A collection of blog posts connected to my teaching on biomedical sciences and biochemistry degrees. All views and opinions expressed are my own, and not connected to my past, present or future employers.
In the video, I examine the history and functions of mitochondria. I start with Rudolf Albert von Kölliker's initial description in 1852 and subsequent naming by Carl Benda in 1898. I explain how these organelles are more than just static power plants of the cell. I highlight the dynamic nature of mitochondria, their ability to form networks, and their crucial roles in energy production and cellular metabolism.
In this video, I explore the organisation within the nucleus, emphasising that it is structured rather than chaotic. I explain how Spectral Karyotyping reveals that chromosomes occupy specific territories and highlights the structured nature of chromatin, which can be either open or closed and influences transcription and replication. I also examine the nucleolus, describing its crucial role in producing ribosomes and signal recognition particles (SRP) and outlining the complex processes of ribosomal RNA (rRNA) synthesis and assembly.
In the video, I explore the structure and function of the nuclear envelope and its critical role in maintaining the environment of the nucleus. I explain how the nuclear pore facilitates gated transport, allowing materials to move between the nucleus and the cytosol. Highlighting its complexity, I described how the nuclear pore is composed of numerous nucleoporins, forming a cylindrical channel that selectively regulates the passage of molecules based on their size, with larger molecules requiring active transport mechanisms.
The video explains that the nuclear envelope, consisting of inner and outer membranes, protects DNA from mechanical stress and regulates the nucleus's internal environment, essential for proper mRNA processing. I highlight the role of the nuclear lamina in safeguarding DNA. I describe the challenges posed by the nuclear envelope, such as the need to disassemble during cell division and manage material exchange via nuclear pores. Overall, the nuclear envelope is crucial for maintaining nuclear integrity and function despite its associated complexities.
The video explains the cell nucleus, highlighting its roughly spherical shape and double membrane structure, which includes an inner and outer membrane with a perinuclear space. It describes the nucleus's contents, such as chromatin for gene transcription and mRNA splicing, and features like nuclear pores for transport and the nuclear lamina for structural support and various cellular functions. Additionally, I note that the outer nuclear membrane and perinuclear space are continuous with the endoplasmic reticulum.
Endosomes are cellular compartments that sort and traffic proteins from the Golgi apparatus and the plasma membrane. They are formed by vesicle fusion and are divided into three types
Early endosomes - receive proteins and decide their next destination
Recycling endosomes - return proteins to the plasma membrane either immediately (constitutive pathway) or based on signals (regulated pathway).
Late endosomes - forward proteins to lysosomes or back to the Golgi.
The endosomal system relies on specific signals on proteins to direct their correct routing, ensuring efficient cellular function.
Blog Bonus: Free step-by-step guide explaining the calculation - download.
The video is a response to two questions I was asked:
How do I calculate the size of a protein on an SDS-PAGE gel?
Can the DNA method be used for proteins?
In the video and the free step-by-step guide explaining the calculation, I go over the necessary steps for working out the size of a protein band on a gel, explain the Retention Factor (Rf value) and how to use it, and outline the method's limitations.
Feel free to leave any questions or comments below. If you need further clarification on any step or have suggestions for future topics, let me know!