Regulation- Part 1&2 Flashcards
What is negative feedback?
When the body senses a change and activates mechanisms to reverse that change
What is positive feedback?
Change that leads to a even greate change in the same direction
What’s an example of negative feedback?
Body temp
What’s an example of positive feedback?
Parturition
Does efferent go towards or away the control center?
Away
afferent _ goes toward or away from the control center?
Towards
What is the mainsource of every in the cell?
ATP
What one the other 2 energy -producing molecules?
NADH and FADH2
Where are NADH and FADH2exchanged for energy?
Electro transport chain
What are the building blocks?
Monosaccharides, Fatty acids, Amino acids, Nucleotides
What is the basis of all physiological change?
Proteins
What one the roles of proteins?
Enzymes, reaction coupling, transport, structural functions, signaling
What 2 things does protein function mainly depend on?
Specificity to its substrate
Allosteric changes
What are active sites?
“Pocket” that has a high specificity to the substrate
What are examples of allosteric changer?
Ligands, voltage, covalent modifications of one or more amino acid side groups, other stimuli
Why do phospholipid molecules naw a bend in one of the hydrocarbon tails?
For obtaining fluid for the membrane
What an example of something that helps keep the membrane in a fluid state
Cholesterol
What % of all membrane proteins are transport proteins?
15-30%
What an examples of hydrophobic molecules?
Water, carbon dioxide, nitrogen, steroid hormones
What are examples of small uncharged polar molecules?
Water, urea, glycerol
What are examples of large uncharged polar molecules?
Glucose, sucrose
What are examples of ions?
H+, Na+, HCP, K+, CA2+, CI, Mg
If a molecule is small and less strongly associated with water, will the molecule diffuse across the membrane quicker or slower?
Quicker
What do transport proteins transfer?
Specific water/soluble molecules across the plasma membrane
What is passive transport?
Transport down a concentration gradient
What is active transport?
Transport that requires energy, moving solutes against their concentration gradient
Passive transport is mediated by what?
Channels and carries (faciitated diffusion)
What is active transport mediated by?
Always carriers
What do channels form?
Pores, for specific solutes
Are channel proteins interactions with solutes strong or weak?
Weak
What do carriers undergo?
Conformational changes that expose solute- binding sites on one side of the membrane, and then to the other to finally transfer the solute across it
Are carriers interactions with substrates strong or weak?
Strong
In the vestibule, what are hydrated?
Ions
What happens to the ions in the selectivity filter?
They have lost their water molecules and oxygens of the carbonyl groups of the channel to accommodate the dehydrated solutes
Why is sodium rejected my the potassium channel?
Its smaller than potassium and cannot be accommodated by the selectivity filter
What are aquaporins?
Specific water channels
What is simple diffusion?
Molecule dissolves in the phospholipid belayer, across it, and then in the aqueous solution on the other side of the membrane
Are membrane proteins involved in simple diffusion?
No
How is the direction of simple diffusion determined?
Relative concentrations of the molecule inside and outside of the cell
What is facilitated diffusion?
The transported molecule does not dissolve in the phosphonpid belayer
What is facilitated diffusion mediated by?
Proteins with no external source of energy
What is the direction of facilitated diffusion determined by?
The concentration gradients and or by the electric potential across the membrane
What is the simple diffusion rate directly proportional to?
Solute concentration
Higher concentration =_ saturation
Faster
What can facilitated diffusion be defined as?
Saturable
What is active transport?
Uses energy or a gradient generated by another active transporter
How can active transporters be classified?
The direction of transport and use of energy
What is the name of the three types of transport directions?
Uniport, symport, antiport
Define uniporters
Passive transport of only one molecule
Define symporters
Coupled transporters of 2 molecules in the same direction
Define antiporters
Transport of a second molecule in the opposite direction
What does primary active transport use?
ATP
What is secondary active transport driven by?
A gradient that is generated by a primary active transporter
What is tertiary active transport driven by?
A gradient that is generated by a secondary active transporter
What are the most popular active tansporters present in the plasma of almost all animal cells?
Na, K, atp-ase
What active transporters maintain Na and k concentration differences between extra and intra-cellular fluids?
Na, K, atp-ase
During each transport cycle how many Na are pumped out of and into the cell?
3
During each transport cycle how many k are pumped out of and into the cell?
2
How many ATP are used to phosphorylate the protein?
1
What does phosphorylation do?
Changes the conformation of the protein and alters the affinities of the Na and k binding sites
What does dephosphorylation do?
Restores the pump into its original state
What is transcellular transport of glucose mediated by?
A secondary active carrier SGLT and a passive transporter GLUT
What is the membrane potential?
Difference in the electrical charge on the two sides of a membrane due to slight excess of positive ions over negative ones on one side and a slight deficit on the other
What is the result of an active transport (electrogenic) and a passive diffusion?
Resting membrane potential of cells
Do electrochemical gradients have a positive or negative membrane potential inside?
Negative
What are the three types of endocytosis?
Phagocytosis, pinocytosis, receptor-mediated endocytosis
What is phagocytosis?
Ingestion of large particles
What is pinocytosis?
Ingestion of small particles/fluids
What is receptor-mediated endocytosis?
Involves specific membrane receptors
What are the 2 types of exocytosis pathways?
Constitutive and regulated secretory pathways
What type of cells are found using constitutive secretory pathways?
All cells
Is signaling necessary in constitutive secretory pathway?
No
What type of proteins is constitutive secretory pathway used for?
Membrane, extracellular matrix, and signaling proteins
What type of cells are regulated secretary pathways in?
Specialized cells
What is regulated secretory pathways necessary for?
Vesicle/membrane fusion
What are regulated secretory pathways used for?
Neurotransmitter and hormone release
Do exo- and endocytosis take place simutareously in a cell?
Yes
How does the exchange between plasma and intertitium occur?
Vesicular transport, diffusion, and bulk flow
What is vesicular transport?
Substances cross the capillary by endocytosis/exocytosis
Diffusions in terms of blood/interstitium exchange
Exchange of oxygen and carbon dioxide between the blood and lungs
What does bulk flow consist of?
Filtration and absorption
What does p stand for in terms of the staling equation?
Hydrostatic pressure
What does (pie sign) stand for in terms of the starling equation?
Oncotic pressure
What is hydrostatic pressure?
Pressure of water inside a system
What is the oncotic pressure?
Pressure created by plasma proteins which cannot pass through the capillary wall
What does a positive net filtration pressure favor?
Filtration
What does a negative net filtration pressure favor?
Reabsorption
Where does filtration predominate?
At the arterial end of the capillaries
Where does reabsorption predominate?
At the venous end of capillaries
What causes an accumulation of fluid in the tissues? (Edema)
A change that increases the rate of filtration or decreases the Rae of reabsorption
