Exam 1 Material Flashcards
Homeostasis
The relatively stable physical and chemical composition of the internal environment of the body which is the result of REGULATORY SYSTEMS
(An ordered system, a steady state, around a set point of an operating point)
Steady State
no net change, needs constant input of energy, dynamic, how living things are
Equilibrium
no net change but no energy is needed, static, non-living things.
Steady State Examples
Temperature, plasma growth hormone, plasma cortisol, urinary potassium
Homeostatic Examples
Water, Ions (Na+, Cl-, Ca2+, K+), plasma glucose, blood pH, temperature
Compartments of Homeostasis
- External is dynamic
- Internal is static
1) Extracellular Fluid (ECF) is 80% intercellular fluids and 20% plasma
2) Intracellular Fluid is inside of the cell
Homeostatic Reflex Arc
1) Stimulus (exogenous=inside Endogenous=external)
2) Receptor/Sensor - responds to stimulus
3) Afferent Pathway
4) Integration Center
5) Efferent Pathway
6) Response
7) Feedback Loop - either negative (most are) or positive (blood clotting or enzyme activity) goes back to receptor or sensor.
Temperature Reflex Arc
1) Stimulus - it is cold
2) Receptor/Sensor - temperature sensitice nerver endings
3) Afferent Pathway - afferent nerves carry action potential
4) Integration Center - the brain
5) Efferent Pathway - efferent nerves carry message to
6a) smooth muscle in blood vessels
6b) skeletal muscles
7a) Response - smooth muscles constrict to limit heat loss
7b) shiver induced to increase heat
8) Feedback Loop - increased heat goes back to temp sensitive nerve endings as negative feedback
Homeostatic Reflex Arc Plasma Calcium
Decrease in plasma calcium
1) parathyroid glad detects drop
2) parathyroid hormone released into circulatory system
3) Osteocytes release calcium
4) plasma calcium increases and thus minimizes initial stimulus
Biologically Insignificant
P is greater that 0.05
Primary Chemical Messengers
Hormone, neurohormone, neurotransmitter, paracrine, autocrine
Thyroid Hormone Releasing Pattern
Hypothalamus = thyrotropin releasing hormone
Anterior Pituitary = thyroid stimulating hormone
Thyroid Glad = Thyroxine or Triiodothyronine
Target Cells = Increase metabolism
Reactive Homeostasis
respond to changes that have already occurred
Predictive Homeostasis
Response is increased in anticipation of a predicted changes. Usually involves circadian rhythms over 24 hour light/dark period for core temp, oxygen consumption, appetite.
Homeostatic Modifications
Acclimatization, biological rhythms, aging
Acclimatization
An adaptive change in the function of a physiologic system induced by prolonged exposure to an environmental stress without any genetic change. Usually reversable
Examples
1) Adapting to ambient temperature
2) Altitude/change in oxygen partial pressure
3) Developmental - very narrow windows of opportunity for growth
Mammalian
Relating to the class mammalia, endothermic mostly homeothermic, amniote, cares for young (milk), hair. D: Eukarya K: Animalia P: Chordata C: Mammalia
Physiology
A branch of biology dealing with the functions and vital processes of living organisms which includes whole organisms, parts of organisms, organs, cells.
Physiology
biology
chemistry math physics
Aging
Decrease in compensation for various challenges as life continues. Due to genetic and environmental reasons. Examples: Wear and tear, exposure, failure of mitosis (apoptosis)
Apoptosis
Programmed cell death. Examples: Webbing between fingers, only 1/5 of nerve cells grow out and survive by connecting to skeletal muscle.
Water Properties
1) bond angle of 105
2) Dipolar
3) Cohesive
4) High specific heat
5) High heat of vaporization
6) Most dense at 4C
7) Transparent
8) Universal Solvent. pH=7
Notes: Water forms hydrogen bonds with itself. The polar molecules surround ions to form hydrated radius.
Buffers
A substance that reversibly binds hydrogen and this reaction minimizes a change in pH. Examples: Bicarbonate, phosphate, heoglobin
Carbonic Anhydrase
Enzyme that mediates the reaction of H2O + CO2 — H+ + HCO3-
Very reversible 500,000/s
A Cell
The smallest structural unit (of an organism) that has the characteristic of life.
Organelles
Small membrane bound compartments, along with some particles and filaments, that preform specialized functions and constitute the inside of the cell.
Secretory Process
Ribosome on the Rough Endoplasmic Reticulum translates mRNA into a chain of amino acids. Then it is packeged into a transition (transport) vesicle. It then goes to the Golgi Body where the molecule is midified. Then put into a secretory vesicle that can either go to the lysosome, perioxisome, endosome, or to the plasma membrane where it can be released or incorporated. Secretory vesicles move on microtubule tracks.
Proteins
Composed of amino acids, formed by peptide bonds, functional and structural component of the cell. Serine has a hydroxyl.
Protein Structural Hierarchy
- Primary- the a.a. sequence
- Secondary- AA rotation, limitations in binding and rotations
- Tertiary- AA associations, disulfide bridges, hydrogen bonds
- Quartinary- multiple subunits
- Quintinary- Other molecular associations like cofactors, lipid interactions, Na/K, ATPase
Allele
Part of genome that will translate to a form of a protein
Membrane Composition
Phospholipids (amphipathic)
Protein (amphipathic)
Carbohydrates
Cholesterol (amphipathic)
Cells Interact with Environment Through
Membrane Folding and Saturable Molecules
Endocytosis
Phagocytosis, receptor mediated endocytosis, pinocytosis
Saturable Molecules
Receptors Enzymes Transport Molecules Antibodies Oxygen Carrying Pigments
Saturable Molecule Characteristics
1) Proteins
2) Chemical specificity
3) Saturation (finite rate)
4) Affinity
5) Competition
6) Modulation/Regulation
7) Use non-covalent binding forces
8) Located in plasma membrane and cytosol
Receptor
Specific protein(s) that bind a specific primary chemical messenger(ligand) and serve to signal the cell or produce a change in cell function. Shape and charge determine specificity.
Saturability
Saturable biochemical group is proteins and there are a finite number of receptors. Some proteins can bind different ligands but most are very specific. Sigmoidal curve corrects for non-specific bonding.
Affinity
Strength at which the ligand binds to its binding site. High affinity=charge/shape low affinity=non-specific. The higher the affinity the lower ligand concentration needed to saturated the receptor.
Allosteric Modulation
Modular molecule binds to active saturable molecule in a non-covalent manner. Control of the properties of a binding site by a regulator/modulator molecule binding at a site other than the binding site. (ionic, hydrogen, van der Waals)
Covalent Modulation
Alteration of the shape and function of the protein by the attachment of (a) chemical group(s) to (a) amino acid(s)
Phosphorylation is the addition via a protein kinase which typically activates. Phosphatase removes phosphate.
Competition
The effect of one ligand on the binding of another ligand when both are able to bind to the same binding site. Affinity dictates which binds better.
Aganist
A foreign molecule which binds to a receptor site and triggers the cell’s response as if the true chemical messenger were present.
Antagonist
foreign molecule which binds to a receptor but does not trigger the cell response because it inhibits chemical messenger action
Primary Chemical Messengers
Outside of the cell
1) Hormone
2) Neurohormone
3) Neurotransmitters
4) Paracrines
5) Autocrines
Receptor Number
May change due to:
Cell function, cell type, receptor production being regulated
Receptors Trigger Changes
1) Membrane transport
2) Synthesis rate
3) contractile forces
4) metabolism
Mitochondria
Mitochondrion, double membrane, aerobic indicator, has own gene, bacteria in origin, produces ATP, location of CAC and oxidative phosphorylation
Endoplasmic Reticulum
Rough = protein synthesis Smooth = lipid synthesis
Secretory Vesicles
release materials/exocytosis
Lysosome
digestive organelles
Peroxisome
breaks down fatty acids
Cytosol
Cytosolic components and the cytoskeleton
Microtubules
long columns of globular protein polymerized together
Intermediate Filaments
?
Microfilaments
actin and myosin
Extracellular Matrix
Collagen fibers and adhesion molecules/proteins
Tight Junctions
Forms a tissue barrier with polarized epithelium. Proteins on lumen side are different than those on the blood side.
Desmosomes
Holds cells together through cell contact/adhesion. Electron dense
Gap Junctions
Proteins called conexons form pores between the cells, permit the movement of small molecular weight molecules and charges
Metabolism
The total of all chemical reactions that occur in a living organism or cell
Energy
characterized as the ability to produce change and measured as work
Potential Energy
stored energy in bonds, charge separation (asymmetrical charge), concentration gradient
Energy of Activation
Energy required to initiate a chemical reaction/kinetic energy applied to alter electrical forces to cause the reaction
Enzymes
a protein that accelerates a specific chemical reaction but does not undergo a net change during the reaction. Biological catalyst ending with “ase”
Cofactor
a nonprotein substance that binds to specific regions of an enzyme and either maintains shape or participates directly in binding the substrate (Cl-, Mg2+, Zn2+, Fe3+)
Coenzyme
a nonprotein organic molecule that functions as a cofactor. It is not consumed in the reaction but may accept hydrogen ions or small organic molecules. NADH, FADH2, CoA
NAD+
Nicotinamide adenine dinucleotide
Competitive Inhibition
takes up active site
Noncompetitive Inhibtion
material binds non-specifically and inhibits activity
Enzymatic Modulation
1) Allosteric through product feedback
2) Covalent phosphorylation via protein kinase (dephosphorylate with protein phosphatase)
Multienzymatic Pathway
Enzymatic reactions may be linked together where the product then forms the reactant or substrate.
Metabolic Pathway
A sequence of enzyme mediated reactions
Rate-Limiting Step
Slowest enzyme that might involve product feedback like phosphofructokinase does
Energy Movement
ADP + Pi + 7 kcal/mol —- ATP + H2O
1) oxidative phosphorylation
2) substrate phosphorylatio
Glycolysis
Glucose -hexose kinase (-1ATP) Glucose 6 Phosphate Fructose 6 Phosphate - phosphofructose kinase (-1ATP) Fructose 1,6 Bisphosphate 2 3Carbon Carbohydrates -2 ATP -2 NADH Phosphoenol Pyruvate - pyruvate kinase (+2ATP) 2 Pyruvate
Branch Point Anaerobic
Anaerobic - lactate formed, 2 NADH oxidized to 2 NAD+ and glycolysis continues and burns a lot of glucose (lactate dehydrogenase). Heart and liver can take lactate to pyruvate. Maintains cell redox.
Branch Point Aerobic
Pyruvate transported into mitochondira and 2 CO2 lost, 2 NADH formed, 2 Acetyl Coenzyme A formed. Then enters Citric Acid Cycle where 1 Acetyl CoA = 3 NADH, 1 FADH2, 1 GTP(ATP), 2 CO2. ECT is in the inner membrane which is tight, chemiosmotic gradient mechanism for ATP production, ATPase going backwards. 36ATP total. Hypothetically 38 but things get lost.
Gluconeogensis
Anabolism of glucose from pyruvate, lactate, glycerol, and amino acids. Need to overcome the 3 irreversible steps. Liver! (maybe kidneys). Lipids in membranes broken down to glycerol (c-16,18,20) broken down to acetyl-CoA via beta oxidation in mitochondira.
Glycogen
storage carbohydrate, animal starch, liver and skeletal muscle. extra carbs become triacylglycerols.
Energy Storage
Triacylglycerols - 9 kcal/gram - 78% (more covalent bonds)
Proteins - 4 (would be 5.4 but nitrogen) kcal/gram - 21% storage
Carbohydrates - 4 - 1%
Amino Acid Metabolism
Proteins broken down to a.a through transamination (NH2 shuffel) and deamination (NH3 formed). Ammonia from from deamnination goes to liver and becomes urea. Other products go to glycolysis/CAC
Products
All metabolic pathways are linked.
New molecules via catabolism/anabolism, ATP directly generated, indirectly NADH FADH2, H20, CO2 which maintains bicarbonate buffer.
Hormones
Travel in blood to specific target cell throughout body. Ex) Insulin, Gastrin, Cortisol
Neurohormones
Travel via blood and are released to modify another hormone releasing activity. Ex) growth hormone releasing hormone, gonadotropin, releasing hormone.
Paracrines
Travel in a local area and are released into and affect a local area like inflammation. Ex) prostagladins, adenosine
Neurotransmitters
Isolated to nerve cells, they affect other nerve cells or adjacent effector organs. Ex) acetylcholine and norepinephrine
Autocrines
Released and affect the same cell. Prostagladins and adenosine.
Secondary Messenger Systems
Electrical potentials, tyrosine kinase, JAK, cAMP, cGMP, Calcium/Calmodulin, Inositol Triphosphate, Diacylglycerol
Secondary Messenger System Common Components
Primary chemical messenger, g-protein, protein kinase, protein activator, cell response
Membrane Potential
Ligand binds to a receptor, opens or closes ion channels, channels are specific to an ion, changes membrane potential and thus cellular function
Tyrosine Kinase
- Ligand binds to the receptor
- Activates a Tyrosine Kinase
- Which phosphorylates a Tyrosine
- Tyrosine-PO4 is part of a protein and has changed its function.
cAMP System
A first messenger binds to a receptor with activates the stiumlatory G protein. The alpha unit then associates with the catalytic part of Adenylate Cyclase which is an enzyme that changes ATP to cAMP. High levels of cAMP activates (cAMP dependent)protein kinase making it active. This goes on activate an enzyme with the aid of ATP into a ActiveEnzyme-PO4. The response is the enzyme Phosphodiesterase will break down cAMP to AMP.
Signal Cascade
One ligand-receptor activates 1 G-prtoein and 1 adenylate cylase. But then 100 adenosine3’5’cyclic monophosphates go on to 1 million products.
cAMP-dependent protein kinase affects
Active transport, ion channels, Ca2+ transport, protein synthesis, lipid and glycogen breakdown.
Ca2+/Calmodulin
Calcium ions are favored to go into the cell but the ER has it stored up. Receptor binds ligand which activates Ca channel and or release from ER. The increase in cytosolic Ca ACTIVATES Calmodulin. This then activates calmodulin-dependent protein kinase, which activates a protein for a cell response.
Inositol Phosphate/DAG
Ligand binds to the receptor.. Activates a G-Protein which activates Phospholipase C which acts on phosphatidylinositol phosphate(PIP2) to for inositol trisphosphate and diacylglycerol. Inositol Trisphosphate goes on and releases Ca from the ER by opening Ca channels. Then Calmodulin pathway ensues. DAG activates Protein Kinase C which phosphorylates a protein which causes a cell response.
Endocytosis
Cellular process in which the plasma membrane invagenates and this invagenation becomes pinched off forming small intracellular, membrane bound vesicles.
Exocytosis
cellular process in which the membrane of an intracellular vesicle fuses with the plasma membrane, the vesicle opens, and the contents are liberated into the extracellular fluid.
Simple Diffusion
Freely goes through PM. Only gasses, water, small molecules like urea, glycerol, some glucose. Use Fink’s law. As temp increases so does permeability.
Tonicity
Total solute strength
Channel Diffusion
Protein mediated for specified ion. Follows electrochemical potential so you can use Nerst Equation.
Membrane Potential
Inside the cell is negative due to K+=-94mV
Facilitated Diffusion
A form of mediated transport. Protein mediated, follows concentration gradient, no other energy required. Works on Glucose and permease.
Active Transport
Protein mediated, does not have to follow a concentration gradient, uses energy.
Primary=direct energy use like 3Na/2K, H, Ca need ATPase
Secondary=indirect energy usage via electrochemical potential and Antiport exchange cotransporter. Na/H ex, Na/Caex, Cl/HCO3ex, Na/AA co, Na/K/2Cl co
Cells of the Nervous System
Neurons = nerve cells
Glial Cells = nerve cells, nonexcitable, speed condution, insulate, absorb K, provide nutrients, remove waste, digest dead cells , aid migration, elaborate and move spinal fluid.
Depolarization
cell becomes more positive
Hyperpolarization
cell becomes more negative
Repolarization
cell returns to resting potential
Graded Potential
Cell membrane potential change that is variable in; amplitude, polarity, and duration
Action Potential
an electrical signal propagated over long distances of nerve or muscle cells. Characterized by and “all or none” reversal of membrane potential.
THE ACTION POTENTIAL
1) at resting potential
2) graded potenital (depolarizating) to
3) Threshold (all or none)
4) Open Voltage-dependent Na channels, Na goes inside the cell
5) Depolarization to a positive cell potential
6) Close VD-Na channels (with the positive potential)
7) Open VD-K channels (with the positive potential), K goes out of cell
8) repolarization
9) VD-K channels closing
10) hyperpolarization
11) Na/K channels back to resting potential.
Proteins of the Action Potential
Na Channel, K channel, Na/K ATPase. Na Channel opens and closes very rapidly with an inactivation gate. K opens and closes slowly.
Water Regulation Na based
Kidney’s reasorb 99.9% filtered water. Instestine reabsorb over 10L/day
Water Regulation Cl Based
Cornea needs cl- transport, dehydrates the stroma. Lungs use cl transport to hydrate surface and dissolve o2
Fugu Sushi
Tetrodoxin blocked VG Na channels
Red Tide Oysters
Saxitoxin blocked VG Na channels
Local Anesthetics
Procain (novacaine) and Lidocaine (xylocaine) blacks Na+ channels and then wears off.
General Anesthetics
Tetrodoxin, Ether, Ethanol (second two enter cell membrane produces sustained depolarization.
Hypoglycemic
0-75mg%
“normal”glycemic
75-125mg%
Hyperglycemic
125+mg%
Lab 3
Trypsin + L-BAPA = p-nitroalanine
