Where are hydrogen bonds located in nucleic acids and carbohydrates?

Question

I'm having trouble answering the following questions: “where would you find hydrogen bonds in nucleic acids?” “where would you find hydrogen bonds in carbohydrates”?

Answer 1

Hydrogen Bonds in Nucleic Acids

In nucleic acids (DNA and RNA), hydrogen bonds are found in two key locations:

1. Between nitrogenous bases — This is the most important location. Hydrogen bonds hold the two strands of DNA together by connecting complementary base pairs:
2. Adenine (A) bonds with Thymine (T) — connected by 2 hydrogen bonds
3. Guanine (G) bonds with Cytosine (C) — connected by 3 hydrogen bonds
4. Within RNA structure — Hydrogen bonds form between complementary bases within a single RNA strand, giving it its folded 3D shape.

Hydrogen Bonds in Carbohydrates

In carbohydrates, hydrogen bonds are found in two key locations:

1. Between hydroxyl groups (-OH) — Carbohydrates are rich in hydroxyl groups that form hydrogen bonds with neighboring molecules or water molecules, making them highly soluble.
2. Within polysaccharide chains — In complex carbohydrates like cellulose and starch, hydrogen bonds form between adjacent glucose chains, giving them their structural stability and rigidity. This is why cellulose is so strong and forms the structural backbone of plant cell walls.

Simple Rule to Remember: In nucleic acids, look for hydrogen bonds between bases. In carbohydrates, look for hydrogen bonds between hydroxyl groups!

Answer 2

Gabriel: A key here is that hydrogen bonds are relatively weak interactions BETWEEN molecules. So a COVALENT bond between an oxygen and hydrogen in one water molecule, for example, is NOT a hydrogen bond.

 

The origin of hydrogen bonding is the unequal 'sharing' of electrons between a hydrogen (with a weak 'pull' on electrons, more formally a relatively low electronegativity) and generally an oxygen or nitrogen that the H is covalently bonded TO. Another way of looking at it is:

H--->O<---H, where the arrowheads indicate the Oxygen is 'winning' the tug-of-electrons.

 

This leaves the HYDROGEN somewhat positive overall (because it's 'lost' its fair share of electrons) and the oxygen correspondingly negative.

 

A hydrogen bond is the interaction that results between the somewhat-postive H from ONE molecule and the somewhat-negative O or N on ANOTHER.

 

Note that carbon also has a relatively weak electron pull, so oxygens & nitrogens that are covalently bonded to carbons are also somewhat negative in charge and can participate in H-bonds on other molecules.

 

If you look at HOW two bases in DNA or RNA are interacting, you should be able to see the H-bonds! (H-bonds are often shown as dashed lines to indicate they are different & weaker than covalent bonds)

Answer 3

Hydrogen bonds occu when a H atom is bonded to a N, O or F atom. So in nucleic acids hydrogen bonding occurs between adenosine and thymine bases and between cytosine and guanine bases.  In carbohydrates,hydrogen bonding occurs between the -OH groups on the molecules.