Unit 3 Flashcards
(119 cards)
1
Q
nonsense mutation
A
causes premature stop codon
2
Q
nonconservative
A
single nucleotide replaced resulting in a change in amino acid and chemical property(ie. polar to non polar)
3
Q
conservative
A
single nucleotide resulting in amino acid change but chemical properties remain the same(ie. basic to basic)
4
Q
silent
A
change in single base but amino acid is the same
5
Q
DNA Proofreading
A
base paired wrong, fix single nucleotide error in the sequence during synthesis; cuts nucleotide off and base is added back in
6
Q
Mismatch pair
A
same error as Proofreading but is fixed after synthesis; chunk is removed and polymers comes back and fixes it; ligase fills gap
7
Q
Excision Repair
A
from Uv damage, two types
8
Q
Base excision repair
A
takes put single base, polymerase fills it and ligase seals it
9
Q
Nucleotide Excision Repair
A
base and backbone damaged; fills gap and links pieces
10
Q
Purpose of DNA synthesis
A
make new DNA
11
Q
Primase
A
synthesizes RNA primer; synthesis of a short RNA strand that is complementary to single-stranded DNA
12
Q
Helicase
A
unzips DNA
13
Q
Topoisomerase
A
untwists and relieves pressure
14
Q
SSBP
A
binds to single strand to keep. them apart
15
Q
ligase
A
joins strands back together
16
Q
telomerase
A
adds DNA to make up for loss in replication; maintains chromosome
17
Q
template strand
A
used as direct template for mRNA
18
Q
coding strand
A
commentary to template strand; same as mRNA strand
19
Q
Purpose of transcription
A
make RNA copy of DNA
20
Q
Purpose of translation
A
turn mRNA into a protein
21
Q
tRNA
A
carries amino acid to ribosome
22
Q
initiation
A
mRNA enter ribosome at A site bind to start codon in P site; translation begins
23
Q
elongation
A
aminoacyl tRNA moves into A site- Anticodon binds to codon; peptide bond forms with amino acid in P site; translocation
24
Q
translocation
A
ribosome moves a codon over after peptide forms between tRNA in the A and P site
25
termination
ribosome reaches stop codon and release factors trigger hydrolysis of bond between tRNA and Polypeptide chain; subunits separate
26
A-site
where tRNA initially binds to mRNA
27
P-site
tRNA attaches to polypeptide chain and amino acid is transferred
28
E-site
uncharged tRNA exits ribosome
29
tRNA synthetase
ensures that tRNA binds to correct amino acid based on anticodon sequence
30
DNA polymerase
replicates DNA by adding nucleotides; hand-like orientation allows it to "grab on to" DNA
31
Synthesis of Okazaki Fragments
5'--> 3' using lagging strand template;
32
Replication of the linear ends of eukaryotic chromosomes results in an unreplicated end due to:
Primer is degraded on the lagging strand and synthesis of the final base pairs cannot proceed
33
Primary Structure of Nuclliec Acid
Phosphodiester bonds form between phosphate of one base to the sugar of another; nucleotide sequence determine structure
34
Antiparallel Orientation
DNA strands run opposite of each other; 5' of one orients with 3' of the other
35
Polymerization of nucleic acids occurs by _________reaction that forms ________ bonds.
condensation; Phosphodiester
36
True or False: Okazaki fragments would be unnecessary if DNA polymerase could synthesize DNA in both the 5' and 3' directions.
True
37
release factor
binds to stop codon in A-site triggers release of polypeptide chain
38
CCA
where amino acid attaches to tRNA
39
Splicing
introns are removed from RNA strand in transcription
40
Where is the start codon located?
at the downstream end of the 5' untranslated region (UTR)
41
Bacterial RNA polymerase
synthesizes RNA
42
frame shift mutation
insertion/deletion of a nucleotide so that the reading frame shift
43
T/F: Both frameshift and point mutations can occur in any DNA sequence.
False
44
True or False: The lac operon is transcribed at the highest rate when extracellular glucose and lactose are abundant.
False
45
alternative splicing
removes/excludes exons
46
LAC operon
works when there's no glucose to breakdown lactose
47
Proximal Promoter
binds to gene-specific transcription factors; control initiation of transcription
48
Transcription factors
bind to DNA to regulate transcription
49
TRP
acts as co-repressor; binds to TRP repressor and inhibits transcription; difficult to make so don't usually use
50
Decondonsed chromatin
accesible
51
condensed
inaccesible
52
What regulation do
bacteria employ?
Allosteric
53
chromatin
complex on DNA and proteins
54
True or False: The repressor protein is bound to DNA of the operator when lactose is present.
false
55
Purines
adenine and guanine
56
Pyrimidines; 9 atoms
cytosine, uracil, thymine; 6 atoms
57
Number of hydrogen bonds between A and T
2
58
Number of bonds between C and G
3 bonds
59
Why is RNA versatile?
single stranded; can catalyze chemical reactions
60
Role of RNA
expression; easy access and DNA is to stable
61
Ribozyme
RNA as an enzyme
62
Sliding Clamp
holds DNA polymerase in place
63
Hersey Chase Experiment
DNA is genetic material
64
Semiconservative(Nelson-Stahl)
strands separate and become template; made of one new and one old
65
Start of DNA synthesis in bacteria
Bubble opens up
66
Replication Fork
bubble opens; strands separate and proteins bind
67
solution for lagging strand
small segments(ozaki fragments) allow for lagging strand to be read in 5' -->3'
68
Central Dogma of Biology
DNA codes for RNA, RNA codes for proteins
69
Where does translation occur?
Ribosomes in the cytoplasm
70
Where does transcription take place?
nucleus
71
genotype
determined by bases
72
phenotype
what's expressed
73
Genetic code is redundant bc ...
allows for errors-code for same amino acids
74
genetic code is Unambiguous
never more than one amino acid per codon
75
genetic code is universal
same in all organisms
76
conservative
amino acids with similar properties are encoded by similar ones
77
missense
changes in amino acid
78
chromosomal deltion
loss of genes
79
chromosomal inversion
backwards
80
chromosomal duplication
additional copies of chromosome segment
81
chromosomal translocation
piece breaks off and fuses to another chromosome
82
+1 site on DNA
first nucleotide to be transcribed
83
promoter
sequence where RNA polymerase binds to begin transcriptions
84
TATA Box
identify start of transcription; binding site for RNA polymerase
85
exon
final mRNA; expressed
86
intron
primary transcript not in mRNA
87
What does transcription synthesize?
non-template/coding strand
88
What does DNA synthesis synthesize?
leading or lagging stand
89
Transcription Initiation in Bacteria
sigma binds to promoter and twists so transcription can start; allows polymerase to bind
90
Sigma
bacterial initiator of transcription
91
5' cap
add to finshed mRNA to make it mature and ready for transcription: protection
92
Poly (A) Tail
added to 3' end of mRNA to stabilize it
93
Splicisome
removes non-coding segments from pre-mRNA: removes introns: post-transcriptional
94
Transcriptional Control
regulatory proteins affect ability of RNA polymerase to bind to promoter; transcription can't start
95
Translational control
regulatory molecules alter amount of time and mRNA survives or affect one of the processes
96
Posttranslational Control
chemical modification
97
Negative control
inhibit expression
98
Positive control
promote expression
99
LAC operon repressor
binds to DNA and prevents transcription
100
Lactose effect on LAC operon
induces by binding to repressor; changes its shape and repressor comes off
101
CAP effect on LAC operon
signals regarding availability of glucose and lactose
102
Permase
facilities transport of lactose into bacterial cell; lactose turn off/on the LAC operon
103
Structure of Chromatin
DNA wrapped around proteins(histones)
104
activators
increase rate of transcription of target genes
105
repressors
inhibit/reduce transcription of specific region of genes
106
Chromatin Remolding
change structure of DNA to allow access for DNA transcription
107
RNA Processing
capping and splicing
108
Histones
provide structure for DNA wrapping
109
nucleosome
histones on string of DNA
110
Heterochormatin
condensed
111
uchromatin
uncondensed/unwrapped
112
DNA methylation
add methyl group, enzymes recognize and condense DNA
113
Histone Modification: Acetylation
lysine added, becomes (-),(-) pair with DNA so DNA opens
114
Histone Modification: Phosphorylation
opens DNA; phosphate is (-)
115
chromatin remolding complex
open DNA by moving nucleosome
116
Epigentic
environmental changes(reversible)- inheritable- can be good or bad
117
operons
cluster of genes controlled by one set of regulatory mechanisms; regulated by presence of nutrient; inducible and repressible
118
Inducer Exclusion
glucose blocks transport of other sugars like lactose
119
