Chapter 2- Nucleic Acids

Question 1

What bond is between a mono-nucleotide and the phosphate group of another ??

Answer 1

Phosphodiester bonds

Question 2

Describe the structure of RNA

Answer 2

Contains bases

• Adenine - Uracil - Cytosine - Guanine
• Ribose sugar
• Phosphate group
• Single stranded

Question 3

Describe the structure of DNA

Answer 3

Contains

• Thymine -Adenine - Uracil - Guanine
• Deoxyribose sugar
• Phosphate group
• Double helix
• Complementary base pairs are joined together by hydrogen bonds.

Question 4

What is the role of the phosphodiester backbone

Answer 4

The phosphodiester backbone protects the organic bases in the double helix

Question 5

Link the structure of DNA to its function

Answer 5

• Stable structure allows it to be passed through generations. Low chance of mutation
• Weak hydrogen bonds allow strand separation during DNA replication
• Base pairing leads to DNA being able to replicate and to transfer information as mRNA

Question 6

Describe the steps of semi-conservative relocation

Answer 6

DNA helicase breaks hydrogen bonds between complementary bases causing the two strands to separate.
Free nucleotides bind to their complementary bases on the strands.
DNA polymerase makes phosphodiester bonds between the nucleotides.
Two identical strands are formed with half of the original DNA material

Question 7

Describe the structure of ATP

Answer 7

Adenine-Ribose-(3) phosphates

Question 8

How does the weak phosphate bonds allow immediate energy release

Answer 8

The unstable phosphate bonds mean that they can be broken easily allowing energy to be released

Question 9

What are the 3 ways in which ATP can be synthesised from ADP

Answer 9

During respiration in plants and animals
During photosynthesis in plants
When phosphate groups are transferred from donor molecules to ADP

Question 10

What are the 5 roles of ATP

Answer 10

Movement- Provides energy for muscle contraction

Metabolic processes- Provides energy for the build up of micro molecules.

Active transport- Provides energy to change shape of channel proteins.

Secretion- Forms lysosomes for secretion of cell products.

Activation of molecules- Can be used to make compounds more reactive.

Question 11

Structure of amino acid

Answer 11

R
|
Carboxyl (HOOC)——C—-Amino group | group
H