Mitochondria and chloroplast

MITOCHONDRIA :

Mitochondria is a double membrane-bound organelle found in most eukaryotic species. The “Powerhouse of the Cell” is how they’re known. They function as the cell’s “digestive system” and are situated in the cytoplasm.

They play an important role in the breakdown of nutrients and the synthesis of energy-dense molecules for the cell. The mitochondria are home to many of the metabolic events that occur during cellular respiration. The terms “mitochondrion” stem from the Greek words “mitos” and “chondrion,” which respectively mean “thread” and “granules-like.” Richard Altmann, a German pathologist, was the first to describe it in 1890.

Mitochondria’s Structure:

The mitochondrion is a double-membraned, rod-shaped structure present in both plant and animal cells, with a diameter of 0.5 to 1.0 micrometre. The structure is made up of an outside membrane, an inner membrane, and a gel-like material termed the matrix. The outer and inner membranes are divided by the intermembrane gap, which is made up of proteins and phospholipid layers.

Mitochondrial Matrix 

A viscous fluid comprising an enzyme and protein mixture makes up the mitochondrial matrix. Also present are ribosomes, inorganic ions, mitochondrial DNA, nucleotide cofactors, and organic compounds. The matrix enzymes are essential for the creation of ATP molecules.

Cristae

The inner membrane of mitochondria has a complicated structure. It features multiple folds that form a layered structure called cristae, which helps to increase the organelle’s surface area. The cristae and proteins of the inner membrane aid in the synthesis of ATP molecules. The inner membrane allows just oxygen and ATP molecules to get through. Several chemical reactions take place within mitochondria’s inner membrane.

Functions of Mitochondria:

Mitochondria’s principal job is to generate energy through the oxidative phosphorylation process. It’s also involved in the following procedures:

1. regulates the metabolic activity of the cell; 2. encourages the formation of new cells and cell multiplication
2. Assists in ammonia detoxification in liver cells.
3. Plays an important role in apoptosis (programmed cell death).
4. Responsible for the production of hormones such as testosterone and oestrogen, as well as some blood components.
5. Assists in maintaining a sufficient calcium ion concentration within the compartments of the cell.

Cellular differentiation, cell signalling, cell senescence, cell cycle control, and cell proliferation are all influenced by this protein.

CHLOROPLAST :

All green plants and algae include chloroplasts. They’re the ones who make the plant’s food. These are found in plant leaves’ mesophyll cells. They have a lot of chlorophyll, which absorbs a lot of light. This cell organelle does not exist in animal cells.

Chloroplasts are semiautonomous since they have their own extra-nuclear DNA, similar to mitochondria. Proteins and lipids are also produced, which are essential for the development of the chloroplast membrane.

Structure of the Chloroplast:

Chloroplasts are found in all higher plants. It is situated within the mesophyll of the plant cell and is oval or biconvex. Chloroplasts typically have a diameter of 4-6 m and a thickness of 1-3 m. They are organelles having outer, inner, and intramembranous space that are double-membrane. Within a chloroplast, the grana and stroma are two separate areas.

Stacks of disc-shaped structures called thylakoids or lamellae make up grana. The chloroplast grana is the functional unit of chloroplasts and is made up of chlorophyll pigments.

Stroma is a homogeneous matrix that contains grana and is similar to cytoplasm cells in that it contains all organelles. Enzymes, DNA, ribosomes, and other components are also found in Stroma. The stacks of thylakoid sacs or grana are connected by stromal lamellae.

The following components make up the chloroplast structure:

Inner and exterior lipid bilayer membranes make up the envelope membrane. The inner membrane separates the stroma from the intramembranous region.

The intermembrane space is the space that exists between the inner and outer membranes.

The Thylakoid System is a type of thylakoid cell that is (Lamellae)

In the stroma, the system is adrift. It is made up of thylakoids or lamellae, which are membrane sacs. The thylakoid membranes contain chlorophyll pigments, which are green in colour. It’s a visual illustration of the light-dependent reactions in the photosynthesis process. Thylakoids are stacked in grana, with each granum containing between 10 and 20 thylakoids.

Stroma

It’s a colourless, alkaline, aqueous, protein-rich fluid found within the chloroplast’s inner membrane, which surrounds the grana.

Grana

In plastids, grana is a stack of lamellae. The areas where light energy is transformed into chemical energy are known as photovoltaic cells.

Chlorophyll

It’s a photosynthetic pigment that helps in photosynthesis.

Functions of the Chloroplast

• The chloroplast’s primary role is to synthesise food by absorbing light energy and converting it into chemical energy. • The chloroplast contains a structure called chlorophyll, which traps solar energy and is used for food synthesis in all green plants.
• When water is photolyzed, NADPH and molecular oxygen are produced (O2). • ATP (adenosine triphosphate) is produced by photosynthesis, and carbon dioxide (CO2) from the air is used to produce carbon and sugar during the Calvin Cycle, or dark reaction of photosynthesis.

Differences between mitochondria and chloroplast :

Conclusion :

Finally, we learnt about mitochondria: what they are, how they work, and how they are structured. We also learned about chloroplast structure and function. There is also a discussion of the differences between these semi-autonomous organelles.