NCERT Solutions Class 9 Science Chapter 5

NCERT Solutions Class 9 Science Chapter 5: Fundamental Unit of Life 

Science is an exciting subject, and it offers many concepts which will be used in the upcoming classes. Students also have the opportunity to prepare for their future careers in the medical and engineering field. It is a transition period for students who wish to take Science as a significant career option.

Class 9 Science Chapter 5 is about the fundamental unit of life. This chapter studies the fundamental entity of life, a living cell. It also covers everything related to the cells in organisms and their growth in the body. Students will get to learn more about the formation of gametes for reproduction. 

Students can access the Extramarks NCERT Solutions Class 9 Science Chapter 5 through their website. They can get detailed notes, illustrations and examples, and past years’ papers through their online portal. As a result, students can efficiently study and understand the critical topics discussed in Class 9 Science Chapter 5. 

Extramarks is a leading online learning platform that provides students with the best study materials and solutions. The NCERT Solutions Class 9 Science Chapter 5 helps develop the skills necessary for advanced learning. It helps to establish a strong foundation of all concepts, where the answers are provided with  diagrams. 

For the latest updates and notifications regarding the NCERT syllabus and examination-related updates, students can visit the Extramarks’ website. Students can also access NCERT Solutions Class 9, NCERT Solutions Class 10, NCERT Solutions Class 11 and NCERT Solutions Class 12.

Key Topics Covered In NCERT Solutions Class 9 Science Chapter 5

NCERT Solutions Class 9 Science Chapter 5 helps students learn all the essential concepts of the fundamental unit of life. Students can learn from the theoretical notes, diagrams, and summarised answers. With the help of Extramarks NCERT Solutions Class 9 Science Chapter 5, students will be able to understand every concept and answer any question easily.  

Some of the critical sub-topics in NCERT Solutions Class 9 Science Chapter 5 are:

What are Living Organisms Made Up of?

Living organisms are usually made up of cells. These cells are the structural and functional units of organisms. Robert Hooke discovered the existence of these cells with the help of a microscope. Later, it paved the way for discovering various other microscopic organisms. Organisms can consist of a single cell, for example amoeba. Other microorganisms are multicellular and have millions of cells. 

Each living cell holds the capacity to perform basic functions. Different parts of the human body perform different functions. It has the heart to pump blood, a stomach to digest food and so on. Just like that, a cell has got certain specific components within it known as cell organelles. All cell organelles perform a special function, which helps to make new material in the cell. 

Interestingly, every cell is found to have the same organelles,no matter what their function is or what organism they were found in. 

What is a Cell Made Up of? What is the Structural Organisation of a Cell?

If a cell is studied under a microscope, one can conclude three features in each cell: plasma membrane, nucleus, and cytoplasm. Every activity inside the cell and interactions of the cell with its environment are possible due to different features such as: 

1. i) Plasma membrane or cell membrane

• The cell’s outermost layer isolates its contents from the outside surroundings. Plasma membranes permit specific substances to move into and out of cells. This is why the cell membrane is described as a selectively porous membrane.

• Diffusion is a method that permits substances like O2 or CO2 to flow through cell membranes.

• Osmosis is moving molecules of water (liquids) through a membrane that is selectively permeable. Osmosis refers to the flow of water molecules through semipermeable membranes, from high concentration areas to areas with low water concentration.

• The cell can gain water via osmosis when the water content in the surrounding medium is higher than the one within the cells. 

To understand the functioning of the plasma membrane, students can refer to our NCERT Solutions Class 9 Science Chapter 5. Our subject matter experts have prepared detailed notes on this topic. 

1. ii) Cell Wall

• It is an external solid covering that plant cells possess. It also serves to be its plasma membrane. The cell wall doesn’t cover the plasma membrane.

• Cellulose is the primary ingredient in the cell wall of the plant. The cell wall is intricate and helps give plant cells their strength. Living plants can lose water through osmosis which causes shrinkage and tightening of the contents. This process is known as plasmolysis.

iii) Nucleus

• It is a two-layered cover that protects the nucleus. The pores within the nuclear membrane permit the transfer of matter within and outside the nucleus, i.e. into the cell cytoplasm.

• The nucleus protects the chromosomes. These can be seen as rod-shaped structures as cells are preparing to divide.

• Chromosomes contain information regarding the inheritance of characteristics from parents and the following generation in DNA [DeoxyriboNucleic Acid molecules]. Chromosomes are composed of DNA and proteins. Genes are functional components of DNA. The nucleus is an essential element in the process of reproduction within cells.

1. iv) Cytoplasm

When we observe a temporary amount of onion peel under a microscope, we can see a large region of each cell enclosed by the cell membrane. Eventually, this region appears to be a little stained. It is called the cytoplasm. In addition, the cytoplasm appears like a fluid content inside the plasma membrane. It contains specialised cell organelles. Further, the organelles are enclosed by membranes. Usually, in prokaryotes, the membrane-bound cell organelles are absent in the absence of a defined nuclear region. 

1. v) Endoplasmic Reticulum 

The endoplasmic reticulum is a vast system of membrane-bound tubes and sheets. It resembles long tubules, bags that are round or oval. 

There are two kinds: rough endoplasmic reticulum and smooth endoplasmic reticulum [SER].

1. vi) Cell Organelles

The membrane of every cell forms and surrounds it to keep its contents distinct from its external environment. The various parts of cells perform various functions and are known as organelles of cells.

• Golgi Apparatus:

Golgi is a collection of membrane-bound vesicles arranged around and parallel to one another in cisterns or stacks. The synthesis of material close to the ER is packed and sent to different targets via the Golgi apparatus within and outside the cell. Its main functions are storage, modification, and packaging of vesicle-based products.

• Lysosomes: 

Lysosomes constitute an element of the cell’s waste disposal and elimination system. Lysosomes assist in keeping the cells clean by digesting any foreign substance and worn-out organelles of the cell.

• Plastids: 

Plastids exist only in plant cells. There are two kinds of plastids, namely chromoplasts and leucoplasts. Chromoplasts are plastids that have colour. They are found in leaves, flowers and fruits. Plastids that have the colour chlorophyll are also known as chloroplasts.

• Vacuoles:

Vacuoles are storage sacs for solid and liquid contents. They are small-sized in animal cells. Besides, plant cells have very large vacuoles. The central vacuole of some plant cells may occupy 50-90% of the cell volume. Plant cell vacuoles are usually full of the cell sap, offering turgidity and rigidity to the cell. Besides, many important substances in the life of the plant cell are stored in vacuoles. 

Cell Division

Every organism must make new cells grow and replace old dead injured cells and additionally to form gametes required for reproduction. The process by which new cells are made is known as cell division. Usually, there are two main cell division types: mitosis and meiosis. Further, the process of cell division by which most cells divide for growth is known as mitosis. In this process, each cell called the mother cell divides to form two identical daughter cells. The cells will eventually have the same number of chromosomes as the mother. 

To get an overview of the cell organelles and their components, students can refer to NCERT Solutions Class 9 Science Chapter 5 and other study materials such as Revision Notes, Previous Year Question Papers, and CBSE Important Questions, all available at the Extramarks website.

NCERT Solutions Class 9 Science Chapter 5: Exercise & Solutions

The NCERT Solutions for Class 9 Science Chapter 5 created by the Extramarks are based on the latest CBSE syllabus and cover all the essential topics. Students preparing for the CBSE Class 9 Term II Examination can refer to NCERT Solutions Class 9 Science Chapter 5. 

The solution guide has various types of questions, including fill in the blanks, match the following, and true or false types of questions. It covers the theoretical aspects of NCERT and offers step-by-step answers to all NCERT questions. 

Click the links below to see exercise-specific questions and their answers for NCERT Solutions Class 9 Science Chapter 5.

• Chapter 5: Exercise 5.1 – 2 Questions
• Chapter 5: Exercise 5.3 – 4 Questions
• Chapter 5: Exercise 5.4 – 2 Questions
• Chapter 5: Exercise 5.5 – 4 Questions
• Chapter 5: Chapter Exercise – 10 Questions

Students can also explore NCERT Solutions for different classes on the Extramarks site:

• NCERT Solutions Class 1
• NCERT Solutions Class 2
• NCERT Solutions Class 3
• NCERT Solutions Class 4
• NCERT Solutions Class 5
• NCERT Solutions Class 6
• NCERT Solutions Class 7
• NCERT Solutions Class 8
• NCERT Solutions Class 9
• NCERT Solutions Class 10
• NCERT Solutions Class 11
• NCERT Solutions Class 12

NCERT Exemplar for Class 9 Science:

Science is a subject that inspires curiosity. To grasp concepts, one must have a deep understanding of the subject. Solving different questions can help students increase their knowledge. This helps students clarify their doubts and gain a solid understanding of the topic.

The NCERT exemplars were designed in the same way to help students understand the topic easily and quickly. There are different types of questions, each with a graded difficulty level. Students can expect to score well in the exam if they practice the Exemplar every day.

The NCERT Solutions Class 9 Science Chapter 5 provides solutions to the questions covered in Exemplar on the topics of fundamental units of life.

Key Features of NCERT Solutions Class 9 Science Chapter 5:

NCERT Science Solutions offers many benefits. Some of them are listed below.:

• These solutions address all Class 9 Science Chapter 5 Questions covered in the exercises given in the textbook.
• Students can find the solution guide on the Extramarks website, so they are easily accessible whenever they are needed.
• To help students understand the concepts, diagrams are provided.
• Students can find the most effective solutions on this platform, which will help them score high in their final exams.
• Students can practice and prepare more efficiently for their final examinations. It is a thoroughly researched material made in sync with CBSE examination guidelines. When students study from it, they will get an edge over their peers. 
• The NCERT Solutions Class 9 Science Chapter 5 will enhance students’ problem-solving abilities and give them a general idea behind different types of questions.