Blood Chemistry

Question 1

18 times more energy is extracted from glucose in the presence of ____.

Answer 1

O2

Question 2

Oxygen carries in all animals ________ in blood and _______ in muscle.

Answer 2

hemoglobin and myoglobin

Question 3

Hemoglobin is…

Answer 3

A red blood cell protein that transports oxygen from the lungs to the tissues.

Question 4

Hemoglobin is an _________ protein that displays _______ in oxygen binding and release.

Answer 4

allosteric, cooperativity

Question 5

Myoglobin binds______ in ________ cells.

Answer 5

oxygen and muscles

Question 6

T or F. The binding of exygen by myoglobin is cooperative.

Answer 6

False. It is not cooperative. Hemoglobin is.

Question 7

The ability of myglobin and hemoglobin to bind oxygen depends on the presence of a prosthetic group called…..

Answer 7

heme

Question 8

Presence of heme is called ______ and the absence of heme is called ______.

Answer 8

haloprotein, apoprotein

Question 9

The heme group consists of an organic component called…..

Answer 9

tetrapyrrole

Question 10

What are the atoms in the middle of the heme?

Answer 10

Iron in the middle bound to 4 nitrogens.

Question 11

What are the two additional bonds that can be formed by iron in Heme and explain them.

Answer 11

Fifth and sixth coordination sites.
Fifth: occupied by the proximal histidine
Sixth: binds oxygen.

Question 12

What was the significance of the complete 3D structure of myoglobin?

Answer 12

Showed binding of heme structure attracted to hydrophobic fold and held by His residue attached to heme iron center.

Question 13

F8 His residue called the _______ His forms a _______ coordination with the Fe atom in the heme.

Answer 13

proximal, fifth

Question 14

E7 His residue is located near/not bonded to the ______ and is called the ______.

Answer 14

heme, distal His

Question 15

Heme is a…

Answer 15

molecule made of four pyrrole rings which are linked together. (tetrapyrrole)

Question 16

The iron atom in a Heme has two common oxidation states, what are they and what are they called?

Answer 16

+2 is ferrous and +3 is ferri

Question 17

What are the three oxidation states of the Fe atom in myoglobin.

Answer 17

Deoxygenated form
Oxygenated form
Ferric form

Question 18

What is the deoxygenated form?

Answer 18

no O2 is bound
Fe+2
bluish color, (Fe movement out of center)

Question 19

What is the oxygenated form?

Answer 19

O2 is bound
Fe+2
red color, (Fe movement back in center)

Question 20

What is the ferric form?

Answer 20

H2O is bound—-> no O2
Fe+3
brownish color (water is bound to Fe atom)

Question 21

T or F. There can be some linear binding of oxygen to the Fe atom.

Answer 21

False. Binding only happens at an angle.

Question 22

What prevents linear formation of bonds between O2 and Fe?

Answer 22

The distal His

Question 23

Name two things that are important to the protein portion of Hemo/myoglobin when it doesn’t bind to O2?

Answer 23

1) O2 will bind to free ferrous heme—>oxidation occurs—>Fe+2—>Fe+3
2) Protein protion of oxygen carrier prevents Heme stacking and linear binding of O2.

Question 24

Carbon monoxide poisoning happens how?

Answer 24

CO binds to ferrohemo or ferromyoglobin and blocks the normal transport of oxygen.

Question 25

What causes CO to not be as stronger as it should be? Why?

Answer 25

Distal His, it sterically hinders linear binding of CO to Fe atom. (Weakens the interaction of molecules.)

Question 26

T or F. If binding were not weakened, CO bound hemo and myoglobin concentrations would be fatal, suffocate ourselves.

Answer 26

True.

Question 27

Hemoglobin is

Answer 27

at tetramer of four polypeptide chains held together y non covalent interactions

Question 28

The binding of O2 in hemoglobin is..

Answer 28

1) dramatically affected by pH

2) also affected by CO2 concentrations.

Question 29

T or F Myoglobin has a higher affinity for O2 than hemoglobin.

Answer 29

True

Question 30

In binding curves, the shape of the curve indicates that O2 binding for (two things)

Answer 30

1) myoglobin is not cooperative

2) hemoglobin is cooperative

Question 31

Hill curve is used as a model to describe what?

Answer 31

the cooperativity of hemoglobin and can be applied to other cooperative binding proteins.

Question 32

What is a oxygen binding curve?

Answer 32

a plot of the fractional saturation versus the oxygen concentration, which is shown as partial pressure with the unit of torr.

Question 33

Cooperativity allows hemoglobin to do what?

Answer 33

bind oxygen in the lungs, where it is plentiful, and release oxygen at the tissues.

Question 34

Myoglobin requries ____ torr or O2 to saturate 50% of available binding sites.

Answer 34

1-2

Question 35

Hemoglobin requries ____ torr or O2 to saturate 50% of available binding sites.

Answer 35

26-28

Question 36

Sickle cell anemia is…

Answer 36

genetic disease caused by a single point mutation resulting in the substitution of Val for Glu at position 6 of beta chains.

Question 37

Sickle cell anemia can be fatal if..

Answer 37

both alleles of the beta chain are mutated

Question 38

Methemoglobin

Answer 38

Stabilized form of Fe+3 in the alpha and beta subunits of hemoglobin, Fe+3 cannot bind to O2

Question 39

Type one of Methemoglobin

Answer 39

deficient in erythrocyte reductase enzyme

Question 40

Type two of Methemyglobin

Answer 40

altered hemoglobin which affects the proximal and distal His and replaces with Tyr

Question 41

Symptoms of Methemyglobin

Answer 41

skin turns bluish, called cyanosis

Question 42

Alpha Thalassemias

Answer 42

Associated with the deletion in the alpha chain genes. Limited production of alpha subunits

Question 43

Beta Thalassemias

Answer 43

Associated with the mutation of the beta chain genes. Severe=limited production of beta subunits