Special Topics

Question 1

Most common method of analyzing plasma proteins

Answer 1

Electrophoresis

Question 2

Plasma Protein Quiz!

1. Binds heme
2. Binds extracorpuscular Hg
3. Binds cortisol
4. Forms a complex with retinol-binding protein and binds T4

Answer 2

1. Hemopexin
2. Haptoglobin
3. Transcortin
4. Tranthyretin

Question 3

The following are examples of acute phase reactants.

Answer 3

1. a1-antitrypsin
2. haptoglobin
3. a1-acid glycoprotein (orosomucoid)
4. fibrinogen
5. C-reactive protein

Question 4

Transcription factor involved in the stimulation of synthesis of acute phase proteins

Answer 4

Nuclear factor kappa B

Question 5

Released by mononuclear phagocytic cells - the PRINCIPAL - stimular of synthesis of acute phase reactants

Answer 5

IL-1

Question 6

Albumin is the major protein of plasma making up ___ of total protein.

Answer 6

60%

Question 7

This protein prevent loss of free hemoglobin into the kidney; conserving Fe present in Hg

Answer 7

Haptoglobin

Question 8

Haptoglobin is decreased in ___ and increased in ___.

Answer 8

Decreased levels in hemolytic anemia. Hemolysis increases free Hg levels (Hg-Hp complex has a short half life of 90 mins vs 5 days for normal halptoglobin.

Increased level seen in chronic inflammatory states (haptoglobin is an acute phase reactant)

Question 9

Site of absorption of Fe

Answer 9

Proximal duodenum

Question 10

Name the proteins important in Fe metabolism.

1. Incoming iron in Fe3+ state is reduced to Fe2+.
2. Carries Fe in serum in the Fe3+ form
3. Downregulates intestinal absorption and release of iron from macrophages
4. Transports iron across the apical surface
5. Transports iron across the basolateral surface
6. Converts Fe2+ back to Fe3+ at the basolateral surface
7. Protein which stores Fe in cells

Answer 10

1. Ferrireductase
2. Transferrin
3. Hepcidin
4. Divalent metal transporter 1
5. Ferroportin
6. Hephaestin
7. Ferritin

Question 11

If Fe levels are sufficient, levels of this protein increase to prevent further absorption of Fe.

Answer 11

Hepcidin

Question 12

Major component of the a1 fraction of human plasma

Answer 12

a1-antitrypsin (a1-antiproteinase)

Question 13

A1-antitrypsin is an example of a ___

Answer 13

Serine protease inhibitor

Question 14

Group of small proteins in the cytosol of liver, kidney, and intestine; with a high content of cysteine and bind Cu, Zn, Cd and Hg

Answer 14

Metallothioneins

Question 15

This plasma protein is synthesized by monocytes, hepatocytes, and astrocytes, inhibits many proteinases and directs many cytokines towards tissues or cells.

Answer 15

a2-macroglobulin

Question 16

Amyloidosis quiz.

1. Increased in multiple myeloma
2. Increased in patients on chronic dialysis
3. Mutant forms exist in familal amyloidotic neuropathies
4. Alzheimer’s disease

Answer 16

1. Ig light chain
2. B2-microglobulin
3. Transthyretin
4. Amyloid B protein

Question 17

Cleavage of immunoglobulin with ___ produces two antigen-binding fragments and one crystallizable fragment

Answer 17

Papain

Question 18

Immunoglobulin Quiz!

1. Lowest concentration in plasma
2. Exists as dimer and may contain a J chain
3. The antigen receptor on B cell
4. Opsonization
5. Complement fixation

Answer 18

1. IgE
2. IgM or IgA
3. IgM
4. IgG
5. IgG or IgM

Question 19

Which two monosaccharides are ACTIVELY transported across the small intestine?

Answer 19

Glucose
Galactose

Secondary active transport (via SGLT1)

Question 20

The major lipids in the diet

Answer 20

Triacylglycerol

Question 21

How does one differentiate lingual/gastric lipases from pancreatic lipases as to its action on TAGs?

Answer 21

Lingual/gastric lipases act on the sn-3 ester bond, forming 1,2-DAGs and free fatty acids.

Pancreatic lipase is specific for the ester links in positions 1 and 3 forming 2-MAG.

Question 22

What is the monoacylglycerol pathway?

Answer 22

In the intestinal cells,

MAGs are hydrolyzes into glycerol and FFA
DAGs are re-acylated to TAGs

Question 23

How are long-chain FAs different from medium-chain/short-chain FAs different in terms of its absorption?

Answer 23

Long chain FAs packaged into chylomicrons which enter lymphatics and thoracic duct.

Medium/short chain FA exist as FFAs and pass into the hepatic portal vein.

Question 24

How are proteolytic enzymes which are secreted as zymogens activated?

Answer 24

Enteropeptidase is secreted by duodenal epithelial cells to activate trypsinogen.
Trypsin activates chymotrypsinogen, proelastase, procarboxypeptidase and aminopeptidase.

Question 25

How is Vitamin D able to increase Ca absorption

Answer 25

It increases synthesis of the intracellular calcium binding protein CALBINDIN.

Question 26

This compound in cereal and unleavened whole-wheat products chelate Ca and Zn causing deficiency.

Answer 26

Phytic acid Phytase in yeast renders it inactive

Question 27

How can fat malabsorption cause Ca deficiency?

Answer 27

Fat in the intestinal lumen form insoluble Ca salts.

Question 28

You know that Vitamin C increases absorption of Fe. How?

Answer 28

Vitamin C is a reducing agent, reduces Fe3+ to Fe2+, which is the form absorbed by the enterocyte.

Question 29

What is the effect of the following on Fe absorption? 1. Alcohol 2. Ca 3. Fructose

Answer 29

1. Increase 2. Decrease 3. Increase

Question 30

Energy expenditure per L of O2 consumed

Answer 30

20 kJ

Question 31

Differentiate cachexia from marasmus.

Answer 31

In marasmus, protein synthesis is reduced but catabolism is unaffected. In cachexia, protein catabolism is increased.

Question 32

Discuss three metabolic changes in cachexia.

Answer 32

1. Tumor releases lactate, which is recycled into glucose (consumes 6ATP/glucose recycled) 2. Stimulation of uncoupling proteins, leading to thermogenesis and oxidation of fuels 3. Futile cycling of lipids (hormone sensitive lipase activated; FFAs produced are re-esterified at ATP cost).

Question 33

Very commonly, a ___ precipitates Kwashiorkor.

Answer 33

Infection

Question 34

Nutritional studies show that the average daily requirement for N is ___.

Answer 34

0.6 g/kg body weight

Question 35

2 amino acids are synthesized in the body but only from essential amino acids.

Answer 35

Cysteine (from Methionine) | Tyrosine (from Phenylalanine)

Question 36

Most frequent post-translational modification of proteins

Answer 36

Glycosylation (>50% have CHO moieties attached)

Question 37

Mucin contains repeating amino acid sequences rich in:

Answer 37

Serine Threonine Proline Mucins exhibit high content of O-glycan chains

Question 38

What is the major class of glycoproteins? It is characterized by ___.

Answer 38

N-linked glycoproteins Asn-GlcNAc linkage (Other classes are O-linked glycoproteins and GPI-linked)

Question 39

Common pentasaccharide found in N-linked glycoproteins

Answer 39

Man3 GlcNAc2

Question 40

The formation of N-linked oligosaccharides is unique because it involves

Answer 40

Dolichol-P-P-oligosaccharide

Question 41

Addition of this molecule causes enzymes to be marked for lysosomes. This is synthesized by which enzyme, deficient in which condition.

Answer 41

GlcNAc-1-P GlcNAc phosphotransferase I-Cell disease

Question 42

Thick transparent, non-cellular envelope surrounding the oocyte

Answer 42

Zona pellucida

Question 43

This O-linked glycoprotein functions as a receptor for the sperm

Answer 43

ZP3. Interacts with galactosyl transferase on sperm; when activated, sperm releases proteases and hyaluronidase (acrosomal reaction)

Question 44

What is the test used to diagnose PNH?

Answer 44

Ham's Test. Red cells much more sensitive to hemolysis in normal serum acidified to pH of 6.2

Question 45

Explain the glycoprotein abnormality in RA.

Answer 45

Alteration in glycosylation of circulating Ig; lacking glactose in Fc and terminating in GlcNAc. Mannose-binding protein binds agalactosyl IgG and activates complement system contributing to chronic inflammation in joints.

Question 46

Binds mannose, GlcNAc and other sugars in bacteria, fungi and viruses marking them for opsonization and destruction by complement.

Answer 46

Mannose binding protein

Question 47

Influenza A binds to cell surface receptor molecules containing ___ via ___. Another enzyme allows it to elute newly synthesized progeny from host cells.

Answer 47

NeuAc via hemagglutinin | Neuraminidase

Question 48

HIV-1 uses two glycoproteins. 1. Attach to cell 2. Fuse with host membrane

Answer 48

1. gp120 | 2. gp41 (Fourty-one Fuses)

Question 49

Helicobacter pylori attaches to two glycans on the epithelial cells.

Answer 49

Adhesin in the tail of H pylori interact with: Neuraminyl-galactose Lewis-B substance

Question 50

___ of chilled platelets has been found to prevent clustering thereby prolonging its life.

Answer 50

Enzymic galactosylation

Question 51

Major cross-links that form in elastin

Answer 51

Desmosine | Condensation of 3 Lys-derived aldehydes with an unmodified lysine

Question 52

This glycoprotein is secreted into the ECM by fibroblasts and incorporated into structures that serve as scaffold for deposition of elastin.

Answer 52

Fibrillin Zonular fiber = ectopia lentis Periosteum = tall, arachnodactyly Aorta = aortic aneurysm

Question 53

A major glycoprotein of ECM with domains than binds heparin, fibrin, collagen, DNA and cell surfaces.

Answer 53

Fibronectin

Question 54

Fibronectin contains an ___ sequence that binds to the receptor.

Answer 54

RGD | Arginine - Glycine - Aspartic acid

Question 55

The basement membrane in the nephron has three protein components and 2 GAGs

Answer 55

Proteins 1. Type 4 collagen 2. Laminin 3. Entactin GAG 1. Heparin 2. Heparan sulfate

Question 56

Proteoglycans 1. Major proteoglycan in cartilage 2. Bind growth factors (TGF-B

Answer 56

1. Aggrecan | 2. Decorin

Question 57

Describe the structure of aggrecan.

Answer 57

Bottle-brush-like. The main stem is hyaluronic acid. Sticking out of it are core proteins. Attached to core proteins are: 1. Chondroitin sulfate 2. Keratan sulfate

Question 58

All GAGs contain GlcNAc as its aminosugar except these two which has GalN. Only these two GAGs have iduronic acid as its glucoronic acid. A

Answer 58

Remember two TV stars named David. GalN: Dermatan sulfate, Chondroitin sulfate (Goofy, David Caruso!) Iduronic acid: Dermatan sulfate, heparin (Idiot, David Hasselhoff! Dahil kulay dilaw, may hepa rin!)

Question 59

GAG Quiz! ``` A. Most abundant B. Intracellular C. Ubiquitous cell surface GAG D. Most heterogenous E. NOT sulfated, NOT attached to protein F. Also found in bacteria ```

Answer 59

``` A. Chondroitin sulfate (in cartilage, tendon, ligaments, bone) B. Heparin (mast cells) C. Heparan sulfate D. Keratan sulfate E. Hyaluronic acid F. Hyaluronic acid ```

Question 60

GAG Quiz 1. GalNAc, GlcUA 2. GalNAc, IdUA 3. GlcN, GlcUA

Answer 60

1. Chondroitin sulfate 2. Dermatan sulfate 3. Heparan sulfate

Question 61

GAG Quiz 4. GlcNAc, Gal 5. GlcN, IdUA 6. GlcNAc, GlcUA

Answer 61

4. Keratan sulfate 5. Heparin 6. Hyaluronic acid

Question 62

Compressibility of cartilage is due to high concentrations of these two proteoglycans

Answer 62

1. Chondroitin sulfate | 2. Hyaluronic acid

Question 63

GAG found in bone, cartilage and certain neurons

Answer 63

Chondroitin sulfate

Question 64

GAG which play a role in corneal transparency

Answer 64

Keratin sulfate Dermatan sulfate Cornea? Klaro dapat.

Question 65

This GAG bind to lipoprotein lipase and cause its release into the circulation.

Answer 65

Heparin

Question 66

This GAG facilitate cell migration

Answer 66

Hyaluronic acid

Question 67

Certain cancers induce fibroblasts to synthesize large amounts of this GAG

Answer 67

Hyaluronic acid

Question 68

Major GAG synthesized by arterial smooth muscle cells

Answer 68

Dermatan sulfate

Question 69

Structure of hydroxyapatite

Answer 69

Ca10 (PO4)6 (OH)2

Question 70

Major protein in bone

Answer 70

Type I collagen