Exam 2 Flashcards
1
Q
(T/F) DNA, RNA, and Protein are different from species to species unlike carbs and lipids which are universal.
A
True
2
Q
What were the 3 laws of inheritance Mendel published?
A
- Proposed traits were not blended but given through sets of pairs (alleles: Aa, aa, AA)
- Proposed mother and father each contributed a pair
- Presented inheritance in punnett square
3
Q
What is the structure of DNA?
A
-A 5 carbon sugar backbone with a phosphate group on the top and a nitrogenous base attached on the side.
4
Q
What are the 4 nitrogenous bases of DNA?
A
- A (Adenine)
- G (Guanine)
- C (Cytosine)
- T (Thymine)
5
Q
How do the 4 nitrogenous bases pair up in DNA?
What does this mean?
A
A to T
G to C
Means that they will always be present in equal amounts
6
Q
Which 2 nitrogenous bases are the purines?
A
A and G
7
Q
Which 2 nitrogenous bases are the pyrimidines?
A
T and C
8
Q
What is a bacteriophage?
A
A virus that has a body made of protein and has DNA within it.
9
Q
How is DNA structure shaped?
A
Double Helix
10
Q
How does DNA form?
A
- Nucleotides chain together and twist into double helix
- Nitrogenous bases bond together in middle
11
Q
DNA must be anti-parallel meaning:
A
One nucleotide strand is oriented in the 5’ to 3’ direction while the other is in the 3’ to 5’ direction.
12
Q
The 5’ end of DNA is a _______
A
5-carbon phosphate group
13
Q
The 3’ end of DNA is a _______
A
3-Carbon hydroxyl group
14
Q
How do nucleotides bond together to form DNA strand?
A
5-carbon phosphate attacks a 3-carbon hydroxyl and bonds to form a chain
15
Q
What is a nucleoside?
A
A sugar + a phosphate group
16
Q
What is a nucleotide?
A
A nucleoside + a nitrogenous base group
17
Q
What type of bond connects nucleotides?
A
phosphodiester bond
18
Q
How many hydrogen bonds are present when A and T bond?
A
2
19
Q
How many hydrogen bonds are present when G and C bond?
A
3
20
Q
Humans have ______ billion base pairs of DNA.
A
3.3
21
Q
Human DNA laid end to end would be ____ft long which is _________ times larger than the nucleus of a cell.
A
6
260000
22
Q
If a nucleus was 1 inch long, DNA to fit in it would be ____ miles long.
A
4.1
23
Q
Because so much DNA must fit into a nucleus, how do organisms fix this problem?
A
-By wrapping DNA around proteins called Histones
24
Q
Do histones exist in prokaryotes?
A
No
25
What are the 5 types of histones?
| Which of these is special?
- H1
- H2A
- H2B
- H3
- H4
Special: H1
26
When a double-helix of DNA is wrapped around a histone ball, this is called a__________.
Nucleosome
27
What is the special role of the H1 Histone?
It attaches to the side of a nucleosome (Wrapped DNA helix and another histone) and continues to roll them into a larger ball.
28
After the H1 histone has dones its job, what is the final product called?
A solenoid
29
DNA is a _____ ___________ molecule.
self-replicating
30
(T/F) DNA is the same in every cell within an organism.
True
31
What were the 3 hypothesized methods of DNA replication?
- Conservative
- Semi-conservative
- Dispersive
32
What is the principle of conservative replication?
The parent DNA helix synthesizes a copy of itself and the result is one DNA helix that uses the same 2 strands as the parent and one new DNA helix that have 2 identically copied strands from the parent
33
What is the principle of semi-conservative replication?
The 2 parent strands of DNA separate and each acts as a template for synthesis of a new complimentary strand. The result is 2 DNA helixes with one parent strand and one daughter strand.
34
What is the principle of dispersive replication?
Parent strands are mixed with daughter strands to form 2 new mixed strands of DNA.
35
What is the parent/old strand of DNA referred to as in replication?
Template strand
36
Does the parental DNA remain intact during replication?
Yes
37
Which form of replication was proven to be the correct one?
Semi-conservative
38
DNA replication is an ________ (endergonic/exergonic) reaction.
endergonic
39
Does a cell use ATP to power process of DNA replication?
NO!
40
What is used to power the process of DNA replication?
dNTP
41
What enzyme enables DNA replication?
DNA polymerase
42
Where is a DNA helix split during replication?
At the origin of replication (OR)
43
What enzyme breaks the Hydrogen bonds during DNA replication? What does it burn to do this?
Helicase
| ATP
44
What enzyme lays the primer stretch on top of one strand for DNA polymerase to hold onto?
Primase
45
During replication, what is the strand that DNA polymerase continues on til the end without fragmenting?
Leading strand
46
During replication, one strand is continually fragmented as DNA polymerase continues to bump into new sections of primase track. What strand is this?
Lagging strand
47
What are the fragments on the lagging strand called?
Okazaki fragments
48
Is primer tracks of primase left or removed after DNA polymerase has got started replicating template strand?
It must be removed
49
What enzyme seals the gap left between DNA fragments after primase tracks are removed?
Ligase
50
What direction does DNA replication happen in in reference to the DNA double helix?
Both but on opposite strands. Once the parent strands are split, and the primer tracks are laid, DNA polymerase takes off down each parent strand in BOTH directions from the origin of replication. Replication always occurs in the 5 to 3 direction. This means that for leading strands, replication is done from the origin of replication outward and for lagging strands, replication is done toward the origin of replication.
51
In what what is DNA ALWAYS replicated?
5' to 3' direction
52
What were the 3 methods of repair that DNA Polymerase has of checking and repairing errors?
- Proofreading Repair
- Mismatch Repair
- Excision Repair
53
What happens if the wrong base pair is copied during DNA replication?
If a wrong pair was copied, the DNA will bulge due to repulsive forces between incorrect base pairs.
54
What happens during proofreading repair?
DNA polymerase will detect the buldge caused by repulsing incorrect base pairs. It will then backup and replace the incorrect letter before continuing replication.
55
A small area at the end of a DNA strand cannot be copied, this causes ______ in organisms.
aging
56
What do some cells do with the bit that gets cut off?
Fills the gap with Telemerase and small bit of RNA template.
57
What are the ends of chromosomes known as?
Telomeres
58
What is the coding in a telomere?
non-sense just to fill space.
59
Humans only create telomeres at the end of _____, ______, and ______ cells.
Sperm, egg, and stem
60
This is used to sequence DNA in a lab
Dideoxynucleotide sequencing
61
You ______ (can/cannot) use dideoxynucleotides to build DNA.
CANNOT
62
How does Dideoxynucleotide sequencing work?
These were mixed with other nucleotides that were labelled with different colors for each of the 4 base pairs. This let him see how they were aligned shortest to longest which gave him the sequence of the DNA.
63
What is the order that central dogma goes in?
1) DNA Replication
2) RNA Transcription
3) Protein Translation
64
What 2 principles did "central dogma of molecular bio. suggest?
- DNA is a self-replicating molecule
| - That it is a strand of information
65
Genes encode for specific ________ that are needed to create/intake/synthesize other ________. This creates the __________ pathway of life.
- enzymes
- enzymes
- biochemical
66
```
DNA (can/cannot) become RNA
DNA (can/cannot) become protein
RNA (can/cannot) become protein
RNA (can/cannot) sometimes become DNA
Protein (can/cannot) become RNA or DNA
```
- can
- can
- can
- can
- cannot
67
What are 4 differences between RNA and DNA?
- RNA uses Ribose as its sugar while DNA uses deoxyribose
- DNA uses base pairs A, G, C and T while RNA uses A, G, C, and U.
- RNA has a portion of genetic code stored not all of it but DNA has all of it
- RNA is typically single-stranded while DNA is typically double stranded
68
What is transcription?
The process by which DNA is converted into RNA.
69
RNA is polymerized similarly to DNA except it uses ____ ___________ instead of _____ __________.
uses RNA Polymerase instead of DNA polymerase
70
RNA is also synthesized in the __ to ___ direction.
5' to 3'
71
The RNA transcript strand is the _____ of the DNA template strand meaning:
- compliment
| - means that RNA transcript strand is identical to the DNA coding strand except you replace the T's with U's.
72
What is the promoter?
Area of code (of base pairs) that promotes transcription to occur. It always exists upstream from the Transcriptional Start Site (TSS).
73
What is the key line of base pair code that identifies the promoter region?
TATA
74
Strand is not important with RNA b/c it only copies __ strand of DNA and it will replace T's with U's so that changes the recipe.
-1
75
Because only one strand is copied, you must know which strand is the template strand. How do you determine this?
- Remember that it must encode from 5' to 3'
| - Remember that it must run anti-parallel to coding strand of DNA.
76
As mRNA is transcribed, it is in an immature form called ___-_____.
pre-mRNA
77
What modifications are made to convert pre-mRNA into mature mRNA?
- ways to tell mRNA apart from other forms of RNA
- prevent degradation
- transport mRNA to cytoplasm
- splice the required form
- stimulate translation
78
What is done to convert pre-mRNA to mature mRNA?
- 5' capping (a chemical G pair cap is put on the 5' end)
- 3' polyadenylation (a bunch of A's are put on the 3' end)
- splicing occurs in the nucleus (co-transcriptional)
79
Do all of regions of coding sequence in pre-mRNA end up in its mature mRNA?
No!
80
What are the regions of coding sequence not included in mRNA called?
introns
81
What are the regions of coding sequence included in mRNA called?
exons
82
What is splicing?
The process of cutting out the introns and pasting the exons together.
83
What is responsible for splicing?
snRNP's
84
How do snRNP's splice?
2 snRNP's will land on each side of the intron. They will then pull together and form a loop out of the intron. They then cut off the loop. It floats away and is destroyed. The remaining exons are now pasted together.
85
What is translation?
The process of using the nucleotide sequence of mRNA as a template to synthesize amino acids in the correct order to form a protein. (converting RNA into proteins)
86
What stores all the info for making proteins?
DNA
87
How does translation occur?
mRNA carries instructions coded by DNA during transcription to the ribosomes where the proteins that are coded for can be assembled.
88
What are the 3 types of RNA?
- mRNA
- tRNA
- rRNA
89
What does mRNA do?
serves as the template that brings the recipe for the protein coded in the DNA to the ribosome
90
What does tRNA do?
translates the message in the mRNA into an amino acid sequence
91
What does rRNA do?
associates with proteins to form the machinery needed to assemble proteins
92
How is the coding stored in mRNA for proteins?
In a sets of 3 nucleotides called codons
93
What is the purpose of a codon?
To correspond 3 nucleotides to a specific amino acid
94
What is the start codon?
AUG
95
How many codons are there?
64
96
How many codons encode?
61
97
What are the 3 stop codons?
UAA, UAG, and UGA
98
Where does translation start?
At the codon in mRNA.
99
What does tRNA do after translation starts?
It adds the amino acid specified by a codon given in mRNA.
100
Where do complimentary bases pair with a codon?
Through a region called the anti-codon
101
What end of tRNA is attached to any specific amino acid?
3'
102
What enzyme causes the attachment of an amino acid?
Aminoacyl tRNA synthetase
103
Humans do not make 61 codons (tRNA's), we make ___. Why?
- 42
| - B/c some codons share (called wobble pairing)
104
What is it called when some codons share meaning that any base may pair with any base in the 3rd position only.
wobble pairing
105
How does protein assembly work?
- Ribosomes bind mRNA and recognize the start codon (AUG)
- They provide an environment that facilitates the proper binding of mRNA and tRNA
- They serve as the catalyst for peptide bond formation between amino acids
- Ribosomes are highly conserved through evolution and are structurally similar in all organisms
106
What are the 3 processes of protein assembly in order?
- Initiation
- elongation
- Termination
107
What order does subunits of proteins go?
- A
- P
- E
108
How does body speed up protein assembly?
Multiple ribosomes can be manufacturing proteins along a strand
109
What happens after a protein is made?
It must be sorted
110
How are proteins sorted?
Through localization sequence. This means there is an amino acid sequence that specifies where the protein needs to go
111
The Rough ER makes proteins for _______.
Secretion
112
Proteins in the rough ER are packaged in _______ and sent to the ______
- vesicles
| - golgi
113
What were the 3 posttranslational methods of modifying proteins?
- Proteolysis
- Glycosylation
- Phosphorylation
114
What is Proteolysis?
Cutting proteins
115
What is Glycosylation?
Combining sugar with proteins
116
What is Phosphorylation?
Combining phosphates with proteins
117
What 4 factors can damage DNA?
- Errors in replication
- Chemical reactions
- Radiation
- Chemical Mutagens
118
How are DNA mutations characterized?
- Point Mutations
- Genomic Mutations
- Transposons
119
What are the 3 forms of Point Mutations?
- base substation
- addition of base(s)
- deletion of base(s)
120
What is a point mutation defined as?
Any DNA mutation that occurs at a specific definable locus
121
What are addition of base and deletion of base point mutations known as?
Indels
122
What are 4 rules of point mutation?
- Silent
- Missense
- Nonsense
- Framshift
123
What are 4 rules of point mutation?
- Silent
- Missense
- Nonsense
- Framshift
124
What does a Missense point mutation mean?
-One letter is different.
125
What does a Nonsense point mutation mean?
-One letter is different but causes a premature stop signal.
126
What does a frameshift point mutation mean?
-A letter is inserted which changes the reading frame. This changes all of the resulting amino acids produced from that point on.
127
What occurs in a base substation point mutation?
Letter is changed (A > G)
128
What are genomic mutations?
Mutations that occur anywhere in genome sequence
129
What are transposons?
Moderately repetitive sequences that can move from place to place in the genome
130
What causes sickle cell?
Missense point mutation
131
What causes sickle cell?
Missense point mutation
132
What are the 4 types of genomic mutations?
- Deletion
- Duplication
- Inversion
- Translocation
133
What is a deletion genomic mutation?
deletion of letters
134
What is a duplication genomic mutation?
when meiosis doesn't swap the letters right so you end up with letters from both strands that make no sense
135
What is a inversion genomic mutation?
when a group of letters flip directions (CDE > EDC)
136
What is a translocation genomic mutation?
When letters of some are pasted into the other strand
137
Transposons make up roughly ______ of human genome.
40%
138
What are the 4 types of transposons?
- SINEs (short-interspered nuclear element)
- LINEs (long-interspersed nuclear element)
- Retrotransposons
- DNA transposons
139
What are the 4 types of transposons?
- SINEs (short-interspered nuclear element)
- LINEs (long-interspersed nuclear element)
- Retrotransposons
- DNA transposons
140
What are SINEs and LINEs most likely from?
Left over from viruses that have targeted humanity over the years.
141
How do SINEs and LINEs work?
They make RNA copies of themselves that are templates for new DNA inserted somewhere else (act as copy&paste mechanism)
142
What percent of genome do retrotransposons make up>
10%
143
How do retrotransposons work?
- They are transcribed as RNA and then they encode as a protein
- They encode as reverse transcriptase
- you end up with 2 copies of this moving around your genome
144
How does DNA transposons work?
- encode for protein which is transposase
- the enzyme cuts out the DNA transposon and moves it somewhere else (called a jumping gene)
- Can and often will jump into middle of a gene which causes extreme problems
145
What is a mutation?
changes in the genetic material of an organism.
146
Are viruses considered living?
NO
147
What is the Lytic cycle?
Process of reproduction for viruses.
148
How does the lytic cycle work?
-a virus attaches its own DNA to the genome of bacteria allowing itself to be copied every time the bacteria divides thus spreading its own DNA to all the daughter cells of the bacteria.
149
What is the lysogenic cycle?
Another process of reproduction for viruses.
150
How does the lysogenic cycle work?
- Once a virus determines the infected bacteria will not divide anymore, it removes its DNA from the bacteria genome and begins copying it using the bacteria's tools
- Then, the new virus emerges from the bacteria killing it so it can go on and infect other healthier bacteria
151
What 2 proteins affect what cycle is active in viruses? (Lytic vs lysogenic)
- cl
| - Cro
152
What protein activates the Lytic cycle?
Cro
153
What protein activates the Lysogenic cycle?
cl
154
What ultimately alternates which protein is active at what time?
Stress on the virus
155
How does stress cause the switch in the active protein in viruses?
It creates heat-shock protein that goes and destroys the active protein which allows activation of the other.
156
What is receptor-mediated endocytosis?
This is how viruses trick other cells into letting them in. They have a protein that binds to the receptor on the target cell which triggers it into bringing it into the cell
157
Are viruses very organism specific or widely universal?
Very specific
158
What determines what organism/what part of the body a virus attacks?
Type of receptor and type of protein on virus. This determines fit which will affect what cells can intake the virus.
159
Flu prints a complimentary strand of _____ using enzyme ________.
- mRNA
| - RDRP
160
Flu has the ability to do what in order for our cells to recognize it its RNA as our own?
- Cut the 5' cap off of our RNA and paste it on its own.
| - Step forward, write A and backup repeatedly thus creating a 3' tale that matches ours
161
What does HIV use instead of RDRP (like Flu) to convert their RNA strand to a complimentary DNA strand?
Reverse Transcriptase
162
What does HIV do after it has created DNA comp. strand?
create a copy of their DNA and form a double-strand DNA helix of their own DNA. It then embeds their DNA in host's nucleus DNA
163
What does HIV do if stressed?
It will begin copying itself and converting itself into proteins and constructing new viral capsules of RNA and will begin killing cells to exit and find new host cells
164
What does HIV do if stressed?
It will begin copying itself and converting itself into proteins and constructing new viral capsules of RNA and will begin killing cells to exit and find new host cells
165
Bacteria are (more/less) complicated than viruses.
more
166
As opposed to viruses, bacteria:
create RNA copy with multiple start/stop codons along the strand.
167
Why do bacteria create RNA strand with multiple start/stop codons?
This allows them to create multiple proteins from 1 RNA
168
What is bacterial RNA with multiple start/stop codons known as?
Polycistonic mRNA
169
Tryptophan turns _____ repressors if present. If absent, then the repressors are _______.
- off
| - active
170
What is tryptophan and what is it needed for?
an amino acid needed for protein construction
171
What acts as the on/off switch for tryptophan production?
Itself- tryptophan
172
What is the promoter for tryptophan?
RNA Polymerase
173
What is an operon?
A cluster of genes under a single promoter
174
Where is the operator for tryptophan? Why? (What does it do?)
- Present in front of the promoter.
| - Bonds to tryptophan and gets out of way allowing for promoter to digest tryptophan and lower the total amount.
175
What is the 3rd switch with tryptophan? How?
- Glucose
- High levels of glucose results in ATP production which lowers levels of cyclic-AMP. If glucose is not present, than there will be high levels of cyclic-AMP. Cyclic-AMP will then bond to responsive protein.
176
Most gene regulation occurs at ________.
Transcription (stage 1)
177
Why does most regulation occur at stage 1?
Provides the best chance to prevent mistakes
178
How does regulation occur?
-Promoter calls in TF2D which binds to transcription factors (B>F>E>H)
179
When does the promoter call in TF2D for regulation?
At the appearance of the promoter region (TATA box)
180
What are transcriptional activators?
they bind to DNA elements to facilitate activation of the target gene
181
What are transcriptional repressors?
they bind to DNA elements to facilitate repression of target genes
182
What are transcription factors?
Proteins that control the rate of transcription of genetic information from DNA to mRNA by binding specific DNA sequence.
183
What are transcription factors?
Proteins that control the rate of transcription of genetic information from DNA to mRNA by binding specific DNA sequence.
184
What must transcription factors have and do?
- must bind to DNA
- must be able to regulate transcription
- must have DNA-Binding-Domain (DBD)
- must react with nitrogenous bases
185
What is a dimer?
2 connected proteins
186
How do transcription factors (specific proteins) react with DNA? Where? Why?
- react with the nitrogenous bases of DNA
- In the crosses of the double helix
- Because the sugar-phosphate backbones are not in the way here.
187
What are the cross-sections of the double helix called?
Major-minor groups
188
What are the 4 types of domains/motifs? What do they each do?
- Zinc Finger
- Helix-turn-helix
- leucine zipper
- helix-loop-helix
189
What is chromatin remodeling complex?
the dynamic modification of chromatin architecture to allow access of condensed genomic DNA to the regulatory transcription machinery proteins and thereby control gene expression.
190
What is chromatin?
The material of which chromosomes of organisms other than bacteria are composed. They consist of protein, DNA, and RNA.
191
DNA is _________ charged.
Negatively
192
the protein ball at the center of a histone is ______ charged.
positively
193
During chromatin remodeling, proteins enter histone and perform acetylation meaning:
they bind to the acetyl group (acetyl CoA) and change the charge of the ball to neutral thus allowing the DNA to fall off and unwrap
194
Steps of Chromatin remodelling complex
- initiation
| - elongation
195
At end of chromatin remodeling, a repressor protein can deacetylate meaning:
it removes the acetyl groups and thus changing the charge of the ball back to positive and wrapping the DNA up again
196
Human mRNA encodes for how many proteins?
1 and only 1!
197
Humans make ____ proteins from 1 regular protein which can regulate 3 different genes.
3
198
What is alternative splicing
The ability to regulate snRNPs at pre-mRNA level allowing us to get 4 proteins from 1 mRNA and that is with only 3 exons.
199
Most humans have ____ exons
10-12
200
How many transcripts can be made from tropomyosin?
15
201
Regulation at the post-transcriptional level is done through:
micro-RNA's (miRNA or miR)
202
micro-RNA's work just like mRNA, they recruit proteins called _______ __________. These cut out center of RNA strand. Cut-out chunk is then sent to __________ and binds to _______ _________. A little loop is cut out here and made ______ ___________. This is the only case of double stranded ______.
- drosha complex
- cytoplasm
- dicer complex
- double stranded
- RNA
203
What is double stranded RNA bound to? What does this do?
- RISC complex
| - picks a strand at random to target and pair up with RNA
204
After a strand is randomly picked to target and pair up with RNA, what happens?
- They may perfectly pair or may not perfectly pair.
- If perfectly pairs: mRNA is destroyed
- If does not perfectly pair: it (protein) is prevented from being made
205
What happens with UPS?
Ubiquitin binds to proteins and destroys them at the very last step.
206
Most major diseases have what associated with them that makes them hard to cure?
miR micro-RNA
207
What is the smallest microorganisms?
viruses
208
What are the largest microorganisms?
eukaryotic ones (protists)
209
Is transcription and translation separated in prokaryotes?
NO
210
Is DNA bound to proteins in prokaryotes?
Somewhat but not like in eukaryotes
211
Do prokaryotes or eukaryotes use promoters?
both
212
How many chromosomes are in the genome of prokaryotes? eukaryotes?
- 1
| - many
213
RNA splicing (often/rarely) occurs in prokaryotes. This is the opposite of eukaryotes.
rarely
214
Enhancers/silencers are (rare/common) in prokaryotes which is opposite of eukaryotes.
rare
215
Noncoding DNA is present within coding sequence in Prokaryotes or Eukaryotes?
Mainly eukaryotes, very rare in prokaryotes
216
Has many repeated sequences? (Prokaryotes or Eukaryotes)
Eukaryotes
217
What do helix-turn-helix domains do?
regulate genes involved in development
218
What do leucine zipper domains do?
regulate cell division genes
219
What do zinc finger domains do?
act as steroid hormone receptors
220
What do helix-loop-helix domains do?
regulate immune system genes
221
What are the 4 ways we discussed that cells can communicate with each other?
- Juxtacrine
- Autocrine
- Paracrine
- Endocrine
222
How does Juxtacrine signaling work?
Homophilic and heterophilic Proteins are extended from each cell to the other and bind allowing them to communicate through the proteins
223
How does Autocrine signaling work?
Cells produce a protein that it secretes. These proteins are then taken into protein receptors on the SAME cell. When the protein and receptor bonds, the cell responds. (Cell is talking to itself)
224
How does Paracrine signaling work?
A cell produces a protein that it secretes. These proteins are then taken into protein receptors on other cells that are nearby. When the protein and receptor bonds, the cell will respond.
225
How does Endocrine signaling work?
A cell secretes a protein (signal) that then enters the blood stream and moves to a cell that is far away that has a receptor. Protein will bind to receptor and cell will respond. Signal protein has travelled a long way in thise case. This is how hormones function in humans and other animals.
226
What is adenylyl cyclase?
An enzyme that catalyzes the cyclization of ATP into cyclic-AMP.
227
What is an effector protein?
A protein that selectively binds to a protein and regulates its biological activity. They act as switches to increase or decrease enzyme activity, gene expression, or cell signaling.
228
How is tRNA charged?
aminoacyl-tRNA-synthetase catalizes an energy releasing action between an amino acid and ATP. ATP will lose 2 phosphates and becomes linked to the amino acid forming AMP. Then the amino acid bonds to the molecule forcing the AMP to be lost. The energy lost here causes the aminoacyl-tRNA-synthetase to attch the amino acid to the tRNA charging it.
229
What is an enhancer?
A short region of DNA that can be bound by activator proteins to increase the likelihood that transcription of a particular gene will occur.
230
What is a G-Protein linked receptor?
A receptor family that detects molecules outside of the cell and activate internal signal transduction pathways thus causing cellular responses.
231
What is an intracellular receptor?
Receptor located on the inside of a cell rather than on its cell membrane.
232
What feature of DNA is required for it to be self-replicating?
Complimentary base pairing
233
Where does a cell obtain the energy to synthesize a new strand of DNA?
From breaking the phosphate bonds of the incoming trinucleotide
234
Why do ddNTPs terminate elongation of the growing DNA strand?
They lack a 3' hydroxyl group
235
What is an ion channel?
A protein expressed by virtually all living cells that creates a pathway for charged ions from dissolved salts to pass through the otherwise impermeant lipid cell membrane.
236
What are the 3 major results of signals within cells?
- regulation of transporters
- regulation of enzyme activity
- regulation of gene activity
237
What is a receptor kinase?
A receptor that doubles as an enzyme. In these, the binding of a signaling protein to the membrane activates the receptors enzymatic activity.
238
What are second messengers?
molecules that relay signals recieved at receptors on the cell surface to target molecules in the cytosol or nucleus.
239
How does IP3/DAG work as a second messenger?
DAG: stays inside the cell membrane
IP3: soluble so it diffuses through the cell where it binds to its receptor (calcium channel on the ER). This causes calcium to be released into the cytosol thereby activating various calcium regulated intracellular signals.
