BIOS 251 Final Exam - –Answer receptor, control center, effector 2....

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BIOS 251 Final Exam

• Components of the homeostatic control loop

–Answer receptor, control center, effector

• Negative feedback

–Answer -works to oppose change -brings condition back to a set point

• Positive feedback

–Answer -works to enhance change -brings condition further away from a set point

• Tonicity

–Answer relates to how the solution influences the shape of body cells

• Hypotonic solution

–Answer RBC undergoes hemolysis (swelling)

• Hypertonic solution

–Answer RBC undergoes crenation (shrinking)

• Osmosis

–Answer -concentration of solutes per liter -water moves from high concentration of water to low concentration of water 1 / 3

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• Factors that influence diffusion across a cell membrane

–Answer -steepness of con- centration gradient -temperature -mass of diffusing substance -surface area -diffusion distance

• Passive processes that move substances across the cell membrane

–Answer -Sim- ple diffusion -Facilitated diffusion

• Osmosis processes that move substances across the cell membrane

–Answer -Ac- tive processes -Active transport -Vesicular transport

• Primary active transport

–Answer energy derived from ATP changes the shape of a transporter protein which pumps a substance across a plasma membrane against its concentration gradient

• Secondary active transport

–Answer -energy stored (in a hydrogen or sodium concen- tration gradient) is used to drive other substances against their own concentration gradients -substance is being transported "against its will"

• Types of active transport in vesicles

–Answer -endocytosis 2 / 3

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-phagocytosis -pinocytosis -exocytosis -transocytosis

• Endocytosis

–Answer cell takes up specific ligands that bind to cell surface receptors into a vesicle

• Phagocytosis

–Answer -cell engulfs large particles such as old cell parts, viruses, bac- teria -used by many immune system cells

• Pinocytosis

–Answer -cells take up small droplets of ECF -no receptors involved -"cell drinking"

• Exocytosis

–Answer -membrane-enclosed secretory vesicles fuse w/the plasma mem- brane and release their contents into the ECF -used to secretions such as sweat, oil

• Transocytosis

–Answer -a combination of endocytosis and exocytosis used to move substances from one side of a cell, across it, and out the other side -example –Answer capillary moves hormones to other side of vessel to be released into blood via exocytosis

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