DNA vs RNA

Question 1

what are the 2 similarities between DNA & RNA?

Answer 1

• both are made up of polynucleotides
• both can act as genetic material

Question 2

what are the 8 differences in features between DNA & RNA?

Answer 2

1. monomer
2. sugar
3. nitrogenous bases
4. number of strands present
5. stability
6. types
7. size
8. amount

Question 3

how are the monomers of DNA different from the monomers of RNA?

Answer 3

• in DNA, the monomer is a deoxyribonucleotide,
• whereas in RNA, the monomer is a ribonucleotide

Question 4

how are the sugars different in DNA & RNA?

Answer 4

• in DNA, the sugar is deoxyribose,
• while in RNA, the sugar is oxyribose

Question 5

how are the nitrogenous bases different in DNA & RNA?

Answer 5

• in DNA, the nitrogenous bases are adenine, thymine, cytosine & guanine,
• while in RNA, the nitrogenous bases are the same as DNA, except thymine, which is replaced by uracil

Question 6

what is the difference in the number of strands between DNA & RNA?

Answer 6

• DNA is usually double-stranded,
• whereas RNA is usually single-stranded

Question 7

what is the difference in stability between DNA & RNA?

Answer 7

• DNA is chemically stable,
• whereas RNA is chemically less stable

Question 8

why is DNA chemically stable?

Answer 8

• presence of hydrophobic interactions between stacked bases
• extensive hydrogen bonds between the numerous complementary base pairs in the molecule
• 2’ hydrogen in the deoxyribose sugar is unreactive

Question 9

why is RNA chemically less stable compared to DNA?

Answer 9

• the 2’ -OH in the ribose sugar is reactive

Question 10

what is the difference in types between DNA & RNA?

Answer 10

• DNA exists in 1 form,
• whereas RNA exists in at least 3 forms (mRNA, tRNA & mRNA)

Question 11

what is the difference in size between DNA & RNA?

Answer 11

• DNA is a large molecule,
• while RNA is smaller than DNA

Question 12

what is the difference in the amounts of DNA & RNA present in cells?

Answer 12

• the amount of DNA is the same in all cells of an organism, except gametes which have half the amount,
• while the amount of RNA is variable between different cells

Question 13

what cells will have a larger amount of RNA present in them?

Answer 13

• cells that are actively synthesising proteins