NCERT Solutions Class 8 Science Chapter 8

NCERT Solutions for Class 8 Science Chapter 8

Science is the observation and experimentation-based study of the physical and natural world. Science exists all around us. Science is also involved in the air we breathe. Science underlies the food we eat, the water we drink, and our clothes. It is impossible to ignore science. Science is all around us and is one of the most important subjects.

NCERT Class 8 Science Chapter 8 is Cell Structure and Functions. This chapter talks about the cell as the fundamental structural unit of all living organisms, whether they are plants or animals. Students will gain significant information about cell operation and composition through these solutions.

Extramarks presents Class 8 Science Chapter 8 Solutions, and these prove to be very beneficial for the students. Cell Structure and Function Class 8 as a chapter is simple to understand since it is created after considerable research by specialists in Extramarks. These solutions are formed with details that students can easily understand and not just memorize.

Apart from NCERT Solutions for Class 8 Science Chapter 8, Extramarks has a variety of study material for all classes. In addition to these, students can use the Extramarks website to access several other learning materials. For example, NCERT books, CBSE revision notes, CBSE sample papers, CBSE past years’ question papers, and other materials are available to students.

Key Topics Covered in NCERT Solutions for Class 8 Science Chapter 8

Listed below are key topics that are covered in NCERT Solutions for Class 8 Science Chapter 8:

Discovery of the cell 
The cell
Organisms show variety in cell number, shape and size
Cell structure and function
Parts of the cell
Comparison of plant and animal cells

Let us look at Extramarks in-depth information on each subtopic in NCERT Solutions for Class 8 Science Chapter 8- Cell Structure and Functions.

Discovery of the Cell

Under a primitive magnifying machine, Robert Hooke viewed slices of cork in 1665. Hooke gave each box the name ‘cell’.

The Cell

Extramarks NCERT Solutions for Class 8 Science Chapter 8 describes cells as the basic units of life and can also be called the structural units of any living being.

Organisms show variety in Cell number, shape and size

NCERT Solutions for Class 8 Science Chapter 8 explains cells based on their number, shape and size. 

Number of cells:

  • Unicellular organisms, such as amoebas, parameciums, etc., are defined as organisms made up of only one cell unit.
  • Unicellular organisms are composed of a single cell that is capable of carrying out all life’s essential processes on its own, including growth, digestion, respiration, excretion, and reproduction.
  • A multicellular organism is one that consists of many cells, such as humans, plants, and other living things.
  • Tissues are collections of specific cells that have a common purpose in multicellular organisms. Organs are made of similar tissues, and organisms are made of organs. As a result, each cell or set of cells has a certain job to do.

Shape of cells:

  • In general, the shapes, sizes, and quantities of the cells vary greatly from one creature to another.
  • A cell can range in size from 0.1 to 0.5 micrometres in a bacterium, which can be seen with the naked eye, to as large as a hen’s egg.
  • A cell can have several forms. It can have a spherical form as red blood cells do, or a spindle- or branch-like shapes, like muscle cells or nerve cells do.

Size of cells:

  • A cell’s function is more significant than its size, which has no bearing on the size of the organism. Whether an elephant or a rat, the nerve cells have the same ability to transmit information.

Cell structure and function

Each organ in the system carries out a variety of tasks, including assimilation, absorption, and digesting. Similar to how different plant organs carry out specific/specialized tasks. For instance, roots help in the uptake of nutrients and water.

Additionally, tissues make up the tiny components that make up each organ. A collection of identical cells carrying out a certain task constitutes a tissue.

Parts of the cell

Cell membrane

An essential aspect that Extramarks NCERT Solutions for Class 8 Science Chapter 8 covers is the cell membrane:

  • The cell membrane separates cells and the contents of the cell from the surrounding media.
  • It is porous, allowing fluids or materials to flow both within and outward.

Cytoplasm

Cell membrane and the nucleus are separated by a jelly-like material called the cytoplasm. The cytoplasm contains several different cell components or organelles.

Cell Wall in Plants

  • In plant cells, a cell wall is an extra coating above the cell membrane.
  • It provides these cells with structure and stiffness.
  • It gives plant cells a stiff structure, which allows them to tolerate stresses such as high-velocity wind, rain, and high temperatures.

Organelles 

Cell organelles are the numerous components found within the cell. These components are unique and functionally specialized—for instance, mitochondria, lysosomes, and so on.

Nucleus 

  • It is spherical and is found in the cell’s centre.
  • A membrane termed the nuclear membrane separates the nucleus from the cytoplasm.
  • It decides what each organelle should perform and how the cell should operate based on the information stored in the chromosomes.
  • The nucleolus is a smaller structure found in the nucleus.

Chromosomes 

Chromosomes are another important aspect covered in Extramarks NCERT Solutions for Class 8 Science Chapter 8. Chromosomes are thread-like structures found in the nucleus. These contain genes and aid in character inheritance or transmission from parents to children. DNA in the form of chromatin and protein makes up chromosomes. Chromosomes store information in the form of DNA molecules to transmit traits from parents to children. 

DNA

The information needed to build and organise cells is contained in DNA molecules. This is because genes are the functional portions of DNA.

Prokaryotic and Eukaryotic Cells

Prokaryotic — Size: typically, tiny (1-10 m), with 1 m equaling 10 6 m.

  • The nucleus, also known as a nucleoid, is not clearly defined.
  • Circular, single chromosome
  • Organelles that are membrane-bound are not present. Bacterial cells, for example.

Eukaryotic — Size ranges from 5 to 100 metres.

  • A nuclear membrane surrounds the nucleus, which is highly delineated.
  • Have more than one chromosome and are linear.
  • There are membrane-bound cell organelles. Consider a human cell.

Cell Structure in Eukaryotic cells

  • Eukaryotes are multicellular organisms.
  • In the nucleus, the nucleolus is present.
  • It contains plastids, mitochondria, Golgi bodies, and other cell organelles.
  • Fungi, plants, and animals have Eukaryotic cells within them.

Vacuoles 

Vacuoles are irregularly shaped storage bubbles present in cells. The vacuole contains food, a range of nutrients, and waste that a cell may require to thrive. Plant cells have far more giant vacuoles than animal cells, which provide rigidity to the cells. 

Plastids

  • Plastids are small coloured structures found in plant cells.
  • Plastids include pigments in various colours, including orange, red, green, and even colourlessness.
  • Chloroplasts are plastids that transport green-colored pigments, such as chlorophyll.

Comparison of plant and animal cells

Animal Cells Plant Cells
Chloroplasts do not exist in animal cells. Chloroplasts are found in plant cells, and they help by carrying out the process of photosynthesis to produce food for the plant.
They are usually relatively little. They tend to be bigger than animal cells.
The cell wall is missing. There is a cell wall present.

NCERT Solutions for Class 8 Science Chapter 8 Exercise and Solutions

On the Extramarks website, students can find NCERT Solutions for all chapters and other study materials such as previous years’ question papers, revision notes, extra problems, and more. Click on the below links to view NCERT Solutions for Class 8 Science Chapter 8:

Class 8 Science Chapter 8: Very Short Answer Type Questions

Class 8 Science Chapter 8: Short Answer Type Questions

Class 8 Science Chapter 8: Long Answer Type Questions

Students can easily access NCERT Solutions for Class 8 Science Chapter 8 and other chapters by clicking here. In addition, students can also explore NCERT Solutions for other classes below.

By getting access to NCERT Solutions for Class 8 Chapter 8, students can easily understand all the concepts of cell structure and components and their functions.

NCERT Solutions Class 8 Science Chapter-wise List

Chapter 1 – Crop Production and Management
Chapter 2 – Microorganisms : Friend and Foe
Chapter 3 – Synthetic Fibres and Plastics
Chapter 4 – Materials : Metals and Non-Metals
Chapter 5 – Coal and Petroleum
Chapter 6 – Combustion and Flame
Chapter 7 – Conservation of Plants and Animals
Chapter 8 – Cell – Structure and Functions
Chapter 9 – Reproduction in Animals
Chapter 10 – Reaching The Age of Adolescence
Chapter 11 – Force and Pressure
Chapter 12 – Friction
Chapter 13 – Sound
Chapter 14 – Chemical Effects of Electric Current
Chapter 15 – Some Natural Phenomena
Chapter 16 – Light
Chapter 17 – Stars and The Solar System
Chapter 18 – Pollution of Air and Water

Key Features of NCERT Solutions for Class 8 Science Chapter 8

To ensure more outstanding marks in their upcoming examinations, Class 8 students are strongly advised to read through NCERT Solution by the end of each chapter. Extramarks presents NCERT Solutions for Class 8 Science Chapter 8 to help students understand the topics. Some of the main reasons to pick Extramarks are listed below:

  • Based on the NCERT standards, Extramarks has compiled the most relevant material on this topic. 
  • These answers are simple and comprehensive, covering all the chapter’s concepts.
  • Extramarks’ subject specialists performed extensive research to develop the solutions and hence these are most relevant and help the students comprehend and score much better.

Q.1 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)

Ans.

(a) Unicellular organisms have one-celled body. (T)

(b) Muscle cells are branched. (F)

(c) The basic living unit of an organism is an organ. (F)

(d) Amoeba has irregular shape. (T)

Q.2 Make a sketch of human nerve cell. What function do nerve cells perform?

Ans.

The nerve cell receives and transfers messages to control and coordinate the working of different parts of the body.

Q.3 Write short notes on the following.
(a) Cytoplasm
(b) Nucleus of a cell

Ans.

(a) Cytoplasm

In a cell, a jelly-like substance present between the nucleus and the cell membrane is called cytoplasm. It contains various cell organelles, such as mitochondria, golgi apparatus, endoplasmic reticulum, lysosomes, etc.

(b) Nucleus of a cell

Nucleus is generally spherical in shape and located centrally in a cell. A porous membrane, called nuclear membrane, separates the nucleus from the cytoplasm. Nuclear membrane allows the exchange of materials between the nucleus and the cytoplasm.

Nucleus contains a smaller spherical body called nucleolus and thread-like structures called chromosomes. Chromosomes carry genes and help in the transfer of characters from one generation to the next generation. In addition to the function of inheritance of characters, nucleus regulates all the activities of a cell.

Q.4 Which part of the cell contains organelles?

Ans. Cytoplasm of the cell contains many organelles.

Q.5 Make sketches of animal and plant cells. State three differences between them.

Ans. Animal cell

Plant Cell

Differences between animal cell and pant cell are as follows:

Parts of cell Animal Cell Plant Cell
Cell wall Absent Present
Plastids Absent Present
Vacuoles Many but small in size One big central

Q.6 State the difference between eukaryotes and prokaryotes.

Ans. Following are the differences between eukaryotes and prokaryotes:

Features Eukaryotes Prokaryotes
Number of cells Unicellular or Multicellular Unicellular
Nucleus Well defined, and true nucleus Poorly defined, and a primitive nucleus
Nuclear membrane Present Absent

 

Q.7 Where are chromosomes found in a cell? State their function.

Ans. Chromosomes are found in the nucleus of a cell. Chromosomes are thread-like structures that carry genes which play a vital role in the inheritance of characters from parents to their offspring.

Q.8 ‘Cells are the basic structural units of living organisms.’ Explain.

Ans. In a living organism, various organs are present which perform various functions such as digestion, respiration, reproduction, movement, etc. Organs are specific for their function that they perform. For example, leaves carry out photosynthesis, ovary produces ova, etc. In an organism, specific tissues are present that facilitate it to perform its specific function. Furthermore, a tissue is composed of similar types of cells. Hence, we can say that cells are the basic structural unit of living organisms.

Q.9 Explain why chloroplasts are found only in plant cells?

Ans. The chloroplast is a type of plastid that contains green coloured pigment, chlorophyll. Chlorophyll is one of the essential requirements for photosynthesis to occur. Plastids are the organelles that are present only in plant cells. Hence, chloroplasts are found only in plant cells.

Q.10 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 chromosome.

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.

Ans.

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FAQs (Frequently Asked Questions)

Making notes during class is a vital step in acing one’s examinations. Taking notes throughout the course will assist you in remembering what was taught. You can even use Extramarks notes and solutions as a guide to help you construct your notes. For example, to take notes for Class 8 Science Chapter 8, develop a list of all the main topics and add keywords for each one. This will improve your memory retention.

The nucleus within the cell is responsible for the cell’s essential functions. It functions as a control centre for the body’s operation, like a firm with a boss. A cell is also exclusively responsible for the body’s division, development, and expansion. The nucleus, which is responsible for creating proteins, houses our DNA. It is only responsible for energy production, metabolic processes, and active and passive transportation. A cell is, therefore, a building block for a live entity.