Midterm 1 Flashcards
(312 cards)
1
Q
Which is more common negative or positive feedback?
A
negative feedback
2
Q
Negative feedback
A
the response counteracts the stimulus, shutting off the response loop
3
Q
Positive feedback
A
the response reinforces the stimulus, sending the variable farther from the setpoint
4
Q
Teleological
A
the branch of physiology where they ask “why?” e.g. “why do red blood cells transport oxygen”
5
Q
Mechanistic
A
branch of physiology where ask “how” e.g. “How do red blood cells transport oxygen?”
6
Q
Translational research
A
combines teleological and mechanistic
7
Q
Structure and function are …
A
closely related
8
Q
Molecular interactions
A
a molecule’s function depends on it’s structure and shape
9
Q
Compartmentation
A
division of space into compartments. Allows a cell, tissue or organ to specialize and isolate functions
10
Q
All processes that take place in an organism require…
A
energy (ATP)
11
Q
Homeostasis maintains..
A
internal stability (how body maintains a range)
12
Q
Internal or external agents cause a ___ to homeostasis
A
disruption
13
Q
Homeostasis leads to an ___ change that the body attempts to ___
A
Homeostasis leads to an internal change that the body attempts to compensate
14
Q
Homeostasis and equilibrium
A
Homeostasis DOES NOT equal equilibrium
15
Q
Homeostasis
A
maintenance of a relatively stable internal environment. Its goal is to maintain a relatively stable state of disequilibrium
16
Q
Failure to maintain homeostasis
A
may result in a disease or pathology
17
Q
Extracellular fluid is a ..
A
buffer between cells and the outside world
18
Q
Extracellular fluid (ECF)
A
the watery environment that surrounds cells
19
Q
Intracellular fluid (ICF)
A
fluid within cells
20
Q
Law of mass balance
A
if the amount of a substance in the body is to remain constant any gain must be offset by an equal loss
21
Q
Load
A
amount of a substance in the body
22
Q
Excretion
A
clears substances from the body (urine, feces, lungs, skin)
23
Q
Mass flow
A
rate of transport through the body
24
Q
Clearance
A
the rate of which a substance disappears from the blood
25
Regulated variables
variables that are kept within normal range by control mechanisms. Homeostasis attempts to keep values near setpoint (range) or optimum value
26
An example of a simple control system
1. Input signal: information about critical variable
2. Integrating center: control center
3. Output signal: corrective signal (if necessary)
4. Response: homeostatic response, keep variable in normal range
27
Local control
restricted to a local tissue or cell
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Reflex control
uses long-distance signaling
29
Response loops begin with
a stimulus
30
Feedback loops modulate
the response loop
31
Control systems use
"negative feedback"
32
Most control systems that maintain homeostasis have a ___, or normal value. The response loop that controls the critical value activates when the variable moves outside a predetermined ___ ___.
Most control systems that maintain homeostasis have a setpoint, or normal value. The response loop that controls the critical value activates when the variable moves outside a predetermined normal range.
33
Feedforward control
provides a response in anticipation of an event
34
Set-points __ between people and over time
vary
35
Biorhythms
some variables follow environmental changes
36
Circadian rhythm
some variables follow a daily (24hr) cycle
37
Variability
there is wide genetic and environmental variability between humans
38
In a ___ study each individual gets the experimental treatment and then "__ __" to also be in the control group
In a crossover study, each individual gets the experimental treatment and then "crosses over" to also be in the control group
39
In a cross-over study, each individual acts as _____
In a cross-over study, each individual acts as their own control, enabling researchers to see the effect of the drug in each participant, rather than between two groups, which helps deal with variability between participants
40
Placebo effect
if you give someone a pill and tell them it will alleviate some problem, that beneficial effect may be observed, even the pill contains sugar or an inert substance
41
Nocebo effect
if you give someone a pill and tell them it may have an adverse side effect, that side effect may be observed, even the pill contains sugar or an inert substance
42
Simplest way to control for placebo and nocebo effects is with
a blind study- in which the participants do not know if they took the treatment or the placebo
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Double-blind study
researchers are also "blinded" until after the experiment. So that they can not influence the outcome
44
Organic molecules
molecules that contain carbon
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Biomolecules
organic molecules in living organisms
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Biomolecules provide ___, store ___ and regulate ___
Biomolecules provide structure, store energy and regulate metabolism
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Conjugated proteins
proteins combined with another molecule e.g. lipoproteins
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Glycosylated molecules
molecules attached to carbohydrates e.g. glycoproteins and glycolipids
49
Polymers
biomolecules made of repeating units e.g. glucose polymers glycogen and starch
50
Ions
if an atom or molecule gains or loses one or more electrons, it acquires an electrical charge and becomes an ion. Ions are the basis for electrical signaling in the body
51
Covalent bonds
electrons shared between atoms form strong covalent bonds that bind atoms together to form molecules
52
Ionic bonds
are electrostatic attractions between ions
53
High-energy electrons
electrons in certain atoms can capture energy from their environment and transfer it to other atoms
54
Free radicals
are unstable molecules with an unpaired electron. They are thought to contribute to aging and to the development of certain diseases
55
Cations
lost electrons, positively charged
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Anions
gained electrons, negatively charged
57
Covalent bonds
when two or more atoms form covalent bonds by sharing electrons, they form molecules
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Ionic bonds are __ ___ between ions
electrostatic attractions
59
Interactions occur between and within molecules as a result of the ....
four types of bonds (covalent, ionic, hydrogen, Van Der Waals)
60
The ____ nature of a molecule determines whether that molecule can dissolve in water
charged, uncharged or partially charged
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Covalent and non-covalent bonds determine ...
molecular shape and function
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Noncovalent interactions allow proteins to ...
interact reversibly, creating functional pairings such as enzymes and substrates or signal receptors and molecules
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Carbohydrates that are used fast
glucose, sucrose, maltose, lactose, maltodextrin, amylopectin (starch)
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Carbohydrates that are used slow
fructose, galactose, amylose (starch)
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Sugars used for nucleotides
ribose and deoxyribose
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Sugars used for glycolysis
glucose
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Monosaccharides
simple sugars, building blocks of complex carbohydrates and have either five carbons or six
68
Disaccharides
consist of glucose plus another monosaccharide e.g. sucrose and maltose
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Polysaccharides
glucose polymers, how living cells store glucose for energy e.g. glycogen
70
Better sport performance with ...
carb blends (glucose:fructose mixes improves performance)
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Backbone of lipids
glycerol
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Lipids are made of ___ and __ ___
Lipids are made of glycerol and fatty acids
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Saturated fatty acid
no double bonds between carbons
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Monosaturated fatty acid
one double bond between carbons
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Polyunsaturated fatty acid
two or more double bonds between carbons
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Unsaturated fatty acids have a ___ in their structure
bend/kink (because of double bonds)
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Solubility
ability of solute to dissolve in a solvent
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Hydrophilic
soluble in water e.g. ions, polar molecules, ionic molecules
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Hydrophobic
not soluble in water e.g. nonpolar molecules
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Hydrophilic interactions
occur between water and ions or other polar molecules. Ions and polar molecules dissolve in water and create biological solutions
81
Nucleotides
play an important role in energy and information transfer
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Single nucleotides
include the energy transferring compounds ATP, ADP and AMP
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ATP (adenosine triphosphate)
common energy currency of the body
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Nucleic acids (DNA, RNA) are __ ___ that store and transmit genetic information
Nucleic acids (DNA, RNA) are nucleotide polymers that store and transmit genetic information
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__ __ are the building blocks of proteins
amino acids
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Oligopeptide
2-9 amino acids
87
Polypeptide
10-100 amino acids
88
Proteins
>100 amino acids
89
Secondary structure of peptides and proteins
created primarily by hydrogen bonds between adjacent chains or loops e.g. alpha helix, beta-strands that form sheets
90
Tertiary structure of peptides and proteins
is the protein's 3D shape, can be a mix of secondary structures e.g. fibrous proteins, globular proteins
91
Quaternary structure of peptides and proteins
multiple subunits combine with noncovalent bonds e.g. hemoglobin
92
___ have the most complex shapes of all the biomolecules
proteins
93
Enzymes
not participants in reactions (not ingredients just get ingredients ready). Biological catalysts that speed up chemical reactions
94
Membrane transporters
in cell membranes help move substances back and forth between ICF and ECF
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Signal molecules
act as hormones and other signal molecules
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Receptors
proteins that bind signal molecules and initiate cellular responses
97
Binding proteins
bind and transport molecules throughout the body
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Immunoglobulins (antibodies)
extracellular immune proteins that help protect the body from foreign invaders and substances
99
Regulatory proteins
turn cell processes on and off
100
Binding site and ligand interact through...
hydrogen bonds, ionic bonds and van der Waals forces
101
The protein's binding site changes shape (___) to fit more closely to the ___
The protein's binding site changes shape (conformation) to fit more closely to the ligand
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Binding sites
the location on a protein where a substrate can adhere. Proteins are selective about the molecules they bind
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Specificity
ability of a protein to bind to a certain ligand or a group of closely-related ligands. Ligand binding requires molecular complementarity, the ligand and the protein binding site must be compatible, but it does not have to be a perfect fit
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Law of mass action
when protein binding is at equilibrium, the ratio of the bound and unbound components remains constant
105
What happens to equilibrium when the concentration changes?
if equilibrium is disturbed by adding or removing one of the products, the reaction equation will shift direction to restore the equilibrium condition
106
Cofactors
required for an active binding site, without the cofactor attached the protein is not active
107
Allosteric activators
a modulator that binds to protein away from binding site and turns it on
108
Chemical modulators
bind reversibly or irreversibly to proteins and alter their binding affinity
109
Antagonists (inhibitors)
chemical modulators that bind to a protein and decrease its activity
110
Competitive inhibitor
blocks ligand binding at the binding site
111
Irreversible inhibitor
bind and cannot be replaced
112
Allosteric inhibitor
modulator that binds to protein away from binding site and inactivates the binding site, causes protein to change shape
113
Physical factors
physical conditions have dramatic effects on protein structure and function e.g. small changes in pH or temperature can modulate protein activity
114
When the protein loses its conformation it is said to be ...
denatured
115
Up-regulation
the programmed production of new proteins
116
Down-regulation
the programmed removal of proteins
117
Free __ can change a molecule's shape or conformation
H+
118
pH
the measure of the concentration of free H+ concentration or the acidity of a substance, power of hydrogen
119
Buffers
substances that moderate changes in pH (homeostatic)
120
Important buffer in the human body
bicarbonate anion (HCO3-)
121
Acids
a molecule that contributes to H+ to a solution, decrease pH
122
Bases
a molecule that decreases the H+ of a solution by combining with free H+, increase pH
123
__ are separated from one another by bones and tissues and they are lined with tissue membranes
Cavities are separated from one another by bones and tissues and they are lined with tissue membranes
124
Lumen
the interior of any hollow organ
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For some organs the lumen is part of the ...
external environment
126
Material must cross the wall of the organ to enter ...
the internal environment
127
Functions of the cell membrane
physical isolation, regulation of exchange with the environment, communication between the cell and its environment, structural support and secretion
128
Physical isolation (Cell membrane)
physical barrier that separates ICF from ECF
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Regulation of exchange with the environment (Cell membrane)
control entry of ions and nutrients, elimination of wastes, release of products
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Communication between the cell and its environment (Cell membrane)
proteins enable the cell to recognize and respond to molecules or changes in the external environment
131
Structural support (Cell membrane)
membrane proteins anchor the cytoskeleton to maintain cell shape or create junctions between adjacent cells or between cells and the extracellular matrix
132
Secretion (Cell membrane)
process by which a cell releases a substance to the ECF
133
Cell membrane
thin layer of lipids that separate the inside and outside of the cell, create a hydrophobic barrier
134
When placed in an aqueous solution, phospholipids align so their ___ ___ interact with water while the nonpolar fatty acid tails "___" by putting the polar heads between themselves and the water
When placed in an aqueous solution, phospholipids align so their polar heads interact with water while the nonpolar fatty acid tails "hide" by putting the polar heads between themselves and the water
135
Micelles
droplets of phospholipids, important in lipid digestion
136
Peripheral proteins
attach to membrane proteins by noncovalent interactions, removal does not disrupt membrane integrity
137
Integral proteins
tightly bound to the membrane, removal disrupts membrane integrity
138
The ___ and ___ ___ build proteins
ER and Golgi Apparatus
139
Inclusions
are substances in the ICF that do not have boundary membranes e.g. glycogen, fat droplets, ribosomes, pigments
140
Ribosomes
small granules of RNA and protein that manufacture proteins under the direction of the cells DNA
141
Fixed ribosomes
attach to the inside surface of organelles
142
Free ribosomes
suspended free in the cytosol
143
Purpose of the insoluble protein fibers
structural support and movement
144
Cytoskeleton
flexible, changeable scaffolding of microfilaments, intermediate filaments, and microtubules that extends throughout the cytoplasm
145
Motor proteins
convert stored energy into directed movement, use energy stored in ATP to propel selves along cytoskeleton fiber
146
Myosins
bind to actin fibers, role in muscle contraction
147
Organelles
subcellular compartments separated from the cytosol by phospholipid membranes, allows the cell to isolate substances and segregate functions
148
Secretory vesicles
contain proteins that will be released from cell
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Storage vesicles
never leave cytoplasm
150
Histology
the study of tissue structure and function- shape and size of the cells, arrangement of cells in the tissue, the way cells are connected, and amount of extracellular material present in the tissue
151
Extracellular matrix (matrix)
extracellular material that is synthesized and secreted by the cells of a tissue
152
Components of extracellular matrix
proteoglycans and insoluble protein fibers
153
Proteoglycans
covalently bound to polysacchaaride chains
154
Insoluble protein fibers
collagen, fibronectin and laminin
155
Cell junctions
membrane proteins and extracellular matrix that hold cells together to form tissues
156
During growth and development, cells form ____ ___ that may be transient or that may develop into more permanent cell junctions
During growth and development, cells form cell-cell adhesions that may be transient or that may develop into more permanent cell junctions
157
Cell-adhesion molecules (CAMs)
membrane-spanning proteins responsible both for cell junctions and for transient cell adhesions
158
Cell-cell or cell-matrix adhesions mediated by CAMs are essential for ___ ___ and ___
Cell-cell or cell-matrix adhesions mediated by CAMs are essential for normal growth and development
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Tissue types
epithelial, connective, muscle, and neural
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Epithelial tissues
protect the internal environment of the body, regulate the exchange of materials between the internal and external environments
161
Epithelia typically consist of ___ or ___ layers of cells connected to one another, with a ___ layer of extracellular matrix lying between the epithelial cells and their underlying tissues
Epithelia typically consist of one or more layers of cells connected to one another, with a thin layer of extracellular matrix lying between the epithelial cells and their underlying tissues
162
Any substance that enters or leaves the internal environment of the body must cross an ___
Any substance that enters or leaves the internal environment of the body must cross an epithelium
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Some epithelia (skin, mucous membranes) act as a ___ to keep water in the body and invaders such as bacteria out
Some epithelia (skin, mucous membranes) act as a barrier to keep water in the body and invaders such as bacteria out
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Nutrients, gases, and wastes often must cross ___ different ___ as they pass between cells and the outside world
Nutrients, gases and wastes often must cross several different epithelia as they pass between cells and the outside world
165
Connective tissues
provide structural support and sometimes a physical barrier that, along with specialized cells, helps defend the body from foreign invaders such as bacteria
166
Bone
calcifies which gives it it's strength and rigidity
167
Cartilage
solid, flexible, lack of blood supply
168
Adipose tissue
(adipocytes), energy storage, temperature regulation, protective layer
169
Blood
transportation of materials
170
Muscle tissue
can contract and produce force and movement. Most skeletal muscles attach to bones and are responsible for gross movement of the body
171
Together muscle and neural tissues are called the ___ tissues because they can generate and propagate electrical signals
Together muscle and neural tissues are called the excitable tissues because they can generate and propagate electrical signals
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Neural tissue
includes two types of cells, neurons, or nerve cells, which carry chemical and electrical signals from one part of the body to another
173
Glial cells or neuroglia
support cells for neurons
174
Necrosis
cells die from physical trauma, toxins or lack of oxygen (may damage adjacent cells triggering inflammatory response)
175
Apoptosis
programmed cell death, regulated by chemical signals (does not damage adjacent cells)
176
Stem cells
undifferentiated cells, retain the ability to divide and develop into the cell types of that tissue
177
First law of thermodynamics or law of conversation of energy
total amount of energy in the universe is constant
178
Energy is the capacity to do ...
work
179
Chemical work
making and breaking of chemical bonds
180
Transport work
- moving ions, molecules, and larger particles
- useful for creating concentration gradients
181
Mechanical work
- moving organelles, changing cell shape, beating flagella and cilia
- contracting muscles
182
Forms of energy
kinetic and potential
183
Second law of thermodynamics
processes move from sate of order to randomness or disorder (entropy)
184
Free energy
is potential energy stored in chemical bonds
185
Net free energy
change determines reaction reversibility
186
Endergonic reactions
energy utilizing
187
Exergonic reactions
energy producing, breaking bonds
188
Enzymes __ the activation energy of reactions
Enzymes lower the activation energy of reactions
189
Enzymes are or are NOT reactants or products
Enzymes are NOT reactants or products
190
Binding site
interacts with substrate and accelerates conversion of substrate into product
191
Enzymes are __ ___ in these reactions so can be used again
Enzymes are not altered in these reactions so can be used again
192
isozymes
different forms of enzymes (isoform)
193
Inactive enzymes
proenzymes or zymogens
194
cofactors types that help enzymes
coenzymes
195
Catabolism
energy-releasing breakdown
196
Anabolism
energy-utilizing synthesis, building something up
197
Kilocalories (kcal)
energy released from or stored in chemical bonds
198
Molecules in pathways are___
intermediates
199
Osmosis
the movement of water across a membrane in response to a solute concentration gradient
200
Osmolarity
the number of osmotically active particles (ions or intact molecules) per liter of solution
201
Most solutes are concentrated in either one compartment or the other, creating a state of ___ ____
Most solutes are concentrated in either one compartment or the other, creating a state of chemical disequilibrium
202
Cations and anions are not distributed equally between the body compartments, creating a state of ___ ____
Cations and anions are not distributed equally between the body compartments, creating a state of electrical disequilibrium
203
Water moves freely between the cells and extracellular fluid, resulting in a state of ___ ____
Water moves freely between the cells and extracellular fluid, resulting in a state of osmotic equilibrium
204
The body fluids are in two compartments: the ___ fluid (__) and the ___ fluid (___)
The body fluids are in two compartments: the extracellular fluid (ECF) and the intracellular fluid (ICF)
205
Homeostasis
stability of body's internal environment (stability of ECF)
206
ECF and ICF exist in state of ___ ___
ECF and ICF exist in state of dynamic disequilibrium
207
The cell membrane is a ___ ___ barrier that restricts free exchange between the cell and interstitial fluid. The movement of a substance across a membrane depends on the ___ of the membrane to that substance
The cell membrane is a selectively permeable barrier that restricts free exchange between the cell and interstitial fluid. The movement of a substance across a membrane depends on the permeability of the membrane to that substance
208
Movement of molecules across membranes can be classified either by ___ ___ or by the ___ ___ the molecule uses to cross the membrane
Movement of molecules across membranes can be classified either by energy requirements or by the physical means the molecule uses to cross the membrane
209
Lipid-soluble substances can diffuse through ____ ___. Less lipid-soluble molecules require the assistance of a ___ ___ or ___ to cross the membrane
Lipid-soluble substances can diffuse through phospholipid bilayer. Less lipid-soluble molecules require the assistance of a membrane protein or vesicle to cross the membrane
210
___ transport does not require the input of energy
Passive transport does not require the input of energy
211
___, ___, ___ ___ and __ move easily across most membranes
Water, oxygen, carbon dioxide and lipids move easily across most membranes
212
___ and most ___ molecules and __ __ molecules e.g. proteins cannot cross easily
Ions and most polar molecules and very large molecules e.g. proteins cannot cross easily
213
Diffusion
passive movement of molecules down a chemical (concentration) gradient from an area of higher concentration to an area of lower concentration
214
Net movement created by diffusion stops when the system reaches ___, although molecular movement continues
Net movement created by diffusion stops when the system reaches equilibrium, although molecular movement continues
215
Membrane proteins have 4 functional roles: ___ proteins maintain cell shape and form cell junctions; ___-___ enzymes catalyze chemical reactions and help transfer signals across the membrane; ___ proteins are part of the body's signaling system; and ___ proteins move many molecules into or out of the cell
Membrane proteins have 4 functional roles: structural proteins maintain cell shape and form cell junctions; membrane-associated enzymes catalyze chemical reactions and help transfer signals across the membrane; receptor proteins are part of the body's signaling system; and transport proteins move many molecules into or out of the cell
216
___ ___ form water-filled channels that link the intracellular and extracellular compartments
channel proteins form water-filled channels that link the intracellular and extracellular compartments
217
___ ___ regulate movement of substances through them by opening and closing. They may be regulated by ligands, by the ___ state of the cell, or by the ___ changes such as pressure
Gated channels regulate movement of substances through them by opening and closing. They may be regulated by ligands, by the electrical state of the cell, or by the physical changes such as pressure
218
___ ___ never form a continuous connection between the intracellular and extracellular fluid. They bind to substrates, then change conformation
Carrier proteins never form a continuous connection between the intracellular and extracellular fluid. They bind to substrates, then change conformation
219
Protein-mediated diffusion is called ___ ___. It has the same properties as simple diffusion
Protein-mediated diffusion is called facilitated diffusion. It has the same properties as simple diffusion
220
Gated channels are usually ___. They __ in response to chemical, mechanical, or electrical signals
Gated channels are usually closed. They open in response to chemical, mechanical, or electrical signals
221
Uniport carriers
transport only one kind of substrate
222
Symport carriers
move two or more substances in the same direction across the membrane
223
Antiport carriers
move substances in opposite directions
224
Both passive and active forms of carrier-mediated transport exhibit ...
specificity, competition and saturation
225
Specificity
ability of a transporter to move only one molecule or a group of closely related molecules
226
Competition
related molecules may compete for a single transporter
227
Saturation
occurs when a group of membrane transporters are working at their maximum rate
228
___ transport moves molecules against their concentration gradient and requires an outside source of energy
Active transport moves molecules against their concentration gradient and requires an outside source of energy
229
In ___ (__) __ transport, the energy comes directly from ATP
In primary (direct) active transport, the energy comes directly from ATP
230
___ (___) ___ transport uses the potential energy stored in a concentration gradient and is indirectly driven by energy from ATP
Secondary (indirect) active transport uses the potential energy stored in a concentration gradient and is indirectly driven by energy from ATP
231
The most important primary active transporter is the __-___-___, which pumps Na+ out of the cell and K+ into the cell
The most important primary active transporter is the sodium-potassium-ATPase, which pumps Na+ out of the cell and K+ into the cell
232
Most secondary active transport systems are driven by the ___ ___ gradient
Most secondary active transport systems are driven by the sodium concentration gradient
233
electrical signals
change cell membrane potential
234
chemical signals
molecules secreted by cells and received by target cells, most common
235
Local communication
gap junctions, contact-dependent, autocrine/paracrine
236
Long distance communication
endocrine, neurotransmitters and neurohormones
237
Gap junctions
create cytoplasmic bridges, found in most cell types, crosses both cell plasma membranes
238
Contact-dependent signals
require cell-to-cell contacts, occur in immune system and during growth and development
239
Autocrine signals
act on same cell that secreted them
240
Paracrine signals
secreted by one cell and diffuse to adjacent cells
241
Hormones
released from endocrine cells to go to the bloodstream
242
Neurocrine
released from neurons (neurotransmitter, neuromodulator, neurohormone)
243
Cytokines
peptides, both local and long-distance
244
Neurotransmitters
chemicals secreted by neurons that diffuse across a small gap to the target cell, neurons use electrical signals as well
245
Neurohormones
chemicals released by neurons into the blood for action at distant targets e.g. epinephrine
246
The ligand is also called..
first messenger
247
lipophobic signal molecules
bind to membrane receptor proteins (on cell membrane) that activates intracellular signal molecules
248
lipophilic signal molecules
diffuse through the cell membrane, inside the cell they bind to cytosolic receptors or nuclear receptors and activates intracellular signal molecules
249
The binding to cytosolic or nuclear receptors of lipophilic or intracellular signal receptors triggers...
slower responses related to changes in gene activity
250
Signal amplification
allows a small amount of signal to have a large effect
251
Transduction pathway steps
1. Signal molecule binds to membrane receptor
2. Membrane receptor initiates signal transduction by proteins and amplifier enzymes
3. Amplifier enzymes leads to second messenger molecules which alter ion channels
4. Second messenger molecules --> protein kinases (ATP)--> phosphorylated proteins OR --> increase intracellular Ca2+ --> calcium-binding proteins = cell response
252
most signal transduction uses....
G proteins
253
ion channels
ligand binding opens or closes the channel, found mostly in nerve and muscle, change permeability to an ion, rapid flow of an ion= rapid response from the cell
254
G protein-coupled receptor
ligand binding to a G protein-coupled receptor opens an ion channel or alters enzyme activity, 3-part transducer molecule, use lipid-derived second messengers (e.g. phospholipase C/PLC, diacylglycerol/ DAG, inositol triphosphate)
255
Many lipophobic hormones use..
G pathways e.g. adenylyl cyclase-cAMP system
256
Adenylyl cyclase-cAMP system
1. signal molecule binds to G protein-coupled receptor (GPCR), which activates the G protein
2. G protein turns on adenylyl cyclase, an amplifier enzyme
3. Adenylyl cyclase converts ATP to cyclic AMP (cAMP)
4. cAMP activates protein kinase A
5. Protein kinase A phosphorylates other proteins, leading ultimately to a cellular response
257
GPCR-phospholipase C signal transduction
1. signal molecule activates receptor and associated G protein
2. G protein activates phospholipase C (PLC), an amplifier enzyme
3. PLC converts membrane phospholipids into diacylglycerol (DAG), which remains in the membrane, and inositol triphosphate (IP3), which diffuses into the cytoplasm
4. DAG activates protein kinase C (PKC), which phosphorylates proteins
5. IP3 causes release of Ca2+ from organelles, creating a Ca2+ signal
258
What kind of receptor does insulin use
tyrosine kinase (TK)
259
Calcium induces ...
calcium release (cardiac muscle), Ca2+ spark
260
Calcium is an important ___ ___
intracellular signal
261
Calcium enters through ..
gated channels (voltage, ligand, or mechanical)
262
Calcium may be released from ..
intracellular compartments by second messengers
263
Calcium binds ___ or other regulatory proteins
calmodulin
264
Soluble gases are __-__ paracrines or ___
Soluble gases are short-acting paracrines or autocrines
265
Best known soluble gase nitric oxic (NO) is produced by ___ cells and is synthesized by the action of ___ ___ ___ (NOS). It diffuses into ___ muscle and causes ___. It activates ___ cyclase --> cGMP. It acts as a neurotransmitter and ___ in the brain.
Best known soluble gase nitric oxic (NO) is produced by endothelial cells and is synthesized by the action of nitric oxide synthase (NOS). It diffuses into smooth muscle and causes vasodilation. It activates guanylyl cyclase --> cGMP. It acts as a neurotransmitter and neuromodulator in the brain.
266
Up and down-regulation enable cells to ___ ___
Up and down-regulation enable cells to modulate responses
267
The primary ligand ___ a ___
The primary ligand activates a receptor
268
An agonist also ____ the receptor
An agonist also activates the receptor
269
An antagonist ___ receptor activity
An antagonist blocks receptor activity= no response
270
Constriction or dilation of vessels: epinephrine+ alpha-receptor
Constriction
271
Constriction or dilation of vessels: epinephrine+ beta2-receptor
dilation
272
Tonic control
regulates physiological parameters in an up-down fashion. The signal is always present but changes in intensity
273
Antagonistic control
modulates the activity of an organ system by two separate regulators which act in opposition e.g. parasympathetic and sympathetic
274
Insulin promotes glucose __ and inhibits ___ ___
Insulin promotes glucose uptake and inhibits fat breakdown
275
Glycemic index (GI)
rating system for foods containing carbohydrates. It shows how quickly each food affects your blood sugar (glucose) level when that food is eaten on its own.
276
Hormones control...
growth and development, metabolism, regulate internal environment and reproduction
277
Hormones act on target cells by controlling...
1. rate of enzymatic reactions
2. transport of ions or molecules across cell membranes
3. gene expression and protein synthesis
278
Solubility is important because it helps to determine...
receptor location (inside or out), transport in plasma (free or bound), and length of action (short or long)
279
Peptide and protein are lipid __
insoluble
280
Steroids are lipid __
soluble
281
Amines are lipid __
soluble (thyroid hormones) and insoluble (catecholamines)
282
Synthesis and storage of peptide hormones
made in advance, stored in secretory vesicles
283
Release from parent cell: peptide hormones
exocytosis
284
Transport in blood: peptide hormones
dissolved in plasma
285
Half-life: peptide hormones
short
286
Location of receptor: peptide hormones
cell membrane
287
Response to receptor-ligand binding: Peptide hormones
activation of second messenger systems; may activate genes
288
General target response: peptide hormones
modification of existing proteins and induction of new protein synthesis
289
Examples of peptide hormones
insulin, parathyroid hormone
290
synthesis and storage: steroid hormones
synthesized on demand from precursors
291
release from parent cell: steroid hormones
simple diffusion
292
transport in blood: steroid hormones
bound to carrier proteins
293
half-life: steroid hormones
long
294
location of receptor: steroid hormones
cytoplasm or nucleus, some have membrane receptors too
295
response to receptor-ligand binding: steroid hormones
activation of genes for transcription and translation; may have nongenomic actions
296
general target response: steroid hormones
induction of new protein synthesis
297
examples of steroid hormones
estrogen, androgens, cortisol
298
synthesis and storage: Catecholamines
made in advance; stored in secretory vesicles
299
release from parent cell: catecholamines
exocytosis
300
transport in blood: catecholamines
dissolved in plasma
301
half-life: catecholamines
short
302
location of receptor: catecholamines
cell membrane
303
response to receptor-ligand binding: catecholamines
activation of second messenger systems
304
general target response: catecholamines
modification of existing proteins
305
examples of catecholamines
epinephrine, norepinephrine
306
synthesis and storage: thyroid hormones
made in advance; precursor stored in secretory vesicles
307
release from parent cell: thyroid hormones
simple diffusion
308
transport in blood: thyroid hormones
bound to carrier proteins
309
half-life: thyroid hormones
long
310
location of receptor: thyroid hormones
nucleus
311
response to receptor-ligand binding: thyroid hormones
activation of genes for transcription and translation
312
general target response: thyroid hormones
induction of new protein synthesis
