Physiology Exams 1 & 2

Homeostasis refers to maintaining a relatively stable internal environment. The "internal environment" is:

a) the blood cells

b) all body parts beneath the skin

c) the cytoplasm of all cells in the body

d) plasma, interstitial fluid, and transcellular fluid

e) intracellular fluid

The "internal environment" is plasma, interstitial fluid, and transcellular fluid

The parathyroid glands release parathyroid hormone when calcium levels drop, and they reduce production when calcium levels rise. Under which type of regulation does this system seem to operate?

a) positive feedback

b) feedforward control

c) negative feedback

negative feedback

A positive feedback mechanism would be an effective way to:

a) maintain a constant internal environment

b) anticipate changes in the environment

c) adapt to a new environment

d) bring about an amplified, rapid change

e) detect changes in the external environment

A positive feedback mechanism would bring about an amplified, rapid change

Each of the following is a means of generating or holding heat in the body EXCEPT:

a) reduced sweating

b) exercising

c) shivering

d) vasodilation of blood vessels in the skin

vasodilation of blood vessels in the skin does NOT generate or hold heat

When pyrogens are present, shivering is used by the body to create a fever.

a) True

b) False

True -- when pyrogens are present, shivering is used by the body to create a fever

One of insulin's mechanisms of action is to:

a) activate the Na+/K+ pump

b) increase the activity of SGLT

c) increase the facilitated diffusion of glucose into certain cells in the body

d) increase the number of sodium-linked glucose transporters in the cell membrane

One of insulin's mechanisms of action is to increase the facilitated diffusion of glucose into certain cells in the body

Mice from a certain lab strain remain healthy as long as you feed them regularly and do not let them exercise. After they eat, their blood glucose level rises slightly and then declines to a homeostatic level. However, if these mice fast or exercise at all, their blood glucose drops dangerously. Which hypothesis best explains their problem?

a) the mice have insulin-dependent diabetes

b) the mice lack insulin receptors on their cells

c) the mice lack glucagon receptors on their cells

d) the mice can't synthesize glycogen from glucose

the mice lack glucagon receptors on their cells

From glycolysis, the net gain of ATP for each molecule of glucose is:

a) 36-38

b) 32

c) 8

d) 2

e) 4

From glycolysis, the net gain of ATP for each molecule of glucose is 2

Cyanide is a molecule that inhibits one of the proteins in the electron transport chain. Which of the following molecules would consequently increase in the cells of a person suffering from cyanide poisoning?

a) ATP

b) glucose

c) pyruvate

d) NAD+

e) NADH

NADH

NADH is produced from each reaction described except one. Identify the EXCEPTION.

a) glycolysis

b) the electron transport chain

c) the Krebs cycle

d) the conversion of pyruvate to acetyl CoA

NADH is NOT produced from the electron transport chain

If lactic acid is produced in a muscle:

a) the lactic acid will remain there for the rest of the life of the muscle cell

b) the lactic acid will deposit its electrons directly on the electron transport chain

c) the lactic acid will be converted to pyruvate once oxygen becomes available again

If lactic acid is produced in a muscle, the lactic acid will be converted to pyruvate once oxygen becomes available again

Which of the following statements about anaerobic metabolism is FALSE?

a) oxygen is limited or absent

b) pyruvate moves into the mitochondrion but then accumulates there, since the Krebs cycle does not occur

c) most of the energy of the glucose molecule remains in the chemical bonds of the carbon molecules

d) the electron transport chain does not occur since oxygen is needed as the final electron acceptor

in anaerobic metabolism, pyruvate does NOT move into the mitochondrion but then accumulates there, since the Krebs cycle does not occur

Which of the following is NOT true of the cell membrane?

a) in certain cells, the phospholipids arrange themselves into the shape of a channel, in order to allow ions to transport across the membrane

b) carbohydrates associate with proteins and lipids on the extracellular side of the membrane

c) membrane proteins have a wide range of shapes, sizes, and functions

d) cholesterol influences how fluid the membrane is

e) phospholipids act as a barrier to the passage of polar substances between the ICF and ECF

NOT true - in certain cells, the phospholipids arrange themselves into the shape of a channel, in order to allow ions to transport across the membrane

The isolation of different proteins to the luminal vs basolateral surfaces of epithelial cells is due to the presence of _________ between the cells in this tissue.

a) desmosomes

b) a pump

c) tight junctions

d) gap junctions

tight junctions

In some cases, signals originating within one cell can diffuse directly to a neighboring cell's Cytoplasm through:

a) desmosomes

b) a pump

c) tight junctions

d) gap junctions

gap junctions - communicate from cell to cell

Which of the following statements about sodium and potassium ions is TRUE?

a) the sodium ion has a greater density of surface charge, so therefore it becomes less hydrated

b) the potassium ion's nucleus has a larger radius, so therefore the potassium ion becomes more hydrated

c) the potassium ion's nucleus has a larger radius, so therefore the radius of the hydrated ion is smaller

the potassium ion's nucleus has a larger radius, so therefore the radius of the hydrated ion is smaller

Assuming that a substance is uncharged and is transported across a membrane by facilitated diffusion carriers, according to Fick's law the net movement of the substance will tend to increase as:

a) the membrane surface area decreases

b) the magnitude of the concentration gradient decreases

c) the number of carriers in the membrane increases

d) the thickness of the membrane surface increases

the number of carriers in the membrane increases

Lipid soluble signal molecules cross cell membranes relatively easily. Therefore, these signal molecules have:

a) a high partition coefficient

b) a low partition coefficient

a high partition coefficient

A distinction between channel proteins and carrier proteins is that:

a) only carrier proteins are specific

b) carrier proteins transport substances faster than channel proteins

c) carrier proteins always require energy to work, whereas channel proteins do not

d) carrier proteins undergo a conformational change, whereas channel proteins do not

A distinction between channel proteins and carrier proteins is: carrier proteins undergo a conformational change, whereas channel proteins do not

The line for Chemical B in the above graph describes which of the following?

a) Na+ dependent transport of glucose by SGLT into an epithelial cell in the small intestine

b) movements of O2 across a lipid bilayer

c) transport of Na+ out of a nerve cell

d) transport of K+ into a muscle cell