DNA and RNA

Question 1

What is the function of DNA?

Answer 1

Deoxyribose Nucleic Acid is used to store genetic information- all the instructions an organism needs to grow and develop.

Question 2

What is the function of RNA?

Answer 2

Ribonucleic acid transfers genetic information from the DNA to the ribosomes.

Question 3

What is a nucleotide made from?

Answer 3

• a pentose sugar (sugar with 5 carbon atoms)
• a nitrogen-containing organic base
• a phosphate group

Question 4

Describe the components of a nucleotide in relation to DNA

Answer 4

• pentose sugar is deoxyribose
• each one has the same sugar and phosphate group, but the base varies
• four possible bases: Adenine, Guanine, Cytosine, Thymine

Question 5

Describe the components of a nucleotide in relation to RNA

Answer 5

• pentose sugar is ribose
• sugar and phosphate stay the same
• one of four different bases: Adenine, Uracil, Guanine and Thymine

Question 6

How do nucleotides join, and what do they form in doing so?

Answer 6

• Join up via condensation reaction between phosphate group of one N and sugar of another.
• Forms a phosphodiester bond (consisting of phosphate group and two ester bonds)
• Forms a polynucleotide
• Chain of sugars and phosphates is known as sugar-phosphate backbone

Question 7

Describe the structure of DNA

Answer 7

• Two polynucleotide strands joined together by hydrogen bonds between bases.

Question 8

What is complementary base pairing?

Answer 8

• Adenine always pairs with thymine
• Cytosine always pairs with guanine
• So, theres always equal amounts of adenine and thymine in DNA molecule and equal amounts of C & G.

Question 9

How many hydrogen bonds form between the bases?

Answer 9

• 2 hydrogen bonds between A and T

- 3 hydrogen bonds between C and G

Question 10

Who determined the double helix structure in 1953?

Answer 10

Watson and Crick

Question 11

Describe the structure of RNA

Answer 11

• Made from a single polynucleotide chain.

- Much shorter than most DNA polynucleotides