exam 2 Flashcards
(287 cards)
1
Q
x ray crystallography
A
makes DNA into crystals and shine x-ray light through to find structure and functions of biological molecules.
2
Q
DNA double helix
A
nucleotides covalently linked into strands that contain any sequences of nucleotides in any order; complementary strand binds through H bonds and twisted into double helix
3
Q
purine nucleotides
A
A and G
4
Q
pyrimidine nucleotides
A
T and C
5
Q
how are complementary base pairs linked
A
hydrogen bonds
6
Q
DNA strand directions
A
antiparallel; 5’ end of one stand line up with 3’ end of the other
7
Q
3’ end
A
3 carbon bonded to phosphate; OH group on end
8
Q
5’ end
A
5 carbon bonded to phosphate group; phosphate on the end
9
Q
what links together nucleotides in the strand
A
phosphodiester bonds (phosphate-sugar-phasphate-sugar)
10
Q
DNA replication
A
- separate 2 strands of DNA
- used as template for new strand
- new strand create; reverse complement
11
Q
what kind of model does DNA replication follow?
A
semi conservative model
12
Q
DNA polymerase
A
enzyme that matches complementary nucleotides to template and binds new strand
13
Q
central dogma
A
base pair matching used for information flows from dna -> rna -> protien
14
Q
DNA polymerase
A
dna replication enzyme that matches complementary nucleotides to template and builds new strand
15
Q
which direction does dna polymerase build new strand
A
5’ -> 3’
16
Q
where was is template strand read
A
3’ -> 5’
17
Q
helicase
A
enzyme that breaks hydrogen bonds between nitrogenous bases of double stranded dna (unzips)
18
Q
replication fork
A
area where double helix is opened and where the replication of DNA will actually take place
19
Q
replication bubble
A
formed because 2 helicase working in opp directions -> 2 replication forks -> creates bubble
20
Q
origin of replication
A
specific dna sequence where helicases and polymerases start replication; proteins distinguish by specific nucleotide sequence
*creates neg feedback loop
21
Q
origin of replication; prokaryotes
A
1 origin of replication bc small circular chromosomes
22
Q
origin of replication; eukaryotes
A
many origins of replication because larger linear chromosomes
23
Q
supercoiling
A
winding up of dna strands (problem separating the replicates)
24
Q
topoisomerase
A
enzyme that cuts strands of dna allowing them to unwind, then rejoins them
25
rna polymerase
brin in first rna nucleotide for replication
26
what is the problem with dna polymerase?
it cannot start dna replication on its own; only can elongate the nucleotide
27
primase
builds short rna primer that dna polymerase can add to
*type of rna polymerase
28
dna ligase
joins the 2 replicated dna fragments
29
replication of the leading strand
chases helicase
30
replication of the lagging strand
fragments created bc replication keeps stopping and starting since polymerase can only work 5' -> 3'
31
tolemere
end of linear chromosome
*only in eukaryotes
32
centromere
middle of a linear chromosome
33
overhang
telomere is single stranded which is less stable -> if nothing done then cell looses nucleotides every division
34
tolemerase
enzyme that adds nucleotides to template strand where the extended rna primer overhang can bind
35
what cells have tolemerase
cells that replicate often; germ line cells (reproductive), stem cells and cancer cells
36
what factors make tolemers get shorter
stress and age
*skin cells don't have telomerase -> aging?
37
dna replication in lab
1) get bacteria to grow plasmid dna
or
2) dna replication in test tube via pcr
38
polymerase chain reaction (pcr)
amplifies part of a dna strand; used template dna, mixture of dNTP's (triphosphate dna nucleotides) and dna primers; heat cycles and amplify
39
mRNA
messenger rna; used to make protein
40
transcription
process of using dna template to make rna
41
transcription: amplification
make many mRNAs from 1 gene (template region of DNA)
*many proteins made from 1 mRNA
42
transcription: control
can change/ control whether or not to make mRNA from DNA and/or how much is translated
43
transcription: evolution
earliest cells might not have had dna; mrna directly made proteins
*rna world hypothesis
44
transcription requirements
rna polymerase (so no primer needed)
45
dna-rna binding in transcription is...
temporary (dna only used as template)
46
how many mrna can be made from 1 dna template
many!
47
transcription unit
a region of dna used as a template for a type of rna ; from promoter to terminator
48
how many transcription units per chromosome
100s-1000s
49
genes
regions of dna that define the coding info for a protein
50
promoter dna
nucleotides bound by rna polymerase that signify the starting point of the transcription unit
51
transcription factors
proteins that bind to dna and recruit rna polymerase/ give it directions
52
tata box promoter
recruits and directs dna polymerase; located upstream of where transcription starts
53
terminator dna
where transcription stops
54
transcription in prokaryotes
no nucleus/ membrane bound sections to move mRNA in and out of; translation begins before transcription ends (5' end once made attaches to ribosome)
55
polyribosome
ribosome attached to an mRNA
56
transcription in eukaryotes
transcription in nucleus separated from translation; nucleus -> cytoplasm -> ribosomes
57
why is mRNA modified in eukaryotes
to help with stability and export out of the nucleus
58
mRNA modifications
- 5' cap: modified nucleotide 5' - 5'
- poly- A tail: binds to proteins at 3' end to stabilize, recognize/mark and export from nucleus
59
primary transcript of mRNA
mRNA before modifications (5' cap and poly-A tail)
60
rna processing
removal of non coding introns and splicing together of remaining exons (coding regions)
61
introns
non coding regions of rna that are spliced out
-thinner than exons
-spliced out at splice site/ exon- intron junctions
62
exons
coding regions of rna (thicker than introns)
63
spliceosome
protiens and small nuclear rna (snRNA) that remove introns
64
what are snRNAs
ribozymes
65
alternative splicing
rna keep different exons in different cells -> get diff mRNA proteins from same dna template
66
how can ribosomes be isolated
-can be seen by e- microscope
-cell fractionalization
67
cell fractionlization
separating cell components by density; create density gradient using sugar solution
68
ribosomes
cell structure that makes proteins;
-made of ribosomal rna (rRNA) and proteins
-have large and small subunits
69
codon
nucleotide triplet in mrna that amino acids are coded with
70
what way do ribosomes build and read amino acids
build: 5' -> 3'
read: 3' -> 5'
71
experiment that discovered codons
feed radioactive amino acids to cell-> look what radioactive proteins were made
72
start codon; and what does it match with?
AUG/ ATG
*matches with initiator tRNA anticodon
73
stop codons
TAA, TAC, TGA
*nonsense codons
74
release factor
protein that bonds to stop condon; releases polypeptide
75
codon steps
1) linear sequence mrna has triplet codons
2) ribosome attaches and reads mrna codon sequence
3)recognize triplet -> bring in right amino acids (reverse complement)
76
adaptors
tRNA (transfer rna) that binds to mrna codon and amino acid
77
anticodon
reverse complement rna that binds to codon in mrna -> brings in attached amino acid
78
aminoacyl trna
amino acid bound to trna amino acid attachment site
79
aminoacyl trna synthases
enzymes that attach amino acids to the correct tRNA.
*specific enzyme for each type of trna
80
untranslated regions (utr)
5' utr: before start codon
3' utr: after stop codon
81
translation in prokaryotes
1 mrna can code for several different proteins
82
operons
several consecutive start/stop regions in 1 mrna; cluster of genes transcribed from the same promoter to give a single mRNA carrying multiple coding sequence
83
what recognized intron-exon splice sites
small nuclear rna (snRNA)
84
info for nucleotide sequence for snRNA comes from....?
dna
85
mutation
dna nucleotide changes that lead to permanent, heritable changes in genome
86
what causes mutations (3)
1) bad replication; mistakes in dna polymerase proofreading
2) chemical/ radiation damage to bases/ dna strands
3) viruses and transposable elements that hijack/ jump around dna damaging it
87
point mutations
change in or gain/loss of single nucleotide base
88
point mutations: synonymous mutation
mutated nucleotide that codes for same amino acid -> no change in protein/ silent mutation
89
point mutations: missense mutation
change nucleotide that leads to the wrong amino acid being made
90
point mutations: nonsense mutation
change in nucleotide sequence makes stop codon -> incomplete protein
91
point mutations frameshift mutation
deletion or insertion of nucleotide -> changes how codon triplets are read
*frame stays the same if 3 nucleotides added together
92
mutations in non coding regions
impacts mRNA made
*could disrupt stop codon, protomer/terminator dna, splice sites, etc
93
transcriptional regulation
use transcription factor proteins to help or inhibit dna polymerase to increase or decrease transcription of nearby genes
94
example of gene regulation: Lac operon
*beta galacto sidase breaks down lactose -> glucose
*repressor protein binds to operator site -> repress
95
how can lactose be broken down into glucose
* presence of lactose; allosterically binds to repressor transcription factor to allow for transcription
*other transcription factors act;; CRP or cyclic AMP (cAMP)
96
CRP
activator transcription protein; active when low levels of glucose (bring lactose in even when repressor is repressing)
97
cAMP
non protein molecule; second messenger whose levels of abundance carry info about how much glucose there is
98
cAMP levels and glucose
* glucose high = cAMP low
* glucose low = cAMP high (signal for more lactose to be broken down)
99
enhancer dna
transcription factor that stimulates transcription
100
silencer dna
transcription factor that represses transcription
101
do transcription factors have to be close to promoter to impact transcription
no
102
chromatin remodeling
change chromosome shape by wrapping dna into nucleosomes
103
what carries out chromatin remodeling
histone proteins
104
impact of chromatin remodeling
more densely packed dna makes it harder to transcribe
105
what do acetyl groups on histone do
cause less winding of dna, therefore more transcription
*taking off acetyl groups silences transcription/ gene expression
106
dna modifictions
change gene expression
107
dna methylation
adding a methyl group to silence region gene expression
*temporary and does not change genetics
108
epigenetic change
changes in transcription factors that do not genetically modify/ alter nucleotide sequence
*stays consistent through cell division
109
microRNA
binds to mRNA after transcription to trigger destruction or to block translation
110
what 2 things can mutations impact
1) can change recognition sites for transcription factor binding (promoter, enhancer, silencer dna)
2) can change the transcription factor itself
111
chromatin
strands of chromosomes (dna, histones, transcription factors)
112
nucleolus
site of rRNA synthesis in the middle of the nucleus; not membrane bound
113
inner and outer envelopes
2 lipid bilayers of the nucleus perforated by nuclear pores
114
how to transport proteins to diff parts of the cell
use signal sequence -> bind to carrier protein for specific part of cell -> transport protein
115
importin
a protein that imports proteins bound to it into nucleus
116
exportin
protein that shuttles a protein out of the nucleus
117
nuclear import signal sequence
specific amino acid sequence on a protein being transferred that binds to importin via lock and key interaction
118
endoplasmic reticulum
network of membrane enclosed tubes/dishes that is continuous with the outer nucleus membrane
119
smooth er
-has no ribosomes (so not involved with protein synthesis)
-has enzymes that synthesize lipids, steroids, carbohydrates
- Calcium ion storage place (pumps in with membrane pumps)
120
rough er
has ribosomes -> synthesises proteins
121
rough er secretion
secretion signal sequence on protein binds to SRP receptor -> secretion by exocytosis -> ER lumen
122
where do proteins go after the rough er and how do they get there
they go to the golgi apparatus via vesicals
123
golgi apparatus
stacks of flattened membrane that modifies/ process proteins
124
golgi apparatus cis face
innermost face
125
golgi apparatus trans face
outermost face
126
how does the golgi modify proteins
- cleave; split into 2
- covalently link other proteins together; disulfide bonds
-glycosylation: adding sugars to protein
127
how do vesicles know where to go
proteins on outside of vesical
128
lysosome
digestive enzymes that break up macromolecules; mini stomach in cell
129
lysosome pH
acidic inside of lysosome so things can be broken down; H+ pumps move H+ into lysosome from cytosol
130
how are vesicles moved
moved by motor proteins along the cytoskeleton
131
cytoskeleton
intracellular roads and fibers made up of many proteins
132
microtubules
thick hollow tubes in cytoskeleton
133
what are microtubules made of
alpha and beta tubulin proteins
134
how do microtubules move things
- lengthening and shortening
-motor proteins
-slide past each other using cilia (lots of short structures) and flagella (one long structure)
135
what motor proteins do microtubules use
kinesin or dynein
136
cilia and flagella
bendable projections of membrane organized into ring with a 9-fold array of stable doublet microtubules; pairs connected by dynein motor protein
137
what do microtubules do during cell division
move chromosomes
138
microfilaments and function
finest/ thinnest part of the cytoskeleton used for:
-rapid cell shape change
- intracellular movements (* cytoplasm streaming)
- muscle contraction
139
what are microfilaments made of
double helix made of actin proteins; shortened and lengthened by actin removal
140
microfilaments motor proteins
myosins
141
how do microfilaments move things
-motor proteins
-move things along microfilaments
-slide microfilaments past each other
142
actin extensions
- pseudopodia
-filopodia
-lamellipodia
143
cytoplasmic streaming
acitive (needs energy) movement of cytoplasm to deliver things to parts of the cell
144
prokaryotic cell division
fission
145
why is prokaryotic cell division so much simpler than eukaryotic
dna in 1 circular chromosome in prokaryotic but in eukaryotic it is in multiple linear chromosomes
146
fission mechanism
-replicate cytoplasm
-replicate dna
-each copy of dna attach to one side of membrane -> seperate through cell elongation
147
number of eukaryotic chromosomes
set number per species
*humans: 46 per somatic cell (not sex cell)
148
mitotic spindle
microtubules used in mitosis to separate sister chromatids to either side of the cell; separate chromosomes for daughter cells
149
what do microtubules do
arrange and move chromosomes
150
where do microtubules attach to chromosomes
kinetochore; specialized point of centromere
151
what do non kinetochore microtubules do
build cage
152
spindle poles (of the microtubules cage)
centriole pairs
153
spindle pole organization
centriole pair w/ centrosome; chromatids attached to single chromosome at centromed
154
kinetochore
proteins surrounding centromere
155
how does spindle move chromatids (2)
1) shortening; microtubules disassemble at kinetochores
2)sliding along microtubules using motor proteins
156
Interphase (G1, S, G2)
cells grows and replicates dna to prepare for cell division
157
Prophase
-winding up of dna into chromosomes
158
Prometaphase
nuclear envelope breaks down (stored to be reformed later); spindle starts to form
159
Metaphase
chromosomes attach to spindle fibers and line up in center
160
Anaphase
spindle pulls sister chromatids to either end of the cell
161
Telophase
separates duplicated genetic material
162
cytokinesis
subdivision of cytoplasm into 2 cells
163
animal cell cytokinesis
cleavage furrow; pinches cell in middle -> 2 cells
164
plant cell cytokinesis
cell plate; form new membrane from vesicles fusing in middle of cell
*cannot do cleavage because of rigid cell wall and turgor pressure
165
cell cycle
life cycle of cells; G1, S phase, G2, M phase
166
cell cycle checkpoints
protein complexes throughout the cell cycle that monitor activity/ make sure everything is going right
167
G1 checkpoint
make sure cell large enough/ with enough neutrance; decide whether or not to divide
168
G2 checkpoint
check if all of the DNA replicated correctly
169
M checkpoint
check that all chromosomes are attached to spindle microtubules
170
MPF
complex of 2 proteins that drives cell through G2 checkpoint
171
how are checkpoints regulated
by "clock" protein cyclin; protein synthesised at a steady pace with specific thresholds
*disappears after mitosis; restarts clock
172
cyclin dependant kinase (CDK)
protein that cyclin binds to and activates tp create active MPF
173
why do cells reproduce to make non genetically identical offspring
genetic variation can make a species more resistant and have better chances of survival
174
prokaryote reproduction -> genetically varied offspring
1) transformation: specialized channels take up DNA from outside -> incorporated into prokaryote chromosome
2) conjugation: bits of dna transfer between prokaryotes
175
how do prokaryotes transfer bit of dna between each other
pili
176
how do eukaryotes produce genetically varied offspring
cell fusion during fertilization
177
diploid
pairs of homologous chromosomes (4 chromatids)
178
ex of diploid cell
somatic cell
179
haploid
only 1 homologue (2 sister chromatids)
180
ex of haploid cell
sperm and egg cells (gametes)
181
homologous chromosome
2 chromatids joined by centromere with same genes in same regions BUT different versions of the gene/ different alleles
182
alleles
one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome
183
meiosis
diploid cell -> 4 haploid cells
184
meiosis 1
meiotic spindle lines up homologous chromosomes next to each other -> separate homologous chromosomes
*sister chromatids stay together!
185
what do chromosome synapses do
pair sister chromatids together
*prophase
186
tetrad/ bivalent
4 sister chromatids/ 2 chromosomes together; recognize similar dna/ nucleotide sequences -> join together
*metaphase
187
crossing over
dna from 1 homologue breaks and joins with other chromosome -> non parental chromosomes (mixes genes from both chromosomes)
188
meiosis 2
sister chromatids separate -> 4 haploid cells
*no dna replication before
189
mendel 1865 experiment
breeding pea plants and observing inheritance of traits (flower color, seed color, seed shape)
190
true breeding parents
offspring keep traits unless you allow/ breed for cross fertilization
191
alleles
different versions of the same gene
*homologous chromosomes with certain gene in the same region -> different alleles
192
mendel's law of segregation
the 2 alleles in the parent segregate from each other during formation of gametes; equal probability of passing on either allele
193
homozygotic
2 of the same allele (recessive or dominant)
194
heterozygotic
2 different alleles
195
mendel's law of independent assortment
the way 1 set of alleles separate from each other into gametes has no impact on the separation of another set of alleles
*if genes on different chromosomes
196
phenotype
physical traits individual has
197
genotype
genetic information individual has passed on from parents
198
how to determine genotype; homozygous dominant vs heterozygous dominant
test cross; breed with homozygous recessive
199
dihybrid cross
cross 2 heterozygous genes on different non homologous chromosomes (independent assortment)nat the same time
200
dihybrid cross genotype ration
9:3:3:1
201
what does independent assortment increase
genetic variation
202
how to see all of the genetic possibilities
punnett square
203
diagram to see what genotype is dominant
pedigree
204
incomplete dominance
heterozygote has phenotype that is intermediate/ in between homozygotes
ex. white + red -> pink
205
co dominance
different alleles give qualitatively different dominate traits -> see both traits
ex. blood type (A and B carbohydrates)
206
transfusion reaction
immune response to unfamiliar blood type cells
207
O blood type
no carbohydrates on blood cells
208
universal blood receiver
AB
209
universal blood donor
O
210
several mutant alleles of the same gene
can inhibit, increase or completely change protien function
211
several mutant alleles of the same gene nomenclature
gene name ^ xxx (superscript)
212
pleiotropy
single mutant allele affects many tissues and processes
ex. beta globin gene mutation causes blindness, liver failure and heart attacks
213
specialization
organs for production of nutrient filled egg (ovary) or mobile sperm (testes)
214
hermaphrodites
have both reproductive organs; can vary over time or exist at the same time
215
autosomes
non sex chromosomes
humans: 22 pairs
216
sex chromosomes
make genetic choice between making sperm or egg
- XX makes ovaries -> egg
- XY makes testes -> sperm
217
SRY gene
gene on Y chromosomes that encodes transcription factor that directs development of testes and hormone testosterone
218
sex linked genes
XY is hemizygous for X- linked gene allele and Y- linked gene allele
219
hemizygotic
individual who has only one member of a chromosome pair or chromosome segment rather than the usual two
220
X- linked gene
gene on X chromosome
221
Y- linked gene
gene on y chromosomes
222
why are males more likely to inherit recessive X linked genes
dependent on only 1X allele because only have 1 X chromosome
223
x linked mutations
more likely to be passed onto males because there are only genes expressed on the one X chromosome
224
sex influenced traits
autosomal mutation influenced by sex physiological factors (ex. sex hormones)
*not on sex chromosome
225
pedigree symbols
circle: XX
square: XY
shades indicate the phenotype
226
x linked recessive trait passing on
male: only mother must have trait on 1 X chromosome
female: both parents must possess trait on X chromosome
227
y linked trait
all XY offspring of XY with the trait will also inherit the trait
228
how are X Y chromosomes paired during meiosis
pairing must be between similar segments of DNA; 40 shared genes between X and Y on tip of chromosome
229
what is the region of similar DNA used to pair X and Y chromosomes called
pseudo- autosomal
230
dosage compensation
XX have double the X linked genes as XY which produces 2x as much mRNA (BAD)
231
dosage compensation; mammals
random inactivation of 1 X chromsome in XX individuals
232
what are the inactive X chromosomes called (used for dosage compensation)
barr bodies
233
how are barr bodies made
histones wrap chromosome so tightly it silences transcription so cannot make mRNA
234
epigenetic mosaic
different mix in gene expression; heterozygous XX expresses both genes
235
nondisjunction
chromosome separation fails during meiosis (either stage) and produces unequal gametes
236
gametes produced by nondisjunction
aneuploidies
237
trisomy
3 of one chromosome; leads to birth defects (only 3 survivable ones)
238
momsomy
only 1 of one chromosome; not survivable to birth on autosomal chromosomes
239
trisomy ex
down syndrome; trisomy on chromosome 21
240
nondisjunction in sex chromosomes
XXY
XXX
X
* ONLY SURVIVABLE HUMAN MONOSOMY
XYY
241
XXY
1 barr body; reduced testes, testosterone and fertility
242
XXX
2 barr bodies
243
X
no barr bodies; only survivable human monosomy
244
XYY
both Y active; extra fertile testes and could lead to more severe defects
245
fruit fly gene nomenclature
x+ = dominant/ normal
x or x- = mutant
named after the mutant form
246
recombinant
non parental chromosome; crossing over has occurred
247
crossing over
parts og homologous chromosomes in meiosis 1 cross and make tetrad; chromosome recombine at chiasm and forms non parental chromosome
*more genetic variability is added
248
tetrad
4 connected chromatids; the point where homologous chromosomes exchange genetic material by the process of crossing over
249
independent assortment test cross
equal amount of all 4 gametes
250
where on gene must crossing over occur for genes linked on the same chromosome
in between the 2 genes of interest
*happens more commonly when genes further apart
251
unit for mapping matants
centimorgans/ map units= % of offspring with non parental geneotype
252
50 map units
50/50 chance of recombinant or parental chromosomes
- less than 50 = recombinant
- greater than 50 = parental
253
polygenic trait
one phenotype caused by more than 1 gene; mutation in all genes causes phenotype
254
what does polygenic inheritance lead to
quantitative variation in interiable quantitative trait
255
epistasis
complex interactions between genes and traits
256
when one gene turns the entire pathway off, how is that gene described
that gene is epistatic to the other genes in the polygenic inheritance
257
how to determine genetic vs. environmental influence
twin tests; monozygotic (identical) vs. dizygotic (fraternal)
258
concordance
the probability that both twins have a certain phenotype given that one has the characteristic
259
cadherin
cell adhesion molecule
260
mitochondrial gene inheritance
male and female offspring of an affected XX parent show the trait; mother to child
*XY parents never transmit the trait to their offspring
261
what does the signalling cell produce
signaling molecule known as the receptor
262
what do ligands produce
signaling cell (which the signalling molecule binds to)
263
kinase function
type of protein adds a phosphate group to another protein
264
inheritance by non nuclear chromosomes
genetic inheritance from dna from semi autonomous organelles (chloroplasts and mitochondria)
265
does non dna information pass down through fertalization; epigenetics/ gene expression
as of now we don't think so; dna methylation and gene expression lost after fertilization
266
protist
single celled
267
colony
collection of individual cells
268
multicellularity
collection of eukaryotes that has a more complex organizational structure than colonies; interconnectedness and communication.
269
how does a multicellular organism forms
single cells goes through division -> leads to differentiation of cells (specialization)
270
cell signaling
coordination between cells in multicellular organisms
271
fungi cell signaling
cytoplasmic connections; breaks in cell wall so cytoplasms are directly connected and anything can go through (proteins, organelles, etc)
272
syncytial arrangment
cells fused together so things can fow between them; direct cytoplasm connections
273
animal cell signaling
gap junctions; small pores that can pass small molecules between cells (ions, monomers, cAMP)
274
plant cell signaling
plasmodesmata; large pores used to pass large molecules between cells (proteins, mRNA, etc)
275
extracellular signaling
cell communication outside of the cell via signaling molecules
276
ligands
a signaling molecule that binds to receptor protein -> trigger response in cell
277
signal transduction pathway
The chains of molecules that relay intracellular signals
278
ligand example; steroids
-easily diffuses across membrane (not normally the case)
-binds and activates receptor proteins
-receptor- steroid complex becomes active transcription factor
- binds to specific enhancer dna
- stimulates transcription
279
factors in information flow (4)
1) specificity of signal/receptor pathway
2) scale of impact (part or whole cell)
3) feedback (pos or neg)
4) amplification caused?
280
amplification
enzymes in pathway receive and amplify protein at every step; pos feedback
281
what receptors exhibit amplification
- transcription factors
- protein kinase
- cyclases
- G proteins
- secondary messengers
282
secondary messengers
non protein messengers; cAMP, Ca2+, ions, lipids, gasses. etc
283
G proteins
family of proteins that act as molecular switches inside cells
284
G protein coupled receptors
activates G proteins by breaking bond with GDP and binding protein with GTP
285
inactive g protein
bound to GDP
286
active g protein
bound to GTP
287
ex of g protein activation
adrenaline; activates alpha G protein -> activates adenylyl cyclases -> makes cAMP -> activates protein kinase A -> increases heart rate
