Nucleic Acids

Question 1

what is a nucleic acid?

Answer 1

a macromolecule

Question 2

what is the monomer of a nucleic acid? what is a polymer?

Answer 2

nucleotide

polynucleotides

Question 3

what are the components of a nucleotide?

Answer 3

a nitrogen base + a 5-carbon sugar + phosphate (functional group)

Question 4

what are the 2 types of nucleic acids?

Answer 4

1. Deoxyribonucleic acid (DNA)

2. Ribonucleic acid (RNA)

Question 5

what is the 5-carbon sugar in the structure of RNA? what is the 5-carbon sugar in the structure of DNA? how do these 2 sugars differ?

Answer 5

RNA –> ribose
DNA –> deoxyribose
different because there is no hydroxyl group (OH) on 2’ carbon in a deoxyribose (2nd carbon after O)

Question 6

how many different nitrogenous bases can nucleic acids be made of? what are the 2 types?

Answer 6

5 different nitrogenous bases

1. Single-ringed pyrimidines
2. double-ringed purines

Question 7

what are the 3 Single-ringed pyrimidines?

Answer 7

1. cytosine
2. thymine
3. uracil

Question 8

what are the 2 double-ringed purines?

Answer 8

1. adenine

2. guanine

Question 9

which nitrogenous bases does DNA use?

Answer 9

1. thymine
2. cytosine
3. adenine
4. guanine

Question 10

which nitrogenous bases does RNA use?

Answer 10

1. uracil
2. cytosine
3. adenine
4. guanine

Question 11

how are polynucleotides formed?

Answer 11

formed by monomers link together by dehydration reactions to form a polymer

Question 12

what are the 2 ends of nucleotide polymers? how can you tell them apart?

Answer 12

5’ end –> has a phosphate attached to the 5’ carbon

3’ end –> has a hydroxyl attached to the 3’ carbon

Question 13

what is the covalent bond joining two nucleotides called?

Answer 13

Phosphodiester bond

Question 14

where does a phosphodiester bond form? which end does a new nucleotide always add to?

Answer 14

Forms between a phosphate from one nucleotide and the hydroxyl group on the 3’ carbon on another nucleotide
-always ends to the 3’ end

Question 15

what is the backbone of a polynucleotide made of? what extends out from backbone?

Answer 15

made of repeating pattern of sugar-phosphate units

-nitrogenous bases extend out from backbone

Question 16

what is the role of DNA?

Answer 16

storing hereditary information in the form of genes

-Essential component of chromosomes

Question 17

what do genes contain?

Answer 17

contains instructions to make a polypeptide

Question 18

what is RNA responsible for in the cell?

Answer 18

Responsible for transcribing DNA and translating it

into protein

Question 19

how many strands do RNA have? how many does DNA have?

Answer 19

Most RNA molecules are single stranded

-DNA is double

Question 20

how many polynucleotides do DNA molecules have? what shape do they form? where are the components of DNA located?

Answer 20

• two polynucleotides
• spiral around an axis forming a double helix
• Sugar-phosphate backbone on outside and paired nitrogenous bases on inside

Question 21

how do the 2 strands in DNA run in relation to each other?

Answer 21

antiparallel –> if parent strand runs 3’ to 5’, than daughter strand runs 5’ to 3’

Question 22

how are the two strands in DNA held together?

Answer 22

held together by hydrogen bonds between the paired nitrogenous bases

Question 23

what er the nitrogen base pairs in DNA?

Answer 23

Adenine & thymine

guanine & cytosine