Video ranking system:

Level 1 - Brief and Easy

Level 2 - NOT Easy

Level 3 - OMG TMI

tRNA in detail - Great video!

Ranking: Level 2
(HeyNowScience YouTube Channel)

mRNA

Ranking: Level 2
(HeyNowScience YouTube Channel)

DNA replication

Ranking: Level 3
(HeyNowScience YouTube Channel)