Biochem Module 7 Flashcards

1
Q

DNA Replication

Genetic information contained in the DNA is transferred to RNA molecules and then expressed in the structure of synthesized proteins.

A

The Central Dogma of Molecular Biology

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2
Q

DNA Replication

process by which DNA is copied with very high fidelity.

A

DNA Replication

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3
Q

DNA Replication

involves two replication forks, which move in opposite directions

A

DNA Replication is bi-directional

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4
Q

DNA Replication

  • The leading strand copies continuously
  • The lagging strand copies in segments (Okazaki fragments)
A

DNA Replication is semi-discontinuous.

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5
Q

DNA Replication

DNA in the chromosomes replicates itself every _____ (before mitosis and meiosis I occurs)

A

cell division

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6
Q

DNA Replication

an enzyme which separate the DNA strand breaking the H bonds at the replication fork

A

DNA Helicase

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7
Q

DNA Replication

replicates DNA using each strand as a template for the newly synthesized strand by adding complementary nucleotides.

A

DNA polymerase III

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8
Q

DNA Replication

DNA polymerases have “_________” (exonuclease) activity.

A

proof reading

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9
Q

DNA Replication

an enzyme that unknots and uncoils

A

topoisomerase

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10
Q

DNA Replication

synthesizes short RNA segments called primers that are starting points for DNA polymerase

A

DNA primase

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11
Q

binding to single-stranded DNA

A

SSB (Single-Stranded DNA binding Proteins)

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12
Q

DNA Replication

filling the gaps; eliminates primers

A

DNA Polymerase I

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13
Q

DNA Replication

Ligates Okazaki fragment to rest of lagging strand; enzyme that catalyzes the formation of the phosphodiester bond between pieces of DNA.

A

DNA Ligase

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14
Q

DNA Replication

______ is synthesized as a single strand from the point of origin toward the opening replication fork

A

Leading strand

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15
Q

DNA Replication

is synthesized discontinuously against overall direction of replication

A

Lagging Strand

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16
Q

DNA Replication

series of short segments on the lagging strand

A

Okazaki fragments

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17
Q

DNA Replication

Must be joined together by an enzyme

A

DNA Ligase

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18
Q

DNA Replication

Replication of the leading strand occurs ______in the _____ direction of the new strand.

A

continuously; 5’ → 3’

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19
Q

DNA Replication

Replication of the lagging strand occurs _______. Short DNA fragments are initially synthesized and then ligated together.

A

discontinuously

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20
Q

Transcription

process by which the DNA genetic code is read and transferred to messenger RNA (mRNA). This is an intermediate step in protein expression.

A

Transcription

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21
Q

Transcription

Only one of the DNA strands is copied

A

coding or antisense strand

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22
Q

replicates the DNA sequence into a complementary sequence of mRNA (template or sense strand).

A

RNA Polymerase

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23
Q

He isolated nuclein from the nuclei of pus cells

A

Friedrich Miescher

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24
Q

Nuclein was shown to have
acidic properties, hence it was called ____?

A

nucleic acid

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25
Q

Nucleic acid was previously known as?

A

Nuclein

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26
Q

Two types of nucleic acids

A
  1. Deoxyribonucleic acid (DNA)
  2. Ribonucleic acid (RNA)
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27
Q

carrier of genetic information

A

DNA

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28
Q

an intermediate in the expression of genetic information and other diverse roles

A

RNA

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29
Q

The amino acid sequence of a polypeptide is programmed by a unit of inheritance called ____?

A

gene

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30
Q

True or False

Nucleic acids are polynucleotides

A

True

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31
Q

Building blocks of nucleic acids

A

nucleotides

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32
Q

linkage between the sugar and organic base residues

A

N-glycosidic bond

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33
Q

linkage between the sugar and phosphate residues

A

Phosphoester bond

34
Q

Nucleotides structure

A
  1. pentose sugar
  2. nitrogenous bases
  3. phosphate group
35
Q

What is the difference between Deoxyribose and Ribose in terms of structure, sugar, and nitrogenous base

A

DNA structure:
* double helix
* Carbon 2 does not have oxygen (H)
* A=T ; C=G

RNA structure:
* single strand
* Carbon 2 has oxygen (OH)
* A=U ; C=G

36
Q

What are the 2 types of nitrogenous bases

A
  1. pyrimidines (C, T, & U)
  2. purines (A & G)
37
Q

have six-membered ring

A

Pyrimidines

38
Q
  • have a six-membered ring fused to a five-membered ring
  • Both present in DNA and RNA
A

Purines

39
Q

pyrimidines attach to the pentose via the ____ position while purines attach through the ____ position

A

N-1 ; N-9

40
Q

Energy currency in cellular metabolism

A

ATP

41
Q

Derived from phosphoric acid, H3PO4, at physiological pH exists in the ionic form.

A

PHOSPHATE GROUP

42
Q

A portion of a nucleotide without the phosphate group

A

Nucleoside

43
Q

nucleoside = ?

A

nitrogenous base + sugar

44
Q

True or False

The stereochemistry of the glycosidic bond found in nucleic acids is β

A

True

45
Q

Nucleotide = ?

A

phosphate + sugar + nitrogenous base

46
Q

2 to 10 nucleotide residues

A

Oligonucleotides

47
Q

more than 10 nucleotide residues

A

Polynucleotides

48
Q

Sigma factors recognize two highly conserved regions of the promoter.

A

Transcription: Initiation

49
Q

Nitrogenous bases are attached to the?

A

1st carbon

50
Q

Refers to the helix formed by the interaction of two DNA strands

A

Secondary Structure of DNA

51
Q

Tertiary Structure of DNA: ____

A

Supercoils

52
Q

Transcription: Initiation

two regions within promoters that are highly conserved:

A
  • Pribnow box
  • −35 region
53
Q

Transcription: Initiation

Stretched of 6 nucleotide (TATAAT) located 10 bases before the start of transcription (−10 region)

A

Pribnow box

54
Q

Transcription: Initiation

located ~35 bases upstream of transcription

A

-35 region

55
Q
  • the promoter region has been recognized by the holoenzyme
  • RNA polymerase begins to synthesize the transcript of the DNA sequence, with the release of the sigma factor.
A

Transcription: Elongation

56
Q

does not require a primer

A

RNA polymerase

57
Q

(ahead of the transcription site) – relaxed by gyrase

A

+supercoil

58
Q

(behind) – relaxed by topoisomerase

A

-supercoil

59
Q
  • RNA polymerase encounter a stop signal or transcription terminator (e.g. rho protein in prokaryotes; C-G rich hairpin loop)
  • the RNA polymerase dissociate from the DNA template
  • the RNA transcript is released.
A

Transcription: Termination

60
Q

are sections that code for proteins, and are spliced
together with spliceosomes

A

Exons

61
Q

which do not code for proteins

A

Introns

62
Q

The process by which the genetic code is converted to a protein, the end product of gene expression

A

Translation

63
Q

A change in the nucleotide sequence of DNA altering the sequence of amino acids which will affect the structure and function of a protein in a cell.

A

Mutation

64
Q

types of mutation

A
  1. BASE SUBSTITUTION “POINT MUTATION”
  2. BASE DELETION OR INSERTION
65
Q

BASE SUBSTITUTION “POINT MUTATION”

The codon containing the changed base codes for the same amino acid

A

Silent Mutation

66
Q

BASE SUBSTITUTION “POINT MUTATION”

The change results in a new different amino acid

A

Missense

67
Q

BASE SUBSTITUTION “POINT MUTATION”

The change leads to premature termination if the codon containing the changed base become a termination codon.

A

Non-Sense Mutation

68
Q

BASE DELETION OR INSERTION

Insertion or deletion of one or two bases will alter the reading frame and this cause extensive change in the translated protein.

A

Frame Shift Mutation

69
Q

BASE DELETION OR INSERTION

This lead to the addition of new amino acids (if three bases were inserted), or to the deletion of one amino acid (if three bases were deleted).

A

Insertion or deletion of one codon or “3 nucleotides”

70
Q

True or False

Each cell contains
about 2 meters of DNA

A

True

71
Q

Arises from supercoiling that involves double helices being twisted into tighter, more compact shapes

A

Tertiary Structure of DNA

72
Q

DNA is “packaged” by coiling around a core of proteins known as?

A

histones

73
Q

rich in lysine and arginine residues

A

histones

74
Q

DNA-histone assembly

A

nucleosome

75
Q

Types of RNA

A
  1. Messenger RNA (mRNA)
  2. Ribosomal RNA(rRNA)
  3. Transfer RNA (tRNA)
76
Q

carrier of genetic information from the DNA in the cell nucleus to the site of protein synthesis in the cytoplasm

A

mRNA

77
Q

True or False

mRNA directs amino acid sequence of proteins and is complementary copy of the gene

A

True

78
Q

True or False

mRNA has a short lifetime and Has the codon (three bases) for an amino acid in a protein

A

True

79
Q

mRNA is also known as?

A

The starting point of translation

80
Q
  • forms ribosomes by reacting with proteins
  • accounts for 80-85% of the total RNA of the cell
A

rRNA

81
Q
  • Transfers amino acids to the site of protein synthesis
  • Has the anticodon
A

tRNA

82
Q

True or False

tRNA is the largest of the nucleic acids

A

False

tRNA is the smallest