WITH ANSWERS
1). Negative feedback
Ans: Promotes stability; cancels out the original response. Ex: High FSBS, increased
insulin by the pancreas
2). Positive feedback
Ans: Promotes a change in one direction; instability, DISEASE. Ex: Blood clotting,
platelet cascade
3). Proteins
Ans: Provide selectivity to a membrane
4). Integral proteins
Ans: channels, pores, carriers, enzymes, receptors, second messengers
5). Peripheral proteins
Ans: Enzymes, intracellular, signal mediatiors
6). Atp
Ans: Converted to ADP to produce energy; chemical bonds between 2nd and 3rd
phosphate groups have abundant energy
7). Simple/passive diffusion
Ans: Occurs down a concentration gradient; from HIGH to LOW concentration
8). Simple/passive diffusion
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, Ans: Diffuse from high to lower pressure; diffusion will not occur if the membrane is
non permeable to the molecule
9). Factors that affect the net rate of diffusion
Ans: 1. Concentration difference (high to low)
2. Electrical Potential (EMF)- charge difference on each side of the membrane matters
TOO!
3. Pressure difference (higher pressure results in increased energy)
10). Osmosis
Ans: Passive transport of fluid across a membrane; from an area of low solute
concentration to high solute concentration (high FLUID to low FLUID)
11). Primary active transport
Ans: Molecules are "pumped" against ("uphill") a concentration; DIRECT USE OF
ENERGY
12). Secondary active transport
Ans: Trasport is driven by the energy STORED in the concentration gradient of another
molecule (Na+); INDIRECT USE OF ENERGY
13). Na+- k+ atpase
Ans: Carrier protein located on the plasma membrane of alll cells; enzyme that
converts ATP to ADP to release energy
-Important role in regulating osmotic balance
-Requires one to two thirds of cells energy
14). Ca2+ atpase
Ans: Maintains a low cystosolic Ca2+ concentration
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, 15). H+ atpase
Ans: - Found in parietal cells of gastric glands (HCl secretion) and intercalated cells of
renal tubules (controls blood pH)
- Concentrates H+ ions up to 1 million-fold
16). Remember: sodium potassium pump
Ans: sodium is pumped out of the cell; potassium is pumped in...
17). Secondary active transport; co-transport
Ans: Co-transport: Substance is transported in the same direction as the "driver" ion
(Na+)
18). Counter transport
Ans: Substance is transported in the opposite direction as the driver ion Na+
19). How do cardiac glycosides increase cardiac contractility?
Ans: Increase intracellular Ca2+
20). Ungated ion channels
Ans: determined by size, shape, distribution of charge
21). Gated ion channels
Ans: -volgate (e.g.) Voltage dependent Na+ channels)
-Chemically (e.g. Nicotinic AcH receptor channels)
22). Ion channels
Ans: Conductance depends on probability that channel is open.
23). Equilibrium potential
Ans: the diffusion potential that exactly balances or opposes the tendency for
diffusion down the concentration difference.
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