Important Questions from Cell - The Unit of Life
A cell is the smallest unit of life. It is the fundamental structural, functional, and biological unit of all living organisms that are known till now. Through the study and analysis of cells, the unit of life and its components, we can ascertain the physiological and behavioral processes of living organisms in molecular terms. This is known as the physio-chemical approach. Additionally, the physio-chemical method of studying living organisms is known as reductionist biology.
The following important question from chapter 7 cell the unit of life will enable you to have a thorough idea of the cell and its various components.
Short Answer Questions
State Cell Theory
Ans. Cell theory states that all living organisms are composed of cells and are products of cells. It also suggests that all cells arise from pre-existing cells.
What are Passive Transport and Active Transport?
Ans. When molecules pass through membranes of the cell the unit of life without the help of energy, it is known as passive transport. On the other hand, active transport is when molecules require energy to move from a lower concentration region to a higher concentration region.
What Are Microbodies?
Ans. Microbodies are membrane-bound tiny vesicles which contain several enzymes. These microbodies can be found in both plant and animal cells.
Mention The Functions of Mesosomes.
Ans. Functions of mesosomes include distribution of daughter cells, replication of DNA and facilitation of cell wall formation. Moreover, it also increases the total surface area and aids in respiration and excretion.
Which is The Powerhouse of The Cell and Why?
Ans. Mitochondria is known as the powerhouse of the cell unit of life as it manufactures cellular energy which is in the form of ATP or Adenosine triphosphate.
What is A Satellite Chromosome?
Ans. In some cases, the fragment of a chromosome is separated from the main body by a secondary constriction. It is known as a satellite chromosome.
Give The Fluid Mosaic Model of A Plasma Membrane
Ans. Singer and Nicholson presented the fluid mosaic model, which shows the structure of the cell membrane as a mosaic of different components – protein, lipid bilayer, cholesterol, sugar. The ratio of each element varies as per cell type. Additionally, the semi-fluid nature of lipids enables the movement of protein.
Long Answer Questions
Describe The Structure of a Prokaryotic Cell With The Help of a Diagram.
Ans. Organisms which have prokaryotic cells are unicellular organisms such as bacteria, mycoplasma, blue-green algae etc. Prokaryotic cells have a wall which surrounds the cell membrane. The fluid matrix within the cell is called cytoplasm. Besides the genomic or single chromosome DNA located in a nucleoid, bacteria have a smaller DNA known as plasmids. It carries unique phenotypic characteristics.
Prokaryotic cells of organisms like bacteria have three-layered cell envelopes. The outermost layer is called glycocalyx, which can be a thick or thin layer. Next comes the cell wall, which acts as a protection and gives shape and structure to the organism. The final layer is the plasma membrane which is semi-permeable and interacts with the external world. The plasma membrane also contains the ribosome and inclusion bodies.
The flagellum of a motile bacteria is made up of three parts – basal body, filament and hook. Other structures in bacteria are Pili which are elongated tubular structures composed of protein. Fimbriae resemble bristle-like structures. These two help the bacteria to function like hosting tissues, rocks in water, etc.
Explain The Structure of A Eukaryotic Cell With A Diagram.
Ans. In contrast to prokaryotic cells, eukaryotic cells contain a nucleus which is membrane-bound. In addition to that, other membrane organelles can also be observed in the cytoplasm such as mitochondria, ribosomes, golgi bodies, chloroplasts, endoplasmic reticulum and so on.
The cytoplasm is bound by a plasma membrane, which is semi-permeable and allows transportation of nutrients and fluids. Plant cells contain a cell wall in addition to plastids and a large central vacuole. Animal cells do not have these. Instead, it has centrioles which are not present in plant cells.
Cell wall protects cells which are the basic unit of life from infection and damage, while also giving it shape. The primary cell wall of a young plant is capable of growth.
The endomembrane system contains the golgi complex, endoplasmic reticulum, lysosomes and vacuoles.
Mitochondria is a double membrane-bound structure. It is called the powerhouse of the cell as it produces cellular energy.
Plastids are found in plants which are responsible for giving each plant-specific colours.
Ribosomes are not bound by membranes and contain RNA and proteins.
Cytoskeleton is a network of filaments which are made up of proteins.
Cilia and flagella are hair-like structures of the cell membrane. They are responsible for cell movement.
Centrosomes contain centrioles which are responsible for cell division.
Nucleus is the largest organelle present in a eukaryotic cell. It is responsible for controlling all the activities of a cell. It also contains DNA.
3. Write a Short Note on Plastids.
Ans. They are present in plant cells and carry pigments which give colour to plants. Plastids can be classified into three types based on the colour of a pigment – chloroplast, chromoplast and leucoplast.
Chloroplasts have carotenoid pigments in addition to chlorophyll which helps in capturing light energy and thereby aid in the process of photosynthesis. Chromoplasts contain carotenoid pigments such as xanthophylls and carotene, which are responsible for red, yellow and orange colour. Leucoplasts have no colour. Its function is to store nutrients.
You will find more cell questions apart from the ones given here on our website along with detailed study materials on each topic. You can also check out solved solutions on class 11 Biology, which will enable you to gain an idea about exam structure.
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FAQs on Cell - The Unit of Life
1. What are the two major functions of a cell?
Two functions of a cell which is a basic unit of life are that it aids in the transportation of essential nutrients and fluid, while also helping in the growth of living organisms through cell division. These are the 2 functions of a cell. Students can learn more about the cell and its structure at Vedantu official website. Here they’ll also find important questions and answers in this chapter with extra notes. They can also check out the video lectures on Cell the Unit of Life at Vedantu’s Youtube Channel.
2. Where is DNA located?
DNA (Deoxyribonucleic acid) is a molecule inside cells that holds the genetic information accountable for the development and functioning of an organism. It allows this information to be passed from 1 generation to the next and is made up of a double-stranded helix held jointly by feeble hydrogen bonds between purine-pyrimidine nucleotide base pairs. In a eukaryotic cell, DNA is located in the nucleus, while in prokaryotic cells, DNA is located in a region that is referred to as the nucleoid.
3. What are the two types of cells?
The two types of cells are eukaryotic and prokaryotic cells.Prokaryotic Cells
Prokaryotic Cells
Prokaryotic Cells are single-celled microorganisms whose cell size varies from 0.1 µm to 0.5 µm (diameter).
Prokaryotic cells don't have any nucleus. Some of these cells have an area within the cell, called the nucleoid, where the genetic material is suspended freely.
The genetic material of Prokaryotic Cells can be either DNA (Deoxyribonucleic Acid) or RNA (Ribonucleic Acid).
These cells typically reproduce through the asexual reproduction process, binary fission. Prokaryotic can also use conjugation as a form of reproduction.
For Example- Bacteria, Cyanobacteria, etc
Eukaryotic Cells
Eukaryotic cells are composed of a nucleus and their size varies between 10 µm to 100 µm (diameter).
The plasma membrane in Eukaryotic Cells is accountable for monitoring the transportation of nutrients and electrolytes, in and out of them and is also accountable for the cell to cell communication.
Eukaryotic Cells reproduce in both forms, sexual as well as asexual.
Some contrasting characteristics between plant and animal Eukaryotic Cells are that the plant cell possesses chloroplast, central vacuoles, and other plastids, while animal cells do not have any of them.
For Example- Fungi, Animals, etc.
4. What are some properties of a cell?
A cell is called the structural and elemental unit of life. All living organisms are made up of cells. Some properties of cells are-
The interior of a cell is organised into distinct individual organelles covered by a distinct membrane
Cells give structure and support to the body of a living organism.
The major organelle which contains the genetic information essential for reproduction and cells' growth is called the nucleus.
Each cell has 1nucleus and membrane-bound organelles in its cytoplasm.
A double membrane-bound organelle that is primarily responsible for all the energy transactions important for the survival of a cell is called Mitochondria.
Lysosomes are ones in the cell that digests all the unwanted materials in the cell.
The endoplasmic reticulum has a substantial role in the internal organisation of the cell. It synthesises particular molecules and processes, handling and sorting them to their suitable surroundings.
5. Explain the structure of a cell?
The cell is characterised as the most basic unit of life that is accountable for all life’s functions. Its structure includes individual components with distinct functions which are essential to carry out life’s functions. Cell's structure includes
1. Nucleus
The nucleus of a cell includes the genetic material called the DNA (Deoxyribonucleic acid)
The nucleus guards the DNA and is an essential component of a plant cell.
The nucleus of a cell transmits signals to the cells to grow, mature, split or die.
The nucleus of a cell is surrounded by the nuclear envelope, which isolates the DNA from the rest of the cell.
2. Cell Wall
The cell wall is a fixed frame-like structure wrapping the cell membrane and is the most evident part of a plant cell.
The cell wall is made up of hemicellulose, cellulose, and pectin.
It is only present in the plant cells and not in the animal cells.
The cell wall protects the plasma membrane and the different cellular components.
It is the outermost layer of a plant cell.
The cell wall gives a cell a shape and support and shields them from any type of mechanical shocks or damages.
3. Cell Membrane
The cell membrane supports and protects the cell.
Cell Membrane separates a cell from its external environment.
It is present in all the cells.
The Cell Membrane forms a wall-like structure between 2 cells and also between a cell and its surroundings.
It is the outer covering of a cell within which encloses all the cell organelles like the cytoplasm and nucleus
Cell Membrane is also called the Plasma Membrane.
Cell Membrane is a porous membrane that enables the movement of particular substances in and out of the cell.
It also shields the cellular component from harm and leakage.
4. Cytoplasm
The cytoplasm of a cell is a thick and jelly-like substance
It exists inside the cell membrane of a cell.
In a cell, most of the chemical reactions occur in the cytoplasm.
The organelles like the mitochondria, ribosomes, endoplasmic reticulum, vacuoles, are suspended in the cytoplasm of the cell.
