Molecular Ecology Summary Questions

What is the nucleic acids unit?

Nucleotides

What are the components of a nucleotide?

1. Pentose sugar

2. Nitrogenous base

3. Phosphate group

What is the difference between purines and pyrimidines?

Purines (A, G) have two rings, whereas Pyrimidines (T, U, C) have one ring

Where do nucleotides attach to each other to form a strand?

Phosphate group attaches the 5’ carbon of one nucleotide to the 3’ carbon of another

What type of bond is formed between two nucleotides in the same strand?

Covalent Phosphodiester Bonds

Are the bonds between nucleotides in a strand strong or weak?

Strong

What is the direction of a nucleic acid strand?

5’ to 3’

What bonds are formed to produce the DNA double helix?

Hydrogen bonds

Are the bonds between bases in DNA strong or weak?

Weak

How many nucleotides are generally found in one 360˚ turn of a DNA double helix?

10

What is the difference between DNA and RNA nucleotides?

1. DNA has Deoxyribose (1 OH), RNA has Ribose (2 OH)

2. DNA has Thymine, RNA has Uracil

What is Chargaff’s rule?

In double-helix DNA, the percent adenine will equal the percent thymine; the percent guanine will equal the percent cytosine

If the proportion of Thymine in a double-helix DNA strand is 32%, what is the proportion of other nucleotide bases?

Adenine: 32%

Guanine: 18%

Cytosine: 18%

How does RNA form secondary structures?

Hydrogen bonds between complementary bases (A to U, G to C) forms short double-stranded segments such as helices, bulge loops, internal loops, multibranched junctions, and stem loops