Topic 2-2

Question 1

the “gold standard” technique to resolve the 3D structures of molecules such as proteins

Answer 1

x-ray crystallography

Question 2

in DNA, base pairs are:

Answer 2

complementary. A pairs with T, C pairs with G

Question 3

what is DNA composed of?

Answer 3

two nucelotide polymer antiparallel strands, and a sugar phosphate backbone

Question 4

how are base pairs held together in dsDNA?

Answer 4

hydrogen bonds

Question 5

what is the advantage to having hydrogen bonds (as opposed to covalent bonds) hold base pairs together?

Answer 5

allows separation of the molecules for replication

Question 6

solving the 3D structure of DNA explained ______ rules about the ratios between A, T, C, and G bases

Answer 6

Chargaff’s

Question 7

what is the biggest difference in the ribose sugars of DNA and RNA?

Answer 7

in RNA, the 2’ carbon has a hydroxyl group attached, and in DNA, the 2’ carbon has a hydrogen

Question 8

why do purine bases only pair with pyrimidine bases (as opposed to other purines and vice verse)?

Answer 8

maintains specific diameter of the DNA molecule

Question 9

which purine base pairs with which pyrimidine base is dictated by:

Answer 9

the number of hydrogen bonds they form

Question 10

how many hydrogen bonds form between adenine and thymine?

Answer 10

2

Question 11

how many hydrogen bonds form between cytosine and guanine?

Answer 11

3

Question 12

in nucleotides, the phosphate group is bound to the ______ carbon of the deoxyribose sugar.

Answer 12

5’

Question 13

during DNA synthesis, the phosphate group of one nucleotide is covalently bonded to:

Answer 13

the 3’ carbone of another nucleotide

Question 14

what are the two exceptions to the central dogma?

Answer 14

1) major information pathways: information can be transferred from one DNA molecule to another
2) special information pathways: in some viruses, information can be transferred from one RNA molecule to another

Question 15

why is our genetic material made of DNA and not RNA?

Answer 15

DNA is more stable due to the 2’H, and RNA is more reactive due to the 2’OH (forms more H-bonds)

Question 16

in single strands of nucleotides, when sequences of nucleotides on the same strand are inverted complements, this is known as:

Answer 16

hairpin structure

Question 17

RNA molecules may contain numerous _______, allowing them to fold up into complex structures

Answer 17

hairpins

Question 18

complx secondary structures in RNA allow it to take on:

Answer 18

catalytic activity

Question 19

is DNA capable of catalytic activity?

Answer 19

no

Question 20

does RNA polymerase require a primer to start synthesis?

Answer 20

no

Question 21

can copy RNA into DNA

Answer 21

reverse transcriptases

Question 22

what is the RNA world hypothesis?

Answer 22

it is thought that the first genetic material in the first life forms was likely RNA, and not DNA