Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCP > Unit 6 > Flashcards

Unit 6 Flashcards

1
Q

(hemo/myo) globin: intracellular oxygen transport and storage protein

A

myoglobin

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

(hemo/myo) globin: predominant oxygen carrier in the circulatory system

A

hemoglobin

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

what is the significance of cyt. oxidase’s low Km for oxygen?

A

high affinity for oxygen so ox phos doesn’t have to slow down until there are very low concentrations of oxygen

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

myoglobin: (8 beta sheets/8 alpha helices) with one heme which binds oxygen

A

alpha helices

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

(ApoHb/HoloHb): the protein without prosthetic groups

A

ApoHb

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

ApoHb + 4 hemes

A

HoloHb (hemoglobin)

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

number of atoms of oxygen that can bind to an Hb tetramer

A

8 (because O2 has two oxygen atoms)

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

(R state/T state) favors oxygen binding

A

R state

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

(R state/T state) favors oxygen release

A

T state

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

basis for cooperativity resulting in the sigmoid binding curve for hemoglobin

A

R state–oxygen binding in one site increases the affinity of the other sites

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

(proximal/distal) histidine coordinates Fe in hemaglobin

A

proximal

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

(proximal/distal) histidine H bonds to O2 in hemaglobin

A

distal

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

dark red: (deoxy/oxy) Hb

A

deoxy

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

scarlet red: (deoxy/oxy) Hb

A

oxy

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

diagnostic value of oxy vs deoxy light absorption

A

cyanosis (blue when not oxygenated enough)

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

pulse oximeter measures (venous/arterial) Hb oxygenation

A

arterial

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

pulse oximeter result that is cause for alarm

A

below 90% (95-100 is normal)

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

how does the pulse oximeter measure % oxygenation

A

uses ratio of oxy:deoxy, based on absorption spectra

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

the pressure at which binding is half-maximal, or the pressure value at which 50% of the maximal oxygen load has been released

A

P50

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

(myo/hemo) globin: hyperbolic curve

A

myoglobin

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

Mb binds O2 under conditions in which Hb releases it, due to Hb’s ______ shaped curve

A

sigmoid (sophisticated O2 transport system)

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

(allostery/cooperativity): effect in which what is happening at promotes the same thing happening at another identical site

A

cooperativity (allostery involves “other” active sites and is more broad)

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

negative effectors shift the Hb curve to the (R/L)

A

right, stabilize T state

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

BPG stabilizes the _ state of Hb

A

T state, shifts curve right (binding site for BPG only exists in T state)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

people in high altitudes have (higher/lower) levels of BPG to promote increased oxygen unloading and delivery to tissues

A

increased levels of BPG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

low pH, high [H+], (raises/lowers) affinity for O2

A

lowers affinity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

lungs: (higher/lower) pH to load more O2

A

higher pH (CO2 is low due to exchange with inhaled air)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

muscles: (higher/lower) pH to unload more O2

A

lower pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

high CO2 (raises/lowers) pH, which (raises/lowers) affinity for O2

A

lowers pH, lowers affinity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

carbamylation stabilizes the _ state of Hb

A

T state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

_ and _ synergize to unload O2 in the capillary where O2 is needed

A

H+ and CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

HbF does not bind BPG as well so O2 affinity is (lower/higher) and curve shifts (R/L)

A

affinity is higher, curve shifts left

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

individuals with a Glu -> Val substitution on the beta chain suffer from:

A

sickle cell anemia–creates a hydrophobic pocket resulting in aggregates)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

HbBARTS: (adults/fetus) thalassemia

A

fetus–gamma tetramer forms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

HbH: (adults/fetus) thalassemia

A

adults–insufficiency of alpha chains so beta tetramer forms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

hemoglobin in which the heme iron has been oxidized the ferric state

A

methemoglobin (does not bind oxygen, leads to cyanosis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

______ (Hemoglobinopathy): can be caused by mutations in Hb that stabilize the oxidized form, defect in enzyme CYB5R that normally reduces it back to Hgb, chemical agents such as sodium nitrite

A

methemoglobinemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what test is used to detect abnormal Hb

A

non denaturing (native) gel electrophoresis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

heme possesses a ____ ring, which is constructed from four pyrrole rings

A

porphyrin ring–they form metal chelates with metal ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

order of eight side chains in the protoporphyrin:

A

MVMVMPPM (methyl, vinyl, propionate)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

the isomer of protoporphyrin in heme:

A

protoporphyrin IX

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

heme (a/b/c): modification of the number 2 vinyl group

A

a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

heme (a/b/c): no modifications from MVMVMPPM

A

b

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

heme (a/b/b): covalently bound to Cys residues of proteins through the two vinyl groups

A

c

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

two precursors of heme

A

glycine and succinyl CoA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

at which step of the heme synthesis pathway is it regulated?

A

first step (glycine and succinyl CoA -> ALA), main target of control is ALA synthase enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

accumulation of which intermediate in heme synthesis causes symptoms of lead poisoning?

A

ALA (lead inhibits the enzyme ALA dehydrase by replacing the Zn cofactor so ALA builds up)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

two enzymes in heme synthesis that are inhibited by lead

A

ALA dehydrase, ferrochelatase (second and last steps in the pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

two sites of heme biosynthesis

A

liver (use as prosthetic group for cytochrome P450) and erythroid cells (use heme for hemoglobin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

(liver/erythroid) cells: synthesize heme at one time in their life and in vast quantities

A

erythroid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

(liver/erythroid) cells: heme is required in varying amounts throughout the cell’s lifetime, synthesis is tightly controlled

A

liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

ALA synthase step in heme synthesis is feedback-inhibited by: (four pathways)

A

1-repression of mRNA synthesis
2-inhibition of translation of the ALA synthase mRNA
3-inhibition of import of the ALA synthase protein into mitochondria
4-direct inhibition of enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

genetic deficiencies in heme metabolism, enzymes are partially defective

A

porphyrias

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

(hepatic/erythropoietic) porphyria: come as attacks that are induced by something

A

hepatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

(hepatic/erythropoietic) porphyria: chronic condition

A

erythropoietic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

(hepatic/erythropoietic) porphyria: hallmarks are sensitivity to sun and anemia

A

erythropoietic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

(congenital erythropoietic porphyria/protoporphyria): partial deficiency in ferrochelatase, autosomal dominant

A

protoporphyria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

(congenital erythropoietic porphyria/protoporphyria): deficiency in uroporphyrinogen III co-synthase, autosomal recessive

A

congenital erythropoietic porphyria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

steroid therapy, alcohol, estrogens, barbituates: cause build up of which intermediate in the heme synthesis pathway

A

ALA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

(acute intermittent porphyria/porphyria cutanea tarda): deficiency in uroporphyriogen decarboxylase, sporadic or autosomal dom, precipitated by alcohol or use of contraceptive pill

A

porphyria cutanea tarda–asymptomatic until liver disorder is imposed, then photosensitivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

(acute intermittent porphyria/porphyria cutanea tarda): most common porphyria, partial deficiency of PBG deaminase, causes accumulation of ALA and porphobilinogen

A

acute intermittent porphyria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

lifespan of RBC

A

120 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

where does removal of aging RBCs occur

A

spleen (reticular endothelial cells)

64
Q

what is the role of haptoglobin, hemepexin, and transferrin

A

haptoglobin binds methemoglobin dimers and hemepexin binds free heme. Transferrin binds free iron. All to prevent loss of iron via kidney

65
Q

product in first step of heme degradation (and color)

A

biliverdin-green

66
Q

enzyme in first step of heme degradation

A

heme oxygenase

67
Q

location in first step of heme degradation

A

spleen, endoplasmic reticulum

68
Q

product in second step of heme degradation (and color)

A

bilirubin (yellow)

69
Q

enzyme in second step of heme degradation

A

biliverdin reductase (uses NADPH for reduction)

70
Q

location in second step of heme degradation

A

spleen (reticular endothelial cells)

71
Q

health benefit of bilirubin

A

antioxidant–binds free radicals in serum

72
Q

location of third step of heme degradation

73
Q

purpose of third step of heme degradation

A

conjugate with two sugars to make it water soluble

74
Q

Crigler-Najjar syndrome is due to a deficiency in what enzyme? results in severe jaundice

A

UDP-glucuronyl transferase (conjugation of bilirubin)

75
Q

neonatal jaundice is a temporary condition due to the production of insufficient levels of what enzyme

A

UDP-glucuronyl transferase (conjugation of bilirubin)

76
Q

therapy for neonatal jaundice

A

phototherapy–irradiation with fluorescent lights

77
Q

conjugated bilirubin passes from the liver into the bile _____ to the gall bladder to the intestinal tract

A

canaliculi

78
Q

intestinal bacteria convert conjugated bilirubin to a series of ______

A

urobilinogens

79
Q

urobilinogens are colorless, but oxidation leads to the formation of urobilin, which colors:

A

urine and feces

80
Q

bilirubin binds to ___ (protein) to be transported from the blood to the liver to be conjugated

81
Q

two possible causes of blockage of bile duct

A

pancreatic cancer, gall stones

82
Q

observable symptom of blockage of bile duct

A

relatively colorless feces, urine

83
Q

example of (prehepatic/hepatic/posthepatic) jaundice: sickle cell anemia, Rh incompatibility with mother

A

prehepatic

84
Q

example of (prehepatic/hepatic/posthepatic) jaundice: prevents uptake and conjugation of bilirubin

85
Q

(prehepatic/hepatic/posthepatic) jaundice: build up of unconjugated bilirubin in blood

A

prehepatic

86
Q

(prehepatic/hepatic/posthepatic) jaundice: build up of conjugated bilirubin

87
Q

accumulation of bilirbuin where it doesn’t belong

88
Q

two molecules for iron storage

A

ferritin and hemosiderin

89
Q

hemosiderin is a degraded form of ____

90
Q

an increase in iron entering tissues results in (an increase/a decrease) in ferritin content

91
Q

where are the body’s iron reserves

A

liver, bone marrow, skeletal muscles, spleen

92
Q

where is iron used to make new RBCs

A

erythroid marrow

93
Q

where are RBCs broken down and iron is released

A

reticulo endothelial cells in the spleen

94
Q

which protein moves the iron from the spleen to the bone marrow

A

transferrin

95
Q

how does transferrin act as an antimicrobial

A

binds free iron to prevent bacteria from using it as food

96
Q

ferro-transferrin binds a receptor on the cell membrane at pH _

97
Q

what happens to ferro-transferrin inside the clathrin coated pits when the pH drops to 5

A

iron dissociates from the transferrin

98
Q

transferrin cannot bind receptor in pH _ if iron is not bound, but it can bind its receptor without iron bound in pH _

A

cannot bind receptor in pH 7 without iron

can bind receptor in pH 5 without iron

99
Q

primary cause of polymerization of HbS

A

deoxygenation

100
Q

fever, acidosis, and dehydration (increase/decrease) rate and amount of sickling

101
Q

polymerization of HbS causes (increased/decreased) RBC destruction

A

increased, and anemia

102
Q

what causes pain during sickle cell dz

A

blockage of capillaries (can also cause organ dysfunction)

103
Q

current childhood death rate for SC dz versus historical

A

3% versus 30%

104
Q

severity of SC dz (is/is not) predictable based on type

A

not predictable–great variation

105
Q

why are infants protected from effects of SC dz

A

HbF for first four months of life (no beta chains)

106
Q

when did newborn screening for SC dz become universal in the US

A

last decade (started in 1970 but not universal)

107
Q

three benefits of newborn screening for SC dz

A

diagnosis, education, prophylactic antibiotics piror to risk of sepsis (primary benefit: start penicillin and recognize fever as first sign of sepsis)

108
Q

what test is used for newborn screening

A

heel prick > gel electrophoresis (HbS vs HbC vs HbA)

109
Q

HbC and HbS are distinct mutations of the _th amino acid on the beta chain of Hb

110
Q

(sickle cell trait/homozygous sickle cell anemia) is a carrier state, clinical complications very rare, genetic implications

111
Q

(sickle cell trait/homozygous sickle cell anemia) 2/3 of patients, most severe

112
Q

variant of SC disease: one parent AS and one AC, milder disease, C does not sickle but increases viscosity

A

hemoglobin SC disease

113
Q

variant of SC disease: HbS from sickle gene, little or no HbA, can be very severe

A

sickle beta thalassemia–ineffective beta thalassemia gene

114
Q

most deaths from bacterial sepsis due to sickle cell within first _ hours of symptoms

115
Q

severe complication of sepsis due to SC dz that results in skin necrosis and can result in the loss of digits and severe tissue loss

A

pupura fulminas

116
Q

vaso occlusive episodes in SC dz cause:

A

excruciating pain, must be treated with a lot of morphine, transfusion usually not helpful

117
Q

presentation of vaso occlusive episode for SC dz in first two years of life

A

hand foot syndrome–swelling

118
Q

in children with SC dz, strokes are caused by (hemorrhage/thrombosis)

A

thrombosis (hemorrhagic strokes in adults)

119
Q

acute chest syndrome refers to

A

sickle cell disease–diffuse and bilateral loss of airspace, resp failure

120
Q

how to avoid death from acute splenic sequestration crisis in SC patients

A

teach patients/parents to palpate for spleen

121
Q

if parents are considering termination in genetic counseling for SC dz, what test can you offer

A

prenatal diagnosis via amniocentesis

122
Q

why would you want to harvest placental blood from newborn sibling of a child with SC dz

A

safest possible transplant

123
Q

first therapy which can effectively reduce incidence of SC dz complications

A

hydroxyurea (mild chemotherapeutic agent)

124
Q

only available cure for SC dz

A

bone marrow transplant

125
Q

candidates for bone marrow transplant for SC dz

A

severe acute chest syndrome, frequent pain episodes

126
Q

future goal of treatment for SC dz

A

viral vector to insert normal beta chain via benign viral illness without immunosuppression of transplant

127
Q

on which chromosome is the SC dz mutation

A

11 (A>T Glu>Val conversion, beta chain)

128
Q

(reversibly/irreversibly) sickle cells constitute 2-40% of circulating RBCs in homozygous SC anemia

A

irreversibly (stay that way even when well oxygenated, results in hemolysis and vasoocclusion)

129
Q

three steps to vasoocclusion in SC dz

A

1-endothelial activation
2-WBC adhesion (extra adhesive in SC pt)
3-RBC/WBC interactions

130
Q

survival probability is (higher/lower) in SC patients with 3 or more episodes per year

131
Q

three places where erythropoiesis occurs throughout life

A

yolk sac, fetal liver, bone marrow

132
Q

C-MYB is a hematopoeitic txn factor which (stimulates/represses) the production of gamma globin

133
Q

BCL11A on chromosome 2 is a txn (stimulator/repressor) and gamma globin (enhancer/silencer)

A

repressor, silencer

134
Q

role of BCL11A and MYB

A

switch from gamma to beta globin

135
Q

(alpha/beta) chain coded on chromosome 16

A

alpha (beta on 11)

136
Q

high presence of HbF (increases/reduces) severity of SC

137
Q

how does SC dz increase reactive oxygen species (ROS) in the blood

A

vasoocclusion causes ischemia so xanthine oxidase is produced. xanthine oxidase converts O2 to superoxide when tissue is reperfused

138
Q

what does NFkB activation lead to

A

inflammation (increase expression of cytokines)

139
Q

NFkB activation >increased expression of adhesion molecules on surface of endothelial cells and leukocytes > causes what?

A

heterotypic adhesion between cells > vasoocclusion

140
Q

NFkB activation > (increased/decreased) NO availability (causes what)

A

decreased NO results in abnormal endothelial dependent vasodilation

141
Q

Sickle cells have (increased/reduced) glutathione

A

reduced&raquo_space;would protect against ROS damage

142
Q

glutathione levels are (inversely proportional/proportional) to density of sickle cells

A

inversely. so when glutathione levels drop, sickling increases

143
Q

peroxide levels are (decreased/increased) in SC dz

144
Q

to maintain phospholipid asymmetry in plasma membrane, flippases must be (more/less) active than scramblases

A

more (when phosphoserine gets to the outside of cell it can bind clotting factors or as a recognition site for macrophages)

145
Q

phosphoserine on the external plasma membrane (increases/decreases) the life of a sickle cell

A

decreases–attracts macrophages

146
Q

which proteins connect spectrin and actin on the RBC membrane skeleton

A

protein 4.1 and adducin

147
Q

oxidative stress causes the RBC membrane skeleton to:

A

become locked in place
1-actin can never depolymerize (S-S bridge from cysteines)
2-spectrin-4.1-actin is tightly associated

148
Q

oxidative stress (increases/reduces) alpha-spectrin ubiquitination in the RBC membrane skeleton

149
Q

sickling (inhibits/activates) a cation leak channel, resulting in a (gain/loss) of intracellular Ca

A

activates leak channel, intraceullar Ca increases

150
Q

the sickling induced cation leak channel causes a (gain/loss) in intracellular K and Mg

151
Q

Gardos channel for (K/Ca) ion, stimulated by (K/Ca) ion

A

for K, stimulated by Ca

152
Q

sickling induced cation leak channel results in a net ion movement (into/out of) cell, and water movement (into/out of) cell

A

out of, cell dehydrates

153
Q

NAC antioxidant treatment (lowers/raises) glutathione levels in SC dz

A

raises glutathione levels

154
Q

NAC antioxidant treatment (lowers/raises) K efflux in SC dz

A

lowers K efflux (reduces cell dehydration)

155
Q

NAC antioxidant treatment (lowers/raises) incidence of the beta-actin disulfide bridge in SC dz

A

lowers (so cells are not locked in sickle state)

156
Q

how does hemolysis in SC dz affect NO

A

Hb released in plasma binds free NO and reduces the amount of NO available for vasodilation

MCP (4 decks)

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