Yeast is a eukaryotic unicellular fungi species able to respire in both aerobic and anaerobic manner. Let us see if yeast has mitochondria or not.
Yeast has mitochondria in its unicellular body. The mitochondria is the most important membrane bound cell organelle present in eukaryotic cells, which is primarily associated with the production of the energy molecule (ATP) within the cellular structure of yeast.
The most important step of respiration, that is, oxidative phosphorylation and electron chain transport occur in mitochondria, which aid the generation of energy in the cell.
Do all yeast have mitochondria?
Mitochondria, the powerhouse of the cell, is an essential component in the respiration of yeast. Let us now see if all yeast have mitochondria or not.
All yeast have mitochondria within its body because without mitochondria, no yeast species can produce the energy molecule (ATP) within its body. If there is an absence of energy, then they cannot survive. Hence all yeast species have mitochondria in their body.
How many mitochondria are there in a yeast cell?
As mitochondria is the most important organelle known for power supply in yeast cells, let us now see the number of mitochondria present in a cell.
According to studies, when yeast grows in ethanol, it contains 20-30 small mitochondria but when it grows in glucose medium, it contains 3-4 large mitochondria within its cell. The number of mitochondria present in a yeast cell widely varies according to its culture, medium and life stage.
Counting the number of mitochondria within a yeast cell is a very tricky process because just like some other organelle mitochondria do not possess a distinct structure. In most of the time, the mitochondria are reticular which makes it difficult to count.
Why do yeast have mitochondria?
Just like any other eukaryotic cell, yeasts also have mitochondria. Let us see why it has mitochondria within its body.
Yeast must have mitochondria within its structure so that they can break the food intake (glucose) and produce energy in mitochondria. The mitochondria is the only site where the oxidative phosphorylation takes place and ATP molecules are formed.
In addition, mitochondria in yeast cells also facilitates several metabolic reactions and also perform cell signalling mechanisms.
Mitochondria in yeast cell from Wikimedia commons
What is the function of the mitochondria in yeast?
Mitochondria is one of the most essential membrane bound organelle to perform several functions within yeast.
Some most important functions of the mitochondria in yeast cells are-
- Protein encoding
- Protein synthesis
- Oxidative phosphorylation
- Metabolite transport
- Amino acid metabolism
- Lipid biosynthesis
- Iron sulfur cluster biogenesis
- Heme biosynthesis
- Cell signalling
Let us have a closer look at the functions of mitochondria in yeast.
According to studies, mitochondria is an endosymbiont, having an independent genome in its own structure. The mitochondrial genome in yeast carries specific protein encoding genes. In between them, the role of most of the product is still unknown.
The protein that the mt genome encods for, are also synthesized in the mitochondria. Mt genome codes for 1205 unique proteins. Among them, 15% are associated with energy metabolism.
There are 8 defined proteins synthesized by mitochondria. Among them 7 proteins are associated with the oxidative phosphorylation and 1 protein serves as ribosomal subunit.
The oxidative phosphorylation and electron transport chain occur in mitochondria through which energy molecules are produced.
In the presence of oxygen, yeast undergoes aerobic respiration and in the absence of oxygen undergoes anaerobic respiration. In both cases, it produces ATP molecules through oxidative phosphorylation.
Besides protein synthesis, mitochondria also plays a crucial role in metabolite transportation process between the cytosol and matrix. Through the mitochondrial membrane, various metabolites such as FAD, ADP +Pi, NAD+ are transported according to their need.
Amino acid metabolism
Mitochondria is involved in amino acid metabolism pathways predominantly with the pyruvate family amino acid metabolism. Alanine along with leucine, isoleucine and valine (branch chain amino acids/ BCAA) metabolism pathways takes place in mitochondria excluding the final step (which occurs in cytoplasm).
Mitochondria is also involved in lipid biosynthesis mechanisms. Phospholipids, cardiolipin, phosphatidylglycerol, phosphatidylethanolamine and several lipid molecules or fatty acids are synthesized in mitochondria. The reactions are catalyzed by acryl carrier protein (ACP) dependent manner.
Iron sulfur cluster biogenesis
Mitochondria plays important role in biogenesis of iron sulfur cluster (ISCs) which are very important for protein functioning. Mitochondria is also involved in the assembly of cytoplasmic and nuclear Fe/S proteins.
Heme or haem is the iron component of hemoglobin, which is mostly synthesized in mitochondria of yeast. The heme synthesis starts in mitochondria because the precursors for that reaction succinyl-CoA is found in mitochondrial region.
After several intermediate steps, Ala is transported to cytoplasm where further synthesis occurs.
Mitochondria plays a major role in cell signalling also. The mitochondria serves as an initiator and transducer of various cell signalling mechanisms. It enables the upregulation of ATP synthesis as a response to the growth-promoting stimuli. It is the platform where protein interactions takes place.
Do yeast cells lack mitochondria?
As mitochondria is the powerhouse of the cell, it is important to know whether yeast cells lack mitochondria or not.
Yeast cells do not lack mitochondria in their body under any condition. They always have mitochondria within their cellular structure as mitochondria is the most important site of energy generation.
Can yeast survive without mitochondria?
Yeast have the capability to respire in both aerobic and anaerobic manner. So let us know if yeast can survive without mitochondria or not.
Yeast cannot survive without mitochondria because it is the primary site of ATP generation. The oxidative phosphorylation only occurs within mitochondria. Without mitochondria they are unable to produce energy which in turn, results in a failure of cellular activity.
As a whole we can say that all yeast have mitochondria within their body. As it is the primary site of energy production of cells, without mitochondria yeast cells cannot survive. Hope the article titled “does yeast have mitochondria or not” is helpful to you.