3.8 Nucleic Acids

What are the full names of the 2 types of nucleic acid?

deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)

Fill in the blanks: DNA and RNA are ____, made from monomers called _____

polynucleotides, nucleotides

What elements do nucleic acids contain?

carbon, hydrogen, oxygen, nitrogen and phosphorus

What are the 3 components of a nucleotide?

phosphate group, pentose sugar and organic nitrogenous base

What type of reactions joins adjacent nucleotides?

condensation reaction

What bonds hold adjacent nucleotides in place?

phosphodiester bonds

What are the pentose monosaccharides found in DNA and RNA called?

DNA - deoxyribose, RNA - ribose

True or false? the phosphate component in DNA and RNA is always the same but there are 5 possible different organic nitrogenous bases

true

What is the difference between a purine and a pyrimidine?

a purine has 2 rings and a pyrimidine has 1 ring

In terms of purines and pyrimidines, how to complementary base pairs form?

a purine always pairs with a pyrimidine

Which organic nitrogenous bases are purines?

adenine and guanine

Which organic nitrogenous bases are purines?

cytosine, thymine and uracil

True or false? the phosphate group in a nucleotide is inorganic, slightly alkaline and negatively charged

false - its acidic

Fill in the blanks: a molecule of DNA consists of __ polynucleotide strands (___ stranded) which are bonded together are twisted into a 3D structure called a ____ _____

2, double, double helix

Fill the blanks: each strand has a phosphate group at one end (__’ (prime)) and a hydroxyl group at the other end (__’ (prime))

5, 3

The two strands of DNA run in opposite directions. What term is used to describe this?

antiparallel

True or false? DNA always runs in the 5’ to the 3’ direction?

true

What part of a DNA molecule do the alternating sugars and phosphate groups form?

sugar-phosphate backbone

What holds the two strands of DNA together?

hydrogen bonds between the nitrogenous bases

Which nitrogenous base joins to adenine and by how many hydrogen bonds?

thymine, 2

Which nitrogenous base joins to cytosine and by how many hydrogen bonds?

guanine, 3

Why does DNA need to be a stable macromolecule?

to protect the coded information within the base sequences

Give 2 similarities between DNA and RNA

• both made of nucleotides and phosphate groups

• both have phosphodiester bonds formed in condensation reactions between nucleotides

• the order of nitrogenous bases forms a code

• both contain the bases A, G and C

• both have pentose sugars

Give 4 differences between DNA and RNA

• DNA contains 2 strands in a double helix but RNA is largely single stranded

• DNA contains sugar deoxyribose - ribose is found in RNA

• DNA contain hydrogen bonds between complementary base pairs. RNA has no hydrogen bonds or CBP

• DNA is a large stable, macromolecule but RNA is small and unstable

• DNA is only found in the nucleus but RNA can be found in the nucleus or the cytoplasm