3.1.5.1

Question 1

What is the function of DNA?

Answer 1

Long term storage of information

Question 2

Describe the structure of DNA

Answer 2

Polymer of nucleotides
Nucleotides joined by phosphodiester bonds formed through condensation reactions forming polynucleotide strands
Each DNA molecule made up of 2 antiparallel polynucleotide strands that twist to form a double helix
Strands held together by hydrogen bonds between specific and complementary nitrogenous bases on opposite strands

Question 3

Describe the components of a DNA nucleotide

Answer 3

Phosphate group
Deoxyribose pentose sugar
Organic nitrogenous base - adenine, cytosine, guanine, thymine

Question 4

Describe complementary base paring in DNA

Answer 4

Adenine and thymine are joined by 2 hydrogen bonds
Cytosine and guanine are joined by 3 hydrogen bonds

Question 5

What are the 2 types of nitrogenous base?

Answer 5

Purine = adenine, guanine
Pyrimidine = cytosine, thymine

Question 6

How are nucleotides joined?

Answer 6

Condensation reaction between deoxyribose of one nucleotide and phosphate group of another
Forms strong covalent phosphodiester bonds
Creates a sugar phosphate backbone within the molecule

Question 7

Describe the structure of RNA

Answer 7

Polymer of nucleotides
Relatively short polynucleotide chain

Question 8

Describe the components of an RNA nucleotide

Answer 8

Phosphate group
Ribose pentose sugar - contains one more oxygen than deoxyribose, allows enzymes to distinguish between DNA and RNA nucleotides
Organic nitrogenous base - adenine, cytosine, guanine, uracil

Question 9

What is the function of RNA?

Answer 9

Transfers genetic information from DNA to ribosomes
Contains a copy of a small section of DNA as DNA is too big to fit through nuclear pores so can’t leave nucleus

Question 10

What are the 3 types of RNA?

Answer 10

mRNA - messenger RNA, carries DNA code from nucleus
tRNA - transfer RNA, carries amino acids across cytoplasm
rRNA - ribosomal RNA, ribosomes are made up of RNA and proteins