Chapter 3 - nucleotides and nucleic acids

Question 1

what is the structure of a nucleotide?

Answer 1

• a pentose monosaccharide
• a phosphate group (inorganic molecule)
• a nitrogenous base
  (organic molecule)

Question 2

what is a nucleic acid?

Answer 2

• polymers formed from many nucleotides
• nucleotides linked together by condensation reactions
• phosphate group of one/covalent bond/hydroxyl group of pentose sugar of other
• phosphodiester bonds

Question 3

what is DNA?

Answer 3

• stores all the genetic info needed by an organism
• a sugar with one fewer oxygen than ribose
• 4 diff bases=4 diff nucleotides
• 4 bases=2 groups
  1) pyrimidines=smaller, single carbon ring, (T and C)

Question 4

what is a double helix?

Answer 4

• 2 strands of polynucleotides coiled into a helix (DNA)
• 2 strands held together by hydrogen bonds between bases
• 2 parallel lines run in opposite direction

Question 5

what is the base pairing rule?

Answer 5

• Adenine (A) and Thymine (T)
  -Cytosine (C) and Guanine (G)
• complementary base pairing
• DNA always has equal amounts of A and T, and C and G

Question 6

what is RNA?

Answer 6

• essential role in transfer of genetic info from DNA to proteins
• a short section of DNA
• T replaced with U
• small enough to leave the nucleus and travel to ribosomes