DNA and RNA

Question 1

What does DNA store?

Answer 1

Genetic information needed for an organism to grow and develop

Question 2

What is RNA for?

Answer 2

To transfer genetic information from the DNA to the ribosomes.Ribosomes read RNA to make polypeptides during translation.
Ribosomes are made from RNA and proteins.

Question 3

What are the bases for DNA?

Answer 3

AGCT

Adenine, guanine, cytosine and thymine

Question 4

What are the bases for RNA?

Answer 4

ACGU

Adenine, cytosine, guanine and uracil

Question 5

What is the structure of a nucleotide?

Answer 5

• A pentose sugar ( called pentose cus it has 5 carbon atoms and is a sugar so is ‘ose’)( elements are C H and O)
• A nitrogen containing organic base (the elements are C H O and N)
• A phosphate group (elements in it are P and O)

Nucleotides are important, they are the monomers that make up DNA and RNA.

Question 6

What is the sugar in DNA called?

Answer 6

Deoxyribose

Question 7

What is the sugar in RNA called?

Answer 7

Ribose

Question 8

What happens when nucleotides join to form polynucleotides?

Answer 8

• Both DNA and RNA form polynucleotides.
• The nucleotides join up via a condensation reaction between the phosphate group of one nucleotide and the sugar of another.
• This forms a phosphodiester bond(phosphate group and 2 ester bonds)
• The chain of sugars and phosphates is known as a sugar phosphate backbone

Question 9

Structure of RNA

Answer 9

Pentose is ribose
Bases are ACGU
RNA is single stranded
RNA is shorter than most DNA polynucleotides
Used for transferring the code from the nucleus to the ribosomes

Question 10

Structure of DNA

Answer 10

• Bases are ACTG
• Double helix structure > 2polynuceotides strands joined
• Hydrogen bonds hold the 2 strands together
• Each base can only join to its complementary base pairing
• First observed in 1800s but was doubted
• By 1953 Crick and Watson had described the double helix structure. In the same year experiments showed that DNA was the carrier of the genetic code

Question 11

The bases in DNA

• what goes with what
• how many

Answer 11

Thymine and adenine pair ~ 2 hydrogen bonds
Cytosine and guanine pair ~ 3 hydrogen bonds
*2 toffee apples and 3 chocolate gateau’s

This means there are always equal amounts of adenine and thymine and equal amounts of cytosine and guanine in a DNA molecule.

Question 12

Why is DNA stable?

Answer 12

• it has a phosphodiester backbone that protects the more chemically reactive organic bases inside the double helix
• hydrogen bonds link the organic base pairs forming bridges between the phosphodiester uprights. As there are three between the hydrogen bonds between cytosine and guanine, the higher the proportion of C-G pairings, the more stable the DNA molecule.
• there are other interactive forces between the base pairs that hold the molecule together(=base stacking)

Question 13

Function of DNA

Answer 13

Stable~passes from generation to generation without change
Joined with hydrogen bonds~separate easily
Extremely large molecule~Carries a lot of genetic info
Helical cyclinder backbone~
Rotectfrom outside chemical/ physical factors
Easy to replicate