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Flashcards in Hemoglobin Deck (57)
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1

Where is myoglobin found

found in muscle for oxygen storage

2

Single ferous _____- containng heme prosthetic group in protective hydrophobic pocket binds oxygen

Fe++

3

If oxidized to ferric (Fe+++)

it binds H20

4

what is myoglobins conformation stabilized by

hydrophobic interactions

5

Posterior 93 His (proximal) binds:

Fe++

6

Distal His provides ___ ____ for unfavorable interactions

steric hindrance (CO)

7

What is a heme

4 pyrrole ring structures linked by methene bridges= porphyrin ring

8

When you add specific side groups to a heme its called:

protophorphyrin IX

9

A heme is not considered a heme until you add

Fe++ = heme

10

Where is heme found

oxygen transporter, and storage proteins and cytochromes

11

Myoglobin has ____ alpha helical conformation

75% (8 regions)

12

Myoglobins saturation curve is ____ and is indicative of its function.

hyperbolic; store oxygen until its critically needed

13

Hematopoietic stem cell directed to erythroid lineage by the hormone

erythropoietin

14

Hemoglobin relies on ___ and ___ for energy

glucose and glycolysis

15

Small ___shape allows passage through capillaries

concave

16

Hemoglobin is found in ____ for ____ transport.

RBC's; oxygen

17

Hemoglobin is a tetramer that has 2 ___chains and 2 ___chains. Thus Hb has a quaternary structure and exhibits _____

alpha; beta; cooperativity

18

What are the similarities between Mb and Hb

1. Each has 8 alpha helical regions connected by beta turns.
2. Heme prosthetic group
3. Distal and proximal histidines

19

Hemoglobin is designed to deliver oxygen :

all the time; therefore it has a sigmoidal curve

20

Myoglobin delivers oxygen only when partial pressure of oxygen is:

low; only delivers when need; therefore the curve is hyperbolic

21

What is the embryonic Hb like

zeta and epsilon chains

22

What is fetal Hb like

Adult alpha and fetal Beta like (gamma) are expressed during the 2nd and 3rd trimesters.

23

What is the adult hemoglobin like

2 alpha 2 beta (after 3 months of birth)

24

Hb conformation and oxygen affinity are dependent on 4 environmental variables:

1. pO2
2. pCO2
3. pH
4. 2,3 bisphospho-glycerate concentration

25

What is the Bohr effect

High [H] (low pH), high pC02, and high [2,3 BPG] lower oxygen affinity and shift oxygen saturation curve to the RIGHT --> Enhances delivery of oxygen to metabolically active tissues where C02 and H+ are accumulating

26

High ____ levels such as those in lung capillaries favors oxygen binding and shifts oxygen saturation curve to the ____

pO2 ; left

27

What is CADET, face RIGHT

O2 saturation curve shift to the right and inc O2 delivery in response to increases in:
1. CO2
2. Acid
3. 2, 3 BPG
4. Exercise
5. Temperature

28

Acidic conditions favor ___ ____ between chains to stabilize the deoxy or ___ form of hemoglobin. Oxygenation breaks these bonds, and converts the tetramer to the oxy or relaxed (R) form.

salt bridges; T.

29

___ serves as an acid sensor. Once protonated, it can participate in ionic bonds.

Histidine

30

When heme ____binds oxygen, the ___moves into the plane of the heme group and ulimately causes conformational shifts that break the ionic bonds (salt bridges) and destabilize the ___ form of Hb.

Fe ++; Fe++; deoxy