* not completed

. Which statement regarding hemoglobin is false?

Its affinity for O₂ can change. correct incorrect

It is primarily an enzyme. correct incorrect

It binds to O₂ via weak, noncovalent bonds. correct incorrect

It is a buffer. correct incorrect

* not completed

. How many molecules of O₂ does a molecule of vertebrate blood hemoglobin normally bind?

1 correct incorrect

2 correct incorrect

4 correct incorrect

8 correct incorrect

* not completed

. Which respiratory pigment contains copper at the O₂ binding site?

Myoglobin correct incorrect

Chlorocruorin correct incorrect

Hemerythrin correct incorrect

Hemocyanin correct incorrect

* not completed

. Which statement about the four chemical classes of respiratory pigments is true?

All are metalloproteins. correct incorrect

All bind reversibly with O₂ at specific O₂-binding sites associated with metal ions. correct incorrect

All share the same heme structure. correct incorrect

All are metalloproteins and bind reversibly with O₂ at specific O₂-binding sites associated with metal ions. correct incorrect

* not completed

. In people at rest, the approximate O₂ saturation of venous blood leaving the tissues is

75%. correct incorrect

5 ml O₂/100 ml blood. correct incorrect

10 ml O₂/100 ml blood. correct incorrect

5%. correct incorrect

* not completed

. During exercise, the body supplies O₂ to the muscles by

increasing muscle fiber declination. correct incorrect

increasing blood flow. correct incorrect

increasing blood flow and unloading more O₂ to tissues from hemoglobin. correct incorrect

increasing muscle fiber declination, increasing blood flow, and unloading more O₂ to tissues from hemoglobin. correct incorrect

* not completed

. The extent of O₂-binding site cooperativity is expressed using a mathematical index called the

Bohr effect. correct incorrect

Root index. correct incorrect

Haldane constant. correct incorrect

Hill coefficient. correct incorrect

* not completed

. Which word best describes the mechanism for the steep portion of the oxygen dissociation curve?

Cooperativity correct incorrect

Loading correct incorrect

Unloading correct incorrect

Coefficient correct incorrect

* not completed

. The process by which low pH aids in the decreasing affinity of hemoglobin for O₂ is called the _______ effect.

Bohr correct incorrect

Root correct incorrect

Haldane correct incorrect

hemoglobin-shift correct incorrect

* not completed

. Which statement about the Bohr effect is true?

A higher temperature decreases the Hb–O₂ affinity. correct incorrect

A lower pH increases the Hb–O₂ affinity. correct incorrect

A higher partial pressure of CO₂ decreases the Hb–O₂ affinity. correct incorrect

A higher H⁺ concentration increases the Hb–O₂ affinity. correct incorrect

* not completed

. Which variable does not affect the properties of the O₂ dissociation curve?

Temperature correct incorrect

Partial pressure of CO₂ correct incorrect

2,3-DPG concentration correct incorrect

Cardiac output correct incorrect

* not completed

. Which hemoglobin has the highest P₅₀?

Hemoglobin at a lower-than-normal temperature, such as 35°C correct incorrect

Fetal hemoglobin correct incorrect

Hemoglobin in a human residing at a high altitude for three weeks correct incorrect

Hemoglobin at a higher-than-normal pH, such as 7.6 correct incorrect

* not completed

. A reduction in the amount of O₂ bound to hemoglobin at saturation could be the result of the _______ effect.

Bohr correct incorrect

fixed-acid Bohr correct incorrect

Root correct incorrect

Haldane correct incorrect

* not completed

. During chronic exposure to high altitude, increased 2,3-DPG

increases hemoglobin–O₂ affinity. correct incorrect

increases the unloading of O₂ at tissues. correct incorrect

permits increased physical exercise. correct incorrect

increases the loading of O₂ at the lungs. correct incorrect

* not completed

. During exercise, squids and octopuses meet their O₂ demand by

drawing additional O₂ from venous reserve. correct incorrect

increasing their circulation rate. correct incorrect

increasing the affinity of hemoglobin for O₂. correct incorrect

decreasing the affinity of hemoglobin for O₂. correct incorrect

* not completed

. In general, what is the relationship between primate size and Hb–O₂ affinity?

Larger primates tend to have a lower Hb–O₂ affinity. correct incorrect

Smaller primates tend to have a lower P₅₀. correct incorrect

Larger primates tend to have a higher P₅₀. correct incorrect

Smaller primates tend to have a lower Hb–O₂ affinity. correct incorrect

* not completed

. Compared to oxygenated blood, fully deoxygenated blood has a

higher affinity for CO₂. correct incorrect

lower affinity for CO₂. correct incorrect

higher affinity for bicarbonate. correct incorrect

lower affinity for O₂. correct incorrect

* not completed

. Bicarbonate created from CO₂ in the red blood cell gets into the plasma

through exclusive bicarbonate channels. correct incorrect

via chloride exchange. correct incorrect

with the assistance of carbonic anhydrase, which shuttles it into the plasma. correct incorrect

via active transport in exchange for Na⁺. correct incorrect

* not completed

. Which of the following is(are) involved in the transport of CO₂ from the tissues to the lungs?

Bicarbonate correct incorrect

Bicarbonate and CO₂ bound to hemoglobin correct incorrect

CO₂ bound to hemoglobin and CO₂ dissolved in plasma correct incorrect

Bicarbonate, CO₂ bound to hemoglobin, and CO₂ dissolved in plasma correct incorrect

* not completed

. According to the _______, changes in pH are a means by which ectotherms maintain a constant state of electrical charge on protein molecules.

Root effect correct incorrect

Bohr shift correct incorrect

alphastat hypothesis correct incorrect

law of buffered reactions correct incorrect