Thymine Dimers and Photolyase Functions

The video explains how DNA can be repaired using the photo reactivation mechanism. UV light can cause thymine dimers to form on the same DNA strand, leading to a bulge. The enzyme photolyase, encoded by the PHR gene, identifies and binds to these dimers. Upon absorbing light, photolyase splits the dimers, effectively repairing the DNA. The video concludes with a call to action for viewers to engage with the content.

What is the primary cause of thymine dimer formation in DNA?

• Exposure to UV light

• High temperatures

• Chemical exposure

• Mechanical stress

How do thymine dimers affect the DNA structure?

• They cause the DNA to break

• They strengthen the DNA strand

• They have no effect on DNA structure

• They cause a bulge in the DNA strand

What unusual pairing occurs due to UV light exposure?

• Cytosine with guanine on the opposite strand

• Adenine with guanine on the same strand

• Thymine with thymine on the same strand

• Adenine with thymine on the opposite strand

Which enzyme is responsible for repairing thymine dimers?

• Photolyase

• DNA polymerase

• Helicase

• Ligase

What gene encodes the enzyme that repairs thymine dimers?

• PHR gene

• TP53 gene

• MYC gene

• BRCA1 gene

What happens when photolyase absorbs a photon of light?

• It forms a new dimer

• It splits the thymine dimer

• It breaks the DNA strand

• It causes DNA to coil

What is the result of photolyase activity on DNA?

• The DNA remains unchanged

• The DNA is damaged further

• The DNA is partially repaired

• The DNA is fully repaired

What is the main function of the photolyase enzyme?

• To synthesize proteins

• To replicate DNA

• To repair thymine dimers

• To unwind DNA

What should viewers do if they found the video helpful?

• Like, share, and comment on the video

• Report the video

• Dislike the video

• Ignore the video