NEET Biology

Understanding Cell Structure and Function For NEET Biology

Let’s Learn About Cell and Cell Structure 

Every organism that has lived and is extinct is made of cells. All living organisms on the planet are formed by cells. Cells are present at various places in the body of an organism.

  • A cell is an organism’s structural and functional unit. Unicellular creatures exist alongside multicellular organisms. Each cell can give birth to a new person. It is referred to as cell totipotency.
  • Cells are divided based on various things, such as organisms being classed as prokaryotes or eukaryotes based on whether or not they have a membrane-bound nucleus. 
  • Plants and animals are classified as eukaryotes, and eukaryotic cells are further divided into plant and animal cells.
  • Plant cells have cell walls, plastids, and a vacuole, which significantly change animal cells. 
  • A cell membrane, cytoplasm, and nucleus make up a normal eukaryotic cell. In animal cells, the cell membrane, also known as the plasma membrane, is the outermost layer, but it is found within the cell wall in plant cells.
  • The endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles are membrane-bound organelles found in eukaryotic cells.
  • Cisternae make up the endoplasmic reticulum. The rough endoplasmic reticulum is the surface of the endoplasmic reticulum, which has ribosomes on it. It has something to do with protein synthesis.
  • The smooth endoplasmic reticulum does not have ribosomes. It is involved in the lipid production process. A flattened sac-like structure makes up the Golgi apparatus.
  • A single layer wall surrounds the lysosomes. They have enzymes that break down all macromolecules. 
  • Large vacuoles with a membrane termed tonoplast are found in plant cells. 
  • The mitochondria are known as the powerhouse of cells because they are involved in the production of ATP. 
  • Grana and stroma are found in the chloroplast, which is a double-layered structure.

You can know more about cells by practising Cell The Unit of Life NEET MCQ.

Cell Theory History

Robert Hooke was the first to characterise cells. In 1665, he invented the microscope to view minute objects. One day, he was staring at a small piece of cork. Cork is a substance derived from cork tree bark. The cork looked like it was made up of little boxes. Hooke named these enclosures as cells, which means “little apartments” in Latin.

Parts of a Cell

Cells have a wide range of functions and can be found in a variety of shapes and sizes. Common parts can be found in every cell.

Cell Membrane and Cytoplasm

  • The cell membrane surrounds all cells. The cell membrane is a protective layer that acts as a barrier on the cell’s surface. 
  • It divides the contents of the cell from its surroundings. The cell membrane also regulates the flow of materials into and out of the cell. 
  • There is fluid inside the cell. The cytoplasm is the name given to this fluid and practically all of its constituents.

Organelles

  • Organelles are small structures found inside cells that carry out a variety of functions. 
  • Organelles are found in a variety of cell types. Membranes envelop the majority of organelles. The algal cell, for example, possesses membrane-bound organelles. Membranes envelop the majority of organelles. Membranes envelop the majority of organelles. 
  • In the cytoplasm, certain organelles float. Membranes and other organelles are connected to other organelles.

Genetic Material

  • At some time in their life, all cells have DNA (deoxyribonucleic acid). The genetic substance is DNA. 
  • It contains the instructions for creating new cells and organisms. DNA directs a cell’s actions and is handed down from parent cells to future cells.
  • DNA does not float around in cells such as plant and animal cells. The nucleus is an organelle that serves as a DNA repository or storage region. Bacterial cells, for example, do not have a nucleus.

Species of Cells

  • Cell membranes, organelles, cytoplasm, and DNA are found in all cells. Regardless, there are two types of cells. 
  • Prokaryotic cells are those that lack a nucleus. The nucleus distinguishes eukaryotic cells from prokaryotic cells. Prokaryotic cells include bacteria and archaea types of cells. 
  • Other prokaryotic and eukaryotic cells may resemble the cells in appearance.

Prokaryotes

  • Prokaryotes include bacteria and archaea. Single-celled creatures without a nucleus are known as prokaryotes. 
  • Even though prokaryotes lack a nucleus, they do have DNA. A prokaryote’s DNA is a lengthy, circular molecule. It resembles a twisted rubber band in shape. 
  • Prokaryotes lack membrane-bound organelles as well. They do, however, have ribosomes. Ribosomes are small; spherical organelles made up of protein and other substances.
  • Prokaryotic cells have thick, weblike cell walls as well.

Eukaryotes

  • The largest cells are eukaryotic cells. Even while most eukaryotic cells are still tiny, they are around ten times larger than prokaryotic cells. Eukaryotic cells, unlike bacteria and archaea, have a nucleus.
  • The DNA of the cell is kept in the nucleus. Other membrane-bound organelles exist in eukaryotic cells as well. Each organelle performs a distinct function in the cell.
  • Eukaryotic cells are found in all living entities that are not bacteria or archaea. 
  • Organisms that are made up of eukaryotic cells are known as eukaryotes. Single-celled eukaryotes include yeasts and amoebas. Plants and animals are eukaryotes or multicellular organisms.
  • Cells use their outside surface to take in nourishment and expel waste. As a cell grows in size, it requires more food and generates more waste.
  • As a result, more materials pass through the outside surface of the device. As the cell’s volume grows, so does its surface area. However, the volume of the cell develops quicker than its surface area. 
  • A cell’s surface area will become too small to take in enough nutrients or pump out enough wastes if it becomes too large.

Conclusion

Hope you now have a clear understanding of cells. Multiple Choice Questions (MCQs) play a very important role in revising the concepts. It helps students to practice and have a grip over the test questions. It also helps in measuring the student’s capacity in understanding concepts. 

After finishing every subtopic of the cell structure, it will boost your confidence and give you a sense of exam questions by improving your testing skills. Practice the questions of Cell The Unit of Life NEET MCQ to test your knowledge.

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