Brainscape's Knowledge GenomeTM

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


See full index

DNA Analysis & Interpretation > Lecture 1 - DNA Structure > Flashcards

Lecture 1 - DNA Structure Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

How many base pairs are there in the human genome?

A

~3 billion base pairs

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

What is DNA?

A

DNA is a polymer composed of two polynucleotide chains that coil around each other

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

How many core components do nucleic acids have?

A

Three

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

What are the core components of nucleic acids?

A
  • Base pairs that scan across and they are the true encodings we get information from
  • Phosphate Groups / Phosphodiesters which are along the outside of the backbone
  • Deoxyribose/sugar
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many bases are nucleobases made up of?

A

Four

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

What are the two types of nucleobases?

A
  • Pyrimidines and Purines
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What bases are pyrimidines?

A
  • Cytosine
  • Thymine
  • Uracil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where is uracil primarily found?

A

In RNA

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

What bases are purines?

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

What is the difference between thymine and uracil?

A

Uracil doesn’t have the methyl group that is present in thymine

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

What is cytosine complementary to?

A

Guanine

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

What is Adenine complementary to?

A

Thymine

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

How many hydrogen bonds are there between Adenine and Thymine?

A

2 Hydrogen bonds

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

What is the NH2 bond in Adenine?

A

It is a hydrogen bond donor

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

What is the N in Adenine?

A

Hydrogen bond acceptor

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

How many hydrogen bonds do guanine and cytosine have?

A

3

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

What is the double-bonded oxygen in guanine?

A

Hydrogen bond acceptor

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

What is the NH in Guanine?

A

Hydrogen bond donor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the NH2 bond in Guanine?

A

Hydrogen bond donor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the NH2 bond in cytosine?

A

Hydrogen bond donor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the C=N bond in cytosine?

A

Hydrogen bond acceptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the C=O bond in cytosine?

A

Hydrogen bond acceptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the C=O in thymine?

A

Hydrogen bond acceptor

24
Q

What is the NH bond in thymine?

A

Hydrogen bond donor

25
Q

How is ribose produced?

A

It is metabolically produced from glucose
Glucose gets reducted

26
Q

How is deoxyribose generated?

A

Enzymes called ribonucleotide reductase catalyses ribose 5-phosphate in a deoxygenation process.

27
Q

Why is it helpful that ribose is a sugar?

A

It can go from a planar structure to a cyclic structure.

28
Q

What is a phosphate group?

A

It is a form of PO4-

29
Q

What position does the phosphodiester link?

A
  • In the 5’ to 3’
  • This linkage drivers the helix structure
  • The asymmetric linkage gives DNA strands direction
30
Q

What are the nucleobases?

A
  • Adenine
  • Cytosine
  • Guanine
  • Thymine
  • Uracil
31
Q

What are nucleosides?

A
  • Adenosine
  • Guanosine
  • Cytidine
  • Thymidine
  • Uridine
32
Q

What are the nucleotides?

A
  • Adenosine 5’-phosphate
  • Cytidine 5’-phosphate
  • Guanosine 5’-phosphate
  • Thymidine 5’-phosphate
  • Uridine 5’-phosphate
33
Q

Primary sequence

A

Sequence of nucleotides

34
Q

Duplex formed with strand complementary sequence =

A

Duplex formed with strand complementary sequence = complementary bases in opposite order

35
Q

Longer duplex with higher G-C content =

A

Longer duplex with higher G-C content = More stable

36
Q

What is the complementary sequence?

ATGTCTTGAACA

A
  1. Split strand into three base units - ATG TCT TGA ACA
  2. Write down the complementary bases - TAC AGA ACT TGT
  3. Reverse the order to give strand in the 5’ to 3’ format - TGT TCA AGA CAT
37
Q

Double Helix Structure

General facts

A
  • Right handed
  • 1 turn = 33Å
  • 10.5 nucleotides per turn
  • width = 20 Å
  • Minor groove
  • Major groove
  • 3.3Å base stacking distance
38
Q

Why is a double helix needed?

A
  • Negatively charged phosphate groups along the backbone has electrostation repulsion from each other.
  • Base pairs form hydrogen bonds
  • Stacking of nucleobases through hydrphobic / van der waals interacts compacts duplex vertically.
39
Q

What would happen if the base pairs were separated?

A

Water would get inside the structure and disrupt the hydrogen bonding which isn’t entropically favoured.

40
Q

Why are the base pairs were closely packed in DNA?

A

To allow for pi stacking to occur and to prevent for a hydrophobic collapse.

41
Q

What would happen if the phosphates were closly packed in DNA?

A

If the phosphates wre stacked on top of each other they would want to repel.

42
Q

Alternatice Double Helix Forms

A
  • B-DNA: Right handed
  • A-DNA: Right handed
  • Z-DNA: Left handed
43
Q

B-DNA

A
  • Right handed
  • Most common
  • Found in cells under physiological conditions
44
Q

A-DNA

A
  • Right handed
  • Occurs under dehydrated conditions or in hybrid DNA-RNA
45
Q

Z-DNA

A
  • Left handed
  • DNA undergone methylation
  • Common in some diseases
  • It still has rotation but is not packed as tightly
  • Occurs sporadically due to some diseases
46
Q

Triplex

A

3rd strand binds in major groove

47
Q

G-Quadruplex

A
  • Found in telomeres (ends of chromosomes)
  • Protects DNA ends and stop DNA repair systems from trating them as damaged.
  • Allows copying of ends which wouldn’t be possible with 3’ end.
48
Q

Examples of secondary structures

A

Triplex, B-DNA, etc

49
Q

What can secondary structures form?

A

These in turn can form even larger tertiary structures if the sequences are right

50
Q

Examples of tertiary structures?

A
  • Hairpin
  • Stem-loop
  • Holliday junction
51
Q

DNA vs RNA

A

DNA:
- 2-deoxyribose
- Thymine
- usually double stranded
RNA:
- Ribose
- Further possible H bonding
- Phosphodiesters more easily hydrolysed
- Uracil
- Usually single stranded

52
Q

RNA structures

A

RNA exists in mant complex structures:
- Bulge
- Bubble / interior loop
- Stem-loop
- Hairpin

53
Q

Nucleosomes

A
  • DNA is coiled around proteins called histones to produce nucleosomes, which are further packed to produce chromosomes
  • 8 protein units required for each nucleosome.
54
Q

Nanotechnology

A

Predictable sequence-specific hybridisation can be used to create 3D nanostructures for a wide variety of nanotechnological applications

55
Q
A

DNA Analysis & Interpretation (19 decks)

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