Friday, 26 April 2024

New video posted: Transcription - making proteins from DNA - the mRNA

This is the first of two videos on how cells make proteins using DNA. The second video looks at how we go from messenger RNA (mRNA) to protein - Translation - making proteins from DNA - decoding mRNA to make the protein

In this video, I will guide you through the first steps in the process of producing RNA from DNA, also known as transcription. In the next video, we will take the next step and examine how we produce the protein from mRNA.

The video looks at the five steps of mRNA production:

  • initiation — activators bind upstream, often thousands of bases upstream, of the gene. The activators assemble the required proteins (the mediator, chromatin remodelling complex, the RNA polymerase and transcription factors) at the TATA box, which is a DNA sequence close to the gene
  • production — DNA is transcribed into the pre-messenger RNA
  • five prime capping — the five prime end of the pre-messenger RNA is capped with some modified nucleotides
  • splicing — introns are spliced out of the pre-messenger RNA to leave just the exons (exons provide the sequence for the protein)
  • three prime polyadenylation — addition of a polyadenylated tail to the three prime end of the pre-messenger RNA to give the final mature messenger RNA molecule

The video not only looks at mRNA production but also introduces the idea of non-coding RNA (ncRNA), which are RNA molecules that do not encode proteins. ncRNAs are essential in regulating gene expression and various cellular processes. For example:

  • transfer RNA (tRNA) — involved in protein synthesis
  • ribosomal RNA (rRNA) — involved in protein synthesis
  • microRNA (miRNA) — control gene expression
  • small interfering RNA (siRNA) — control gene expression 
  • long non-coding RNA (lncRNA) — diverse functions
  • circular RNA (circRNA) — gene regulation
  • Piwi-interacting RNA (piRNA) — genome protection
  • enhancer RNAs (eRNAs) — modulate gene activity
Finally, I cover how to write out DNA sequences, the means of the terms sense and antisense strands, and what we mean by upstream and downstream when talking about DNA and RNA molecules.

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

Additional Reading

The video was produced with help from the following resources:

Thursday, 25 April 2024

New video posted: DNA Recombination and Holiday Junction: The Key to Genetic Variation

In this video, I explore DNA recombination, a process where DNA strands swap segments, usually between similar sequences on sister chromatids. This swapping creates brand-new genetic combinations. DNA recombination isn't just a biological curiosity; it's crucial for increasing genetic diversity and ensuring the stability of our genome.

If you would like to support my blogging efforts, 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.
 

Additional Reading

The video was produced with help from the following resources:

Wednesday, 24 April 2024

New video posted: DNA Repair - BER, direct, proofreading, HR, MMR, NHEJ and NER

DNA can be damaged in a number of ways (see How can DNA become damaged in the cell? for more information— and the damage must be corrected for the cell to function correctly. 

There are seven ways cells can repair damage to their DNA: 

  • Base Excision Repair (BER)
  • Direct repair
  • DNA proofreading
  • Homologous recombination repair (HR)
  • Mismatch Repair (MMR)
  • Non-homologous end joining (NHEJ)
  • Nucleotide Excision Repair (NER)
And in this video, I look at the seven methods.

If you would like to support my blogging efforts, 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.
 

Additional Reading

The video was produced with help from the following resources:

Thursday, 18 April 2024

New video posted: How can DNA become damaged in the cell?

In this video, I look at how DNA can become damaged in cells and introduce four ways damage can occur:

  • deletions
  • insertions
  • substitutions
  • transitions
  • and transversions. 
I also look at exogenous and endogenous damage sources of the damage.

If you would like to support my blogging efforts, 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.
 

Additional Reading

The video was produced with help from the following resources:

Wednesday, 17 April 2024

New video posted: DNA replication: How does a cell make a copy of its DNA?

Have you ever been curious about the precision with which DNA is replicated in our cells, or why human pregnancies don't extend to an unimaginable sixteen years?

In my latest video, I examine the process of DNA replication. First, I explore how the DNA double helix is unwound by DNA helicase and how the unwound DNA is stabilised by Single Stranded Binding Proteins. I look at the replication fork and how DNA polymerases copy the DNA strands.

I also cover the formation of Okazaki fragments—short sequences of DNA synthesised on the lagging strand—and how DNA ligase is responsible for stitching these fragments together. Additionally, the video highlights the importance of topoisomerase in preventing the DNA from becoming overly twisted and tangled during replication.

If you would like to support my blogging efforts, 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.
 

Additional Reading

The video was produced with help from the following resources:

Monday, 15 April 2024

New video posted: DNA Packaging - how do we package DNA into the nucleus?

In the video, I examine how the long DNA molecule is packaged into the relatively small nucleus of a cell. I examine how DNA is broken up into chromosomes, how the DNA wraps around the histones to form nucleosomes and chromatosomes, and finally, chromatin.

Please use the form below to download a fact sheet for the video. The fact sheet contains twenty-four key facts from the video, a summary of the packing of DNA into the nucleus and the definitions of twenty-five key terms used in the video.

If you would like to support my blogging efforts, 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.
 

Additional Reading

The video was produced with help from the following resources:

Thursday, 11 April 2024

New video posted: How long is the DNA in a human cell?

In this video, I calculate the length of the DNA in one human cell, and my answer may surprise you.

How long do you think? 0.2 mm, less? 2 mm, 2 cm, 2 m, 2 km? Watch the video to find out.

The video walks you through the math I used to calculate the length of DNA, and then I will reveal the length it would be if the cell were the size of a football.

If you would like to support my blogging efforts, 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.
 

Additional Reading

The video was produced with help from the following resources: