BIOC32H3 : Gas Transport and Oxygen - Haemoglobin binding summary

57 views5 pages

blackrabbit616

7 Mar 2011

School

Department

Course

Professor

For unlimited access to Study Guides, a Grade+ subscription is required.

Document Summary

Haemoglobin consists of 4 subunits 2 alpha subunits and 2 beta subunits. Each of these subunits consists of a globin molecule (alpha globin or beta globin) plus a heme group. Heart of the heme group is an iron (fe) molecule that is the site of oxygen binding. The vast majority of the oxygen in blood is bound to haemoglobin. Only about 1. 5% of the oxygen in blood is in the dissolved form within plasma. It is not found in the plasma or any other tissues. Carbonic anhydrase is an enzyme that catalyses the reversible co2 hydration/dehydration reaction. It is found within the red blood cells. This reaction goes both ways depending upon the relative concentrations of the constituents on each side. Sometimes you see the intermediary carbonic acid (h2co3) appear in the equation. However, carbonic acid is so short-lived that it is impossible to ever quantify it. It is usually left out of the equation.

Related Questions

Police find a man unconscious in his car near Marion Shopping Centre. The car engine was running
with a hose taped to the exhaust carrying exhaust gases to the car's interior. The police take the
man to the FMC Emergency department where an arterial blood sample is taken and the man given
oxygen. Lack of oxygen may lead to changes in arterial blood gas results. In this case, carbon
monoxide, which is found in car exhaust, to various extents prevents oxygen from binding to
haemoglobin resulting in tissue hypoxia. Blood gas and co-oximetry measurements (the values of
oxyhemoglobin and carboxyhaemoglobin which show how much oxygen and carbon monoxide is bound to
haemoglobin, respectively) on the pre-treatment arterial blood give the following values:

RESULT UNITS REFERENCE RANGE
PO2 85 mmHg (80-100)
PCO2 30 mmHg (35-45)
HCO3- 18 mmol/L (21-28)
pH 7.31
(7.35-7.45)
Total
Haemoglobin 151 g/L
(130-175)
Oxyhaemoglobin 57%
(94-100%)
Carboxy-
haemoglobin 40%
(<2%, non-smoker)

a) Briefly explain the likely reason for this manâs unconsciousness. (1 mark)
b) Explain why his blood pH is below the normal range. Outline any relevant metabolic events and
indicate why these occur in this situation. (4 marks)
c) suggest explanation for the low PCO2 and HCO3- levels observed,
outlining any relevant mechanism(s). (5 marks)

Question 2

a.) Describe the structure and function of haemoglobin (Hb). You should include a description of both tertiary and quaternary structures of the protein and the location and function of non-protein components.

b.) List the sequence of intra-molecular movements that results in the conformational change of haemoglobin when it binds oxygen.

c.) Explain why binding affinity of carbon monoxide (CO) to haem (heme) is reduced when haem is incorporated into myoglobin or haemoglobin.

A. Hemoglobin is a heterotetramer with two alpha subunits and two beta subunits. Each subunit has the capability of binding to one oxygen molecule.

a. True

b. False

B. Which hemoglobin subunit is most likely to be in the R state?

a. a de-oxygenated beta subunit in a tetramer where two other subunits are de-oxygenated

b. a de-oxygenated alpha subunit in a tetramer where the other three subunits are oxygenated

c. a de-oxygenated beta subunit in a tetramer where the other three subunits are also de-oxygenated

d. a de-oxygenated alpha subunit in a tetramer where two other subunits are oxygenated

BIOC32H3 : Gas Transport and Oxygen - Haemoglobin binding summary

Document Summary

Get access

Related Documents

BIOL1003 Lecture 13: Lecture 13 BIOL - Homeostasis Blood Gas Levels

BIOL 003 Lecture Notes - Lecture 23: Carbonic Anhydrase, Hemoglobin, Heme

BIO203H5 Lecture Notes - Carbonic Anhydrase, Fetal Hemoglobin, Hemolymph

Related Questions