Hi, I just had some questions is anyone could help me...
1. For RNA, my teachers have always told me that the complimentary base pairs are A-U and C-G but how can they have pairs when it's single stranded? Like it doesn't have another strand to pair with?
2. In the phospholipid bilayer, why is the head polar, while the tails are non-polar? Because doesn't that mean that even if water can get through the head, it won't be able to get through the middle of layer (non-polar tails)?
3. Can a protein that stops at secondary or tertiary structure, or even primary structure (can it stop there?) be considered complete?
4. I read a document written by a teacher in the US and he said that for covalent bonds, because they're strong they can't be formed spontaneously and are formed through use of enzymes. But when I searched the internet for more info relating to it I couldn't find anything which said the same thing; I was just wondering if maybe that information was wrong?
Thanks! If you could help me, that'd be great.