Difference Between Molds and Yeasts

Hailing from the same family of Eukaryotes and the kingdom Fungus, yeast and mold are microbes which have many properties in common, along with having uncountable significant differences.

On one hand, both of them, being Eukaryotes, have well-developed nuclei and other cell parts segregated for carrying out distinct functionalities. On the other hand, both of them differ from each other in how they look, how they function and how they reproduce. 

Yeasts are basically unicellular organisms, possess a thread-like appearance, are white or colourless, do not have true hyphae and reproduce asexually. Conversely, molds are multicellular, have a round shape, come in various colours and can exhibit both sexual or asexual reproduction. 

With this in mind, let’s revise a few concepts with a pop quiz. 

Pop Quiz 1

1. Which of these are Unicellular and have a Filamentous Appearance?

  1. Yeasts. 

  2. Molds. 

  3. None of the above. 

Both yeast and mold are used by us in many ways. Yeasts are commonplace fungi, found in fruits, vegetables and other food products. There are around 1500 different types of yeasts and are extensively used in food and beverages industry.

For instance, these are used for making bread, baking commodities, additives and alcohol. Though molds are also used for making cheese, they are sometimes harmful to humans causing respiratory infections. They are most naturally found growing in dark and humid places.

Definition of Yeasts

Yeasts, as said earlier, are single-cell micro-organisms, that reproduce via a process called budding or binary fission. In this process, the main nucleus splits into two parts, and the daughter cell lives temporarily inside another cell called the bud cell. In due time, when the bud cell is fully grown, it separates off from the parent cell, continuing to live on as another single cell.

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They usually derive nutrition from organic hosts and possess the ability to break down carbohydrates. This is why they are used substantially in fermentation processes.

While fermenting, they produce energy aerobically or anaerobically in the form of alcohol and carbon dioxide. This is the reason yeast spoilage is characterized by a particularly sour smell in food products. 

Some common strains of yeast include Saccharomyces cerevisiae, also known as the baker’s yeast, and Candida albicans, which is a significant pathogen for humans and cause asthma and Crohn’s disease.

Definition of Molds

Molds are eukaryotes having many cells, and they produce either via mitosis, asexually or through meiosis, sexually. Molds usually feature filamentous hyphae, unlike yeasts, and have spores which sway in the air.

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Excreting hydrolytic fluids from their hyphal tips, molds help by decomposing much of natural organic wastage, which includes cellulose, starch and lignin. In addition, they are also used in making antibiotics like Penicillin and Lovastatin and by food manufacturers for making cheese, rennet and salami.

Penicillium, Rhizopus and Aspergillus are some of the most popular varieties of molds.

Pop Quiz 2

1. Penicillium is a type of _____.

    a. Mold

    b. Yeast

    c. None of the above

Now that we are thorough with the definitions for yeast and mold, let’s dive more into the difference between yeast and mold. 

Significant Differences Between Yeast and Mold

Basis

Yeasts

Molds

Definition

Yeasts are unicellular eukaryotes, usually colourless, from the kingdom Fungus.

Molds have several cells and are also colourful.

Appearance

Thready and filamentous.

Round and oval.

Cell Structure

Well-defined nucleus but unicellular.

Well-defined nucleus but multicellular.

Presence of hyphae

Do not have true hyphae. 

Possess hyphae or microscopic filaments. 

Types

Have over 1500 types of yeasts.

More than 400,000 types of molds.

Presence of spores

Non-sporous.

Have spores which sway in the air.

Colour and feel

Smooth and colourless. 

Woolly and colourful.

Reproduction

Asexual, by budding or binary fission.

Asexually via mitosis or sexually via meiosis. 

Condition of growth

Yeasts can grow in both aerobic or anaerobic conditions. 

Molds grow only in aerobic condition. 

Uses

Used in making baking products, alcohol and additives.

Used in making cheese and essential antibiotics.

Pathogen for humans

Candida albicans contribute to Crohn’s disease and asthma.

May cause allergies and other respiratory infections.

To learn more about yeast mold, refer to our collection of free study material and reference notes. You can also install the Vedantu app to join live classes on Biology and other subjects. 


FAQ (Frequently Asked Questions)

1. What is the Key Difference Between Yeast and Mold?

Ans. Yeasts are unicellular micro-organisms, have a thread-like appearance and are colourless. Whereas, molds are multicellular, round and come in different colours.

2. How to Kill Yeasts and Molds?

Ans. Yeasts and molds usually die when subjected to extreme temperatures, in the range of 140 to 160-degree Fahrenheit. 

3. What are the Most Favourable Conditions for the Growth of such Microbes?

Ans. Low moisture and optimum water activity are the two most favourable conditions for the growth of yeasts and molds.