Bio 400 Chapter 1 Exam Questions
and ANSWERS 100% PASS
What is homeostasis? - CORRECT ANSWER-A: Maintenance of relatively stable
internal conditions despite external changes.
What are the three main components of a homeostatic system? - CORRECT
ANSWER-A: Sensors (detect change), Integrators/control centers (process info),
Effectors (implement corrective action).
What is a set point? - CORRECT ANSWER-A: The value a system aims to
maintain.
Difference between negative & positive feedback? - CORRECT ANSWER-A:
Negative feedback counteracts deviations; Positive feedback amplifies deviations
(e.g., childbirth, clotting).
What is a feed-forward mechanism? - CORRECT ANSWER-A: An anticipatory
response to prepare for a change before it occurs.
, Conformers vs Regulators? - CORRECT ANSWER-A: Conformers' internal
environment changes with external; Regulators maintain stability despite external
changes.
Typical resting membrane potential? - CORRECT ANSWER-A: ~ -70 mV (inside
negative).
What maintains resting potential? - CORRECT ANSWER-A: Na⁺/K⁺ ATPase
pump (3 Na⁺ out, 2 K⁺ in), K⁺ leak channels, ion gradients.
Ion concentration differences (inside vs outside)? - CORRECT ANSWER-A: K⁺
high inside, Na⁺ high outside, Cl⁻ high outside, proteins trapped inside.
What does the Nernst equation calculate? - CORRECT ANSWER-A: Equilibrium
potential for a specific ion.
Approximate equilibrium potentials? - CORRECT ANSWER-A: K⁺ ≈ -90 mV,
Na⁺ ≈ +60 mV.
Why is resting potential closest to K⁺ equilibrium potential? - CORRECT
ANSWER-A: Membrane is most permeable to K⁺ at rest.
What is an action potential? - CORRECT ANSWER-A: Rapid, temporary reversal
of membrane potential along excitable membranes.
Threshold potential? - CORRECT ANSWER-A: ~ -55 mV.
© 2026 Copyright. All Rights Reserved. This document is
protected by copyright law
and ANSWERS 100% PASS
What is homeostasis? - CORRECT ANSWER-A: Maintenance of relatively stable
internal conditions despite external changes.
What are the three main components of a homeostatic system? - CORRECT
ANSWER-A: Sensors (detect change), Integrators/control centers (process info),
Effectors (implement corrective action).
What is a set point? - CORRECT ANSWER-A: The value a system aims to
maintain.
Difference between negative & positive feedback? - CORRECT ANSWER-A:
Negative feedback counteracts deviations; Positive feedback amplifies deviations
(e.g., childbirth, clotting).
What is a feed-forward mechanism? - CORRECT ANSWER-A: An anticipatory
response to prepare for a change before it occurs.
, Conformers vs Regulators? - CORRECT ANSWER-A: Conformers' internal
environment changes with external; Regulators maintain stability despite external
changes.
Typical resting membrane potential? - CORRECT ANSWER-A: ~ -70 mV (inside
negative).
What maintains resting potential? - CORRECT ANSWER-A: Na⁺/K⁺ ATPase
pump (3 Na⁺ out, 2 K⁺ in), K⁺ leak channels, ion gradients.
Ion concentration differences (inside vs outside)? - CORRECT ANSWER-A: K⁺
high inside, Na⁺ high outside, Cl⁻ high outside, proteins trapped inside.
What does the Nernst equation calculate? - CORRECT ANSWER-A: Equilibrium
potential for a specific ion.
Approximate equilibrium potentials? - CORRECT ANSWER-A: K⁺ ≈ -90 mV,
Na⁺ ≈ +60 mV.
Why is resting potential closest to K⁺ equilibrium potential? - CORRECT
ANSWER-A: Membrane is most permeable to K⁺ at rest.
What is an action potential? - CORRECT ANSWER-A: Rapid, temporary reversal
of membrane potential along excitable membranes.
Threshold potential? - CORRECT ANSWER-A: ~ -55 mV.
© 2026 Copyright. All Rights Reserved. This document is
protected by copyright law
