Genetics Flashcards
1
Q
The flow of genetic information
A
Central dogma
2
Q
Flow of central dogma
A
Replication
Transcription
Translation
3
Q
DNA will replicate into DNA
A
Replication
4
Q
DNA is transcribed to mRNA, tRNA and rRNA
Only one strand of DNA is copied
After this process the DNA strands rejoin
A
Transcription
5
Q
RNA to protein
Process where ribosomes synthesize proteins using the mature mRNA transcript produced during transcription
Synthesis of proteins
Uses Genetic Code
A
Translation
6
Q
RNA transcribed to DNA
A
reverse transcription
7
Q
Enzyme responsible for catalyzing reverse transcription
A
Reverse transcriptase
8
Q
Virus utilizing reverse transcriptase
RNA - DNA
A
HIV
hepa B
9
Q
Presence of several factors lead to disease
A
Mutation
Environment
10
Q
RNA translated into amino acid and is then facilitated to become protein via folding by
A
chaperone
11
Q
CHON misfolding lead to
A
disease
12
Q
A group of proteins that have functional similarity and assist in protein folding
A
Chaperones
13
Q
Protein misfolding will lead to either
A
Degradation
Aggregation
14
Q
Aggregates of tau protein
Improper protein folding
A
Alzheimer’s disease
15
Q
3 famous diseases that result from protein misfolding
A
Alzheimer’s
Huntington’s
Creutzfield Jacob Disease
16
Q
Double stranded polymer of nucleotides
A
DNA structure
17
Q
Nucleotides are linked by a
A
phosphodiester bonds
18
Q
Each nucleotide is made up of a
A
Base and Sugar
19
Q
Sugars of DNA
A
Deoxyribose
Phosphate
20
Q
DNA structure:
A
Base
Deoxyribose sugar
Phosphodiesterase bond
21
Q
The DNA is a double helix with the arrangement of strands in
A
antiparallel strands
22
Q
DNA starts from the
A
R side
Antiparallel
Double stranded
23
Q
Double-stranded
Helical
Antiparallel
Right-handed
A
Watson and Crick Model
24
Q
Sugar-Phosohate backbone
Nitrogenous base pairs
Held by H bond
A
Watson and Crick Model
25
The DNA structure according to the Watson and Crick model is what type of DNA?
B form
26
Forms of DNA
B form
A form
Z form
27
R handed
With 11 residues/turn
28 A helix pitch
2.55 Rise/residue
A-DNA
28
How many angstroms are there in B DNA?
34 A
29
How many residues per turn in B DNA
10
30
Rise/Residue in B DNA
3.4
31
Chromatin consists of very long double stranded DNA molecules and a nearly equal mass of rather small basic proteins
Histones
32
Anti histones is encountered in
Drug induced SLE
33
Drug inducing lupus include
Procainamide
Isoniazid
Methyldopa
Hydralazine
34
DNA is wound around this protein
Histone
35
```
Deoxyribose
Pyrimidine: C and T
Double stranded
follows Chargaff’s rule
Preserves genetic information
Found in 2 copies of diploid cells in eukaryotes
```
DNA
36
Only pyrimidine in RNA
Uracil
37
```
Ribose
Pyrimidine: C and Uracil
Single stranded
Does not follow Chargaff’s rule
Performs various biologic functions
Multiple copies
```
RNA
38
Factors that stabilize DNA
Cooperative H bonding
Stacking interaction
Van der Waals forces
Ion-ion interactions
39
Attraction
Repulsion
between molecules and atoms
Weak intermolecular force
Van der Waals Forces
40
Correspondence between a sequence of bases and a sequence of amino acids
The Genetic Code
41
The Genetic Code (three-base codons) are found on
mRNA
42
Termination codons
UAG
UGA
UAA
43
The properties of the Genetic Code
Universal
Contiguous
Degenerate
Unambiguous (specific)
44
Redundant, because a single amino scid may be coded for by more than one codon
Degenerate
45
Watson and Crick double-stranded model of DNA strongly suggests that replication of the DNA molecule occurs in a
semiconservative manner
46
Remain intact in two separate daughter DNA
| Are hybridized with an entirely new complementary strands
Parental strand
47
Where protein synthesis occurs
Rough ER
48
Transfers the genetic information from the nucleus where the DNA is located to ribosomes where protein synthesis is performed
Codon
49
The link between the nucleotide and the amino acid sequence of the mRNA and the amino acid sequence of the protein
Anticodons
50
The base sequence t RNA which pairs with codon of mRNA during translation
anticodon
51
Anticodon can easily be changed at this position
Wobble position
52
Initiation codon
| Starts protein synthesis
AUG
53
AUG initiating codon codes for the amino acid
Methionine
54
The template began by initiating codon
mRNA
55
Are an important factor in cutting short the length of the protein chain
Stop codon
56
Type of mutation associated with stop codon
Nonsense
stop talking nonsense
57
Nucleic acids
DNA (deoxyribobucleic)
| RNA (ribonucleic)
58
Nucleotide components
Inorganic phosohate
Simple sugar
Nitrogenous base
59
Base + Sugar + Phosphate =
Nucleotide
60
Two types of nitrogenous bases
Purine
| Pyrimidine
61
Purine amino acids
Adenine
Guanine
PURe as gold
62
Pyrimidine amino acide
Cytosine
Thymine
Uracil
RNA
Cut the PY
63
Are derivatives of purines and pyrimidines that have a sugar linked to a ring nitrogen of a purine or pyrimidine
Nucleoside
| N-glycoside
64
The sugar in ribonucleosides is
D-ribose
65
The sugar in deoxyribonucleosides is
2-deoxy-D-ribose
66
Both sugars are linked to the heterocycle by this bond always to the N1
alpha 1 gycosidic bond
67
Cytosine + cytidine
Cytidine monophosphate CMP
68
Uracil + Uridine
Uridine monophosphate UMP
69
Thymine + Thymidine
Thymidine monophosphate TMP
70
Chargaff’s rule states that DNA from any cell of all organisms should have a 1:1 ratio of
Pyrimidine and purine
71
The amount of gusnine is equal to cytosine and the amount of adenine is equal to thymine
Chargaff’s rule
72
The conjugated double bonds of purine and pyrimidine derivatives absorb
Ultraviolet light
Nucleotides absorb UV light
73
All the common nucleotides absorb light at a wavelength close to
260 nm
74
The concentration of nucleotides and nucleic acids thus often is expressed in terms of
absorbance ar 260nm
ex. photospectometry
75
The mutagenic effect of UV light is due to
absorption by nucleotides in DNA that result in chemical modifications
76
The wavelength in nm used in the quantitative determination of nucleic acids using UV spectrophotometry is
260 nm
77
In man, end product of purine metabolism is
uric acid
78
In animals, uric acid is converted into
Allantoin, allantoate, urea
79
Hypoxanthine
Xanthine
Uric acid
6-oxopurine
| 2,6 dioxopurine
80
An addictive trimethylxanthine
Caffeine
81
Dimethyl-xanthines that lack the methyl group at N1 and N7
Theobromine
| Theophylline
82
Uric acid metabolism
Ribose 5 PO4 (HMP/Pentose)
5-phosphoribosyl-1-Pyro PO4 (PPRP)
Adenosine monophosphate, inosine monophosphate, guanosine monophosphate
83
Inosine monophosphate becomes
Inosine
84
Inosine becomes
Hypoxanthine
85
Hypoxanthine becomes
Xanthine by enzyme xanthine oxidase
86
Xanthine becomes
Uric acid by the enzyme xanthine oxidase
87
Catalyzes conversion of inosine to hypoxanthine
HGPRT
88
Rate limiting step in uric acid synthesis
Xanthine oxidase
89
Salvage reaction for purine nucleotide
Hypoxanthine Guanine Phosphoribosyltransferase HGPRT
90
A hypoxanthine analog that competitively inhibits xanthine oxidase
Allopurinol
91
Another drug that competitively inhibits xanthine oxidase
Febuxostat
92
Acute Gout attack treatment
Colchicine
93
Chronic gout attack treatment
Allopurinol
94
Their toxic effects reflect either inhibition of enzymes essential for nucleic acid synthesis or their incorportation into nucleic acids with resulting disruption of base pairing
Synthetic nucleotide analogs are used in chemotherapy
95
Synthetic nucleotide pyrimidine and purine analogs used in chemotherapy
```
5-fluoro or 5-iodouracil
flucystosine
6-mercaptopurine
allopurinol
cytarabine
azathioprine
```
96
Chemotherapy drug of choice for AML
Cytarabine
97
Following exposure to nucleophiles (glutathiones) this drug is cleaved to 6-mercaptopurine which in turn is converted to additional metabolites that inhibit de novo purine synthesis
Azathioprine (Imuran)
98
Metabolite of azathioprine
6-mercaptopurine
99
Derivative of mercaptopurine
Prodrug
Cleaved to 6-mercaptopurine then to 6-mercaptopurine nucleotide, thioinosinic acid (nucleotide analog)
Inhibits de novo synthesis of purines required for lymphocyte proliferation
Prevents clonal expansion of both B and T lymphocytes
Azathioprine
100
DUMP is converted to TMP by the enzyme
Thymidylate synthase
101
5-FU inhibits conversion of dUMP to TMP by
inhibiting thymidylate synthase
102
Inhibits dihydrofolate reductase
Methotrexate
103
Folate is converted to tetrahydrofolate via
Dihydrofolate reductase
104
Tetrahydrofolate is used in conversion to
Thymine
| Purine
105
Severe X-linked disease
Nearly total absence of HGPRTase activity
Lesch-Nyhan Syndrome
106
Mental retardation
Self-mutilation
Aggressive behavior
Gout / hyperuricemia
Lesch-Nyhan HGPRTase deficiency
107
Rare hereditary condition
High levels of orotic acid in urine
Absent orotate phophoribosyltransferase and orotate monophosphate decarboxylase
Orotic aciduria
108
```
With hyperammonemia (no megaloblastic anemia)
Orotic aciduria
```
Decreased OTC (urea cycle)
109
Orotic aciduria
| Megaloblastic anemia
Deficiency of U ??
110
The three processes that contribute to purine nucleotide biosynthesis are
Synthesis from amphibolic intermediates (synthesis de novo)
Phosphoribosylation of purines
Phosphorylation of purine nucleosides
HGPRTase
Xanthine oxidase
111
The major site for purine nucleotide biosynthesis is the
liver
112
alpha ribose 5 phosphate will be converted to
Final product is
Phosphoribosyl pyrophosphate PRPP
Via PRPP synthetase
First step
Inosine monophosphate
113
Adenine is converted to AMP by
Adenosine phosphoribosyl transferase
114
Hypoxanthine becomes IMP via
Hypoxanthine guanine phosphoesterase ?
115
Conversion of IMP to AMP and GMP is via
IMP dehydrogenase
| Transaminidase
116
IMP is converted into
AMP
| GMP
117
Synthesized from amphibolic intermediates
In the same pathway there is synthesis and degradation
Inosine monophosphate
118
Mutation of PRPP synthetase
Abnormal PRPP amidotransferase structure
Partial HGPRTase deficiency
Hyperactive glutathione reductase
Gout
119
Contains actual genetic information coding for protein
Exons
120
Are intervening noncoding segments of DNA
Introns
121
The sequence of a gene that is represented (expressed) as mRNA
Serve as the template
Exon
mRNA
122
An enzyme that cleaves nucleotides from either the 3’ or 5’ ends of DNA
Exonuclease
123
An enzyme that cleaves internal bonds in DNA or RNA
Endonuclease
124
The removal of introns from RNA accompanied by the joining of its exons
Splicing
125
Informational metabolism
Major Processes
Central Dogma
Replication
Transcription
Translation
126
Informational metabolism
Subprocesses
Initiation
Chain elongation
Termination
127
```
Pre-priming stage
Chain initiation
Chain elongation
Polymerization
Removal of primer
Sealing of nicks
```
Replication
128
Unwinding of DNA by helicase
Binding of ssDNA-Binding Protein (DBP)
Formation of swivels by DNA topoisomerases
Pre-Priming Stage
129
Synthesis of RNA primer by RNA polymerase and primase
Chain initiation
130
Leading strand synthesized by
Single DNA strand replicates in the 3’ - 5’ direction
5’
| RNA polymerase
131
Lagging strand synthesized by
3’
| Primase
132
Synthesis of daughter strands
Synthesis proceeds in 5’ to 3’ direction
Addition of nucleotides by DNA polymerase III and I
Chain elongation
133
Formation of daughter strands by DNA Polymerase I
Leading strands and lagging strands
Polymerization
134
Lagging strands are also
short sequences of DNA nucleotides linked or joined by enzyme DNA ligase
Okazaki fragments
135
Removal of RNA Primer
Replacement of RNA primer with DNA by DNA Polymerase I
Replication
136
Transcription is facilitated by the enzyme
Synthesizes RNA primer during chain initiation
RNA polymerase
137
mRNA is processed before leaving the nucleus
Non coding introns are removed
Remaining sections are spliced together -> functional mRNA
Processing
138
Binding of RNA Polymerase to DNA template
Initiation of polymerization
Chain Elongation
Chain Termination
RNA Transcription
139
Type I Antibiotic Transcription Inhibitors
Bind to RNA polymerase
Rifampicin
| Streptolygidin
140
Type II Antibiotic Transcription Inhibitor
Bind to DNA Template
Actinomycin D
141
Type III Antibiotic Transcription Inhibitors
Inhibit topoisomerases/gyrase
Coumermycin
Nalidixic acid
Novobiocin
quinolone
142
Swivel formation is caused by
DNA polymerase/topoisomerase
| DNA gyrase
143
sealing of nicks during replication is done by
also joins Okazaki fragments
DNA ligase
144
Discontinuity in double stranded DNA
No phosphodiester bond
Nick
145
```
Helicase unwinds DNA
SSB prevents reannealing
Primase makes primers
DNA polymerase III adds additional base nucleotides extending primers
Lagging strand is made discontinuously
DNA Polymerase 1 removes primers
Okazaki fragments ligated by DNA ligase
Leading strand made continuously
```
DNA replication
146
Spontaneous realignment of two single DNA strands to reform a double helix
Reannealing
147
Prevents reannealing
SSB
