CBSE Class 8 Science Cell Structure and Functions Assignment Set A

Fill in Blanks. 

Question. Chloroplasts convert _____energy to _____ energy.
Answer : Chloroplasts convert solar energy to chemical energy.

Question. Vacuoles are the_____ sacs for solid or liquid contents.
Answer : Vacuoles are the storage sacs for solid or liquid contents.

Question. Mitochondria are _____ in RBCs.
Answer : Mitochondria are absent in RBCs.

Question. Golgi complex is the_____organ of the cell.
Answer : Golgi complex is the secretory organ of the cell.

Match the following.
a) Purple        Carotene
b) Yellow        Betalains
c) Orange       Anthocyanin
d) Dark Pink   Xanthophyll

Answer :
a) Purple        Anthocyanin 
b) Yellow        Xanthophyll
c) Orange        Carotene 
d) Dark Pink   Betalains

True or false. 

Question. Cytoplasm is stable substance.
Answer : FALSE

Question. Cell walls are found around plants.
Answer : TRUE

Question. Rough ER has ribosome grannules on its outer surface.
Answer : TRUE

Question. Plasma membranes are fat, strong and rigid cell.
Answer : FALSE

Answer the following questions. 

Question. State the difference between Isotonic solution and Hypertonic solution.
Answer : b) Isotonic solution                 -      Hypertonic solution -
Medium outside and inside the        The cell has more water
cell has same proportion of water,    than the outside
water doesn’t go in or out.               medium so water comes out of the cell.

Question. What happens to the agricultural waste after a few days when it is dumped in a compost pit ?
Answer : Lysosomes digest the waste.

Question. Explain the functions of endoplasmic reticulum ?
Answer : 1. It is the framework that supports cell.
2. Conduction of proteins.
3. Toxins that have entered the body through food, air and water are made water soluble by ER and then flushed out of the body.
d) Lysosomes digest the waste.

Question. What is the cell wall ?
Answer : Cell wall is an elastic and strong coat around cell membrane. It is mainly composed of carbohydrates like cellulose and pectin.

Answer any 2 questions in brief.

Question. Explain functions of Golgi complex ?
Answer :  1. Golgi complex is the secretory organ of the cell.
2. It modifies, sorts and packs materials synthesized in the cell (enzymes, mucus, proteins, pigments etc.) and dispatches them to various targets like plasma membrane, lysosome etc.
3. It produces vacuoles and secretory vesicles.
4. It helps in the formation of cell wall, plasma membrane and lysosomes.

Question. Difference between Eukaryotic cell & Prokaryotic cell.
Answer :
Eukaryotic Cell                        
Size - 5 - 100 micrometer Number of chromosomes Nucleus - with nuclear membrane, and nucleoplasm Mittochondria and plastids - present.
Examples-Present in highly evolved unicellular Bacteria and multicellular plants and animals.

Prokaryotic Cell - 1- 10 micrometer. Only one. Nucleoid resembling nucleus They don’t have membrance bound Bacteria

Question. What is vacuoles ?
Answer : Vacuoles are the storage sacs for solid or liquid contents They don’t have any typical shape or size. The structure of the vacuole changes according to the need of the cell. Vacuole is bound by single membrane.

Question. Explain functions of Lysosomes. is dumped in a compost pit ?
Answer : 1. Immune system - It destroys viruses and bacteria that attack the cell.
2. Demolition squads - It is destroys worn out cellular organelles and organic debris. (Autolysis)
3. Suicide Bags - When a cell becomes old or is damaged, lysosomes burst and enzymes digest their own cells.
4. During starvation, lysosomes digest stored proteins, fats.