2.1 — nucleic acids: DNA and RNA

Question 1

what are nucleotides?

Answer 1

the building blocks of nucleic acids such as DNA and RNA

Question 2

what dimers and polymers do nucleotides form?

Answer 2

dinucleotides and polynucleotides

Question 3

what is a nucleic acid the functional molecule made up of?

Answer 3

one or more polynucleotide chains

Question 4

what components make up a nucleotide?

Answer 4

1. a pentose sugar — contains 5 carbon atoms
2. a nitrogenous base — contains carbon and nitrogen
3. a phosphate group — contains a phosphate group

Question 5

how are polynucleotides made?

Answer 5

nucleotides are joined together via condensation reactions.

Question 6

what type of bonds join the nucleotides in polynucleotides?

Answer 6

(covalent) phosphodiester bonds

Question 7

how is a phosphodiester bonds formed?

Answer 7

when the phosphate group of one nucleotide forms a covalent bond with the sugar of another

Question 8

what is a sugar phosphate backbone?

Answer 8

a chain of phosphates and sugars (joined by phosphodiester bonds)

Question 9

how can a phosphodiester bond be broken?

Answer 9

hydrolysis reactions

Question 10

what is released when phosphodiester bonds undergo hydrolysis reactions?

Answer 10

the nucleotide and monomers

Question 11

what does DNA stand for?

Answer 11

deoxyribonucleic acids

Question 12

what does DNA contain the information for?

Answer 12

the instructions needed to make proteins

Question 13

what components make up a DNA nucleotide?

Answer 13

1. deoxyribose sugar — a pentose/ 5 carbon sugar
2. A, T, G, or C —nitrogen containing organic base
3. a phosphate group

Question 14

who was credited in working the structure of DNA?

Answer 14

James Watson and Francis Crick

Question 15

what is the structure of DNA made up of?

Answer 15

two polynucleotide strands wound around each other to form a double helix

Question 16

what are the features that allow DNA to pass genetic information from one generation to another?

Answer 16

1. sugar phosphate backbone — protects coding bases on the inside of the helix
2. double stranded — allows strands to act as templates in DNA replication
3. large molecule — stores lots of information
4. double helix — makes it compact
5. complimentary base pairing — allows accurate DNA replication
6. weak hydrogen bonds — allows strands to serve rate in DNA replication

Question 17

how does having a sugar phosphate backbone allow DNA to pass genetic information?

Answer 17

protects coding bases on the inside of the helix

Question 18

how does being double stranded allow DNA to pass genetic information?

Answer 18

this allows strands to act as templates in DNA replication

Question 19

how does being a large molecule allow DNA to pass genetic information?

Answer 19

it stores a lot of information

Question 20

how does being a double helix allow DNA to pass genetic information?

Answer 20

makes the molecule compact

Question 21

how does having complimentary base pairing allow DNA to pass genetic information?

Answer 21

allows accurate DNA replication

Question 22

how does having a weak hydrogen bonds allow DNA to pass genetic information?

Answer 22

they allow strands to separate in DNA replication

Question 23

what are the four nitrogenous bases found in DNA?

Answer 23

adenine (A), guanine (G), thymine (T) and cytosine (C)

Question 24

what groups can the nitrogenous bases in DNA be grouped into?

Answer 24

purines and pyrimidines

Question 25

what nitrogenous bases in DNA are purines?

Answer 25

adenine and guanine

Question 26

what nitrogenous bases in DNA are pyrimidines?

Answer 26

thymine and cytosine

Question 27

what is a purine?

Answer 27

larger nitrogenous bases that contain two carbon ring structures (A and G)

Question 28

what is a pyrimidine?

Answer 28

smaller nitrogenous bases that contain one carbon ring structures (T and C)

Question 29

how are the complimentary base pairings in DNA held together?

Answer 29

by hydrogen bonds (between A+T and C+G)

Question 30

what type and how many bonds form between adenine and its complimentary base?

Answer 30

two hydrogen bonds between adenine and thymine

Question 31

what type and how many bonds form between cytosine and its complimentary base?

Answer 31

three hydrogen bonds between cytosine and guanine

Question 32

what allows a constant distance between the two sugar phosphate backbones of the DNA double helix?

Answer 32

the (smaller) pyrimidine bases always bond to the (larger) purine bases.

Question 33

what does RNA stand for

Answer 33

ribonucleic acid

Question 34

what is RNA?

Answer 34

a nucleic acid that uses information from DNA to synthesise proteins

Question 35

what is RNA made from?

Answer 35

1. **ribose** — a pentose sugar 2. **A, U, G, or C** — nitrogen containing organic base 3. a phosphate group

Question 36

unlike DNA, RNA nucleotides contain the sugar ______ rather than __________. they also contain the base ______ in place of _______. fill in the missing terms:

Answer 36

1. ribose 2. deoxyribose 3. uracil 4. thymine

Question 37

what is RNA?

Answer 37

RNA is a single stranded molecule made up of just one polynucleotide strand, which are much shorter than DNA strands.

Question 38

what pentose sugar does DNA contain?

Answer 38

deoxyribose

Question 39

what pentose sugar does RNA contain?

Answer 39

ribose

Question 40

what bases does DNA contain?

Answer 40

A, T, G, C

Question 41

what bases does RNA contain?

Answer 41

A, U, G, C

Question 42

what is the relative size of DNA?

Answer 42

long

Question 43

what is the relative size of RNA?

Answer 43

relatively short

Question 44

what is the number of strands in DNA?

Answer 44

2

Question 45

what is the number of strands in RNA?

Answer 45

1