Dna +Rna

Question 1

What does a nucleotide consist of

Answer 1

Phosphate group
Pentose sugar
Nitrogenous bases

Question 2

What are the nitrogenous bases and what two groups seperate them

Answer 2

Purines : adenine and guanine
Pyrimidines : cytosine and thymine

Complimentry pairs = A+T ( 2 H bonds) C+G (3 H bonds)

Question 3

Describe dna structure

Answer 3

Double helix - 2 strands running anti parallel

Question 4

What are bonds between nucleotides called

Answer 4

Phosphodiester bonds

Question 5

Define gene

Answer 5

Length of DNA that contains the code to make a polypeptide

Question 6

Features of DNA

Answer 6

Stable molecule, difficult to disrupt shape in order to protect base sequence
Polymerised by DNA polymerase
Deoxyribose sugar
Double helix

Question 7

Features of RNA

Answer 7

Ribose sugar
Single stranded
Uracil swaps with thymine
Polymerised by RNA polymerase

Question 8

Features of both DNA and RNA

Answer 8

Both contain nucleotides
The phosphate group of one nucleotide is joined to the pentose sugar of another by a condensation reaction

Question 9

Features of mRNA

Answer 9

Formed in nucleus
Single chain helix, length and base sequence vary
Short life
Involved in protein synthesis (transcription and translation)

Question 10

Features of tRNA

Answer 10

Made in nucleolus
Single chain in clover leaf shape
Many different types
Always same length
Have attachment site for an amino acid on top
Involved in protein synthesis (translation)

Question 11

Features of rRNA

Answer 11

Made in nucleolus
Forms over half the mass of ribosomes