AP Biology Unit 4 REVISED ACTUAL
Exam Questions and CORRECT Answers
Endocrine system - CORRECT ANSWER - Secretes hormones into blood from ductless
glands that coordinate slower but longer-acting responses
Paracrine - CORRECT ANSWER - Signals act on cells near the secreting cell
Local regulators - CORRECT ANSWER - Chemical signals that travel over short distances
due to diffusion
Autocrine - CORRECT ANSWER - Signals act on the secreting cell itself (usually for
apoptosis)
Pheromones - CORRECT ANSWER - Chemical signals that are released from the body and
are used to communicate with other individuals
Signal Transduction - CORRECT ANSWER - The linkage of mechanical, chemical, or
electromagnetic stimulus to a specific cellular response
Hormone - CORRECT ANSWER - A regulatory substance produced in an organism and
transported in tissue fluids such as blood or sap to stimulate specific cells or tissues into action.
Neurohormones - CORRECT ANSWER - A hormone produced by nerve cells and secreted
into the circulation.
Epinephrine - CORRECT ANSWER - A hormone secreted by the adrenal glands, especially in
conditions of stress.
, Negative Feedback - CORRECT ANSWER - The diminution or counteraction of an effect by
its own influence on the process giving rise to it, as when a high level of a particular hormone in
the blood may inhibit further secretion of that hormone, or where the result of a certain action
may inhibit further performance of that action.
Growth Hormone - CORRECT ANSWER - hormone secreted by anterior pituitary gland that
usually stimulates growth of bones
second messengers - CORRECT ANSWER - Small, non-protein water soluble molecules or
ions that send messages throughout the cells by diffusion.
Plant growth regulator - CORRECT ANSWER - Organic compounds other than nutrients (like
hormones that affect plant growth.
plant hormone - CORRECT ANSWER - abscisic acid, auxin, cytokinins, ethylene,
gibberellins act as chemical messengers
tropism - CORRECT ANSWER - A growth response that results in the curvature of whole
plant organs toward or away from stimuli owing to differential rates of cell elongation.
phototropism - CORRECT ANSWER - Growth of a plant shoot toward or away from light.
circadian rhythms - CORRECT ANSWER - The 24-hour biological cycles found in humans
and many other species.
action potential - CORRECT ANSWER - A neural impulse; a brief electrical charge that
travels down an axon.
abiotic stresses - CORRECT ANSWER - Stresses that come from non-living factors such as
wind, temperature, drought or pollution
Exam Questions and CORRECT Answers
Endocrine system - CORRECT ANSWER - Secretes hormones into blood from ductless
glands that coordinate slower but longer-acting responses
Paracrine - CORRECT ANSWER - Signals act on cells near the secreting cell
Local regulators - CORRECT ANSWER - Chemical signals that travel over short distances
due to diffusion
Autocrine - CORRECT ANSWER - Signals act on the secreting cell itself (usually for
apoptosis)
Pheromones - CORRECT ANSWER - Chemical signals that are released from the body and
are used to communicate with other individuals
Signal Transduction - CORRECT ANSWER - The linkage of mechanical, chemical, or
electromagnetic stimulus to a specific cellular response
Hormone - CORRECT ANSWER - A regulatory substance produced in an organism and
transported in tissue fluids such as blood or sap to stimulate specific cells or tissues into action.
Neurohormones - CORRECT ANSWER - A hormone produced by nerve cells and secreted
into the circulation.
Epinephrine - CORRECT ANSWER - A hormone secreted by the adrenal glands, especially in
conditions of stress.
, Negative Feedback - CORRECT ANSWER - The diminution or counteraction of an effect by
its own influence on the process giving rise to it, as when a high level of a particular hormone in
the blood may inhibit further secretion of that hormone, or where the result of a certain action
may inhibit further performance of that action.
Growth Hormone - CORRECT ANSWER - hormone secreted by anterior pituitary gland that
usually stimulates growth of bones
second messengers - CORRECT ANSWER - Small, non-protein water soluble molecules or
ions that send messages throughout the cells by diffusion.
Plant growth regulator - CORRECT ANSWER - Organic compounds other than nutrients (like
hormones that affect plant growth.
plant hormone - CORRECT ANSWER - abscisic acid, auxin, cytokinins, ethylene,
gibberellins act as chemical messengers
tropism - CORRECT ANSWER - A growth response that results in the curvature of whole
plant organs toward or away from stimuli owing to differential rates of cell elongation.
phototropism - CORRECT ANSWER - Growth of a plant shoot toward or away from light.
circadian rhythms - CORRECT ANSWER - The 24-hour biological cycles found in humans
and many other species.
action potential - CORRECT ANSWER - A neural impulse; a brief electrical charge that
travels down an axon.
abiotic stresses - CORRECT ANSWER - Stresses that come from non-living factors such as
wind, temperature, drought or pollution
