Ch. 10 - Hemoglobin Metabolism (Incom. start at Hb synthesis...)

Question 1

This is the first protein whose structure was described using x-ray crystallography.

Answer 1

Hemoglobin (Hb)

Question 2

This molecule is a conjugated globular protein consisting of four heme groups and two heterogenous pairs of polypeptide chains.

Answer 2

Hemoglobin

Question 3

The hemoglobin molecule has how many heme groups?

Answer 3

4

Question 4

The hemoglobin molecule has how many heterogenous pairs of polypeptide chains?

Answer 4

2

Question 5

This is the main cytoplasmic component of erythrocytes.

Answer 5

Hemoglobin (Hb)

Question 6

This type of hemoglobin (Hb) is generated from RBCs through hemolysis; it has a short half-life, is rapidly salvaged and is catabolized or excreted renally.

Answer 6

Free (non-RBC) Hemoglobin (Hb)

Question 7

What is the approximate concentration of hemoglobin within the RBCs?

Answer 7

34 g/dL

Question 8

What is hemoglobin’s main function?

Answer 8

To transport oxygen from the lungs to the tissues.

Question 9

Hemoglobin also modulates vascular dilation by transporting nitric oxide (NO) and transports _____ from the tissues to the lungs for exhalation.

Answer 9

Carbon dioxide

Question 10

Heme consists of a ring of carbon, hydrogen, and nitrogen atoms called _____ with an atom of divalent ferrous iron (Fe2+) attached.

Answer 10

Protoporphyrin IX

Question 11

Heme consists of a ring of _____, _____, and _____ atoms called protoporphyrin IX with an atom of divalent ferrous iron (Fe2+) attached.

Answer 11

Carbon
Hydrogen
Nitrogen

Question 12

Heme consists of a ring of carbon, hydrogen, and nitrogen atoms called protoporphyrin IX with an atom of divalent _____ attached.

Answer 12

Ferrous iron (Fe2+)

Question 13

Each heme molecule combines reversibly to how many oxygen molecules.

Answer 13

One

Question 14

Each heme molecule combines (irreversibly/reversibly) to one oxygen molecule.

Answer 14

Reversibly

Question 15

The four globin chains comprising each hemoglobin molecule consists of how many identical pairs of unlike polypeptide chains?

Answer 15

Two

Question 16

The four globin chains comprising each hemoglobin molecule consists of two identical pairs of unlike polypeptide chains with how many amino acids each?

Answer 16

141 - 146

Question 17

Each globin chain is divided into how many helices and nonhelical segments?

Answer 17

Eight helices

Seven nonhelical segments

Question 18

This part of the globin chain is designated as A to H and contains subgroup numberings for the sequence of the amino acids in each helix and are relatively rigid and linear.

Answer 18

Helices

Question 19

This part of the globin chain connects the helices, as reflected by their designations.

Answer 19

Flexible nonhelical segments

Question 20

This hemoglobin structure refers to the amino acid sequence of the polypeptide chains.

Answer 20

Primary structure

Question 21

This hemoglobin structure refers to the chain arrangements in helices and nonhelices.

Answer 21

Secondary structure

Question 22

This hemoglobin structure refers to the arrangement of the helices into a pretzel-like configuration.

Answer 22

Tertiary structure

Question 23

This hemoglobin structure describes the complete hemoglobin molecule.

Answer 23

Tertiary structure, or tetrameric molecule

Question 24

Each globin chain contains a heme group that is suspended between the _____ and _____ helices of the polypeptide chain.

Answer 24

F and E

Question 25

The iron atom at the center of the protoporphyrin IX ring of heme is positioned between two _____ radicals, forming a proximal histidine bond within F8.

Answer 25

Histidine

Question 26

Globin chain amino acids in the cleft are (hydrophobic/hydrophilic) whereas amino acids on the outside are (hydrophobic/hydrophilic).

Answer 26

Hydrophobic

Hydrophilic

Question 27

(T/F) The hemoglobin molecule is water soluble.

Answer 27

T

Question 28

What is the shape of the complete hemoglobin molecule?

Answer 28

Spherical

Question 29

How many heme groups and polypeptide chains does the complete hemoglobin molecule have?

Answer 29

4; 4

Question 30

How many molecules of oxygen can the complete hemoglobin molecule carry?

Answer 30

4

Question 31

(T/F) The complete hemoglobin molecule is composed of 4 alpha globin chains and two non-alpha globin chains.

Answer 31

F (2-alpha globin chains)

Question 32

(T/F) Each heme group, attached to a globin chain, can carry multiple molecules of oxygen.

Answer 32

F (Only one molecule of oxygen per heme)

Question 33

Heme biosynthesis occurs in the _____ and _____ of bone marrow RBC preursors.

Answer 33

Mitochondria

Cytoplasm

Question 34

The production of globin chains takes place in _____ from the pronormoblast through the circulating polychromatic (polychromatophilic) erythrocytes.

Answer 34

RBC precursors

Question 35

(T/F) The production of globin chains can take place in mature RBCs.

Answer 35

F

Question 36

The combination of two a (alpha) and two B (beta) chains along with their four heme molecules forms what heemoglobin? This is the predominant hemoglobin in postnatal life.

Answer 36

Hemoglobin (Hb) A

Question 37

This type of hemoglobin contains two alpha and two delta chains; the delta chains are inefficiently expressed; only small amounts of this Hb are found in the RBCs.

Answer 37

Hb A2

Question 38

This type of hemoglobin contains two alpha and two gamma chains; in adults, this is distributed unevenly among RBCs.

Answer 38

Hb F; present in a few RBCs called F cells