New Video Posted: The History, Structure and Functions of Mitochondria

This video - The History, Structure and Functions of Mitochondria is the first of three on the mitochondria. The other two videos are:

• The History, Structure and Functions of Mitochondria
• Understanding the Function of Mitochondria | Dr. Peter Mitchell's Nobel Prize-Winning Work
• Understanding Mitochondrial DNA: Structure, Function, and Disease

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.

If you would like to say thanks for the video, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

New Video Posted: Exploring Nuclear Organisation: Chromatin, Chromosomes, and the Nucleolus

This video - Exploring Nuclear Organisation: Chromatin, Chromosomes, and the Nucleolus - is the final video in a series of four videos on the nucleus.

The other three are:

• Understanding the Nucleus: Structure and Function | Cell Biology Explained 
• Understanding the Nuclear Envelope: Protecting and Regulating the Nucleus
• Understanding the Nuclear Pore: Gatekeeper of the Nucleus

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.

If you would like to say thanks for the video, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

New Video Posted: Understanding the Nuclear Pore: Gatekeeper of the Nucleus

This video - Understanding the Nuclear Pore: Gatekeeper of the Nucleus - is the third in four videos on the nucleus.

The other three are:

• Understanding the Nucleus: Structure and Function | Cell Biology Explained 
• Understanding the Nuclear Envelope: Protecting and Regulating the Nucleus
• Exploring Nuclear Organisation: Chromatin, Chromosomes, and the Nucleolus

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.

If you would like to say thanks for the video, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

New Video Posted: Understanding the Nuclear Envelope: Protecting and Regulating the Nucleus

This video - Understanding the Nuclear Envelope: Protecting and Regulating the Nucleus - is the second of four videos on the nucleus.

The other three are:

• Understanding the Nucleus: Structure and Function | Cell Biology Explained 
• Understanding the Nuclear Pore: Gatekeeper of the Nucleus
• Exploring Nuclear Organisation: Chromatin, Chromosomes, and the Nucleolus

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.

If you would like to say thanks for the video, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

New Video Posted: Understanding the Nucleus: Structure and Function | Cell Biology Explained

This video - Understanding the Nucleus: Structure and Function | Cell Biology Explained - is the first of four videos on the nucleus. The other three are:

• Understanding the Nuclear Envelope: Protecting and Regulating the Nucleus
• Understanding the Nuclear Pore: Gatekeeper of the Nucleus
• Exploring Nuclear Organisation: Chromatin, Chromosomes, and the Nucleolus

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.

If you would like to say thanks for the video, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

New Video Posted: Understanding Endosomes: The Cell's Sorting House | Quick Science Explanation

In my video on endosomes - Understanding Endosomes: The Cell's Sorting House | Quick Science Explanation - I look at the role of the endosomal system in cells.

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.

If you would like to say thanks for the video, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

New Video Posted: How to Calculate Protein Size on an SDS-PAGE Gel: A Step-by-Step Guide

I have just posted a video on how to determine the size of a protein on an SDS PAGE gel - How to Determine Protein Size on an SDS-PAGE Gel | Step-by-Step Tutorial.

Blog Bonus: Free step-by-step guide explaining the calculation - download.

The video is a response to two questions I was asked:

1. How do I calculate the size of a protein on an SDS-PAGE gel?
2. 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!

If you would like to say thanks for the video, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free step-by-step guide explaining the calculation - download.

New Video Posted: The Golgi Apparatus and Protein Processing

In the video - The Golgi Apparatus and Protein Processing - I look at the role of the Golgi in processing proteins.

The Golgi apparatus (possibly my favourite organelle) was discovered by Camillo Golgi in 1898 and confirmed in the 1950s.

Structurally, the Golgi resembles a stack of plates, and it has three distinct regions: the cis face (closest to the ER), the medial Golgi, and the trans face (furthest from the ER). The primary function of the Golgi is to process and sort proteins received from the ER, directing them to lysosomes, endosomes, or the plasma membrane.

There are two main theories for how the Golgi operates:

• Vesicle Transport Model - proteins move to the machinery.
• Cisternal Maturation Model - machinery moves to the proteins.

Evidence, such as vesicular tubular clusters and vesicles' size constraints, supports the Cisternal Maturation Model. In this model, the Golgi's cisternae mature over time, recycling enzymes via COPI vesicles.

Upon leaving the Golgi, proteins can enter one of two pathways:

• Constitutive secretory pathway - direct to the cell surface)
• Regulated secretory pathway - via secretory vesicles and requires a signal for the vesicles to traffic further.

If you would like to say thanks for the video, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

New Video Posted: Understanding the Endoplasmic Reticulum: Rough vs Smooth ER and Protein Import

In the video Understanding the Endoplasmic Reticulum: Rough vs Smooth ER and Protein Import, I look at the smooth and rough Endoplasmic Reticulum (ER), and discuss how proteins are targeted to and imported into the ER.

The ER is a vital cellular structure with two types: rough ER (RER) and smooth ER (SER). The RER is covered in ribosomes and is essential for protein production. Proteins are synthesised and threaded into the ER lumen via a process involving signal recognition particles (SRP) and the Sec61 complex. 

Membrane-spanning proteins are produced at the RER by using various signal sequences that direct their insertion into or through the membrane. The ER also plays a role in N-linked glycosylation, adding N-linked oligosaccharides to proteins and in quality control, ensuring proteins are correctly folded and functional. 

In contrast, the SER lacks ribosomes, synthesises lipids, and forms vesicles for transporting proteins and lipids to the Golgi apparatus.

If you would like to say thanks for the video, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

New Video Posted: Exploring the Endoplasmic Reticulum: Functions, Vesicle Trafficking, and Quality Control

In the video Exploring the Endoplasmic Reticulum: Functions, Vesicle Trafficking, and Quality Control, I look at the important role played in the cell by the Endoplasmic Reticulum (ER).

The endoplasmic reticulum (ER) is involved in a number of key processes in the cell connected with protein production, including:

• Disulphide Bond Formation: Occurs as proteins are imported into the ER, crucial for protein stability and function.
• Protein Glycosylation: Starts in the ER and finishes in the Golgi, important for protein folding and interactions.
• Quality Control: Marks incorrectly folded proteins for destruction, though it may sometimes incorrectly target properly folded proteins.

The newly made proteins are trafficked from the ER to the Golgi in COPII Vesicles. 

If you would like to say thanks for the video, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

The Biosciences Glossary

When I was a student, one of my go-to books was a glossary of terms for bioscientists. I used the glossary when I was learning new material to look up things I didn’t understand and remind myself of what I had previously learned. I found it an invaluable learning and revision tool.

Sadly, the book is no longer in print, so I decided to write my own and I have just published The Biosciences Glossary on the Google Play Book Store.

The Biosciences Glossary

The book defines over 2,000 words, phrases, terms, and abbreviations used in the biosciences. It also includes 80+ chemical structures with links to additional information and to my videos on YouTube.

If you go to The Biosciences Glossary on the Google Play Book Store, you can review 20% of the book for free and decide if it would help you in your studies.

The book is available as a PDF and an ePub.

New Video Posted: How Proteins Get Into Peroxisomes | Biology Explained

In the video - How Proteins Get Into Peroxisomes | Biology Explained - I look at how the cell targets proteins to the peroxisomes.

Peroxisomes are involved in fatty acid oxidation and detoxification. The import of proteins into the peroxisomes relies on a short SKL motif at the C-terminal of the protein, which acts as an address. 

The SKL motif binds to the PTS1R receptor in the cytosol, which then interacts with the Pex14P receptor on the peroxisome membrane. The protein can either be imported with or without the receptor entering the peroxisome.

If you would like to say thanks for the video, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

New video posted: Organelles: Targeting Proteins to the Mitochondria

In this video, Organelles: Targeting Proteins to the Mitochondria, I look at how the cell targets proteins to the mitochondria.

Proteins destined for the mitochondria begin their journey in the cell's cytosol, guided by a signal peptide that acts like a "postcode." This signal, located at the N-terminal of the precursor protein, directs the protein to the mitochondria.

The video looks at the role of the Translocase of the Outer Membrane (TOM) and the Translocase of the Inner Membrane (TIM), along with the OXA complex, during the import process and discusses how proteins are targeted to the outer and inner membranes, the intermembrane space and the matrix of the mitochondria.

If you would like to say thanks for the video, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

New Video Posted: Understanding Vesicle Trafficking and the SNARE Hypothesis

In this video, Understanding Vesicle Trafficking and the SNARE Hypothesis, I look at the SNARE hypothesis and how it helps the targetting of vesicles to the correct membrane.

 

Vesicle trafficking is a crucial cellular process where vesicles transport materials to specific organelles or membranes. This process involves the SNARE hypothesis, where vesicles have vesicle SNAREs (vSNAREs) and target membranes have target SNAREs (tSNAREs). The vSNAREs and tSNAREs recognise each other, ensuring that vesicles dock at the correct membranes.

However, the SNARE proteins are promiscuous and can bind with multiple partners, posing challenges for precise docking. To address this, cells use Tether proteins, which operate over greater distances and add an additional layer of specificity. Tether proteins help vesicles recognise their target membranes, while SNAREs facilitate the fusion process.

This combined mechanism ensures accurate vesicle targeting and fusion, which is regulated by a GTP timer that coordinates the events. 

If you would like to say thanks for the video, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

New Video Posted: Understanding Protein Sorting: Cellular Transport Mechanisms Explained

Protein sorting involves directing proteins, which originate on ribosomes in the cytosol, to their appropriate cellular locations using specific amino acid sequences known as sorting signals. These sorting signals function like postcodes, guiding proteins to various organelles or membranes within the cell, such as the nucleus, peroxisomes, or the endoplasmic reticulum. The cell employs different types of transport mechanisms—gated, transmembrane, and vesicular—to move proteins to their correct destinations, ensuring proper cellular function.

If you would like to say thanks for the video, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

New Video Posted: Vesicle Trafficking: How vesicles are formed for trafficking between membranes

Vesicles are crucial for transporting molecules, and they are formed in one of three ways:

1. Clathrin-coated vesicles - Traffic from the Golgi to the endosomes and from the plasma membrane to the endosomes.
2. COPI-coated vesicles - Move from the Golgi to the endoplasmic reticulum, within the Golgi stack, and from the Golgi to the plasma membrane.
3. COPII-coated vesicles - Travel from the endoplasmic reticulum to the Golgi.

In this video, I look at how vesicles are formed and targeted within a cell. 

In the video, I explore some common themes and look at the formation of the coat (clathrin, COPI, or COPII) and the pinching off of the vesicle from the membrane. 

If you would like to say thanks for the fact sheet, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

New Video Posted: Organelles and Membranes - how much membrane is in a cell?

This is an interesting question: "How much membrane is in a cell?".

In this video, I use a football and some sheets of material to explore how much membrane we have in a cell and which organelles have the most membrane.

This was a fun video to make, and I got some very odd looks from passing dog walkers.

If you would like to say thanks for the fact sheet, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

New Video Posted: Organelles - Understanding Vesicular Transport

Cells have organelles, and they need to transport the correct molecules to those organelles — if they don't, the cell will not function correctly and will die. 

The cell has three ways of moving molecules around:

1. Vesicular transport
2. Gated transport
3. Transmembrane transport

This video also looks at vesicular transport, which uses small membrane-bound sacs to move proteins, lipids, and other molecules throughout the cell.

The video introduces the concepts of Endocytosis and Exocytosis - including Phagocytosis, Pinocytosis and Receptor-Mediated Endocytosis, along with Constitutive and Regulated Pathways.

If you would like to say thanks for the fact sheet, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.

New Video Posted: An introduction to cell organelles - why do cells have organelles?

In this video, I look at why cells have organelles - my answer might surprise you.

I also examine the different organelles, discuss how proteins are targeted to these organelles, and describe the mechanisms used to get proteins across membranes. 

If you would like to say thanks for the fact sheet, then please feel free to buy me a coffee at https://www.buymeacoffee.com/drnickm

Blog Bonus: Free information sheet summarising the video and defining the key terms - download.