Cell Transport
Which type of transport moves substances down their concentration gradient without energy input?
Passive transport
What type of energy powers active transport?
ATP hydrolysis
What is the first law of thermodynamics?
Energy cannot be created or destroyed, only transformed
What is the role of enzymes in chemical reactions?
Enzymes are protein catalysts that speed up reactions why lowering activation energy (Ea)
Why is ecstasy dangerous for electrolyte balance?
Acts as an antidiuretic, preventing kidney water loss and excess water retention, electrolyte imbalance
What is the difference between carrier proteins and channel proteins in facilitated diffusion?
Carrier proteins: Change shape to move specific molecules like glucose. Channel proteins: Form hydrophilic tunnels for ions/polar molecules.
What is the difference between primary and secondary active transport?
Primary transport uses ATP directly, Secondary uses energy stored in an ion gradient established by primary transport
What is the second law of thermodynamics?
Entropy increases in closed systems, energy transfers lose usable energy as heat.
What is the "induced fit" model of enzyme activity?
Enzymes slightly changes shape at active site to better bind the substrate
What condition results from over hydration and low sodium levels?
Hyponatremia
What problem occurs in cells if pure water is given intravenously?
Creates a hypotonic environment, making red blood cells swell and burst (hemolysis).
What are endocytosis and exocytosis used for in cells?
Bulk transport, endo for import, exo for export of large molecules
Whats the difference between kinetic and potential energy in cells?
Potential energy is stored in gradients, kinetic is released when bonds break or ions flow across the membrane
How do temperature and pH affect enzyme activity?
Enzyme denatures or reduces binding efficiency at too high or too low temperature or pH
Why is turgor pressure important in plants?
Keeps plant cells rigid, wilting will result without it
Name the 3 types of protein pumps used in active transport. (Think carrier proteins)
Uniporter, antiporter, symporter.
Receptor-mediated endocytosis
What is the equation for Gibbs free energy?
Delta G = delta H - T delta S
What is a competitive inhibitor?
Blocks the active site by mimicking the substrate
What adaptation helps Antarctic octopuses keep Na+/K+ pumps working in the extreme cold?
Single amino acid substitution in Na+/K+ ATPase that preserves enzyme efficiency in the cold
Explain how the sodium-potassium pump contributes to the electronegativity of the chemical gradient.
Establishes electrochemical gradient and polarization by making the cell interior more electronegative. 3NA+ out, 2K+ in.
How does Prozac affect vesicle dynamics at the synapse?
Alters serotonin recycling, inhibits reuptake, impacts neurotransmission.
Explain why energy is required to break bonds but released when new bonds form.
Breaking bonds requires input, like magnets pulling apart, while bond formation releases energy, like magnets snapping together
What is allosteric regulation, and how can activate or inhibit enzymes?
Molecules bind away from the active site, can inhibit or activate enzyme activity by increasing or reducing binding
How does ATP synthase use stored hydrogen ions to generate ATP?
ATP synthase allows H+ to flow down their electrochemical gradient; this kinetic energy is converted into chemical energy by creating ATP