Biol. 4510 Animal Physiology Lab Midterm

The driving force for diffusion is:

the kinetic energy of the molecules in motion.

The net movement of water would be into the cell in a:

hypotonic solution.

T/F  Water molecules can freely move across a semi-permeable membrane, as long as they are not bound to another molecule.

True

Which of the following is true of osmosis?

It is a type of diffusion.

Describe the difference between the rate of diffusion seen for sodium and urea.

Urea diffused more slowly because it is larger than sodium

Diffusion can be:

All of the above

T/F  Shrinkage of a plant cell in a hypertonic solution is called crenation.

False

True or False: Larger, more hydrophilic solutes penetrate the cell membrane faster than small, hydrophobic solutes.

False

When water moves out of an animal cell the cell goes through

crenation

Avogadro’s number is a constant for the number of:

molecules

What Family do field crickets belong to?

Gryllidae

T/F - Catabolic reactions build larger molecules from smaller components?

False

T/F  The Respiratory Exchange Ratio (RER) and Respiratory quotient (RQ) can indicate which fuel (sugar, lipid, or protein) is being used for metabolism.

True

Overall metabolic rate is closely tied to the rate of ______.

Respiration

T/F - Ectothermic animals maintain high metabolic rates and body temperatures than endothermic animals because of insulation (fur/fat/feathers).

False

What was used to anesthetize the earthworms?

15% ethanol in earthworm saline

Ion channels can be gated by

ligand or voltage

Depolarization is followed by ___________ of the membrane as sodium levels return to baseline and potassium permeability is increased.

Repolarization

Action potentials occur when sodium channels are activated, leading to a large increase in sodium permeability, resulting in_______ of the membrane.

Depolarization

Each segment of the earthworm has a median giant fiber. These segments are coupled electrically via _____.

Gap Junctions

True or False: dendrites are responsible for receiving signal from sensory cells and other neurons

True

Which of the following is easier?

extracellular recordings of the action potential

Axons are:

long, thin structures that extend from a neuronal cell body.

What is the scientific name for the cockroaches use in this lab?

Periplenata

In cockroaches, what cuticle structures are associated with perceiving touch and vibrations?

Leg spines

How are tactile sensory cells depolarized?

Mechanical distending of the cell membrane that triggers mechanical Na⁺ channels

What are sensory nerve cells responsible for?

Converting external stimuli from the organism's environment into electrical and chemical signals for transmission

What is the approximate threshold membrane potential value for an axonal action potential?

-50mV

Which of the following is true of an action potential?

All of these

Which of these is not a type of sensory cell?

Solar

At rest, neuronal plasma membranes are relatively impermeable to ______ and slightly permeable to _____ via leakage channels

Na+; K+

An all or nothing response requires to meet a threshold to be reached before firing.

True

Hyperpolarization occurs because of_______.

A sluggish closing of the K+ channels

Which of the following occurs after the peak of the action potential?

All of these

Large diameter fibers conduct impulses slow than those of smaller diameter.

False

Depolarization occurs when ________.

Na+ Channels open

Nerve fibers are grouped into bundles called ______.

Fascicles

______ Recording is accomplished by placement of two electrodes near an active nerve.

Differential

An action potential is propagated by the opening of _______ in the membrane.

Voltage gated Na+ and K+ channels

The threshold voltage in an axon is usually:

less negative than the resting membrane potential.