Lecture 13 - Nucleic acid structure

Question 1

Information encoded in a DNA molecule is transcribed via

Answer 1

synthesis of an RNA molecule

Question 2

The sequence of the RNA molecule is “read” and is translated into

Answer 2

the sequence of amino acids in a protein

Question 3

Nucleic acids are

Answer 3

linear polymers built from similar units connected end to end

Question 4

Nucleotide

Answer 4

each monomer unit

Question 5

A single nucleotide consists of

Answer 5

a sugar, a phosphate, and one of four bases

Question 6

DNA and RNA differ in

Answer 6

the sugar component and in one of the bases

Question 7

The prefix deoxy indicates that the _____ carbon lacks oxygen

Answer 7

2’

Question 8

The sugars in nucleic acids are linked to each other by

Answer 8

phosphodiester bridges

Question 9

Nucleic acid backbone

Answer 9

The chain of sugars linked by phosphodiester bridges

Question 10

Which groups join to phosphate groups

Answer 10

3’ and 5’ OH groups

Question 11

Purine bases

Answer 11

adenine and guanine

Question 12

Pyrimidine bases

Answer 12

cytosine, thymine, and uracil

Question 13

Which nucleic acid is more prone to hydrolysis?

Answer 13

RNA

Question 14

A nucleoside is a

Answer 14

base linked to a sugar

Question 15

A nucleotide is a

Answer 15

base linked to a sugar and phosphate

Question 16

Nucleoside units in RNA

Answer 16

adenosine, guanosine, cytidine, uridine

Question 17

Nucleosides in DNA

Answer 17

deoxyadenosine, deoxyguanosine, deoxycytidine, and thymidine

Question 18

Rotation about the ________ gives rise to syn and anti conformations in nucleosides

Answer 18

N-glycosidic bond

Question 19

In nucleosides, the _____ conformation is generally favored

Answer 19

anti

Question 20

Nucleoside triphosphates are

Answer 20

nucleosides joined to three phosphoryl groups

Question 21

Where does the energy come from in ATP?

Answer 21

Energy is released from the cleavage of the triphosphate group

Question 22

NADH stands for

Answer 22

Nicotinamide adenine dinucleotide

Question 23

NADH exists in what two forms

Answer 23

NAD+ (oxidized), and NADH (reduced)

Question 24

ACG indicates that

Answer 24

the unlinked 5’-P group is on A and the unlinked 3’-OH group is on G

Question 25

In DNA, the 5’ end is usually attached to a

Answer 25

phosphate group

Question 26

In DNA, the 3’ end is usually attached to a

Answer 26

free hydroxyl group

Question 27

How is DNA or RNA written?

Answer 27

from 5’ to 3’

Question 28

Nucleic acids carry information in the form of

Answer 28

a sequence of bases

Question 29

The two strands of DNA base pair through

Answer 29

hydrogen bonds

Question 30

Are chains in DNA parallel or antiparallel?

Answer 30

antiparallel

Question 31

Which regions of DNA are more stable?

Answer 31

G:C rich regions (3 H-bonds compared to 2 in A:T)

Question 32

The DNA double-helix is stabilized by

Answer 32

• Hydrogen bonds
• Base stacking interactions (vdW)
• Hydrophobic interactions

Question 33

Which interaction most stabilizes DNA?

Answer 33

base-stacking

Question 34

In a double helix, the pyrimidine and purine base lie on the

Answer 34

inside of the helix

Question 35

The major groove in the double helix is large enough to accommodate

Answer 35

an alpha helix from a protein

Question 36

Which alpha-helix motif interacts with DNA?

Answer 36

Zinc finger

Question 37

Regulatory proteins (transcription factors) can recognize

Answer 37

the pattern of bases and H-bonding possibilities in the major groove

Question 38

The Watson-Crick model of DNA is also known as the ______ helix

Answer 38

B-DNA

Question 39

Most DNA is in the ___ form

Answer 39

B-DNA

Question 40

B-DNA is more _____ than A-DNA

Answer 40

hydrated

Question 41

The A-form of DNA is what shape compared to the B-form?

Answer 41

wider and shorter

Question 42

The structural differences between B-DNA and A-DNA come from

Answer 42

different sugar puckerings

Question 43

Dehydration of DNA drives it to the

Answer 43

A-form

Question 44

What is unique about Z-DNA

Answer 44

It is left-handed

Question 45

Z-DNA is a derivative of

Answer 45

B-DNA

Question 46

Where is Z-DNA found?

Answer 46

In G:C rich regions

Question 47

DNA molecules in human chromosomes are ______ while in bacteria and archaea they are ______

Answer 47

linear: circular

Question 48

The most common nucleic acid secondary motif is a

Answer 48

hairpin-loop