Chapter 4, Problem 1CT

Summary Introduction

To write:

An essay describing the role that each organelle plays in a cell.

Concept introduction:

“Organelles” are specific structures, which have particular functions inside the cell. They are bounded by outer compartments or boundaries, which separates the functioning of each organelle inside the cell. The functions of organelles include energy generation, production of ATP (adenosine triphosphate), and metabolic reactions inside the cell.

Explanation of Solution

There are various organelles inside a cell like endoplasmic reticulum, mitochondria, nucleus, ribosomes, Golgi apparatus, chloroplasts, cytoskeletal filaments, lysosomes, peroxisomes and vacuoles. The description of each of the following organelle is given below:

(1) Endoplasmic reticulum: It is involved in protein post-translational modification with enzymes.  It is like a road in a city, which allows the movement of proteins inside the city cell.

(2) Mitochondria: It is a double membrane structure, which is involved in the generation of energy and ATP in the cell. It is a power company in a cell.

(3) Nucleus: It is a dense component, which contains the genetic material DNA (deoxyribose nucleic acid). The process of transcription and synthesis of mRNA takes place inside this organelle. It is like a city hall.

(4) Ribosomes: They are protein subunits, which synthesize proteins from amino-acids in the form of a polypeptide chain. It is like a construction company.

(5) Golgi apparatus: It is involved in targeting of a protein to specific organs like mitochondria, peroxisomes and cell membrane.

(6) Chloroplasts: They are green plastids in plants which contain chlorophyll. They are used for performing the function of photosynthesis inside the cell. It is like a solar plant factory inside a cell.

(7) Cytoskeletal filaments: There are different types of filaments like microtubules, intermediate filaments and actin filaments. They help in the process of cell division during mitosis and meiosis.

(8) Lysosomes: These organelles are involved in degradation of dead proteins and foreign bodies inside the cell. It is like a food processing plant.

(9) Peroxisomes: They contain enzymes involved in the degradation and detoxification of fats and alcohols.

(10) Cilia and flagella: They are present on cells of small unicellular prokaryotic organisms like bacteria, protists and diatoms.

(11) Cell wall: It is present in plants, which protects the organelles from the surrounding environment inside the cell.

(12) Vacuoles: They contain food and nutrients in various cells like animal, plant and unicellular prokaryotes. It is like a warehouse in a cell.

Conclusion

Various organelles inside a cell have diverse functions like post-translational modification of proteins, energy generation, ATP production and metabolic reactions inside the cell.

Summary Introduction

To explain:

The situation of a city if the organelle stopped working.

Concept introduction:

The cell is an essential living component, which contains a number of organelles for its essential functioning. These include functioning of enzymes for metabolic reactions inside the cell, generation of energy, degradation of foreign particles, production of metabolites and protection of organelles from the external environment.

Explanation of Solution

The functioning of a city includes buildings, shopping malls, eating restaurants and showrooms which are similar to the working of a cell with organelles as described below:

(1) The plasma membrane is like a city wall and if it stops functioning, then it will destroy the functioning of a cell.

(2) Mitochondria are a powerhouse of a cell and energy process generation will be inhibited if it stops functioning inside the cell.

(3) Ribosomes: Synthesis of protein polypeptides will be inhibited if it stops functioning.

(4) Rough endoplasmic reticulum: The post-translational modification and transport of proteins will be inhibited.

(5) Nucleus contains DNA and the process of transcription will be inhibited if it stops working.

Conclusion

The working of organelles in a cell is similar to the working of buildings in a city. The inhibition of functioning of a cell will inhibit the metabolic reactions inside the cell.