Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Hematology > Unit 4 - Hgb Synthesis > Flashcards

Unit 4 - Hgb Synthesis Flashcards

1
Q

What is 90% of the dry weight of RBCs?

A

Hemoglobin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is most of internal RBC metabolism geared toward?

A

Maintaining Hgb function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What promotes gas exchange in the capillaries in RBCs?

A

RBC membrane structure and deformability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What kind of protein is hemoglobin?

A

Conjugated protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the molecular weight of hemoglobin

A

~67,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How much of the RBC does hemoglobin occupy?

A

1/3 the mass of the RBC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Moieties means

A

portions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is heme made up of?

A

Iron + porphyrin ring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How many heme per RBC?

A

4 per molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is globin made up of?

A

Protein portion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How many chains of globin in an RBC?

A

4 chains
2 chains of one type
2 chains of another type (a2B2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How much hgb synthesis at pronormoblast stage?

A

Minimal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How much hgb synthesis at normoblast stage?

A

Maximum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What stage of RBC is producing the least amount of hgb synthesis?

A

Pronormoblast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What stage of RBC is producing the most amount of hgb synthesis?

A

Normoblast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens to mRNA production after nucleus is extruded?

A

No new mRNA is produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does the remaining mRNA in a reticulocyte do?

A

Continues hgb synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Hgb from retic synthesis is ___ of total hgb in rbc

A

20-25%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Biochemical pathways for synthesis include

A

Heme portion
Global portion
Assembly of molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Different forms of hemoglobin

A

Normal human hgb types
Variant human hgb due to genetics
Chemically modified hemoglobin variants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Heme is also known as

A

Ferroprotoporphyrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the heme structure

A

Ring structure of 4 pyrrole rings attached together at methylene bridges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the ring structure of heme called

A

Protoporphyrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the 4 rings that join in a heme?

A

Pyrrole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is it that holds the 4 pyrrole rings together in a heme group?
Methylene bridges
26
What is at the center of the protoporphyrn?
Ferrous iron
27
What form of iron cannot bind oxygen?
Ferric iron
28
What is heme considered in biochemical terms
A prosthetic group attached to a protein
29
What are globin chains
Protein chains folded into complex tertiary structure with a pocket to hold heme
30
Normal globin variants are named by what?
Greek letters
31
What kind of structure is hemoglobin?
A tetramer of protein chains, 2 of each type
32
What are the heme moiety
Iron Glycine Succinyl Co-A
33
What are the global moiety
Amino acids
34
When does hemoglobin synthesis occur
Pronormoblast stage through reticulocyte stage
35
Where in the cell is heme produced
Mitochondria Cytoplasm
36
Where in the cell is globin produced
Ribosomes
37
What is the rate limiting step and regulatory point of heme synthesis?
Glycine + succinyl CoA -> Delta ALA
38
What is the first step of heme synthesis?
Glycine + succinyl CoA --> Delta ALA
39
What is the second step of Heme synthesis?
Delta ALA moves into cytoplasm
40
What is the third step of Heme synthesis?
2 Delta ALA condense into pyrrole, porphobilinogen (PBG)
41
4 PBG form what kind of structure?
Linear structure
42
What are the two rings formed after porphobilinogen forms?
Uroporphyrinogen Coproporphyrinogen
43
What happens after the formation of coproporphyrinogen in the cytoplasm?
Coproporphyrinogen returns to the mitochondria
44
What occurs once coproporphyrinogen returns to the mitochondria?
COP undergoes two oxidation steps COP III --> Protoporphyrinogen IX PRO IX --> Protoporphyrin IX
45
What is the final step of heme synthesis in the mitochondria?
Protoporphyrin IX --> Heme by inserting Fe++ Catalyzed by Ferrochelatase
46
Transferrin
Carrier protein in serum
47
How many iron does one transferrin carry?
2 Fe++ to cytoplasmic membrane of developing RBC
48
Once transferrin crosses RBC membrane, what occurs next?
Fe inserted into protoporphyrin IX OR Stored as ferritin or hemosiderin
49
Iron storage forms
Ferritin Hemosiderin
50
What can cause iron deficiency anemia
Heme synthesis stops at protoporphyin Insufficient hgb, small RBC
51
Porphyrias
Congenital defects of heme synthesis enzymes
52
Substrates
Accumulate Prior to defect
53
Products
Insufficient After defect
54
What can cause defects in heme synthesis
Congenital defects/Porphyrias Lead poisoning
55
Accumulated substrates can cause what problems
Photosensitivity Neuropathy Red urine
56
Where does globin synthesis occur
On ribosomes
57
When does globin synthesis occur
Same time as heme synthesis
58
What stimulates globin synthesis
The presence of heme
59
Globin chains in an adult
Alpha Beta Delta Gamma
60
Globin chains in embryo
Zeta Epsilon
61
Each molecule of hemoglobin moiety
4 heme 2 globin chains (one type) 2 globin chains (another type)
62
Normal adul hemoglobin's contain what globin chains
2 alpha 2 of either B, Y, d
63
Normal adults have a mixture of what types of hemoglobin
Hgb A1 Hgb A Hgb F
64
Hgb A1 is composed of
a2 B2
65
What percent of hgb is A1? In an adult
92-95%
66
Hgb A1 subset
Glycosylated Hgb (aka Glycated Hgb)
67
How does Glycosylated/Glycated Hgb appear?
a2B2 + Glucose attached somewhere
68
Where is the glucose attached on Hgb A1c?
N-terminus of the beta chain
69
How long does the glucose remain attached to HgbA1c beta chain?
The rest of the RBCs life Irreversible
70
What is an excellent indicator of long term blood glucose levels
Hgb A1c
71
What percent of total A1 hgb is hgbA1c?
4-6%
72
What is Hgb A2 comprised of?
a2 d2
73
What percent of total hgb in a normal adult is a2d2?
2-3% of total hgb in a normal adult
74
Hgb F composition
a2 Y2
75
What percent of Hgb is HgbF in a normal adult?
1-2%
76
Alpha gene on chromosome 16 -->
Alpha chain of 141 aa
77
Beta gene on chromosome 11 -->
beta chain of 146 aa
78
What can lead to an abnormal hemoglobin?
The substitution of even ONE amino acid
79
Where are embryonic hemoglobins detectable?
Yolk sac and liver
80
When should embryonic hemoglobins be undetectable?
~3 months gestation
81
Gower 1
Z2 e2
82
Gower 2
a2 e2
83
Portland
Z2 Y2
84
Hemoglobin F
a2 Y2
85
What percent of fetal hemoglobin if Hgb F?
90-95%
86
What form of hgb has higher oxygen affinity than A1?
HgbF
87
When does Hgb A1 synthesis begin?
~35 weeks gestation
88
How long does residual Hgb F production remain?
For life
89
When does adult pattern of hemoglobins appear?
1 year of age

Hematology (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions