Brainscape's Knowledge GenomeTM

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


See full index

BioChemistry > Chapter 9: Nucleic Acids > Flashcards

Chapter 9: Nucleic Acids Flashcards

1
Q

Types of nucleic acids

A

RNA (ribonucleic acid) and DNA (Deoxy ribonucleic acid).

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

Functions of nucleic acids

A
  1. Responsible for storage.
  2. Transfer of information needed for protein synthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

DNA

A

Consists of 2 strands and has primary, secondary, and tertiary structures.

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

DNA primary structure

A
  1. DNA.
  2. Nucleotides.
  3. Backbone of DNA.
  4. Nitrogenous bases.
  5. Polynucleotides.
  6. Order of nucleotides.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

DNA primary structure: DNA

A

Formed of deoxyribonucleoside mono phosphate:
1. dGMP
2. dAMP
3. dTMP
4. dCMP

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

DNA primary structure: nucleotides

A

Linked by phosphodiester bond between the 5 OH of 1 nucleotide and the 3 OH of the next nucleotide.

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

DNA primary structure: backbone of DNA

A

Formed of alternating phosphate and sugar.

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

DNA primary structure: nitrogenous bases

A

Projecting to the inside of the 2 strands.

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

DNA primary structure: polynucleotides

A

Each polynucleotide strand has 2 terminals:
1. 5’ end: free phosphate attached to the 5’ end of the pentose.
2. 3’ end: free 3’ OH.

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

DNA primary structure: order of nucleotides

A

5’ to 3’ direction (direction of synthesis of DNA).

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

DNA secondary structure

A

Proposed by Watson and crick in 1953 and won the Nobel prize in 1962.

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

DNA secondary structure characters

A
  1. 2 anti parallel strands forming a right-handed helix.
  2. Complementary base pairing.
  3. Stacking of bases.
  4. Spiral staircase.
  5. Dimensions.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

2 anti parallel strands forming right handed double helix

A

The 2 strands run anti parallel:
1. Runs in 5 to 3.
2. Runs 3 to 5.

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

Complementary base pairing

A
  1. Adenine and thymine by 2 hydrogen bonds.
  2. Guanine and Cytosine by 3 hydrogen bonds.
    Number of adenine is equal to number of thymine.
    Number of guanine is equal to number of cytosine.
  3. The sequence of 1 strand determines the sequence of the other.
  4. Important for DNA replication in which one strands acts as a template for synthesis of a new strand.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Stacking of bases

A

The nitrogenous bases are stacked above each other by:
1. Van der waal forces.
2. Hydrophobic interaction.
The stability of the double helix is maintained by:
1. Hydrogen bonds between bases.
2. Van der waals forces.
3. Hydrophobic interactions.
Excessive stacking of bases is balanced by negative charges of the phosphate groups.

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

Spiral staircase

A

The double helix of DNA appears like a spiral staircase or twisted ladder.

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

Dimensions

A

Each turn: 3.4 nm, 10.4 bp.
2 grooves:
- Major groove: 2.2 nm.
- Minor groove: 1.2 nm.
Many drugs and proteins bind to DNA through these grooves without the need to open the helix (regulation of gene expression).

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

Desaturation of DNA

A

Rupture of hydrogen bonds and separation of the 2 DNA strands.

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

Desaturation of DNA occurs by

A

Heating

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

Denaturation of DNA is associated with

A

Hyperchromicity (increased absorption of UVL).

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

Renaturation or Renannealing

A

Rebinding of the 2 strands.

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

Renaturation occurs by?

A

Cooling

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

Renaturation melting point

A

Temperature that produces loss of 50% of DNA helical structure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Structural forms of the double helix

A
  1. B form: described by Watson and crick.
  2. A (anyhydride) form.
  3. Z (zig zag) form.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

I

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

B- DNA type of helix

A

Right handed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

A-DNA

A

Right handed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Z DNA

A

Left handed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

A DNA shape

A

Shorter and thicker

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Z DNA shape

A

Longer and thinner

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

B DNA Major groove

A

Wide and deep

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

A DNA major groove

A

Narrow and deep.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Z DNA

A

Flat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Variation on major groove

A

Affect binding of regulatory proteins to DNA which may be important in regulation of gene expression.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

B DNA site

A

Major DNA in the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

A DNA site

A

Dehydrated DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Z DNA

A

Formed of alternating CG bases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

DNA tertiary structure

A
  1. DNA is mainly linear.
  2. Circular DNA.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Circular DNA is present in?

A
  1. Mitochondria.
  2. Plants (chloroplast).
  3. Bacteria.
40
Q

Super coiling of DNA may be:

A

Positive supercoil: more tight.
Negative supercoil: less tight.

41
Q

What type of coils are more present under physiological conditions?

A

Negative supercoils.

42
Q

Supercoiling of linear DNA

A
  1. Toroidal.
  2. Inter wound coil.
43
Q

Toroidal

A

DNA is coiled around a cylinder.

44
Q

Interwound coil

A

DNA cross over and under itself.

45
Q

Supercoiling of circular DNA

A
  1. Right handed supercoil.
  2. Left handed supercoil.
46
Q

Circular DNA in mitochondria

A

Eukaryotes have circular DNA in mitochondria.

47
Q

Plasmid

A

Circular double stranded DNA present in prokaryotes (bacteria).

48
Q

Chromatin

A

DNA in non dividing cells.

49
Q

Chromatin LM

A

Not visible

50
Q

Chromatin EM

A

Network of fibrils and fibers like beaded thread.

51
Q

Chromosome

A

Condensed DNA appears just before cell division (double DNA).

52
Q

Chromatid

A

Each chromosome is formed of two identical chromatids.

53
Q

Each chromatid consists of:

A
  1. Single DNA molecule.
  2. Histone proteins.
  3. Non histone proteins.
54
Q

Histone proteins

A

Basic protein rich in basic amino acids (Arginine, lysine, and histidine).

55
Q

Charge of Histone proteins

A

Positively charged (note that DNA is negatively charged).

56
Q

Histones site

A

Attached to DNA at the minor groove.

57
Q

Types of Histone proteins

A
  1. H1.
  2. H2A.
  3. H2B.
  4. H3.
  5. H4.
58
Q

Histones play a role in:

A
  1. DNA Supercoiling.
  2. Regulation of gene expression.
59
Q

Nucleosome

A

Simple unit of chromatin.

60
Q

Nucleosome is formed of

A
  1. Core protein (Histone octamer): 2 copies of (H2A, H2B, H3, and H4.
  2. One and 3 quarters turns of toroidal DNA: 140 bp.
61
Q

Nucleosome shape

A

Nucleosome are linked by linker (spacer) DNA (60 bp) like beads on a string. H1 is attached to linker DNA.

62
Q

Non Histone proteins

A
  1. Attached to major groove.
  2. Important for regulation of gene expression and help in replication and transcription.
63
Q

Structure of chromosome

A
  1. Formed of 2 identical chromatids connected at the centromere.
  2. Centromere is rich in A=T base pairs
64
Q

Telomere

A

End of chromatid.

65
Q

Telomere is formed of?

A

Variable repeats (several kilo bases long) of specific sequence which is (TTAGG).

66
Q

Packing of DNA

A

Supercoiling of DNA is important for its packing in the nucleus.

67
Q

Largest human chromosome is packed in to how many um?

A

Largest human chromosome is 82mm in length and is packed into 10 um long and 1 um in diameter.

68
Q

Levels of Supercoiling

A

Start from packing of DNA around Histone octamer forming Nucleosome reaching the level of a chromosome.

69
Q

Mitochondrial DNA percentage

A

0.3%-1% of total cellular DNA.

70
Q

Mitochondrial DNA shape

A

Circular double stranded DNA.

71
Q

MtDNA inheritance

A

Maternally inherited (provided by ovum).

72
Q

MtDNA function

A

Formation of 22 tRNA, 13 protein, and 2 rRNA for oxidative phosphorylation or ETC.

73
Q

MtDNA defect

A

Myopathies

74
Q

MtDNA replication

A

By DNA polymerase y

75
Q

Gene

A

Sequence of nucleotides on DNA coding for a certain character (protein).

76
Q

Alleles

A

2 similar genes on the 2 chromosomes coding for the same character.

77
Q

Genome

A

Total genetic information (all genes on all cells).

78
Q

Exons (expressed sequence)

A

Coding sequence of DNA, unique and never repetitive.

79
Q

Introns

A

Non coding sequence, repetitive.

80
Q

Discontinuity of DNA

A

DNA is discontinuous, coding sequence (exons) is separated by non coding sequence.

81
Q

Percentage of exons

A

2% the rest is non coding.

82
Q

Introns function

A

Introns decrease the incidence if mutations and regulate gene expression.

83
Q

Introns site

A

Intervening sequence that stay in the nucleus.

84
Q

Chromosomes

A

Condensation of DNA (each chromosome contains hundreds to thousands of genes. Each cell has 2 copies of each chromosome (parental and maternal).

85
Q

Number of chromosomes

A

Each cell contains 23 pairs of chromosomes:
22 pairs autosomal.
1 pair sec chromosome (XY or XX).

86
Q

Haploid

A

Haploid number of chromosomes are present in the gametes (ova and sperms).

87
Q

Genotype

A

What is on the inside the gene.

88
Q

Homozygous

A

The 2 genes are similar.

89
Q

Heterozygous

A

The 2 genes are different.

90
Q

What is hemizygous?

A
91
Q

Phenotype

A

The physical or biochemical expression of genotype.

92
Q

Why can the same genotype give more than 1 phenotype?

A

As many characters as skin, hair color, height, DM) are influenced by many genes and by the environment.

93
Q

RNA structure

A
  1. Formed of ribonucleoside mono phosphate (AMP, GMP, CMP, UMP).
  2. Nucleotides are connected by phosphodiester bond between 5 OH of 1 nucleotide and 3 OH of the next nucleotide.
  3. Single stranded.
94
Q

RNA function

A

Responsible for protein synthesis.

95
Q

Types of RNA

A
  1. mRNA (messenger RNA).
  2. rRNA (ribosomal RNA).
  3. tRNA (transfer RNA).

BioChemistry (8 decks)

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