Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochemistry > DNA Lecture 5 > Flashcards

DNA Lecture 5 Flashcards

1
Q

Any regular, stable structure adopted by the nucleotides in the nucleic acid

A

DNA Secondary Structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the shape of DNA?

A

Double Helix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

DNA is comprised of two complementary strands of

A

Polydeoxyribonucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What term describes how the opposite strands of DNA are arranged?

A

Anti-Parallel

5’—–>3’
(3’—–>5’)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

In DNA, the ratio of A/T and G/C is…

A

1:1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How many base pairs per repeat were determined in the x-ray diffraction pattern produced by wet DNA fibers?

A

10 base pairs per repeat

Layer line spacing is 1/10 of the pattern repeat, 10 resides/turn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

These interactions are important to double helix stability

A

Base stacking interactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Base pairing is only possible if the major _____ forms are present. Other base pairs would form but they’re less favorable

A

Tautomeric

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The fact that strands are complimentary suggested a model for DNA replication.

In the replication process, base pairs are formed through _____

A

Hydrogen bonding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

A bonds to T through ___ H bonds

G bonds to C through ____ H honds

A

2

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Each stand can act as a template for a new complimentary strand, and two new daughter DNA molecules are formed which are identical in sequence to the parent molecule

A

!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Are hydrophilic backbones of alternating deoxyribose and phosphate groups on the outside or inside of the double helix?

Purine and pyrimidine bases are on the outside or inside of the double helix?

A

Outside, facing water

Inside

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The furanose ring of each deoxyribose is in the _____ endo conformation

A

C-2’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Hydrophobic and nearly planar rings are very close together and parallel/perpendicular to the long axis

Offset pairing of the two strands creates a major and minor ____

A

Perpendicular

groove

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The three types of DNA are..

A

A-DNA
B-DNA
Z-DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

This type of helix corresponds to the curvature of your left hand as you move along the helix in the direction of your thumb

This type is the opposite

A

Left Handed Helix

Right Handed Helix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The sugar phosphate backbone forms a right handed helix in ______ DNA

In _____ DNA the sugar phosphate backbone forms a left-handed helix

A

A and B DNA

Z DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Indicates the angle of rotation of one base pair relative tot he neighboring base either above or below it in the helix

If there are 10 steps per turn, then the rotation per step (base pair) is

A

Rotation per base

36 degrees

19
Q

This corresponds to the step height per nucleotide

A

Helical rise per base pair

20
Q

In B-DNA, the avg. rise is

In A-DNA, its

The rise corresponds mainly to the ___ of a pyrimidine or purine ring

A
  1. 33nm
  2. 23nm

Thickness

21
Q

Defined as the distance along the helix axis corresponding to one turn

A

Pitch

22
Q

Rotation about the C-N bonds (glycosidic bond) moves the base away from or on top of the deoxyribose ring. What is it called in both circumstances?

A

Anti - away from

Syn - On top of the deoxyribose ring

23
Q

In all nucleotides in DNA, four of the five atoms are in a single plane.

The fifth atom (C-2’ or C-3’) is on the same side of the plan relative to the C-5’, and this is called

When the fifth atom is on the opposite side of the plan relative to the C-5’, it is called

A

Sugar Pucker Confirmations

Endo

Exo

24
Q

The most stable structure for a random sequence DNA molecule under physiological conditions is..

It’s the form that Watson and Crick proposed

A

B-DNA

25
Q

In this DNA form the bases lie close to the helix axis (center of the helix) and the base pairs are approximately perpendicular to the helical axis

The phosphate groups are on the surface of the helix. They will come into contact with the solvent

A

B-DNA

26
Q

The B-form has major and minor grooves.

What do they result from?

What does this allow for B-DNA, but not A-DNA?

A

The glycosidic bonds between the sugars and bases in a given base pair not being directly opposite one another

B-DNA can accommodate a spine of water molecules lying in the minor groove

27
Q

This type of DNA is favored in many solutions which lack water

A

A-DNA

28
Q

What type of helix is A-DNA? Same as B-DNA.

What’s different?

A

Right handed

11 base pairs per turn (wider helix)

29
Q

In this form of DNA, the bases come out farther from the helix axis, and the plane of the base pairs is tilted about 20 degrees with respect to the helix axis.

Does the A-form have grooves?

A

A-DNA

Yes and they are equal in depth

30
Q

Is there evidence that A-DNA occurs in cells?

A

No.

31
Q

This type of DNA is a left handed double helix. It is more slender and elongated

A

Z-DNA

32
Q

How many base pair per helical turn in Z-DNA?

A

12

33
Q

Describe the appearance of Z-DNA

A

Zig-Zag

34
Q

Does Z-DNA have grooves?

A

One deep helical groove, it is the minor groove and is narrow and deep

35
Q

Certain ______ sequences fold in left-handed Z-helices

A

Nucleotide

ex) Sequences with alternating pyrimidine and purine residues —-C&G, or 5-methyl C&G

36
Q

Is Z-DNA found in the cell?

A

Yes, short stretches in both prokaryotes and eukaryotes

37
Q

What role might the short tracts of Z-DNA play in prokaryotes and eukaryotes?

A

Regulation of gene expression or genetic recombination

38
Q

Structural variations have been detected with larger chromosomes which are sequence dependent, and the function and metabolism of DNA segments in their vicinity may be affected

When ______ or more _____ residues appear sequentially in one strand, bends occur. This may be important for ________

A

4 or more adenine strands

It may be important for protein binding

39
Q

A word or phrase that is spelled identically when read forwards or backwards, and is applied to regions of DNA with inverted repeats of base sequence

What structures can result?

A

Palindromes

Hairpin or cruciform

40
Q

When an inverted repeat occurs within each individual strand of DNA, a _____ is formed

A

Mirror Repeat

41
Q

In this type of position/pairing, the N-7, O6 and N6 of purines, the atoms that participate in hydrogen bonding are called

The non-Watson-Crick pairing is called

What can result?

A

Hoogsten positions

Hoosten Pairing

Triplex DNAs

42
Q

Four DNA strands can also pair to form a _____ if a very high proportion of____ residues is present

A

Tetraplex; guanine

43
Q

This type of DNA is found in polypyrimidine or polypurine tracts that also incorporate a mirror repeat

A

H-DNA

Biochemistry (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions