Chapter 2 Flashcards
(131 cards)
1
Q
gene
A
series of DNA nucleotides that generally codes for the production of a single polypeptide or mRNA, tRNA, or rRNA
2
Q
eukaryotes
A
have more than one copy of one gene
3
Q
prokaryotes
A
have one copy of each gene
4
Q
genome
A
entire DNA sequence of an organism
5
Q
Central Dogma
A
DNA is transcribed to RNA which is translated to AA forming a protein
6
Q
DNA
A
polymer of nucleotides
7
Q
Purines
A
adenine and guanine – two ring structures
8
Q
pyrimidines
A
cytosine and thymine – single ring structures
9
Q
phosphodiester bonds
A
how nucleotides are bound to each other – btwn the 3rd carbon of one deoxyribose and the phosphate backbond of a single strand of DNA
10
Q
5’-3’ directionality
A
3’ carbon attached to an -OH group and the 5’ carbon is attached to a phosphate group
11
Q
anti parallel, double stranded
A
two DNA strands lie side by side in opposite 3’->5’ directions, bound together by H bonds btwn nitrogeneous bases to form a structure
12
Q
base pairing
A
this hydrogen bonding is commonly referred to as ___
13
Q
length of DNA measured in
A
bp
14
Q
complementary strands
A
purine-pyrimidine pairs adenine and thymine and guanine and cytosine
15
Q
double helix
A
when complementary strands bind together
16
Q
DNA replication is semi conservatice
A
new double strand created, contains one strand from the originial DNA and one newly synthesized strand
17
Q
bidirectional process
A
two replisomes proceed in opposite directions along the chromosome making replication a _____ process
18
Q
DNA polymerase
A
enzyme that builds the new DNA strand, only add nucleotides to an exisiting strand
19
Q
primer
A
primase creates an RNA ____ approximately 10 ribonucleotides long to initate the strand
20
Q
lagging strand
A
made up of Okazaki fragments
21
Q
DNA ligase
A
ties Okazaki fragments together
22
Q
semidiscontinuous
A
since the lagging strand replication is fragmented
23
Q
leading strand
A
continuous new strand
24
Q
replication steps
A
helicase unzips , rna polymerase builds a primer, dna polymerase assembles the leading and lagging strands, primers are removed, okazaki fragments are joined
25
telomeres
repeated 6 nucleotide units that protect chromosomes from being eroded through repeated rounds of replication
26
RNA
has a hydroxyl group attached, single stranded, contains pyrimidine uracil, not confined to the nucleus
27
mRNA
delivers DNA coded for AA to the cyotosol where the proteins are manufactured
28
rRNA
combines with proteins to form ribosomes, synthesized in the nucleolus
29
tRNA
transfer RNA, collects AA in the cytosol and transfers them to the ribosomes for incorporation into a protein
30
transcription
RNA is manufactured from a DNA template
31
intiatition
beginning of transcription, a group of proteins called iniation factors finds a promter on the DNA strand, and assembles a transciption iniation complex which includes RNA polymerase
32
RNA polymerase
prokaryotes have one, eukaryotes have three
33
promoter
a sequences of DNA nucleotides that designates a beginning point for transcription
34
elongation
RNA polymerase transcibes only one strand of the DNA nucleotide sequence into a complementary RNA nucleotide sequence
35
termination
requires special termination sequence and special proteins to dissociate RNA polymerase from DNA
36
activators and repressors
bing DNA close to the promoter and either activate or repress the activity of RNA polymerase; often allosterically regulated by small molecules such as cAMP
37
operon
genetic unit consisting of the operator, promoter, and genes that contribute to a single prokaryotic mRNA
38
primary transcript
addition of nucleotides; deletion of nucleotides; modification of nitrogenous bases
39
5' cap
5' end is capped in a process using ATP; serves as an attachment site in protein synthesis and as a protection against degradation of exonucleases
40
poly A
3' end is poladenylated with a ___ to protect against exonucleases
41
introns and exons
primary transctipt is cleaved into introns and exons; introns stay in nucleus, exons exit nucleus to be translated
42
snRNPs
recogonize nucleotides sequences at the ends of the introns
43
spliceosome
several snRNPs+ proteins; introns cut out and exons are put together -- makes single mRNA
44
denatured
when heated, put in high concentration salt solution or high pH solution, h bonds are disrupted and the two strands of the double helix are separated
45
nucleic acid hybridization
DNA-DNA, DNA-RNA, RNA-RNA ; enable scientists to identify nucleotide sequences by binding a known sequence with an unknown sequence
46
restriction enzymes
cut nucleic acid only at certain nucleotide sequences along the chain
47
palindromic sequence
restriction site will be a ______ _____ four to six nucleotides long
48
recombinant DNA
artifically recombined DNA, DNA fragments cleaved by the same endonucleaes can be joined together regardless of the origin of the DNA
49
vector
what to use to insert DNA into a bacteria
50
plasmid
what recombinant DNA could be placed into
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clone
large quantity of DNA containing the vector with the recombinant DNA fragment
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library
clones can be saved separately producing a clone _____
53
screened
Libraries can be ___ for the appropriate clones, that have the appropriate resistances
54
probe
radioactively labeled complementary sequence of the desired DNA fragment
55
complementary DNA
mRNA is produced by the DNA is reverse transcribed using reserve transciptase
56
PCR
double strand DNA amplified placed in a mixture with many copies of two DNA primers, mixture is heated and cooled; heat resistant polyermase is added, amplifies the comp strands which double amount of DNA, exponential increase of DNA
57
anneal
hybridize; to their complementary ends of the DNA strands
58
southern blotting
DNA to be identified is cleaved into restriction fragments; fragments move according to size by gel electrophoresis, large frags move more slowly, gel is made alkaline to denature DNA, membrane used to blot the gel that transfers the single strand DNA onto the membrane, probe with nucleotide sequence complementary to the target fragment is added to the membrane, add probe made from DNA or RNA; visualize with radiographic film
59
northern blot
identifies RNA fragments v
60
western blot
detect a protein with antibodies
61
RFLP
identified individual as opposed to identifying specific genes
62
genetic code
translates the DNA nucleotides sequence into an AA sequence that ultimately form into a protein
63
degenerative
more than one series of 3 nucleotides may code for any AA
64
unambiguous
single series of 3 nucleotides will code for one AA
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almost univeresal
nearely every living organism uses the same code
66
codon
3 consecutive nucleotides on a strand of mRNA
67
stop codons
UAA, UGA and UAG
68
start codon
AUG
70
anticodon
tRNA contains a set of nucleotides that is complementary to the codon
71
ribosome
rRNA with protein, provides site for translation to take place
72
small and large subunit
made from rRNA and many separate proteins, assembled in nucleolus, exported to the cytoplasm
73
nucleolus
complex structure of ribomsomes requires this
74
P site
tRNA with 5'-CAU-3' anticodon sequesters the AA methionine and settles in at the
75
iniation complex
large subunit to join and form the
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iniation
tRNA and large subunit coming together
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elognation
tRNA with its AA attaches to A site at the expense of two GTP
78
translocation
ribosome shifts 3 nucleotides along the mRNA toward the 3'end , the first tRNA moves toward E site where it can exit the ribosome
79
termination
translation ends when a stop codon is reached. release factors bing to the A site allowing a water moleculte to add to the of the polypeptide chain, polypeptide is freed from the tRNA and the ribosome, ribosome breaks up its subunits to be used again
80
post translational modification
sugar, lipids or phosphate groups may be added to AA ,
81
translation location
may happen in the cytosol or the ribosome may attach itself to rough ER and inject proteins into the ER lumen,
82
mutation
alteration in the genome that is not genetic recombination
83
gene mutation
alteration in the sequence of DNA molecules in a single gene
84
chromosomal mutation
when structure of chromosome is changed
85
mutagens
mutations arising from chemical agents
86
point mutation
mutation changes a single base pait
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base pair substitution mutation
one base pair is replaced by another
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missense mutation
base pair mutation that occurs in the AA coding sequence of a protein
89
frameshift mutation
when deletions or insertions occur in multiples other than three
90
nonsense mutation
base pair substitution or an insertion or deletion that creates a stop codon
91
chromosomal deletion
when a portion of the chromosome breaks off, or when a protion of the chromosome is lost during homologus recombination and/or crossing over events
92
duplications
when a DNA fragment breaks free of one chromosome and incorporates into a homologous chromosome
93
translocation
segment of DNA is inserted into another chromosome
94
inversion
orientation of DNA is reversed on a chromsome
95
transpons/transposable elements
excise themselves from a chromosome and reinsert themselves at another location; can cotain one gene, several genes or just a control element; how somatic cell can alter its genetic makeup without meiosis
96
forward mutation or backward mutation
change organism back to original -- wildtype or make it further away from wildtype
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cancer
uncontrolled growth of cells
98
oncogenes
genes that cause cancer
99
carcinogens
mutagens that can cause cancer
100
nucleosome
eight histones wrapped in DNA
101
chromatin
entire DNA/ protein complex
102
histones
DNA that are not in use are wrapped tightly around globular poteins
103
somatic cells
46 double stranded DNA molecules
104
chromosome
chromatin associated with each one of these molecules
105
homologous
each chromose possess a partner that codes for the same traits as itself--gene might be different, both eye color one is blue eyes other is brown eyes
106
diploid
any cell that cotains homologous pairs
107
haploid
any cell that does not contain homologues
108
interphase
G1, S and G2
109
G1
cell just split, cell grows in size, RNA sythensis and protein synthesis are very active, usually longest stage
110
S phase
cell devote energery to replicating DNA, chromosome exactly duplicated, each chromsome is made of two identical sister chromatids
111
G0
nongrowing state, allows for difference in lenth of the cell cycle, mature neurons and muscle cells remain in G0 permamently
112
G2
cell prepares to divide, cellular oganelles continue to duplicate, G2 checkpoint checks for mitosis promoting factor
113
mitosis
nuclear division without genetic change
114
prophase
codensation of chromatin into chromosomes, centrioles move to poosite ends of the cell, spindle appartus begins to form consisting of aster
115
metaphase
chromosoms align along the equator of the cell
116
anaphase
sister chromatids split at their attaching centromeres
117
cytokinesis
actual separationo of the cellular cytoplasm due to constriction of microfilaments about the center of cell may start at the end of ana phase
118
telephase
nuclear membrane reforms followed by the reformation of the nucleolus
119
meiosis
double nuclear divison which produce 4 haploid gametes/germ cells
120
spermatogonium and oogonium
human cells that undergo meiois
121
primary oocyte
arrested at this stage in females until puberty; undergoes first divison before ovulation to become secondary oocyte
122
2nd oocyte and sperms
stimulates anaphase II in the oocye
123
prophase I
homologous chromsomes lines up along side each other; exchange DNA nucleotides in a process called crossing over, genetic recombination-- 4 chromatids -- tetrads
124
linked
genes located on a chromsome are more likely to cross over together
125
metaphase I
homoloues remain atached, move to metaphase plate
126
anaphase 1
separates homologues from their partners
127
telpehase 1
nucelear membrane may or may not reform, cytokinesis may occur
128
2nd spermatocyes and oocytes
if cytokinesis occurs
129
polar body
from 2nd ooctye much smaller and degenerates
130
meiosis 1
reduction division
131
meiosis II
same is mitosis, final product 4 sperm cells, single oovum
132
nondisjuction
during anaphase I or 2 centromere of chromosome does not split
