Exam 4 - Quiz 1 Flashcards Preview

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Flashcards in Exam 4 - Quiz 1 Deck (22):
1

In nucleic acids, the difference between deoxyribose and ribose lies at which carbon?

2'

2

In nucliec acids, the nitrogenous base is attached to the ____ carbon of the sugar

1'

3

Which of the following bases has a single heterocyclic ring structure?
Cytosine
Adenine
Thymine
Two of the above
None of the above

Two of the above
Cytosine and Thymine

4

The DNA double helix resembles the structure of a spiral staircase. Which DNA component is analogous to the spiral staircase's banister (side rails)?

The sugar-phosphate backbone

5

The form of DNA found in living cells is

B-DNA

6

The percentage of cytosine in a bacterial genome was determined to be 20%. What is the percent of Adenine?

30 %

A%= T% C% = G%
A% + T% + C% + G% = 100%

C% = 20%
G% = 20 %
A% + T% = 60% 60%/2 = 30%

7

The 5' end of nucliec acid molecule refers to the _______ group on the 5' carbon of the first nucleotide.

Phosphate

8

How many hydrogen bonds would connect the DNA sequences CATG and its complement on the other strand in a double helix?

10
C => 3 bonds
A => 2 bonds
T => 2 bonds
G => 3 bonds
Total 10 bonds

9

Which of the following bases has a double heterocyclic ring structure?
Cytosine
Guanine
Thymine
Uracil
None of the above

Guanine
Guanine and Adenine have double heterocyclic ring structures

10

For double-stranded DNA which of the following base ratios ALWAYS equal 1?
A/G
C/T
C/G
Two of the above
All of the above

C/G

Chargaff's Rule

A = T ; C = G

11

Deoxyribonucleotides lack a ______
Nitrogenous base
5' Phosphate
3' hydroxyl group
2' hydroxyl group
Pentose sugar

2' hydroxyl group

12

Ribonucleosides lack a ______
Nitrogenous base
5' phosphate group
3' Phosphate group
2' hydroxyl group
Pentose Sugar

5' phosphate group
Ribonucleosides lack 5' phosphate group

13

Which of the following is NOT a difference between RNA and DNA?
- RNA is generally shorter than DNA
- RNA is usually single-stranded whereas DNA is double-stranded
-RNA contains ribose whereas DNA contains deoxyribose
-RNA contains uracil whereas DNA contains thymine
- All of the above are differences

All of the above are differences

14

The double-stranded DNA molecule of the newly discovered Elradicus libanii was found by electron microscopy to have a length of 17 micrometers. How many base pairs are present in this molecule?

50,000

1 micro meter = 1000 nanometer (nm)

10 base pairs (BP) in one complete turn
One turn = 3.4 nm
(17,000 nm / 3.4 nm) = 5000 turns
5000 turns * 10 BP = 50,000

15

The double-stranded DNA molecule of the newly discovered Elradicus libanii was found by electron microscopy to have a length of 17 micrometers. How many complete turns of the helix are present in this molecule?

5,000 turns

1 micro meter = 1000 nanometer (nm)

10 base pairs (BP) in one complete turn
One turn = 3.4 nm
(17,000 nm / 3.4 nm) = 5000 turns

16

A nucleic acid molecule that has 20% A, 30% C, 20% G and 30% T is most likely?

single-stranded DNA single-stranded RNA double-stranded DNA double-stranded RNA

Single- stranded DNA

Chargaff's rule
In double-stranded, DNA

A = T; G = C
A and T are not equal, therefore it's a single stranded DNA

17

A large nucleic acid molecule that has 20% A, 30% C, 30% G and 20% U is most likely?

single-stranded DNA single-stranded RNA double-stranded DNA double-stranded RNA

Double stranded RNA

T is replaced with U, therefore it's RNA

Chargaff's rule is full-filled. It's double stranded

18

A double-stranded DNA molecule is 5,000 base-pairs long. How many complete turns are present in this molecule?

500
10 base pairs per turn
5000/10 = 500

19

A double-stranded DNA molecule is 5,000 base-pairs long. How long is this molecule?
170 nm
500 A
1.7 micrometers
0.17 micrometers
none of these choices

1.7 micrometers

5,000 / 10 = 500 turns

500 turns * 3.4 nm = 1700 nm
1700 nm/ 1000 = 1.7 micrometers

20

When DNA is ______, hydrogen bonds are broken.
renatured
denatured
saturated
polymerized

Denatured

21

For double-stranded DNA which of the following base ratios ALWAYS equals 1?
(A+T)/(C+G)
(A+G)/(C+T)
(G+T)/(A+C)
two of the above
all of the above

Two of the above
(A+G)/(C+T)
(G+T)/(A+C)

Chargaff
1. A + G = T + C
2. A = T ; C = G
3. A + T almost never equals to C + G

22

Which of the following DNA molecules is the most thermodynamically stable?
5’GGGGAAAACCCCTTTT 3’
3'CCCCTTTTGGGGAAAA 5’

5’AGCGCGCAGCGTTTTT 3’
3’TCGCGCGTCGCAAAAA 5’

5’AAAGGAATTCCGTTAA 3’
3’TTTCCTTAAGGCAATT 5’

5’AAAAAAGGGGGGTTTT 3’
3’TTTTTTCCCCCCAAAA 5’

5’GCATCGAGGCCGGCTG 3’
3’CGTAGCTCCGGCCGAC 5’

5’GCATCGAGGCCGGCTG 3’
3’CGTAGCTCCGGCCGAC 5’