Unit 1 Chapter 4: Nucleic Acids

Question 1

What is a nucleic acid

Answer 1

a polymer made up of monomers called nucleotides

Question 2

What are the 3 components of a nucleotide

Answer 2

5C sugar, nitrogenous base and a phosphate group (phosphate bonded to sugar which is bonded to N-base)

Question 3

What is a sugar

Answer 3

an org. compound with a carbonyl group and several hydroxyl groups

Question 4

Which carbon is the phosphate group attached to in the nucleotide

Answer 4

5’

Question 5

What are the differences between RNA and DNA

Answer 5

• ribose vs. deoxyribose
• OH at 2’ C vs H at 2’C
• single strand vs. double
• hairpin vs. double helix
• uracil vs. thymine

Question 6

Purines

Answer 6

guanine. adenine

* larger than pyrimidines

Question 7

Pyrimidines

Answer 7

cytosine, thymine, uracil

Question 8

How do nucleotides polymerize to form RNA and DNA

Answer 8

by forming phosphodiester linkages through condensation rxns (between the phosphate group of one nucleotide and the hydroxyl group of the sugar of another)

Question 9

A phosphodiester linkarge joins the ______carbon on the ribose of one nucleotide to the ______carbon on the ribose of another

Answer 9

5’, 3’

Question 10

The sugar-phosphate backbone of a nucleic acid is

Answer 10

directional (one strand goes 5’ -> 3’ and the other goes 3’ -> 5’)

Question 11

The sequences of bases found in RNA/DNA are always written in the ____ direction

Answer 11

5’->3’

Question 12

Where are new bases added

Answer 12

3’ end

Question 13

The primary structure of a nucleic acid is

Answer 13

the sequence of nitrogenous bases

Question 14

Are base pairs located in the interior or exterior of the double helix

Answer 14

interior

Question 15

What does the phosphate group do for nucleotide

Answer 15

make it charged

Question 16

What do N-bases do

Answer 16

store info

Question 17

Why do organisms living in high temperatures have more C and G bases

Answer 17

because they have one more H-bond which makes them stronger

Question 18

Which carbon do N-bases bond to on the 5 C sugar

Answer 18

1st C

Question 19

What did Rosalind Franklin do

Answer 19

collected the X-ray diffraction pattern of DNA and also helped discover the double helix

Question 20

What type of bonds form between base pairs

Answer 20

H-bonds

Question 21

What does the addition of one or more phosphate groups do

Answer 21

raises the pot. energy of substrate molecules enough to make an otherwise endergonic rxn possible

Question 22

Where does most DNA and RNA synthesis occur

Answer 22

the nucleus

Question 23

What are the 2 empirical rules of DNA

Answer 23

1. # of purines=# of pyrimidines

2. # of A and T are equal and # of C and G are equal

Question 24

DNA strands are… (direction)

Answer 24

anitparallel

Question 25

How many H bonds form between each base pairing

Answer 25

- 2 between A and T | - 3 between C and G

Question 26

What part of DNA is hydrophob/philic/ what is the whole molecule?

Answer 26

inside is phobic, outside is philic, total is hydrophilic

Question 27

How is DNA stabilized

Answer 27

hydrophobic interactions in the interior and H-bonding between base pairs

Question 28

What is the secondary structure of DNA

Answer 28

double helix

Question 29

Who discovered the double helix

Answer 29

watson and crick with help from the findings of rosalind franklin

Question 30

How is DNA copied (3 steps)

Answer 30

1. heat or enzyme rxns cause double helix to separate 2. free deoxyribonucleotides form H-bonds with complementary bases on the original DNA making a template strand (direction opposite to og strand) 3. complementary base pairing allows each double helix to be copied making 2 daughter molecules

Question 31

Is DNA or RNA more stable, why

Answer 31

DNA because it doesnt have the OH on its 2'C and its antiparallel strands form a double helix

Question 32

What are the 2 functions of a self replicating molecule

Answer 32

1. carry info | 2. perform catalysis

Question 33

What is the primary structure of RNA

Answer 33

sequence of nucleotides

Question 34

Which evolved first DNA or RNA

Answer 34

RNA

Question 35

What is the secondary structure of RNA

Answer 35

- results from base pairing | - hair pin(single strand =loop, double =helix)

Question 36

How do the secondary structures of RNA and DNA differ

Answer 36

in RNA bases undergo H-bonding with complementary bases on the SAME strand where in DNA they bond with those on a different strand

Question 37

What is the tertiary structure of RNA

Answer 37

forms that fold distinctive 3D shapes

Question 38

What is the quaternary structure of RNA

Answer 38

associations between several RNA molecules

Question 39

What is the intermediate between the complexity of proteins and simplicity of DNA

Answer 39

RNA

Question 40

Are N-bases more accessible in the major or minor groove of the DNA helix

Answer 40

major