Exam 1 Flashcards
(260 cards)
1
Q
If a species DNA is composed of 22% amine, how much thymine does it contain?
A
22%
2
Q
How many base pairs are the linker DNA between the Nucleosome
A
53
3
Q
How many base pairs wrap around a nucleosome
A
147
4
Q
What are the key players in DNA packaging
A
Histones and Nucleosomes
5
Q
What reduces a DNA helix to about 1/3 of its og length
A
10 nm diameter fibers
6
Q
How many histones are in one nucleosome
A
8
7
Q
How many Nucleosomes are in the human nucleus
A
2.5X10 ^7
8
Q
What are the benefits of of hydrogen bonds
A
More stability to the helix structure
9
Q
A phosphate group of one nuclei acid is attached to the oxygen that is connected to to the 3’ carbons of the Pentose sugar of another nucleotide
A
Phosphodiester bond
10
Q
If a species has more chromosomes than another that automatically means has a larger genome?
A
False
11
Q
Which of the following stage of packing DNA typically existist in our cells
A
30nm fiber
12
Q
DNA is always in the condensed chromosome state
A
False
13
Q
What types of bonds aer important for structure of DNA
A
Hydrogen
14
Q
Which of the following is not apart of nucleic acids thymine cytosine ribose deoxyribose phosphate purines
A
Phosphate
15
Q
When is our dna condensed into stick Like figures
A
Interphase
16
Q
Euchromatin is
A
Loose and active
17
Q
Heterochromatin is
A
Dense inactive
18
Q
When is uncoiled chromatin fiber in the cell
A
Interphase
19
Q
What is the benefits of 30 nm diameter fiber
A
6 fold increase in compaction of DNA
20
Q
Occurs when numerous nucleosome coiled around d and stack upon one another
A
30 nm diameter
21
Q
What reduces a DNA helix to about 1/3 of its og length
A
10 nm diameter fiber
22
Q
How many Nucleosomes are in the human nucleus?
A
2.5x10^7
23
Q
147 base pair wrap around a
A
Nucleosomes
24
Q
What keeps DNA wrapped around the nucleosome
A
H1 Histones
25
DNA wraps around the
Nucleosome
26
What are the 4 types of histones
H2A, H2B, H3, H4
27
A nucleosome is a
Octomer
28
How many histones are in one nucleosome
8
29
What are the 2 key players in DNA packaging
Histones Nucleosomes
30
What is chromatin
Uncoiled components of the chromosome dispesed into the nucleus
31
Where are base pairs stored
Chromatin then chromosomes
32
What is the cause of variations between us
Variation within the gene sequence
33
What % of human DNA are protein coding genes
1-2%
34
What is a gene
Sequence of nucleotide that code for proteins
35
What is a genome
All the nucleotides that compose our genetic material
36
What is the commentary strand
The reverse of the og DNA strand, staring at the opposite end
37
The percentage of all base pairs should add up to what
100
38
What is on the 3’ end of DNA
Free hydroxyl (OH)
39
What is on the 5’ end of DNA
Phosphate group
40
What are the benefits of hydrogen bonds
Stability to the helix structure
41
DNA nitrogenous bases are
Anti-parallels
42
The nitrogenous base bonds create the ________ shape
Double helix
43
Thymine pairs with
Adenine
44
Guanine pairs with
Adenine
45
Guanine pairs with
Cytosine
46
Each nitrogenous base that is written within a nucleotide has a complementary
Nitrogenous base
47
What is a phosphodiester bond
A phosphate group (attach to the 5’) of one nuclei acid is attached to the oxygen that is connected to the
48
Where does DNA stay?
Nucleus
49
In RNA, The main place where biological products are produced are in the…
Cytoplasm
50
What is the intermediate molecule that takes the info that the DNA holds in the Nucleus to the cytoplasm
Messenger RNA (mRNA)
51
What does an expressed gene mean?
The gene is being transcribed (read)
52
In RNA what does it have as the Pentose sugar
Ribose
53
In RNA what takes place as thymine
Uracil
54
RNA is often _________ stranded (with exceptions)
Single
55
What is the role of mRNA
Encodes proteins
56
What is the role of tRNA
Carries amino acids
57
What is the role of rRNA
Forms the ribosome
58
Transcription is all about the making of…
mRNA
59
What is the template of mRNA
DNA
60
DNA strand that serves as the templates is denoted the template strand, and the complementary DNA is called the ….
Coding strand
61
Enzymes that make our nucleic acids are referred to as….
Polymerases
62
Polymerases do the work of stringing together…
Nucleotides
63
Polymerases are ______ molecules with different __________.
Complex, subunits
64
Polymerases create _________ bonds
Phosphodiester
65
What are the 3 steps of creating mRNA
1. Initiation
2. Elongation
3. Termination
66
Bacteria transcription is simple bc al it takes is __________ RNA polymerase
Single
67
the main part of bacteria RNA polymerase, in bacteria transcription is the _____________
Sigma Subunit
68
In Bacteria transcription, the sigma factor recognizes specific DNA sequences called..
Promoters
69
- A specific region of DNA located near the beginning of a gene sequence
- Serves as the binding site for RNA polymerase
Promoters in Bacteria transcription
70
What is the TATAAT
Conserved DNA sequence found in the promoter region of bacterial gene
71
In Bacteria transcription where is the recognion site for RNA polymerase
TATAAT
72
The TATAAT is a -10 box because it is…
10 base pair upstream from where a gene starts
73
Transcription in bacteria is initiated almost completely by the sigmas factor unit of the _______ _____________ in prokaryotes
RNA polymerase
74
What are the 3 steps in initiation…
1. RNA polymerase bind to the promoter
2. Finds the transcription start site
3. And catalyzes initiation
75
What is chain elongation..
The addition of ribonucleosides
76
During Chain Elongation what direction is the DNA read
3’ to 5’
77
Elongations walks on the template strand of DNA in the 3’ to 5’ direction but the new RNA Is made in the ____________________ directions
5’ to 3’
78
Made between ribnucleotides by RNA polymerases
Phosphodiester bonds
79
The strand of DNA that serves as a template for synthesizing mRNA
Template Strand
80
What is the function of the Template Strand
-Complementary to the coding strand and guides RNA plyumerase during transcription.
-the mRNA that is made of complementary to this strand
81
The strand of DNA that contains the sequence of nucleotides that codes for proteins
Coding Strand
82
What is the function of the coding strand
Directly corresponds to the mRNA sequence during transcription
-except where there are T’s in the DNA, they are Us in the RNA sequence
83
RNA polymerase continues along until it encounters a specific nucleotide sequences that acts as a
Termination signal
84
What are the 2 main mechanisms termination
-Rho-dependent termination
-intrinsic (rho-independent) termination
85
The RNA transcript forms a _________________ structure due to complementary base pairing
Hairpin loop
86
A sequence of uracil residues follow the hairpin, causing the RNA polymerase to detach
Poly-U-tail
87
What Are the 2 parts of intrinsic termination
-hairpin loop
-poly-u-tail
88
What is intrinsic termination
A quick and efficient way for cells to end transcription
89
Termination Factor rho :
Large protein w/ RNA helicase activity
90
What causes dissociation of RNA polymerase by breaking hydrogen bonds betweeen the DNA template and the only newly made transcript
Rho- dependent termination
91
In prokaryotes Often translation occurs at the same time as
Transcription
92
What are 3 distinct forms of RNA polymerase in eurkaryotes
1. NO sigma unit
2. Larger and more complex that’s the single form found in bacteria
3. Numerous genes throughout the genome that code for RNA polymerases
93
In Eukaryotes RNA polymerase 1 creates
rRNA
94
In Eukaryotes RNA polymerase III creates
tRNA
95
In Eukaryotes, RNA polymerase I and III is expressed all the time because its products
Are needed at all times
96
How many RNA polymerase II are found in humans
16
97
What are transcription factors in eukaryotes
Other protein that are involved in the process of transcription
98
What do transcription factors control?
How much and when genes are expressed
99
What is is required for all RNA polymerase II mediated transcription
General Transcription Factors
100
What is key to start transcription in eukaryotes
Preinitiation complex
101
Similar to bacteria, eukaryotes have the
TATA box
102
Recognizes the TATA box and binds to it in Eukaryotes
TFID
103
What happens after the TFID binds to the TATA box
This results in the recruitment of all of the other general transcriptions factions and eventually RNA polymerase II
104
What happens if the preinitation complex does not occur
The transcription of the gene can’t happen
105
Elongation is the same in prokaryotes and eukaryotes and is the
Putting together of ribonucleotides
106
Transcription is cleaved roughly 10-35 base pair downstream after the transcription of
Polyadenylation signal sequence
107
Cause DNA polymerase to destabilizes and erase the RNA and DNA template
Cleavage
108
Right after termination we have
Pre-mRNA
109
What is mRNA processing
Additions of the 7-methylguanosine (mG) cap
110
Which end of the mRNA does the 7- methulguanosine (mG) cap add too
5’ end
111
What is the role of the the 7-methyguanosine cap
- stabilizes the mRNA by protecting the 5’ end from degradation
-faciliatates transport of mature RNA from the nucleus into the cytoplasm
-required for the translation of the mRNA to protein
112
What is the structure of a poly-a-tail
A bunch of adenines in a row
113
What does the poly A tail add
Addition to the 3’end of the transcript
114
Poly-a- binding protein binds to it and
Prevents degradation
115
Aid in exporting the mRNA out of the nucleus
Poly-a-tail
116
Coding sequences that remain in the mature mRNA and are translated into proteins
Exons
117
Non-coding sequences that are removed from the pre-mRNA during splicing
Introns
118
RNA splicing is a post-transcriptional modification process where
Introns are removed from pre-mRNA
119
What is the purpose of introns?
-some genes encode for more than one protein product through the alternative us of exons
-alternative splicing produces different mature mRNA fro methods same pre-mRNA by splicing and lighting different combinations together
120
Differs between Bacteria and Eukaryotic Transcription Location
-Bacteria occurs in the ________
- Eukaryotes it occurs in the ________
-Cytoplasm
-nucleus
121
What differs between bacteria and Eukayotic transcription initiation…
-bacteria need that sigma factor within its _____ ___ _______
-Eukayotes need __________
-Single RNA Polymerase
-A lot more factors
122
What differs between bacteria and eukaryotic transcription termination…
-Bacteria have intrinsic and __________
-Eukaryotes rely on that _________
-rho dependent
-polyadenylation sequence
123
Modification from premRNA to mRNA
Does not occur in bacteria
124
If bacterial mRNA does not go through processing, do you think their mRNAs have introns and exons
No
125
If you put a eukaryotic gene within a bacteria, do you think it will work
NO
126
Transciption is going from from ______ to ______ because DNA typically does not need to leave the nucleus
DNA, RNA
127
What are some of the major difference between DNA and RNA?
-DNA= deoxyribose, thymine, 2x stranded
-RNA= ribose, uracil, 1x stranded
128
If there was an issue with the sigma factor and it no longer worked, what would be the consequence of this?
Transcription wouldn’t occur
129
What is the general description of a plymerases job
It to string together nucleotides
130
Is the product produced from the template stand different than the product produced from the coding strand?
Yes
131
List two things about about 7-methylguanosine cap (5’) and the poly-a-tail (3’)
1. They prevent the ends of MRNA from being broken down
2.they are needed for the mRNA to be able to exit the nucleus
132
The following is the coding strand of DNA. What mRNA would be produced by it?
-ATTTGCGCAATCG
UAAACGCGUUAGC
133
The following is coding stand of DNA, what mRNA would be produced by it?
-ATTTGCGGCAAUCG
AUUUGCGGCAAUCG
134
________Are the portions of mRNA that are expressed and ______ are the portions of mRNA that cut out and not expressed
Exon, Introns
135
What are some of the ways that the transcription process differs between eukaryotes and bacteria
-in bacteria, transcription ouccus in the cytoplasm in eukaryotes, transcription occurs in the nucleus
-bacteria have single RNA polymerase while eukaryotes have numerous that have different job
-bacteria have rho dependent and intrictice termination while eukaryotes rely on the polyadenylation signal sequence (AAUUAA)
-mRNA is bacteria do not have intros, while in eukaryote mRNA does have introns.
136
What type of bonds do RNA polymerase make
Phosphodiester bonds
137
If bacteria RNA polymerase lost its sigma factor, what would be consequences?
The RNA polymerase would not be able to find the promoter region of gene therefore transcription could not begin
138
In eukaryotes, the mRNA that is release from the RNA polymerase is ready to go outside of the nucleus right away
False
139
Transcriptions is going from
DNA to RNA
140
RNA polymerase III
Produces RNA
141
RNA polymerase I
Produces rRNA
142
RNA polymerase II
Produces mRNA
143
An important sequence in eukaryotes that needed to be recognized to start transcription
TATA Box
144
Termination type in bacteria
Intrinsic termination
145
What is translation
Going from mRNA to proteins
146
Large biomolecules consisting of one or more chains of amino acids
Proteins
147
What are 3 roles of proteins
-structure
-function
- regulation of the body’s tissues and organs
148
Each word within mRNA consists of _______ ribonucleotide letters
3
149
Each group of three ribonucleotides is called a codon and specifies one
Amino acid
150
Each codon (triplet) specifies only a single
Amino acid
151
Characteristics of the genetic code
-unambiguous
-degenerate
-comma less
-non overlapping
-universal
152
The letters with in the chart corresponds with those group of three from the
MRNA
153
Initation:AUG:methionine
Only one that codes for this amino acid
154
Multiple termination codons
-Do not code for an amino acid
-t RNA does not recognize them
155
Mutations that produce a stop codons and there for early termination of transcription are called a
Nonsense mutation
156
Messenger RNA is what is being translated to a
Protein
157
Ribosomal RNA provide the place and the catalytic abilty for ___________ to occur
Translation
158
RRNA molecules perform the important ___________ functions associated with translation
Catalytic
159
One of the largest and most intricate of all cellular structures
Ribosomes
160
Provides structural stability and are importnat for the binding of tRNA to mRNA during translation
Modified nitrogenous bases
161
Arranged in a way where there are stretches off base pairing with itself
TRNA
162
Trinucloeotide sequence complementary to that of a corresponding codon in a messenger
Anti- codon loop
163
What is the first step in translation
Shine-dalgarno
164
Sequence base pairs with the the small ribosomal unit and facilitates translation
Shine-dalgarno
165
What is the second step in translation
Stabilization in the P site
166
What happens in the second step of translation
IF2 interacts with the small ribosomal subunit the mRNA and the first tRNA stabilizing them in the P site
167
What happens in the third step of translation
IF3 real ease the small subunit which combines with the large subunit, IF2 and IF1 are released
168
Charged tRNAs are brought to the ribosomes to the
A site
169
Amino acid in the _______ is linked with the amino acid that is on the tRNA in the A site
P site
170
Creates a polypeptide chain of amino acids
Elongation
171
Creates a polypeptide chain of amino acids
Elongation
172
Breaking of the ester bond between the tRNA and adding to the growing polypeptide chain is done by
Peptidyl transferase
173
Uncharged tRNA in the P site then movies to the _______ and whole complex shifts down the mRNA
E site
174
Conformational change that ratchets the ribosome so now that the A site is open, this is called a
Translocation
175
The ribosome encounters a codon on the mRNA
Stop signal
176
This stop codon doesn’t call for any amino acid to be added
No more amino acids
177
Instead it signals that the protein is complete and ready to be released
Protein Release
178
Proteins recognize the stop signal and assist in ending the process
Release factors
179
These release factors break the link between the finished protein and the last t RNA
Breaking the bond
180
The newly made protein is then freed from the ribosome
Protein Freedom
181
Bacteria transcription and translation occur at the ____________ in the cytoplasm
same time
182
Eukaryotes transcription is in the nucleus and them the _________ moves to the cytoplasm for translation
M RNA
183
Eukaryotes has ________ ribosomes
Larger
184
Modified guanine nucleotide attached to the 5’ end of the mRNA
The Cap
185
Special proteins recognize and bind to this cap structure
Recognition
186
The cap-binding proteins help bring in the ribosome, which is the cells protein-making machine
Ribosome recruitment
187
The ribosome moves along the mRNA, looking for the start signal
Scanning
188
Once the start signal is found, the full protein-making complex comes together
Assembly
189
The proces of tRNAs moving into the A,P, and E sites is the ______ in eukaryotes and bacteria
Same
190
This loop shape helps ribosomes move easily from the end of one protein to the stratified other next making protein production faster
Closed looped formation
191
At the end of mRNA, there a long sting of A’s called the poly-a-tail
The tail
192
Special proteins bind to both the cap and the tail
Protein bridge
193
These proteins being the two ends of the MRNA close, forming a loop
Loop formation
194
Precursor of proteins
Polypeptides
195
Polypeptide fold and assume a higher orders of structure
Functional protein
196
What are the 4 major classes of amino acids
Non polar
Polar
Positively charged
Negetively charged
197
A proteins job/function is determined by the protein
Shape
198
Determined by the sequence of amino acids that compose it which is ultimately determined by the genetic sequence
Protein shape
199
True or false: the protein product made from the coding strand of DNA will look like the protein product produced from the temples strand of DNA
False
200
What amino acid chain will be made from this template strand of DNA
ATGCATTACCGATCGATCGATCGA
UACGUAAUGGCUAGCUAGCUAGCU
201
What amino acid would the tRNA w/ the Anti codon of AGC carry?
…
202
Translation is…
Going from RNA to proteins
203
What are some differences between bacterial translation and eukaryotic translation
Eukaryotes need the 3’ cap and 5’ cap and the mRNA to aid w/ translation but bacteria do not
-bacteria have smaller ribosomes than eukaryotic
204
What polypeptide chain will be created from the following mRNA
-AACUUAAUGAAACCGGUGCCCUGU
Met-lays-pro-Val-pro-cys
205
Which of the following is not one of the characteristics of genetics code
Every amino acid only has one codon that codes for it
206
True or false: the nucleotide sequence has nothing to do with the amino acids sequence that produces, no influence
False
207
Aneuploidy
Gain or loss of one or more chromosomes (not the whole set)
208
Loss of a single chromosome
Monosomy
209
Gain of a single chromosome
Trisomy
210
Pair homologous chromosome fail to disjoin during segregation
-Klinefelter and Turner syndromes
-can occur during the first ands second stage of meiosis
Nondisjunction
211
Haploinsuffieciency
A single chromosome copy is not enough
212
Trisomy 21
Down syndrome critical region
-dosage sensitive
-extra copy of the DSCR 1 gene (decreased risk of cancers)
213
Patau and Edward’s syndrome
Extra 13 and extra 18
214
More than two multiples of the haploid chromosome set
Polyploidy
215
Addition of one or more extra set so f chromosomes that are identical to the normal set of the same species
Autopolyploid
216
Combination of chromosomes sets from different species as a consequence of hybridization
Allopolyploid
217
What is the main cause of autoploidy
A failure of chromosomes to separate properly during cell division
218
What causes a autotriploid
Failure of all chromosomes to segregate during meiotic divisions can produce a diploid gamete
219
what happens in a autotriploid
-Produce unbalanced gametes
-results in seedlessness
220
Hybridization of two closely related species
May or may not be able to produce viable gametes
Allopolyploidy
221
When chromosome doubling allows allophone individuals to produce viable gametes
Amphidiploid
222
Depletion Occurs near the end of a chromosome
Terminal
223
Depletion occurs within the interior of the chromosome
Intercalary
224
Homologous chromosome to a chromosome with a larger intercalary deletion must loop
Depletion or compensation loop
225
What caused duplication
May arise was the result of unequal crossing over between chromosomes, or a Dna replication error
226
Segment of a chromosome is turned around 180 degrees within a chromosome
Inversions
227
Doesn’t include the centromere
Paracentric inversion
228
Does include the centromere
Pericentric inversion
229
-Inversion loop during meiosis
-Crossing over within the inversion loops can result in aberrant chromosomes
Inversion heterozygotes
230
Movement of chromosomal segment to a new location
Translocations
231
Involves the exchange of segments between two nonhomologous chormosomes
Recriprocal translocations
232
Creates a T like formation during crossing over
Meiosis for heterozygotes
233
-Some have the proper amount and will produce viable offspring if fertilized
-some do not and will not produce viable offspring
Genetically unbalanced gametes
234
The base pairs of mRNA is read in groups of three called a
Codon
235
Change of one base pair to another base pair within the DNA
Mutation/base substitution
236
A change of one nucleotide that does not result in a change in the amino acid brought
Silent mutation
237
Changing of one nucleotide that results in a new triplet that codes for a different amino acids
Missense mutation
238
The substitution of one amino acid for another may disrupt the protein there dimensional structure
Structure
239
Change in protein structure can lead to altered or imparted protein function
Function
240
Change of base pair that results in a triplet coding for a stop codon
Nonsense
241
Occur in the noncoding regions the genome
Neutral mutation’s
242
Pyrimidine replaces a pyrimidine or a purine replace a purine
Transition
243
Purine replaces a pyrimidine
Transversions
244
Loss or addition of nucleotides
Frameshift mutations
245
Reduces or eliminates the functions of the gene product
Loss of function mutation
246
Codes for a gene product with enhanced,negative or new functions
Gain of function mutation
247
Dominant negative mutations that leaves and individual with only one functioning gene when two is really needed to produce the amount of gene product needed for cell function
Haploinsufficiency
248
A second mutation that either reverts or relives the effect of the previous mutation
Suppressor mutation
249
A mutation that produces a trait when only one cope of the altered gene is present
Dominant mutation
250
Recessive mutation
A mutation that produces a trait only when two copies of the altered gene are present
251
Mutation located on the X chromosomes
X linked mutations
252
Mutation located on the Y chromosomes
Y linked mutations
253
A single mutation can fall under multiple different
Type of mutations
254
What causes mutations
Exposures, inherited genetics, chance
255
-Changes of the nucleotide of genes that appear to occur naturally
-no specifics agents are causing the mutation
Spontaneous mutations
256
-Result from the influence of extraneous factors
-Natural or artificial agents
Induced Mutations
257
Likelihood that a gene will undergo a mutation in a single generation or in forming a single gamete
Mutation rate
258
Rate of spontaneous mutations is _________ for organisms
Exceedingly
259
Substances that can lead to cancer by causing mutations in DNA
Carcinogens
260
Ultraviolet radiation can create
Pyrimidine dimers
