Key difference - mitochondria vs. plastids

Mitochondria and plastids are two vital organelles found in eukaryotic cells . Mitochondria and plastids are membranous organelles with fluid-filled sacs in them. The main difference between mitochondria and plastids is that mitochondria participate in the cell's energy production through cellular respiration , while plastids have various functions such as food storage and photosynthesis .  

Key areas covered

1. What are mitochondria - definition, properties, functions 2. What are plastids - definition, properties, functions 3. What are the similarities between mitochondria and plastids - overview of common characteristics 4. What is the difference between mitochondria and plastids - comparison of Main differences

Key Terms: Cell Respiration, Chloroplasts, Chromoplasts, Cristae, Differences, Inner Mitochondrial Membrane, Leukoplasts, Mitochondria, Plastids, Similarities, Thylakoids, White Plastids

What are Mitochondria?

Mitochondria are membranous organelles that are found in all eukaryotic cells. The metabolic energy in the form of ATP is produced in the mitochondria in a process called cell respiration. Mitochondria contain their own DNA within the organelle. The number of mitochondria present in a particular cell depends on the cell type, tissue and organism. The mitochondrial matrix is ​​separated from the contents in the cytoplasm by inner and outer mitochondrial membranes. The inner mitochondrial membrane forms folds in the matrix called the cristae. Cristae increase the surface area of ​​the inner membrane. The citric acid cycle, the second step in cellular respiration, takes place in the matrix of the mitochondria. ATP is created during oxidative phosphorylation, which takes place on the inner membrane of the mitochondria. A mitochondrion is shown in Figure 1 .

Figure 1: A mitochondrion

What are plastids

Plastids are membranous organelles that are only found in plant cells. Three types of plastids can be identified based on the type of pigment present in each plastid. They are leucoplasts, chromoplasts, and chloroplasts . Leucoplasts, or white plastids, are found in the roots of sweet potatoes, inner leaves of cabbage, and stems of potatoes. They lack any kind of pigment. Leukoplasts serve as food stores in the form of starch. Chromoplasts are colored plastids found in the petals, fruits, and roots of some plants. They contain carotenoid pigments with different colors from red, orange to green. Chloroplasts are the green coloring agents found in the stems and leaves of plants. They contain the green pigment chlorophyll , which is responsible for photosynthesis. The light energy of sunlight is captured by chlorophyll and simple sugars are made from carbon dioxide and water. Chloroplast is made up of an inner and outer membrane that separates the chloroplast's stroma from the cytoplasm. It also includes thylakoids , which are disk-like structures that make up grana. Leukoplasts in a plant cell are shown in Figure 2.

Figure 2: Leucoplast®

Similarities Between Mitochondria and Plastids

• Both mitochondria and plastids are double membrane organelles found in eukaryotic cells.

• Both consist of fluid-filled sacs within the organelles that maintain a unique environment within the organelles.

Difference Between Mitochondria and Plastids

definition

Mitochondria: Mitochondria are a type of organelle in which the biochemical processes of breathing and energy production take place.

Plastids: Plastids are double membrane organelles found only in plants and algae, where the production and storage of chemicals takes place in the cell.

Pigments

Mitochondria: Mitochondria lack pigment.

Plastids: Many plastids contain pigments.

Appear

Mitochondria: Mitochondria are found in both plant and animal cells.

Plastids: Plastids are only found in plant cells and algae.

Inner membrane

Mitochondria: The inner mitochondrial membrane contains folds known as the cristae.

Plastids: No folds are found in the inner membrane of plastids.

Chambers

Mitochondria: There are completely separate chambers in the matrix.

Plastids: plasmids lack completely separate chambers within the matrix.

function

Mitochondria: Mitochondria are mainly involved in the generation of energy through cell respiration.

Plastids: Plastids are mainly involved in the production and storage of food in the cell.

Types

Mitochondria: The mitochondrial structure can vary depending on the needs of the cell.

Plastids: leukoplasts, chromoplasts, and chloroplasts are the three types of plastids.

Organelle DNA

Mitochondria: Mitochondria have their own DNA within the organelle.

Plastids: only chloroplasts have their own DNA.

diploma

Mitochondria and plastids are two types of membranous organelles found in eukaryotes. Plastids are only found in plants and algae. Mitochondria are the cell's powerhouse that produces metabolic energy in a process called cell respiration. Plastids are mainly involved in the production and storage of food in the cell. Chloroplasts are plastids that photosynthesize. The main difference between mitochondria and plastids is their function.

Reference:

1. Cooper, Geoffrey M. "Mitochondria". The cell: a molecular approach. 2nd Edition. US National Library of Medicine, January 1, 1970. Web. Available here . June 23, 2017. 2nd Battista, Jeremy. "Plastids: Definition, Structure, Types, and Functions." Study.com. Np, nd web. Available here. 23rd June 2017.

Image courtesy:

1. "0315 Mitochondrion new" By OpenStax - (CC BY 4.0) via Commons Wikimedia 2. "010-Sol-tub-40xHF-Tissue" By Dr. phil.nat Thomas Geier, Department of Botany at the Geisenheim Research Institute. - Preparation and photo by Thomas Geier, upload by Martin Bahmann (CC BY-SA 3.0) via Commons Wikimedia