6. Nucleic Acids and Protein Synthesis

Question 1

What do DNA and RNA each stand for?

Answer 1

DNA: deoxyribonucleic acid
RNA: ribonucleic acid

Question 2

What is the structure of DNA and RNA?

Answer 2

• macromolecules, therefore are polymers called polynucleotide
• made of monomers called nucleotides

Question 3

What are DNA and RNA known as together?

Answer 3

nucleic acids

Question 4

What is the structure of nucleotides?

Answer 4

1) nitrogen base
2) pentose sugar
3) phosphate group

Question 5

What are the 4 different bases in DNA?
* include the separate one in RNA

Answer 5

A, G, T, C
1) adenine
2) guanine
3) thymine
4) cytosine
5) uracil; replaces thymine in RNA

Question 6

Which of the bases are purines, and what does that mean?

Answer 6

adenine and guanine, 2 rings wide

Question 7

Which of the bases are pyramidines, and what does that mean?

Answer 7

thymine, cytosine and uracil, 1 ring wide

Question 8

Which bases have 2 hydrogen bonds, and which bases have 3 hydrogen bonds?

Answer 8

2 hydrogen bonds: adenine and thymine
3 hydrogen bonds: cytosine and guanine

Question 9

Describe the structure of ATP

Answer 9

consists of adenine, ribose, and phosphate
adenine + ribose = adenosine
adenosine:
+ 1 phosphate = adenosine monophosphate (AMP)
+ 2 phosphate = adenosine diphosphate (ADP)
+ 3 phosphate = adenosine triphosphate (ATP)

Question 10

What reaction joins 2 nucleotides?

Answer 10

condensation reaction

Question 11

What is a phosphodiester bond?

Answer 11

• bond in polynucleotides to form long, unbranching strands of nucleotides
• phosphate group with 2 ester bonds on each sugar

Question 12

Features of a DNA molecule

Answer 12

• made of 2 polynucleotide chains
• right-handed helix
• coil around each other to form double helix
• antiparallel, 5’ is phosphate, 3’ is sugar
• sugar-phosphate backbone
• bases project at right angles
• held together because base in one chain attracted to base of other chain, due to hydrogen bonding between chains (AT, CG)
• complementary base pairing
• complete turn of double helix every 10 base pairs

Question 13

What is the importance of complementary base pairing in DNA?

Answer 13

• complementary sequence acts as a coded message
• how DNA stores information
• how DNA copies itself

Question 14

How does DNA replicate?

Answer 14

1) unwinding the 2 strands (unzipping down the middle), weak hydrogen bonds in the middle
2) enzyme DNA polymerase used to make complementary copy of nucleotides, form hydrogen bonds to the strands being copied
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