Growth Factors: Videos & Practice Problems

Growth factors are essential biological substances that promote cellular growth, particularly in prestigious organisms with complex nutritional needs. These organisms require multiple growth factors from their environment. When a growth factor binds to its specific receptor on a cell membrane, it initiates a cascade of intracellular events leading to cell division and growth. Understanding the role of growth factors is crucial for comprehending cellular processes and the nutritional requirements of various microorganisms.

Growth Factors

In this video, we're going to begin our lesson on growth factors. Some microbes require growth factors from the environment that they cannot synthesize on their own. Growth factors can be defined as biological substances that promote cellular growth. Prestigious organisms are organisms that have complex nutritional requirements. In other words, prestigious organisms require many growth factors. If we take a look at our image down below, notice on the left-hand side, these little yellow circles that you see represent growth factors that a cell would obtain from its environment. The growth factor can bind to a specific growth factor receptor found in the membrane of the cell. When the growth factor binds to the growth factor receptor, it triggers a cascade of events inside the cell that ultimately leads to the cellular response. That cellular response is cell division, allowing the cell to divide and grow. Thus, the name "growth factors" leading to cellular growth. Again, a prestigious organism is an organism that has complex nutritional requirements and requires many different growth factors. Notice here we're showing you a prestigious organism saying, "I need tons of these growth factors." This concludes our brief introduction to growth factors. We'll be able to get some practice applying these concepts moving forward. I'll see you all in our next video.

Small organic molecules that must be provided to bacteria for them to grow are called:

• A. Minerals.
• B. Growth factors.
• C. Water.
• D. Vitamins.

Answer: (B)

Some microorganisms are difficult to culture because they require very specific growth factors to flourish. For example, Neisseria gonorrhoeae is difficult to culture because it requires blood, hemoglobin, many amino acids and many vitamins to grow. Neisseria gonorrhoeae, is an example of what type of organism?

• A. A halophilic organism.
• B. A photoheterotrophic organism.
• C. A fastidious organism.
• D. A facultative anaerobic organism.

Answer: (C)

Here’s what students ask on this topic:

What are growth factors in microbiology?

Growth factors in microbiology are biological substances that promote cellular growth and division. They are essential for certain microbes, particularly those with complex nutritional needs, known as fastidious organisms. These organisms cannot synthesize the necessary growth factors on their own and must obtain them from their environment. When a growth factor binds to its specific receptor on a cell membrane, it triggers a cascade of intracellular events that lead to cell division and growth. Understanding growth factors is crucial for comprehending the nutritional requirements and cellular processes of various microorganisms.

Why do fastidious organisms require many growth factors?

Fastidious organisms require many growth factors because they have complex nutritional requirements that they cannot meet on their own. These organisms lack the metabolic pathways needed to synthesize certain essential compounds, so they must obtain these growth factors from their environment. The growth factors bind to specific receptors on the cell membrane, initiating a series of intracellular events that promote cellular growth and division. This dependency on external growth factors makes fastidious organisms more challenging to cultivate in laboratory settings.

How do growth factors promote cellular growth?

Growth factors promote cellular growth by binding to specific receptors on the cell membrane. This binding triggers a cascade of intracellular signaling events that ultimately lead to cell division and growth. The process begins when the growth factor binds to its receptor, activating a series of proteins and enzymes inside the cell. These activated molecules then transmit signals to the cell's nucleus, where they influence gene expression and other cellular activities necessary for growth and division. This mechanism ensures that cells grow and divide in response to the presence of appropriate growth factors.

What is the role of growth factor receptors in cellular growth?

Growth factor receptors play a crucial role in cellular growth by serving as the binding sites for growth factors on the cell membrane. When a growth factor binds to its specific receptor, it activates the receptor and initiates a cascade of intracellular signaling events. These events lead to the activation of various proteins and enzymes that transmit signals to the cell's nucleus. This signaling ultimately influences gene expression and other cellular activities necessary for cell division and growth. Without these receptors, growth factors would not be able to exert their effects on the cell.

What are some examples of growth factors required by fastidious organisms?

Fastidious organisms often require a variety of growth factors to thrive. Some common examples include vitamins, amino acids, purines, and pyrimidines. For instance, Haemophilus influenzae requires hemin (a source of iron) and NAD (nicotinamide adenine dinucleotide) for growth. Another example is Lactobacillus species, which may require specific amino acids and vitamins such as niacin and riboflavin. These growth factors are essential for the metabolic processes and cellular functions of fastidious organisms, making them crucial for their cultivation in laboratory settings.