Kandpal Flashcards
(97 cards)
1
Q
Central dogma of molecular biology
A
DNA –> RNA –> protein
2
Q
What are the constituents of DNA?
A
DNA is a polymer of 4 bases and a five carbon sugar (deoxyribose); alternating sugar and phosphodiester bonds create backbone; bound to other strands by hydrogen bonds
3
Q
M phase
A
mitosis & cytokinesis
4
Q
POLI
A
low processivitiy (DNA repair); for rRNA
5
Q
POLII
A
somewhat high processivity;
involved in repair;
for mRNA
6
Q
POLIII
A
DNA replication;
for tRNA
7
Q
In what direction does replication occur?
A
5’ –> 3’
8
Q
Topoisomerase I
A
only cuts one strand
9
Q
Type II topoisomerase
A
relieves overwinding; ATP dependent
10
Q
Primase
A
synthetsizes an RNA as a primer; absolute requirement for replication!
11
Q
RNA is removed by
A
POLI
12
Q
DNA ligase
A
seals the gap between okasaki fragments
13
Q
Novobiocin
A
binds to the B subunit of gyrase
14
Q
Rifiampin
A
binds to beta-subunit of Pol to block initiation
15
Q
Actinomycin D
A
acts through blocking movement of RNA polymerase; ring gets stuck b/n 2 GC (minor groove of DNA)
16
Q
Zidovudine (AZT)
A
analog of deoxy thymidine; prevents DNA chain elongation by reverse transcriptase
17
Q
End replication problem
A
when the replication fork reaches the end there is no place for an RNA primer for the last Okazaki fragment
18
Q
Telomere
A
piece of DNA which does not code for any protein but has repeating adenine base pairs; used to seal off ends of chromosomes and facilitate replication
19
Q
Telomerase
A
extends the leading strand DNA synthesis into the telomere
20
Q
Histone
A
highly alkaline proteins found in eukaryotic cell nuclei; package and order DNA
21
Q
What is the fundamental subunit of chromatin?
A
nucleosomes
22
Q
Heterochromatin
A
tightly wound, inaccessible
23
Q
Euchromatin
A
loose, available
24
Q
Genomic imprinting
A
certain genes are expressed in a parent-of-origin specific manner; ex: Prader-Willi and Angelman syndromes
25
Prader-Willi syndrome
paternal inheritance of a deletion of 15q11-13
26
Angelman syndrome
maternal inheritance of same deletion as Prader-Willi
27
Pyrimidine base
Cytosine, Thymine, Uracil; 6-membered ring; two N + 4 Cs
28
Purine base
Adenine, Guanine; 9-membraned double-ring system; 4 Ns + 5 Cs
29
Transitions
purine replaced with a purine or a pyrimidine replaced with a pyrimidine
30
Transversion
purine replaced with a pyrimidine or vice versa
31
Uracil glycosylase
eukaryotes don't want uracil in their DNA so this recognizes and cleave it
32
Misincorporation
creates a distortion in the structure; strand directed mismatch repair decides which strand is correct
33
Base excision repair
specific base is removed and repaired
34
Nulceotide excision repair
stretch of DNA strand is removed and new strand with correct base is synthesized
35
Hereditary nonpolyposis colon cancer (HNPCC)
due to a mismatch repair deficiency; if there is an inherited mutation in one copy of mismatch repair gene, there is a predisposition to this; second copy of gene is spontaneously mutated
36
DNA polymerase
moves from 3' - 5' (same direction as RNA synth); the replicate strand is building in the opposite direction
37
Promotors of prokaryotes have 3 characteristics:
1. -10 sequence
2. -35 sequence
3. separation between two above
38
Promotors of eukaryotes are one of 3 types:
1. TATA containing: TATA is at -25 and -35
2. Initiator containing: initiator is a consensus sequence surrounding the start site of transcription
3. TATA-less and initiator-less promotors: GC rich island of about 100 nucleotides upstream of the initiation start site
39
Ribosomal RNA (rRNA)
transcribed by RNA polymerase I; rRNA + protein combine to form a ribosome that serves as the site of protein synth
40
Messenger RNA (mRNA
transcribed by RNA polymerase II; carries the genetic code from the nucleus to the cytoplasm where protein synth occurs
41
Transfer RNA (tRNA)
transcribed by RNA polymerase III; reads the genetic code from the mRNA and carries the amino acids needed to be incorporated into the developing protein
42
Prokaryotic mRNA
unmodified ends; several proteins made from one mRNA
43
Eukaryotic mRNA
uncoupling of transcription and translation by the nuclear membrane
44
What carries out transcription?
RNA Polymerase
45
Where does RNA polymerase bind?
promoter region
46
Promoter
region of nucleotides that promotes transcription
47
RNA polymerase
made up of 5 subunits; sigma subunit recognizes promoter
48
Transcription factors
regulate initiation
49
Rifampin
inhibits E Coli RNA polymerase thereby blocking new RNA from synth
50
Alpha-amantin
inhibits E Coli, Pol II and Pol III
51
Pit-1
transcription factor specific for pituitary development essential to human growth hormone
52
Silent mutation
a mutation in the codon that does not lead to a change
53
Missense mutation
a substation of one amino acid for another
54
Nonsense mutation
replacement of a sense codon with a stop codon
55
Frameshift mutation
insertion of deletion of one of two bases
56
Erythromycin
inhibits transcription by binding to the 50s ribosome
57
Chloramphenicol
inhibits peptidyl transferase in prokaryotes
58
Tetracycline
binds the 30s ribosome and prevent aminoacyl-tRNA binding
59
Streptomycin
binds to the 30s bacterial ribosome to prevent initiation of protein synth
60
Puromycin
causes premature chain termination in protein synth
61
Kozak sequence
located 3 base pairs upstream from start codon; plays major role in initiation of translation process
62
Translation
RNA --> proteins
63
Transcription
DNA --> RNA
64
Thrombopoeitin (TPO)
regulates the production of platelets
65
Hereditary thrombocyotpenia
autosomal dominant disorder;
attributed to mutations in TPO genes
sx: high levels of TPO, high platelet counts;
66
Specificity factors
enzymes that change the RNA poly specificity for promoters
67
Transcription factors
complex of proteins that position the RNA pol onto the protein coding template
68
Repressors
bind to non-coding sequences on the DNA strand that are close to or overlapping the promoter region
69
Activators
enhance the binding between RNA pol and its promoter, encouraging the expression of a gene
70
Enhancers
short regions of DNA that bind to activators in order to enhance transcription
71
Exons
codes for a protein
72
Introns
does not code for a protein; gets spliced out
73
Alternative splicing
eons of the RNA produced by transcription are reconnected in multiple ways during RNA splicing resulting in different protein isoforms
74
Receptor mediated endocytosis
uptake of soluble proteins and high mol weight material
75
Coat-recruitment GTPases
control the assembly of clathrin, COPI and COPII coats
76
Rab proteins
important for regulating flow of vesicles to correct target membrane
77
SNAREs
proteins mediate fusion with the target membrane
78
Zellweger syndrome
empty peroxisomes; won't last long after bith
79
I-Cell disease
phase-dense intracytoplasmic inclusions in the fibroblasts; won't live long but will survive longer than Zellweger pts
80
Hereditary emphysema
deficiency in a1-antitrypsin which normal inhibits trypsin; without this elastase is not inhibited and is then able to degrade fine lung tissue
81
What does viagra inhibit?
The degradation of cGMP which is what causes relaxation of smooth muscle after being activated by GTP
82
PKG
requires NO; activated cGMP
83
What is HSP90 and what does it do?
inhibitory protein that is released upon ligand binding, freeing the COOH end to wrap around the ligan
84
Olfactory signal transduction
activates adenylate cyclase, elevates cAMP
85
Rhodopsin signal transduction
light activated and photon acts as ligand; activated cGMP PDE and lowers cGMP which --> closure of Na+ channels which --> hyper polarization which inhibit synaptic signaling
86
Sanger method
for known and unknown mutations;
can detect SNPs/point mutations, deletions, insertions;
used in BRCA1/2 testing
87
Alpha-thalassemia
Hg is a tetramer of 2 alpha and 2 beta parts; chrome 16 has 3 copies of normal alpha-globin genes
88
Positional cloning
method of gene identification in which a gene for a specific phenotype or disease is identified; links the disease to a region of genome by using polymorphic markers
89
Neurofibromatosis 1
autosomal dominant disease linked to chromosome 17 (determined through linkage mapping);
sx: brownish spots on skin, benign nodules on iris, neurofibromas
90
Gene therapy
use of DNA as a pharmaceutical agent to treat diseases
91
Ex vivo gene therapy
correct the defect in pt's cells outside of the body and then inject the correct cells
92
In vivo gene therapy
directly inject the cloned gene
93
Hardy-Weinberg equilibrium
states that both allele and genotype frequencies in a population remain constant from generation to generation unless specific distributing influences are introduced;
p2 + 2pq + q2 = 1
94
What are the 4 assumptions of the HW equilibrium?
1. Mutation is not occurring
2. Natural selection is not occurring
3. Completely random mating
4. There is no migration in or out of population
95
Chromosomal mapping
linkage analysis that involves logarithm of likelihood ratios for a marker's linkage to a gene vs no linkage
96
Recombinant fraction
indicative of genetic distance that can be converted into an approximate physical distance
97
LOD score
logarithm of ratio of likelihoods; likelihood of linkage b/n two loci at a specific recombination fraction :: likelihood that loci are unlinked
