell.

Q.11. What do the chloroplasts contain? 

They possess photosynthetic pigment called chlorophyll.

Q.12. What kind of cells are surrounded by a cell wall? 

Plant cells are surrounded by a cell wall.

Q.13. What sort of cells does not have a cell wall around them? 

Animal cells do not have a cell wall around them.

Q.14. Name the layer which is outside the cell membrane of a plant cell.

Cell wall

Q.15. How is the outside of a plant cell different from that of an animal cell? 

Plant cells differ from animal cells in having an additional layer around the cell membrane termed the cell wall.

Q.16. Name the organelle of a plant cell where photosynthesis takes place. 

Chloroplast is the organelle of a plant cell where photosynthesis takes place.

Q.17. Which part of a plant cell protects outside of the cell? 

The cell wall protects outside the plant cell.

Q.18. Which part of the plant cell releases energy from food? 

Mitochondria release energy from food in the plant cell.

Q.19. What causes the red color in tomatoes? 

Colored plastid (Chromoplasts) gives the red color to tomatoes.

Q.20. Which part of the two has a large vacuole: a plant cell or an animal cell? 

A plant cell has a large vacuole.

Q.21. Name any two parts which are present in a plant cell but not in an animal cell. 

Cell walls and plastids are present only in a plant cell.

Q.22. Which cells transmit messages between the brain and other parts of the body? 

Nerve cells transmit messages between the brain and other parts of the body.

Q.23. Which cells in the human body can contract (and relax)? 

Muscle cells in the human body can contract and relax.

Q.24. Name the spindle-shaped cells present in the human body. 

The spindle-shaped cells present in the human body are muscle cells.

Q.25. State an important characteristic of muscles cells. 

A muscle cell is pointed at both ends and has a spindle shape.

Q.26. Name a single cell (other than the Amoba cell) that can change its shape. 

White blood cells present in human blood are a single cell (other than the Ameoba cell) that can change its shape.

Q.27. Name one ‘single cell’ which behaves like a complete organism. 

Amoeba is a single cell that behaves like a complete organism.

Q.28. Name one cell which can be seen easily with naked eye and one cell which can be seen only through a microscope. 

The bird’s egg are very large cell which can be seen easily with naked eye while bacterial cells are extremely small which can be seen only through a microscope.

Q.29. State whether the following statements are true or false :
(a) Unicellular organism have one- celled body.
(b) Muscle cells are branched.
(c) Amoeba has irregular shape.
(d) All the cells in our body are alike.
(e) A hen’s egg is a group of cells.
(f) The basic living unit of an organism is organ.

(a) True, unicellular organisms (single celled organisms) are made up of only one cell.
(b) False, muscle cell are not branched.

Q.30. Name the smallest unit of life.

Cell is the smallest unit of life.