DNA structure/function

Question 1

What does DNA stand for?

Answer 1

DNA stands for deoxyribonucleic acid

Question 2

What does DNA code for?

Answer 2

DNA codes for the sequence of amino acids in the primary structure of proteins

Question 3

What does the primary structure of a protein determine?

Answer 3

The primary structure determines the final 3D structure and function of a protein

Question 4

What monomer makes up DNA?

Answer 4

Nucleotide

Question 5

Draw the structure of a nucleotide

Answer 5

Draw the structure of a nucleotide and compare your answer

Question 6

What is a nucleotide made up of?

Answer 6

A pentose sugar (deoxyribose), a phosphate group and a nitrogenous containing base (cytosine, guanine, adenine and thymine)

Question 7

Label the structure of a nucleotide

Answer 7

Darker orange - phosphate group

Light orange - pentose sugar (deoxyribose)

Pink rectangle - nitrogenous containing bases

Question 8

What is formed when two mononucleotides join together?

Answer 8

A dinucleotide

Question 9

What bond forms between two mononucleotides?

Answer 9

A phosphodiester bond

Question 10

How is a polynucleotide formed?

Answer 10

Polynucleotides are formed from multiple condensation reactions between mononucleotides, which involve the removal of a water molecule and the formation of a phosphodiester bond

Question 11

1. What is a phosphodiester bond
2. Why important in DNA?

Answer 11

1. Phosphodiester bonds are strong covalent bonds
2. Important in DNA because they ensure the genetic code is not broken down

Question 12

Brief description of DNA: (two points)

Answer 12

DNA is a polymer with a double helix structure

Question 13

How are the two stands of DNA held together?

Answer 13

By hydrogen bonds between complementary bases

Question 14

What is the sugar phosphate backbone?

Answer 14

The sugar phosphate backbone has strong covalent bonds between the sugar and phosphate groups that hold the polymer together

Question 15

What does each nitrogenous base pair with?

Answer 15

Adenine and thymine forms a hydrogen bond

Guanine and cytosine form a hydrogen bond

Question 16

How does the structure of DNA relate to its function? (4pts)

1. Large = carry lots
2. Bonds, weak = rep. easy + quick
3. Protection of weak bonds
4. Base pairing = copies easy

Answer 16

1. DNA being a large molecule enables it to carry lots of information
2. The hydrogen bonds are weak so when DNA replication occurs the bonds will be easily broken, making replication more efficient
3. DNA has a stable structure due to the phosphodiester bonds which create the sugar phosphate backbone. This structure means the strong covalent bonds on the outside of the helix, leaving the weaker hydrogen bond in the middle of the helix protected
4. Complementary base pairing allows identical copies of DNA to be made