BIOS 251 Final Exam Questions And
Actual Answers.
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
Factors that influence diffusion across a cell membrane - Answer -steepness of concentration
gradient
-temperature
-mass of diffusing substance
-surface area
-diffusion distance
Passive processes that move substances across the cell membrane - Answer -Simple diffusion
-Facilitated diffusion
Osmosis processes that move substances across the cell membrane - Answer -Active
, 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 concentration
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
-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, bacteria
-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 membrane
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: capillary moves hormones to other side of vessel to be released into blood via
exocytosis
Merocrine secretion - Answer cells excrete their substances by exocytosis
Actual Answers.
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
Factors that influence diffusion across a cell membrane - Answer -steepness of concentration
gradient
-temperature
-mass of diffusing substance
-surface area
-diffusion distance
Passive processes that move substances across the cell membrane - Answer -Simple diffusion
-Facilitated diffusion
Osmosis processes that move substances across the cell membrane - Answer -Active
, 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 concentration
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
-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, bacteria
-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 membrane
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: capillary moves hormones to other side of vessel to be released into blood via
exocytosis
Merocrine secretion - Answer cells excrete their substances by exocytosis
