2- Biochemistry Of Blood Tissue

Question 1

What are the basic functions of blood?

Answer 1

• Respiration
• Alimentation
• Removal of waste
• Buffering
• Osmotic balance
• Body temperature regulation
• Immunologic defense
• Coagulation
• Transport hormones and metabolites

These functions are essential for maintaining homeostasis and supporting life processes.

Question 2

What is the composition of whole blood?

Answer 2

• Plasma: 55%
• Buffy Coat: <1%
• Erythrocytes: 45%

Plasma is the liquid medium of blood, while erythrocytes are red blood cells responsible for oxygen transport.

Question 3

What is the primary component of blood plasma?

Answer 3

92% water

8% Plasma also contains proteins and trace amounts of :
Blood clotting factors, immunoglobins ( antibodies ), lipoprotein particles and electrolytes ( mainly sodium and chloride )

Question 4

What is the normal pH range of blood?

Answer 4

7.35 – 7.45

This pH range is crucial for proper physiological function.

Question 5

What are the main types of plasma proteins?

Answer 5

• Albumin
• α1-globulins
• α2-globulins
• β-globulins
• γ-globulins
• Both solubility and electrophoretic migration rates of globulins are lower
  than albumin.
• These proteins serve various functions including transport, immunity, and maintaining osmotic pressure.

Question 6

What is the function of albumin in blood plasma?

Answer 6

• Transport of fatty acids, bilirubin, steroid hormones, vitamins, and drugs
• Maintenance of oncotic pressure
• Acts as a buffer

Albumin constitutes about 60% of all plasma proteins.

Question 7

True or False: Most plasma proteins are synthesized in the liver.

Answer 7

True

Over 90% of plasma proteins originate from the liver, with some exceptions like immunoglobulins.

Question 8

Fill in the blank: The half-life of albumin in blood is ______.

Answer 8

20 days

This long half-life contributes to albumin’s stability in circulation.

Question 9

What role do α1-globulins play in the body?

Answer 9

• Inhibit proteases
• Act as acute phase reactants
• Transport cortisol and other substances

Examples include alpha-1-antitrypsin and prothrombin.

Question 10

What is the main function of haptoglobin?

Answer 10

Binding of free hemoglobin

Haptoglobin helps to prevent kidney damage by binding free hemoglobin released from red blood cells.

Question 11

What are γ-globulins primarily known for?

Answer 11

Immunoglobulins (antibodies)

They play a crucial role in the immune response by identifying and neutralizing pathogens.

Question 12

What is the significance of ceruloplasmin in blood?

Answer 12

Transport of copper ions

Ceruloplasmin contains six copper atoms per molecule and is important for iron metabolism.

Question 13

What condition is associated with α1-antitrypsin deficiency?

Answer 13

Emphysema and liver disease

This deficiency can lead to unchecked activity of neutrophil elastase, damaging lung tissue.

Question 14

What is the role of transferrin in blood plasma?

Answer 14

Transport of iron ions

Transferrin is crucial for iron homeostasis in the body.

Question 15

What is the primary role of immunoglobulins?

Answer 15

Defense against infections

They identify and neutralize foreign objects like bacteria and viruses.

Question 16

How is protein electrophoresis used in laboratory settings?

Answer 16

To separate proteins in serum and body fluids into component albumin and globulins.

This technique helps in diagnosing various diseases by analyzing protein patterns.

Question 17

What is the function of fibrinogen in blood?

Answer 17

Coagulation factor I

Fibrinogen is converted into fibrin during blood clotting, essential for wound healing.

Question 18

What are the five types of immunoglobulins?

Answer 18

IgG, IgA, IgM, IgD, IgE

Question 19

What is the main antibody in the secondary response?

Answer 19

IgG

Question 20

Which immunoglobulin crosses the placenta?

Answer 20

IgG

Question 21

What is the primary function of secretory IgA?

Answer 21

Prevents attachment of bacteria and viruses to mucous membranes

Question 22

Which immunoglobulin acts as an antigen receptor on B cells?

Answer 22

IgM

Question 23

Which immunoglobulin is involved in allergic responses?

Answer 23

IgE

Question 24

What is the structure of immunoglobulins?

Answer 24

Y-shaped, with two heavy chains and two light chains

Question 25

What are the common light chains found in all immunoglobulin types?

Answer 25

κ (kappa), λ (lambda)

Question 26

What is the role of acute-phase proteins?

Answer 26

Increase or decrease in plasma concentration in response to inflammation

Question 27

Name two positive acute-phase proteins.

Answer 27

* CRP * Haptoglobulin

Question 28

What is the third most abundant body protein?

Answer 28

Hemoglobin

Question 29

What is the composition of hemoglobin?

Answer 29

4 globin chains: 2 alpha and 2 beta

Question 30

How many oxygen molecules can hemoglobin bind?

Answer 30

4

Question 31

What is the significance of cooperative binding in hemoglobin?

Answer 31

Hb’s affinity for O2 increases as its O2 saturation increases

Question 32

What does the oxygen dissociation curve (ODC) illustrate?

Answer 32

How blood carries and releases O2

Question 33

What is the P50 value in relation to hemoglobin?

Answer 33

Partial pressure of O2 at which red blood cells are 50% saturated with O2

Question 34

What effect does an increase in P50 indicate?

Answer 34

Decreased affinity for O2

Question 35

What factors can cause a right shift in the oxygen dissociation curve?

Answer 35

* Increase in PCO2 * Increase in temperature * Decrease in pH * Increase in 2,3-DPG concentration

Question 36

What is the Bohr effect?

Answer 36

Decreased O2 affinity of Hb allowing more O2 release to tissues

Question 37

What is the role of 2,3-bisphosphoglycerate (2,3-BPG)?

Answer 37

Decreases hemoglobin’s oxygen affinity

Question 38

How is CO2 transported in the blood?

Answer 38

* 7-10% dissolved in plasma * 10-15% as carbaminoHb * ~80% as bicarbonate ions (HCO3-)

Question 39

What happens to hemoglobin when it binds CO2?

Answer 39

It stabilizes the T (tense) form, resulting in decreased O2 affinity

Question 40

How do CO2 levels affect the oxygen dissociation curve?

Answer 40

Increase in CO2 causes a right shift; decrease in CO2 causes a left shift

Question 41

What color does carbaminohemoglobin exhibit, and what is its significance?

Answer 41

Distinctive blue color contributing to the appearance of deoxygenated venous blood

Question 42

What is carbaminohemoglobin and its color?

Answer 42

Carbaminohemoglobin has a distinctive blue color that may contribute to the dark red color of deoxygenated venous blood ## Footnote It is compared to the bright, saturated red of oxygenated arterial blood.

Question 43

What is cyanosis?

Answer 43

Cyanosis is high levels of deoxyHb in blood caused by decreased oxygenation of tissues ## Footnote It develops when arterial oxygen saturation drops below 85% or 75%.

Question 44

How does temperature affect the oxygen dissociation curve (ODC)?

Answer 44

An increase in temperature shifts the curve to the right, while a decrease shifts it to the left ## Footnote Increasing temperature denatures the bond between O2 and hemoglobin, increasing O2 release.

Question 45

What is methemoglobin?

Answer 45

Methemoglobin is an abnormal form of hemoglobin where the ferrous (Fe++) form is converted to the ferric (Fe+++) state ## Footnote It causes a left shift in the curve as methemoglobin does not unload O2.

Question 46

How does carbon monoxide affect oxygen transport?

Answer 46

Carbon monoxide interferes with oxygen transport by forming carboxyhemoglobin (COHb) ## Footnote CO has approximately 240 times the affinity for hemoglobin that oxygen has.

Question 47

What is fetal hemoglobin (HbF)?

Answer 47

Fetal hemoglobin is the main oxygen transport protein in the human fetus during the last 7 months of development ## Footnote It has a different composition than adult hemoglobin, allowing for greater affinity for oxygen.

Question 48

How does fetal hemoglobin differ from adult hemoglobin?

Answer 48

Fetal hemoglobin is composed of two alpha and two gamma subunits, while adult hemoglobin consists of two alpha and two beta subunits ## Footnote This results in a left-shifted oxygen dissociation curve for fetal hemoglobin.

Question 49

What is myoglobin (Mb)?

Answer 49

Myoglobin is a globular heme pigment protein found in high concentrations in skeletal and cardiac muscle, functioning as an oxygen storage site ## Footnote It binds one molecule of O2 and has a higher affinity for oxygen than hemoglobin.

Question 50

How does the oxygen dissociation curve (ODC) of myoglobin compare to hemoglobin?

Answer 50

The ODC for myoglobin lies to the left of the hemoglobin curve, indicating that hemoglobin can oxygenate myoglobin ## Footnote Myoglobin's curve has a hyperbolic shape, unlike hemoglobin's sigmoidal shape.

Question 51

What adaptation occurs in Tibetan people for high altitudes?

Answer 51

Tibetan people possess many genes that aid in efficiently utilizing smaller amounts of oxygen ## Footnote This adaptation allows them to supply enough oxygen to their limbs while exercising at high altitudes.

Question 52

What happens to hemoglobin's oxygen affinity at high altitudes?

Answer 52

At high altitude, hemoglobin's O2 affinity increases, allowing for better extraction of O2 from low-pressure areas ## Footnote This results in a left shift in the ODC.

Question 53

What is the general properties of plasma proteins ?

Answer 53

• Most (>90%) synthesized in liver, • y-globulins (immunoglobulins) produced in plasma cells. • Some plasma proteins are synthesized in endothelial (von Willebrand factor) and other cells. • Most plasma proteins (all globulins) are glycoproteins. These proteins have N- and/or O-glycosidic disaccharides. • Albumin and C-reactive protein (CRP) are not glycoproteins.

Question 54

What is the half-life plasma protein ?

Answer 54

Half-lives (t½) of albumin and haptoglobulin are 20 and 5 days, respectively. Blood levels of some plasma proteins (Acute Phase Proteins) rise or decrease in acute inflammatory reactions and certain types of tissue damages.