uworld bio rev Flashcards
(305 cards)
1
Q
what comprises the inner wall of all blood vessels
A
a single layer of endothelial cells
2
Q
single layer of endothelial cells forms a
A
barrier that regulate entry/exist of materials into/out of bloodstream
3
Q
what do endothelial cells secrete?
A
chemical signals that prevent clotting
4
Q
injury to a blood vessels triggers
A
1) formation of platelet plug
2) clot is strengthened
5
Q
formation of platelet plug means…
A
endothelial damage exposes connective tissue outside blood vessels
platelets bind connective tissue (i.e. collagen fibers) to form PLATELET PLUG out of vessel
6
Q
where are platelets derived from
A
bone marrow
7
Q
bound platelets and endothelial cells near site of damage continue…
A
to release signals that enhance platelet aggregation
8
Q
where are clotting factors synthesized
A
mainly in the liver
9
Q
clotting factors are specialized…
A
proteins that activate in response to platelet aggregation + signaling factors outside vessel
10
Q
activated clotting factors induce processes that lead to…
A
formation of the enzyme thrombin
11
Q
thrombin induces
A
protein strands (i.e. fibrin) to form an adhesive mesh-like structure over the platelet plug (reinforcing clot)
12
Q
synapses are
A
gaps b/w presynaptic and postsynaptic neuron
can be electrical or chemical in nature
13
Q
synapses are important in allowing
A
communication bw an axon terminal of a presynaptic neuron
AND dendrites of a postsynaptic neuron from an action potential
14
Q
neurons communicate with
A
one another via action potentials
15
Q
an action potential travels down the…
A
signaling cell (presynaptic neuron) until it reaches the axon terminals
16
Q
axon terminals are responsible for
A
signal transmission across synapse to the postsynaptic neuron
17
Q
synaptic transmission via ligand-gated ion channels
A
1) action potentials reach axon terminal
2) Ca2+ channels open
3) Ca2+ ions enter cell
4) Ca2+ triggers neurotransmitter release via exocytosis
5) neurotransmitter binds ligand-gated ion channels to allow ions thru
6) inhibitory or excitatory cell response
18
Q
glutamate (glu)
A
primary excitatory neurotransmitter of CNS
involved in learning and memory
19
Q
GABA
A
primary inhibitory neurotransmitter of brain
20
Q
glycine (gly)
A
primary inhibitory neurotransmitter of the spinal cord
21
Q
dopamine (DA)
A
can be excitatory or inhibitory
involved in cognition, attention, movement, reward
22
Q
serotonin (5-HT)
A
mainly inhibitory
involved in sleep, appetite, mood
23
Q
norepinephrine (NE)
A
can be excitatory or inhibitory
involved in sympathetic signaling in the ANS
24
Q
acetylcholine (ACh)
A
involved in parasympathetic signaling in the ANS
released by motor neurons at neuromuscular junctions of the somatic NS –> excites skeletal muscle
25
synaptic transmission of excitatory neurotransmitters
1) AP reaches axon terminal
2) AP causes Ca2+ channels to open --> Ca2+ in presynaptic neuron's axon terminal
3) Ca2+ triggers neurotransmitter release via exocytosis
4) excitatory NT binds ligand-gated ion channels to allow Na+ ions into postsynaptic neuron
5) Na+ ions depolarize membrane potential + promote AP initiation
26
synaptic transmission of inhibitory NTs
1) AP reaches axon terminal
2) AP causes Ca2+ channels to open
3) release Ca2+ into presynaptic neuron's axon terminal
4) inhibitory NT binds ligand-gated ion channel to allow Cl- ions into post synaptic neuron
5) Cl- ions cause membrane potential to hyperpolarize + inhibit AP initiation
27
what happens to chemical synapses?
AP in presynaptic neuron releases NTs
NTs bind receptors on membrane of postsynaptic neuron
28
classification for NTs
excitatory - AP MORE likely to occur in the postsynaptic neuron
inhibitory - AP LESS likely to occur in postsynaptic neuron
29
APs are electrical signals that travel from
a neuron's cell body down its axon and to its axon terminals
30
during APs, membrane potential of the neuron...
changes due to opening/closing of voltage-gated Na+ and K+ ion channels
31
at rest, a neuron maintins a potential difference known as...
resting membrane potential (RMP) of ~ -70 mV
meaning that intracellular space is 70 mV more neg than extracellular space
32
RMP is maintained by the
Na+/K+ pump and K+ leak channels
33
Na+/K+ pump and K+ leak channels are always..
open and allow passive diffusion of K+ across membrane
34
stimulus may cause voltage-gated Na+ channels to open and then....
Na+ rushes into cell --> depolarize membrane
membrane potential is (+)
35
if depolarization is enough to reach a certain...
threshold, an AP is initiated in the neuron
36
if the threshold is reached...
voltage-gated Na+ channels remain open
futher rapid depolarization of membrane occurs
37
Na+ entry causes AP to reach its
peak (overshoot) --> membrane potential is at most positive
voltage gated Na+ channels close and voltage gated K+ channels open to go back to RMP
38
K+ rushes out of neuron after K+ channels open and result in
REPOLARIZATION
39
voltage gated K+ channels close more slowly so...
membrane potential becomes more neg briefly than the RMP (i.e. HYPERPOLARIZATION)
40
when voltage gated K+ channels close...
RMP is restored
41
during an AP, the opening/closing of voltage gated channels determines
state of membrane polarization and propogation of AP
42
if voltage gated K+ channels are downregulated...
repolarization would occur more slowly
results in neuron hyperexcitability
43
neurons are responsible for
sending electrical signals to other cells
44
neuroglia provide support functions to
neurons and the nervous system
45
types of neuroglia in CNS
ependymal cells
oligendrocytes
microglia
astrocytes
46
what type of cell lines compartments and produced cerebrospinal fluid
ependymal cells
47
what do oligondendrocytes do
form myelin sheath around axons to reduce ion leakage
decrease capacitance
increase AP propagation speed along axon
48
microglia serve as
immune cells which phagocytize pathogens/damaged cells/waste materials
49
astrocytes
contact blood vessels
regulate blood flow to coordinate synaptic activity/chem changes
important in maintaining extracellular fluid/ion/pH/NT homeostasis
provide nutrient for neuron function
50
types of neuroglia in PNS
schwann cells
satellite cells
51
schwann cells form
myelin sheaths around axons to increase conduction speed
52
satellite cells provide
structural support and support nutrients to neurons
53
oligendrocytes myelinate
CNS axons
54
pathway of fluid/liquid transport in lympathic system
interstitial fluid
lymph capillaries
lymph vessels
lymph duct
vein
55
reflexes are involuntary responses to
stimuli
may or may not require input from brain
56
a reflex arc is the specific neuronal pathways that
helps the direct muscular or glandular effect associated w a specific reflex
57
reflex arcs begin with the
stimulation of a sensory neuron
electrical impulse then travels down spine/brain along sensory nerve
58
electric impulse from reflex arc can be transmitted either:
directly
indirectly
59
direct impulse transmission
directly transmitted to effector neuron (monosynaptic reflex arc)
60
indirect impulse transmission
indirect transmission through interneuron
interfaces w/ effector neuron (i.e. polysynpatic reflex arc)
61
electrical impulses initiated in effector neurons leave the CNS and...
travel along effector neuron to stimulate muscle fiber/gland/ganglionic neuron
this is done either directly or after synapsing w/ a postganglionic effector neuron
62
when the effector neuron synapses with a muscle fiber, it is referred to as
a motor neuron
63
autonomic reflex arcs are always
polysynaptic
e.g. gustatory-salivary reflex
64
reflexes can be modulated by...
input from the brain
65
in the case of polysynaptic reflexes, this modulation takes the form of...
descending signals from higher areas in the CNS that act on preganglionic neurons in the reflex arc
66
soma of both interneuron + preganglionic neuron within CNS could be....
acted upon by descending input from higher brain centers to alter gustatory-salivary reflex
67
what are reflexes mediated by?
reflex arcs
neuronal pathways (incl a sensory neuron)
an effector neuron
possibly an interneuron
68
membrane-bound receptors respond to ligands that are either:
endogenous (originating from organism)
exogenous (foreign to organism)
69
agonists are ligands that
activate the receptor and promote its downstream effects
70
antagonists are ligands that
deactivate or inhibit the receptor
prevent its downstream effects
71
cholinergic signaling involves
acetylcholine (ACh)
72
cholinergic neurons secrete
ACh which binds to cholinergic receptors
73
parasympathetic pathways utilize ACh for signaling between
pre and postganglionic neurons
as well signalling bw the postganglionic neuron and target tissue (e.g. salivary glands)
74
the gustatory-salivary reflex arc is mediated primarily by
parasympathetic pathways
exerts effects (i.e. stimulation of salivation) through cholinergic signaling
75
name what the parasympathetic division of the NS promotes
E conservation and storage
lower heart rate
decreased air flow
stimulating digestion (e.g. salivation, release of digestive enzymes, peristalsis)
inc glucose uptake
glycogenesis
76
name what the sympathetic division of the NS promotes
oxygen delivery to skeletal muscles is maxed
increased heart rate
dilated airways
constricted blood vessels
glycogen in liver --> glucose to provide energy for skeletal muscles
pupils dilate to max light intake
77
step 1 of neural process of receiving/acting on sensory info in a reflex arc
sensory receptors detects stimulus
78
sensory receptors are highly specialized nerve endings that
respond/recognize to highly specific types of stimuli (e.g. chemical, light, pressure, vibration)
79
2nd step of neural process
activated sensory neuron sends an afferent sensory signals (electrical impulse) --> CNS
elec impulse is transmitted to an interneuron or effector neuron
remember: Afferent Approaches CNS
80
3rd step in neural process
interneurons in cns in brain/spinal cord act as integration center
sensory/CNS input are processed and consolidated
interneurons can relay sensory info to brain + integrate signals from brain into reflex response
interneurons transmit signal directly to effector neuron
interneurons are not present in every reflex arc
input from brain is not always needed for reflex completion
81
4th step in neural process
effector neuron generates/sends an efferent signal that travels TOWARD the target organ (muscle or gland)
REMEMBER: Efferent info Exits CNS
82
5th step in neural process
effector (target) organ generates desired response to stimulus
83
within the gustatory-salivary reflex, the sensory neuron makes up the
afferent component of the reflex arc
sensory neuron transmits impulses toward the CNS
84
pre and postganglionic fibers make up the
efferent component of the reflex arc
fibers transmit impulses away from the spinal cord
85
preganglionic neuron corresponds to
the efferent component of the gustatory-salivary reflex
pregang neuron sends impulses AWAY from CNS
86
sensory neuron corresponds to the
afferent component of the gustatory salivary reflex
sensory neuron sends impulses TOWARD the CNS
87
interneuron propogates signals within the
CNS
impulses are not generated
impulses do not travel directly or away from the CNS
interneurons is neither afferent/efferent
88
input from higher areas in the CNS can modulate
activity of reflexes by either strengthening or weakening magnitude of the response
89
the nodes of Ranvier increase the rate of
depolarization toward the axon terminal
90
nodes of Ranvier are sites of
ion flux across myelinated axons
91
nodes of ranvier are sites of interrupted myelination that
contain voltage-gated channels
92
when and where are an AP generated?
generated in a neuron when
the soma depolarizes enough that membrane potential reaches a threshold for voltage-gated channels opening
93
after AP is generated, voltage-gated channels open in a...
coordinated fashion, allowing a series of ionic movements across plasma membrane to occur
94
ionic movements across plasma membrane allow...
rapid maximal depolarization of a small area of the membrane due to Na+ transport into cell
95
after maximal depolarization of membrane occurs...
rapid repolarization as Na+ channels close and K+ channels open
allowing K+ to leave the cell
96
APs 'move' along an axon toward the
axon terminal as successive regions are depolarized
97
manner in which APs move is
influenced by myelin
98
what forms myelin
formed by plasma membrane from glial cells
99
portions of glial cell plasma membrane are wrapped....
many times around an axon
insulating axon and preventing ion flow across axon membrane
100
wave of ion transport is continuous along...
myelinated axons
but 'jumps' in a discontinuous fashion along myelinated axon bc of the insulation provided by myelin
101
what influences rate at which a neural impulse is conveyed?
axon size
myelination
102
larger diameter axon that are myelinated transmit
neural impulses FASTER than smaller/unmyelinated axons
103
myelination can prevent
the loss of current along an axon
104
by exposing a short segment of an unmyelinated axon, the node of Ranvier promote...
entry of extracellular Na+ into axons
while limiting number of open ion channels
GREATLY increases rate at which neural impulses conduct along myelinated axons
105
drug that blocks release of adrenocorticotropic hormone from anterior pituitary would
decrease secretion of cortisol from adrenal cortex
106
viroids are
subviral infectious particles that consist of short circular single strand of RNA
107
viriods have regions where
RNA binds with itself
creating some double-stranded areas of circular genome
108
RNA-composing viroids does not
generally code for protein unlike VIRUSES that have protein coats (capsids)
109
when infecting cells, viroids can bind....
host cellular RNA sequences
results in gene silencing preventing synthesis of necessary proteins
110
ribosomes are composed of
specific proteins and rRNA
111
ribosomes translate...
mRNA sequences into proteins in all cells
112
substituting first (5') nucleotides often
alters the AA
113
substituting the second nucleotide always
alters the AA
114
substituting the 3rd (3') nucleotides doesn't
often alter the AA
115
64 codons =
genetic code
116
64 codones code for how many AAs
20 AAs
117
what does it mean that the genetic code is degenerate?
multiple codons can code for the same AA
118
protein-coding genes consist of
multiple codons
sequences of three nucleotides that code for a specific AA
119
during translation, each mRNA codon base-pairs with...
a corresponding tRNA that is charged w/ a specific AA
120
DNA mutations in the protein-coding regions of a gene may alter...
the sequences of transcribed mRNAs
creating changes in AA structure of encoded proteins
121
what do silent mutations alter
DNA/RNA sequences
122
silent mutations DON'T alter
protein structure
123
mutations in the third position often
code for the same AA
making them silent mutations
124
why do mutations in the third position often code for the same AA?
wobble (less stringent base pairing) at third position of mRNA codone and tRNA anticodon
125
resting state in sliding filament model fo muscle contraction
Ca2+ absence makes tropomyosin block myosin-binding sites of actin filament
126
cross-bridge formation involves myosin heads binding to
myosin-binding site
127
ATP hydrolysis is where
myosin head shifts back to high-energy position
128
power stroke is where myosin head
pulls actin filament to center of sarcomere
129
cross-bridge dissociation involves the myosin head...
being released into low-energy position
130
what is muscle contraction dependent on?
interaction bw myosin (thick) and actin (thin) protein filaments in sarcomere
131
sarcomere is the
basic contractile unit of muscle tissue
132
immune system comprises both of what types of immunity
adaptive and innate
133
cells of the innate immune system can
RAPIDLY and NONSPECIFICALLY recognize and destroy foreign antigens
134
adaptive immune system is subdivided into
cell mediated immunity
humoral immunity
135
adaptive immune system comprises of cell that can
recognize SPECIFIC antigens
mount more specialized immune responses against pathogens
136
in cell mediated immunity, what do t-cells do
recognize + mount immune responses against foreign antigens displayed by MHC proteins
137
MHC proteins on any given cell display...
fragments of any proteins present within that cell
138
cells containing foreign pathogens will generally...
display protein fragments (antigens) on their MHC proteins
139
helper t-cells are t-cells that
recognize foreign antigens displayed by MHC proteins of other immune cells
140
B-lymphocytes are cells that
bind and engulf a foreign antigen
141
the antigen engulfed by the B-lymphocyte is
broken down into fragments and transported to be displayed on MHC proteins on cell membrane
142
helper T cell bind the foreign antigen presented by the
b-lymphocyte and releases cytokines
cytokines induce division of b-lymphocute into identical cells
143
division of b-lymphocyte by cytokines leads to...
differentiation of identical cells to b-lymphocyte to secrete antibodies against invading pathogen
144
macrophages and dendritic cells engulf
foreign antigens via phagocytosis
145
macrophages and dendritic cells present antigen fragments on
MHC proteins found on cell membrane
146
a low count of helper T cells would affect the
activation of cytotoxic t cells and b-lymphocytes (produce antibodies against bacterium)
147
MHC protein's expression is solely dependent on
transcriptional and translational machinery
148
because of MHC"s dependence on a cell's transcriptional/translational machinery...
cells would still be able to display bacterial antigens on their MHC proteins regardless of helper T cell count
149
helper T cells bind
foreign antigens presented on other immune cells
150
helper t cells release
signalling molecules that enhance immune responses
such as cytotoxic T cel activation and antibody production by B lymphocytes
151
in the absence of external energy input, molecules in solution will
diffuse from areas of high to low concentration
this is THERMODYNAMICALLY FAVORABLE
152
molecules that separated from an area of lower concentration by a membrane will...
STILL FLOW across a membrane down their concentration gradient
as long as the membrane is permeable to those molecules
153
osmoregulation is the
homeostatic process by which organisms actively assess their environment + regulate internal concentration of fluid/electrolytes
154
in the absence of osmoregulation, what happens
saltwater fish would tend to absorb salt and lose water
155
because saltwater fish tend to absorb salt and lose water, their osmoregulatory systems do what
combat this process by using energy to excrete salt and absorb water
156
freshwater teleosts live in an environment where water concentration is (x) and salt concentration is (y)
higher water concentration and lower salt concentration outside their bodies than inside
157
in the absence of osmoregulation, salt ions will tend to move to
the lower concentration environment of the exterior freshwater
water molecules do the opposite
158
what is involved in osmoregulation in marine teleosts?
1) seawater ingestion
2) retrieval (absorption) of salt and water from the intestine
3) excretion of DIVALENT ions through urine
4) excretion of MONOVALENT ions through urine
159
examples of divalent ions
Mg2+ and SO4^2-
160
monovalent ions examples
Na+ and Cl-
161
start codon is
AUG
162
stop codons
UAA
UAG
UGA
163
STEP 1 OF TRANSLATION: nuclear genes are initially transcribed by
RNA polymerase to pre-mRNA
164
STEP 2 OF TRANSLATION: pre-mRNA is then converted into
mature mRNA in a process including splicing to remove introns
165
STEP 3 OF TRANSLATION: mature mRNA is then
transported out of the nucleus into the cytoplasm
mature mRNA --> protein by ribosomes
166
each AA in a protein is encoded by
a corresponding mRNA codon that binds anticodon of tRNA that is charged with a specific AA
167
direction of mRNA translation
5' to 3' direction
168
mRNA translation starts at
start codon (AUG)
continues until stop codon (UAA, UAG, UGA) is reached
169
stop codon does not code for an AA but instead
binds a release factor that promotes dissociation of the translation complex
170
regions upstream of the start codon and downstream of the stop codon are referred to as
untranslated regions (UTRs)
171
UTRs do not
code for AAs
172
a mature mRNA consisting of 500 molecules was translated into a 110 AA protein, what is the number of nucleotides?
110 amino acids x 3 nucleotides per codon = 330 nucleotides
173
the 330 nucleotides of this mRNA molecules are translated into
amino acids of the protein
174
number of nucleotides that do not code for AAs can be calculated via
500 total nucleotides - 330 coding nucleotides = 170 noncoding nucleotides
175
what acts like the framework in eukaryotic cells?
internal cytoskeleton
provides shape and internal structure to cells + organization
176
cytoskeleton is made of a network of fibers...
interspersed throughout the cytoplasm and consists of three major components
177
three major components of cytoskeleton
intermediate filaments
microfilaments
microtubules
178
intermediate filaments are composed of
several protein types
e.g. keratin and lamin
179
intermediate filaments perform the following functions:
1) work with microfilaments to determine shape
2) make up the nuclear lamina (inner lining of nuclear envelope)
3) assist in anchoring organelles to specific compartment within the cell
4) provide crucial support for cell to be able to withstand mechanical forces (e.g. compression)
180
when model organisms are deficient in keratins, what would happen?
organisms's hepatocytes more fragile and unable to withstand/resist mechanical forces
may display abnormal hepatocyte phenotypes
181
microfilaments are made of
actin protein subunits organized into double-stranded rods
182
what do microfilaments help determine?
overall shape of a cell and assist in some cellular locomotion
183
microfilaments are responsible for
muscular contractions and forming the cleavage furrow during cytokinesis
184
the reduced ability of a cell to undergo cytokinesis would be a result of
the cell's being deficient in microfilaments
185
microtubulues are made of
alternating alpha and beta tubulin subunits organized into hollow tubes
186
microtubules force the
mitotic spindle during the cell division process
187
microtubules are involved in
movement within the cell
facilitate vesicular transport
188
reduced intracellular transport of substances would be a result of
a deficiency in microtubules
189
what forms the cores of cilia and flagella?
microtubules
190
a cell having a reduced number of cilia on its surface would be a result of
a microtubule deficiency
191
where does fertilization occur
fallopian tube
192
multipotent stemms can develop into
multiple specialized cell types
193
what gene is responsible for the initiation of male sex determination and coding for testicles?
SRY gene
Sorry You're A Male
194
afferent neurons ascend the
spinal cord and carry info to the brain
afferent = approach CNS
195
what hormone induces ovulation and testosterone production?
LH (luteinizing hormone)
196
a blastula is a
hollow sphere of cells that implants in the endometrial lining
197
once blastula implants itself in uterine wall, i.t. becomes...
a BLASTOCYST
198
bile is an important part of the absorption of what?
fat-soluble substances (vitamins A, D, E, K)
199
what neurons exit the spinal cord?
efferent neurons
they bring signals from the brain to the muscles/glands
200
golgi apparatus does what?
modifies and distributes proteins
eukaryotes only
201
mesoderm comprises of
muscoskeleton, circulatory system, gonads, adrenal cortex
MOVING THINGS
202
interneurons are part of
a reflex arc
203
centrioles contain
9 groups of microtubules
204
centrioles do what?
pull chromosomes apart
205
gram negative is
pink/red
has a thin wall
wall made of peptidoglycan
206
temporal summation is when
one presynaptic neuron releases multiple neurotransmitters over a period of time
triggers an action potential
207
gram positive is
purple
has a thick wall
wall is made of peptidoglycan/lipteichoic acid
208
lysosomes are the
demolition and recycling center
made by golgi
209
spatial summation si when
multiple presynaptic neurons releasing neurotransmitters at the same time
triggering an action potential
210
what is released in response to stress and low blood glucose concentration?
CORTISOL
released by the adrenal cortex
211
ectoderm develops into the
nervous system
skin, hair, mouth
212
action potential is the mechanism by which
electrical signals travel through the nervous system
213
CNS and PNS derive from
ectoderm
214
amplitude of an AP is
independent of the amount of current that produced it
215
what makes alkaline fluid to help sperm survive acidic environment of reproductive tract?
seminal vesicles and prostate glands
216
Na+ concentration is higher or lower outside the cell
HIGHER
217
microfilaments make up the cell's
cytoskeleton
polymers of actin
218
K+ concentration is higher or lower inside cell
HIGHER
219
a polarized membrane has an electrical
potential difference across the cell membrane
220
electrical potential difference =
voltage
221
endoderm develops into
GI tract, respiratory tract, endocrine glands, bronchi, bladder, stomach
222
morula results from
division of a fertilized ovum
solid ball of cells
223
what does the hepatic portal system do
delivers deoxygenated blood to the liver to be detoxed further
before returning to the heart
224
when membrane is depolarized, the membrane potential becomes
MORE POSITIVE compared to resting potential
225
membrane potential is an
electrical potential difference b/w inside and outside of a cell
226
lysozyme is an
antimicrobial enzyme forming part of the innate immune system
227
where are lysozymes found
tears and saliva
228
resting membrane potential (voltage) of a cell is
~70 mV
229
when membrane potential is depolarized during an AP,
peak is around +40 mV
230
memory B cells
- formed following primary infection
- generate more robust immune response in case of re-infection
231
MHC-II displays
exogenous antigen to helper CD4+ T cells
232
when membrane is depolarized, membrane potential becomes
more positive compared to resting potential
233
rough ER makes proteins from
mRNA
234
what flows in during depolarization
Na+
235
what does Na+ ions flowing in do
increases charge inside cell
result in depolarization of cell membrane
236
fat-soluble vitamins are absorbed through the
lacteals in villi
237
where do Na+ ions enter cell thru
voltage-gated Na+ channels
238
Na+ concentration gradient drives the
movement of Na+ ions
239
during what phase are mRNA and proteins synthesized
G1
prepares for subsequent steps leading to mitosis
240
interphase includes
G1, S, G2 phases
phase where cell spends most of its life
241
what happens at the G2 checkpoint
cell will check that DNA has replicated correctly
242
what phase do cells grow and make organelles
G2
243
where does ETC take place in eukaryotes
inner mitochondrial matrix
244
explain nondisjunction
when sister chromatids don't separate properly during anaphase
results in ANEUPLOIDY
245
246
transposons are
DNA sequences that can change their position within a genome
creates/reverses mutations
247
what generates antibodies to specific antigens?
B cells
require stimulation from helper T cells
part of adaptive immune system
248
repolarization occurs when
K+ ions EXIT the neuron
249
what occurs during prophase
DNA condenses
centrioles migrate to opp poles
microtubules form
250
hyperpolarization is when
membrane potential dips below the resting potential
251
when hyperpolarized, the neuron is in a
refractory period during which another stimulus is given to the neuron
2nd AP will not occur
252
why does hyperpolarization occur
K+ channels are slow to close
253
large intestine absorbs
water and salts
forms feces
254
t-cells are a type of
white blood cell that circulates around our bodies
scans for cellular abnormalities/infection
255
examples of t-cells
helper t cells
cytotoxic t-cells
suppressor t-cells
memory t-cells
256
hormone released by thyroid gland and builds bone
calcitonin
257
calcitonin increases/decreases
increase in bone/kidneys
decreases in blood/gut absorption
258
virions are
extracellular individual virus particles
259
virion contains
DNA or RNA
SS or double stranded
protein coat (capsid)
260
function of G0 phase
cell enters G0 phase if division isn't necessary
261
what enzymes breaks AAs apart
aminopeptidase
262
what catalyzes the hydrolysis of peptide bonds?
trypsin
breaks proteins into smaller peptides
263
what happens during telophase
chromosomes decondense
nuclear membrane
cytokinesis occurs
264
secretin does what
release of pancreatic juices
slows motility
265
transduction is the
transfer of genetic material using a bacteriophage
266
what enzymes start the chemical digestion
amylase
lipase
267
helper t-cells
activate cytotoxic t-cells and macrophages to attack infected cells
or stimulate b-cells to secrete antibodies
268
what connects the mouth to the esophagus
pharynx
269
epiglottis function
prevents food from entering larynx
270
functional unit of exocrine pancrease
pancreatic acinar cell
271
acinar cell does what
synthesizes, stores, secretes digestive enzymes
272
pancreatic juices contain
bicarbonate
pancreatic amylase
peptidase
lipase
juices flow into the duodenum
273
what makes trypsin
enteropeptidase
274
main inhibitory neurotransmitter in spinal cord
glycine
275
principal site of conversion of tyrosine into catecholamines
adrenal medulla
276
where is the adrenal medulla located
center of adrenal gland
surrounded by the adrenal cortex which sits on top of the kidneys
277
CCK stimulates
bile release from gallbladder
release of pancreatic juices
promotes satiety
278
what responds to antigen on MCH-I and kill virally infected cells
killer cells / cytotoxic t-cells
279
mastication does what
breaks food down into small pieces
forms a bolus and is swallowed
280
what causes agglutination?
opsonizing pathogens
281
hormones in the duodenum that stimulate release of pancreatic juices + bile
secretin and CCK
282
systole
some chambers of heart muscle contract after refilling w/ blood
AV valves close
semilunar valves open
283
natural killer cells are a type of lymphocyte that can
recognize and kill cancer cells or cells that have been infected
284
natural killer cells do not
attack invading organisms directly
285
natural killer cells destroy
body's own cells that have become infected or cancerous
286
top 3rd of esophagus is under
somatic control
287
middle third of esophagus is under
autonomic control
288
bottom third of esophagus is under
autonomic control
289
middle third of esophagus has combo of both
skeletal and smooth muscle
290
full length protein -->
free digested protein fragments --> MHC II --> T cell receptor
291
all nucleated cells contain
major histocompatibility complex (MHC) I molecules
292
pro antigen-presenting cells also contain
MHC II molecules
293
MHC molecules form complexes with
antigens displayed on cell surface
294
antigens displayed in complex with MHC molecules on cell surface bind to
T-cell receptors
295
neurotransmitters bind to receptors on
postsynaptic cell and make it more or less likely to fire an AP
296
larger current do not create
larger APs
297
action potentials are said to be
all or none signals
occur fully or NOT AT ALL
298
types of granulocytes
neutrophils
eisonophils
basophils
part of innate immune system
299
types of agranulocytes
monocyte
lymphocute
part of innate immune system
300
CO2 and H+ will trigger heme group to
release its O2
301
Co2 and H+ allosterically
inhibit hemoglobin
302
allosteric inhibition of hemoglobin means oxygen is
released near lots of Co2 or in acidic sites
which is where respiration is happening and O2 is needed
303
agranulocytes have no
granules
304
transduction is the
transfer of genetic material using a bacteriophage
305
