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Fill in the blank
Many chemical reactions take place in the ________ to keep the cell alive.
In a plant cell, the cell wall is made up of _________
Centrioles help in _______
Several organ systems together form a ____________ organism.
________destroy old and worn out cells.
The longest cell in human body is _________
_________ is the power house of the cell.
The nucleus and the cytoplasm together make up the ___________
__________ are organelles responsible for the colour other than green in plants.
The organelle which is associated with protein synthesis ________
The new cell that arise after cell division are called __________ cells.
The plastid that help prepare food for the plant are ___________
__________passing hereditary characters to the next generation.
____________giving rigidity to the cell.
The organelle storing wastes in the plant cell is ____________
Answer
Cytoplasm
Cellulose
Cell division
Multicellular
Lysosomes
Nerve cell
Mitochondria
Protoplasm
chromoplasts
ribosomes
daughter
chloroplast
DNA ( deoxyribo nucleic acid)
Cell wall
Vacuoles
Short Answer Questions
Question 1.
What is a tissue?
Answer
A group of similar cells that perform a particular function is called tissue. For e.g. muscles cells make up the muscular tissue.
Question 2.
What are genes? Write their function?
Answer
Genes are the segment of DNA. Genes are units of inheritance i.e. they help in transmitting characters from parents to offspring.
Question 3.
Why is the cell wall present in plant cells and not in animal cells?
Answer
The plants do not have a skeleton for support and protection, nor can they move to escape environmental stress so they need a cell wall as a protective layer around them which is not at all needed by animal cells.
Question 4.
Write the function of vacuole in animal cells?
Answer
In animal cells, vacuoles are smaller and may be greater in number. They help in waste removal and digestion.
Question 5.
Write the difference between cytoplasm and nucleoplasm?
Answer
The jelly-like substance inside the cell in which nucleus and cell organelles are present is called cytoplasm whereas the liquid or dense material inside the nucleus is called nucleoplasm.
Question 6.
Why is a cell membrane important to a cell?
Answer
Cell membrane is important to a cell because it regulates the entry and exit of substances in the cell and it protect the cell and gives it a shape.
Question 7.
What is cell division and why it is necessary?
Answer
New cells for growth and repair are formed by cell division. Cell division is also necessary for replacement of dead cells.
Question 8.
What are dictyosomes?
Answer
In plant cells, golgi bodies are not well defined and are called dictyosomes.
Question 9.
What is microscope?
Answer
It is a instrument used for viewing objects that are too small to be seen with the naked eye.
Question 10.
Write the function of nucleolus?
Answer
A smaller spherical structure present inside the nucleus, called Nucleolus plays an important role in protein synthesis.
Long Answer Questions
Question 1.
Differentiate between prokaryotic and eukaryotic cells?
Answer
Question 2.
Write the functions of different types of plastids?
Answer
Plastids with green�coloured photosynthetic pigment (chlorophyll) are called chloroplasts. They are also called kitchen of a plant cell.
Leucoplasts are colourless plastids and store food in the form of starch and fat.
Plastids with pigments other than green are called chromoplasts. These plastids give the flowers and fruits their bright colours, which attracts insects and animals for pollination.
Question 3.
Name any two types of cells that are capable of changing their shape. How does this feature help them in their functions?
Answer
The two types of cells that are capable of changing their shape are:
(i) White blood cells (WBCs): The white blood cells present in our blood can change their shape. This helps them to kill germs by engulfing them.
(ii) Amoeba: Amoeba can change its shape with the help of pseudopodia that are projections of its body. The pseudopodia help the Amoeba to capture its food and move from one place to another.
Question 4.
Explain the relationship between organ and organ system?
Answer
Many tissues combine to form an organ that carries out a particular function. For example, various types of tissues form organs such as heart, kidney etc. Various organs working together to carry on life activities constitute an organ system. For example heart, arteries and veins work together to form circulatory system.
Question 5.
What are the lower levels of organization in multicellular organisms? Are these levels present in unicellular organisms?
Answer
In a multicellular organism, the lower levels of organization are as follows:
Cells → Tissues → Organs → Organ systems → Organism
No, these levels are not present in unicellular organisms because unicellular organism consists of single cell.
Practice questions:
1. What is cell?
2. State the key features of cell theory?
3. Who saw cells first and when?
4. Why is a cell membrane important to a cell?
5. Name two organelles present in plant cell but not present in an animal cell?
6. What do you mean by protoplasm?
7. What are the building blocks of life? Why are they so called?
8. Differentiate between unicellular and multicellular organisms?
9. What is cell division? Why it is necessary?
10. Write the functions of nucleus and chromosome?
11. What is function of ribosomes?
12. What are the differences between animal cell and plant cell?
13. Why are cells of different shapes and sizes? Give suitable example?
14. Why is lysosomes known as suicidal bag of the cell?
15. Draw a diagram of animal cell and plant cell?
Multiple Choice Questions
Question 1.
Which one of the following term is not a part of the nucleus?
(a) ribosome
(b) nucleolus
(c) chromosome
(d) gene
Question 2.
A suitable term for the various components of cells is
(a) tissue
(b) cell organelles
(c) chromosomes
(d) genes
Question 3.
Cell is discovered by
(a) Robert Brown
(b) Robert Hooke
(c) John Mendal
(d) Charse Darwin
Question 4.
Green colour of leaves is due to presence of the pigment_____
(a) chloroplast
(b) ribosomes
(c) mitochondira
(d) chlorophyll
Question 5.
The control unit of cell is
(a) Cytoplasm
(b) Cell wall
(c) Nucleus
(d) All of these
Question 6.
Identify the correct statement about cells.
(a) All the cells have nucleus.
(b) Cells of an organ have similar structure.
(c) Cells of a tissue have similar structure.
(d) Shape of all types of cells is round
Question 7.
Name the outer most boundary of the cell?
(a) Nuclear membrane
(b) Cytoplasm
(c) Plasma membrane
(d) None of the above
Question 8.
The jelly like substance present inside the cell is known as:
(a) Cytoplasm
(b) Ectoplasm
(c) Nucleoplasm
(d) mitochondira
Question 9.
Which of the following is not a cell?
(a) virus
(b) bacterium
(c) spermatozoa
(d) RBC
Question 10.
Living substance of cell is called ____.
(a) Cytoplasm
(b) Chromosmes
(c) Nucleus
(d) Protoplasm
Answer
1. a
2. b
3. b
4. d
5. c
6. c
7. c
8. a
9. a
10. d
Summary
This Cell structure and functions Class 8 CBSE Practice questions and asnwers is prepared keeping in mind the latest syllabus of CBSE . This has been designed in a way to improve the academic performance of the students. If you find mistakes , please do provide the feedback on the mail.
