Chapters 4-5 Flashcards
A + B –> C+ D reactants products
k eq: [C] [D] [A] [B]
free energy
The potential energy stored in the chemical bonds of a molecule is known as the free energy of the molecule The larger, more complex the molecule, the higher its free energy Change in free energy = delta G
exergonic reaction
delta G is less than 0 reaction is spontaneous Energy released can be used by other molecules to do work, may be given off as heat, may be stored in a concentration gradient
endergonic reaction
delta G is more than 0 reaction is NOT spontaneous Products retain some of the activation energy that was added, trapped in the chemical bonds of the products
homeostasis does not equal equilibrium
the ECF and ICF are in osmotic equilibrium, but are in chemical and electrical disequalibrium
osmolarity
the number of osmtically active particles per litre of solution
To convert between molarity and osmolarity:
molarity (mol/L) x particles /molecule (osm/mol)= osmolarity (osmol/L or OsM )
- Consider creating a 1 M solution of glucose in water:
- 1M glucose x 1 osmol/mole glucose=1 OsM glucose
- Consider creating a 1 M solution of NaCl in water:
- 1M NaCl x 1.8 osmol/mole NaCl = 1.8 OsM NaCl
•Osmolarity alone doesn’t tell you what happens to cell volume in a solution: depends on whether the particles are penetrating or non-penetrating
tonicity
Tonicity describes a solution and how that solution would affect cell volume if the cell were placed in the solution and allowed to come to equilibrium
Normal osm of the human body is 300 mosm
always compares a solution and a cell
osmolality
concentration expressed as osmoles of solute per kilogram of water Physiologists often use the terms osmolarity and osmolality interchangeably
bulk flow
a pressure gradient causes fluid to flow from regions of higher pressure to lower pressure eg: blood moving through the circulatory system air flow in the lungs
Properties of diffusion
Passive process (of uncharged molecules) Molecules move from high concentration to low concentration areas (down a concentration gradient) Net movement of molecules until equilibrium of concentration Diffusion is rapid over short distances Diffusion is directly related to temperature* Diffusion rate is inversely related to molecular weight and size Can take place in an open system or across a partition Ions do NOT move by diffusion Diffusion is random molecular motion down a concentration gradient Slower over long distances and for larger molecules Ions can move in response to electrochemical gradients Random movement of molecules continues even after equilibrium is reached
Fick’s Law of Diffusion:
the diffusion rate increases when surface area, the concentration gradient, or the membrane permeability increase
intracellular fluid high in
potassium and proteins
extracellular fluid high in
sodium chloride
properties of living organisms
Complex structure with CELL as basic unit of organization Acquire, store, transform and use ENERGY
energy source for all animals
energy trapped by photosynthesis
when energy intake is greater than energy used
body stores energy as lipids or polysaccharides
Facilitated diffusion
does require energy
ex: kidney tubules, far in the nephron the body has to decide if it needs to hang on to salt, or water,
intentionally high concentrations of ions in the tubules so that the body can regulate these
an example of mechanical work in the cell
mechanical work= movement
cilia and flagella in the cell
energy in living systems
energy is stored as potential, and then it is transformed into kinetic when needed to do chemical, mechanical, or transport work
chemical work
making and breaking of chemical bonds
enables cells to move ions, molecules, larger particles through the cell membrane
Strength in the amount of energy to make it, and strength of amount of energy keeping it together
transport work
moving ions, molecules, larger particles across cell membrane
utilizes a concentration gradient
first law of thermodynamics
The total amount of energy in the universe is constant
the universe is a closed system
the body is an open system
second law of thermodynamics
Natural, spontaneous processes move from a state of order to a condition of randomness or disorder
Entropy, or Bentropy :)
activation energy
The initial input of energy required to bring reactants into a position that allows them to react with one another
sickle cell anemia results from a mutation in
the tertiary structure of the protein.
isoenzyme
•catalyze the same reactions but under different conditions or in different tissues
reversible reactions
•If a reaction requires 2 different enzymes for the forward and the reverse reaction, the cell can regulate the reaction
Allosterism
A change in the activity and conformation of an enzyme resulting from the binding of acompound at a site on the enzyme other than the active binding site.
ATP Production
osmotic equilibrium
water moves freely through cells and the ECF, so the ECF and the ICF reach a state of osmotic equilibrium
the ECF and the ICF are in osmotic equilibrium but have very different chemical compositions
the ECF and the ICF are in chemical disequilibrium
Q: What determines how solutes are distributed in the human body?
A: their ability to cross the cell membrane
•
vWater can move freely in and out of nearly every cell in the body by traversing water-filled ion channels and special water channels created by aquaporin (AQP)
body fluid compartments
•A mother brings her baby to the emergency room for vomiting and diarrhea for the past 2 days. The baby has lost 3 pounds. How much fluid has the baby lost?
(2. 2 lbs = 1 kg)
2. 2 lbs = 3 lbs x=1.4 kg ~1.4 litres lost
1 kg x kg
passive transport
•no input of energy required other than potential energy stored in a concentration gradient
simple diffusion
facilitated diffusion
osmosis
active transport
requires input of energy from outside source, such as the high-energy phosphate bond of ATP
phagocytosis
exocytosis
endocytosis
rate of diffusion
dependent on:
surface area
particle size
permeablility
concentration gradient
lipid solubility
4 major functions of membrane-spanning proteins
- Structural proteins
- Enzymes
- Receptors
- Transport proteins
membrane transporters
symporter and antiporter are co-transporters
gated proteins
gating strategies:
- chemical-controlled by intracellular messenger molecules or extracellular ligands
- voltage-open and close when the electrical state of the cell changes
- mechanical-open in response to mechanical movement of adjacent structures
epithelial transport
epithelia tight junctions limit what can come between the cells.
polarized epithlia have different transport proteins on the apical and basolateral membranes. this allows directional and selective transport to occur across the epithelium. Transport from Lumen to ECF is call absorbtion
transport from ECF to lumen is call secretion.
NA+- glucose transportation
the Na+ glucose symporter brings glucose into a cell against its concentration gradient by utilizing the Na+ concentration gradient.
GLUT transporter transfers glucose to the ECF by facilitated diffusion.
the Na/K pump is able to pump Na out of the cell, keeping the Na ICF concentration low, allowing for more glucose to get transported into the cell
vesicle transport
utilizes pH differences
recylcing of receptors
another way to move substances from point a to point b, through a cell
