respiration 5

Question 1

Solution to the high cellular demand of oxygen

Answer 1

98.5 % of oxygen is bound to Haemoglobin, only 1.5% is dissolved

Question 2

Oxygen can be _________ dissolved or ________ bound

Answer 2

physically

chemically

Question 3

Each iron molecule in the heme portion can combine with an oxygen molecule. How many O2 molecules per Hb molecule

Answer 3

4 O2 molecules per Hb molecule

Question 4

What drives the reduction reaction of Oxyhemoglobin [HbO2 Hb + O2]

Answer 4

Partial pressure drives the reaction

Question 5

The average hematocrit for women is ______, with plasma occupying _____
The average hematocrit for men is ______, with plasma occupying _____

Answer 5

42%
58%

45%
55%

Question 6

A hemoglobin molecule consists of _____ highly folded ________ (the globin portion) and four __________ heme groups.

Answer 6

four
polypeptide chains
iron-containing

Question 7

Percentage O2 carried when physically dissolved

Answer 7

1.5%

Question 8

Percentage O2 carried when bound to hemoglobin

Answer 8

98,5

Question 9

PO2 in resting cell (mm Hg)

Answer 9

40

- 75% saturation

Question 10

PO2 in alveoli (mm Hg)

Answer 10

100

- 97.5% saturation

Question 11

At 40 mmHg, ____% of all Hg must dissociate

Answer 11

25

Question 12

If tissue cells metabolize more actively, a small change in ______ (eg 10 mmHg) yields a ______ of O2 dissociation to meet metabolic demands

Answer 12

partial pressure

large amount

Question 13

Plateau between 60 and 100 mm/Hg:

Answer 13

• large pressure change causes hardly any change in O2 content
• Hb: “soaks up” the O2, keeping the partial pressure high for longer

Question 14

when does blood PO2 start falling to that of the surrounding tissue

Answer 14

Only when Hb is maximally unloaded at the given pressure gradient

Question 15

storage depot for oxygen, facilitating large net transfer by maintaining the partial pressure for longer

Answer 15

Hemoglobin

Question 16

What causes a favor in unloading?

Answer 16

increased PCO2, H+ (acid) , temperature, or 2,3-bisphosphoglycerate

Question 17

of increased PCO2, H+, temperature, and 2,3-bisphosphoglycerate causes what

Answer 17

right-shift in the curve

Question 18

Effect of increased PCO2, H+, temperature, and 2,3-bisphosphoglycerate on the O2–Hb curve

Answer 18

shift the O2–Hb curve to the right. As a result, less O2 and Hb can be combined at a given PO2 so that more O2 is unloaded from Hb for use by the tissues. Similarly, 2,3-bisphosphoglycerate, whose production is increased in red blood cells when arterial HbO2 is chronically below normal, shifts the O2–Hb curve to the right, making more of the limited O2 available at the tissue level.

Question 19

Breathing pure oxygen: can it provide more Oxygen to the tissue?

Answer 19

Very little is added

Question 20

How does carbon monoxide poisoning occur?

Answer 20

Hemoglobin: high affinity for carbon monoxide
[CO Hb affinity: 240x higher than O2]
Carboxyhemoglobin HbCO
Even small amounts of CO can make large amounts of Hb unavailable for oxygen
Odorless, colorless, tasteless, non-irritating
Not sensed: no response in ventilation
Treatment: 100% oxygen