Biology(blood)

What are the two major components of blood?

Plasma (~55%) and formed elements (~45%).

What are the formed elements?

Red blood cells, white blood cells, and platelets.

Three major functions of blood.

• Transport

• Protection

• Regulation

What percentage of plasma is water?

About 90%.

Difference between plasma and serum.

Plasma contains clotting factors (including fibrinogen); serum does not.

Most abundant plasma protein?

Albumin

Main function of albumin?

Maintains osmotic pressure and transports substances.

Function of globulins?

Transport and immune defense (immunoglobulins).

Function of fibrinogen?

Blood clotting

Function of red blood cells.

Transport oxygen.

Why are red blood cells biconcave?

Increased surface area and shorter diffusion distance.

Why do mature red blood cells lack nuclei?

To provide more space for hemoglobin.

Why do red blood cells lack mitochondria?

So they do not consume the oxygen they transport.

Lifespan of a red blood cell

About 120 days.

Which organ removes old red blood cells?

The spleen.

Function of hemoglobin.

Binds and transports oxygen.

How many oxygen molecules can one hemoglobin molecule carry?

Four

Which ion is found in each heme group?

Iron (Fe²⁺).

How is most oxygen transported?

Bound to hemoglobin.

How is most carbon dioxide transported?

As bicarbonate ions (HCO₃⁻).

Function of white blood cells.

Defend the body against pathogens.

Which white blood cells perform phagocytosis?

Neutrophils and macrophages.

Function of B lymphocytes.

Produce antibodies and memory cells.

Function of T lymphocytes.

Coordinate immune responses and destroy infected cells.

What is an antigen?

A molecule that triggers an immune response.

What is an antibody?

A protein that specifically binds an antigen.

Which cells produce antibodies?

Plasma cells.

Why are memory cells important?

They enable a faster and stronger secondary immune response.

Difference between innate and adaptive immunity.

• Innate: immediate, non-specific.

• Adaptive: specific, has memory.

Give three innate defenses.

• Skin

• Stomach acid

• Phagocytosis

Why do vaccines work?

They stimulate memory cell formation.

What are platelets?

Cell fragments involved in clotting.

First step in blood clotting.

Platelets adhere to the damaged vessel.

Fibrinogen vs fibrin.

• Fibrinogen: soluble plasma protein.

• Fibrin: insoluble fibres forming the clot.

Function of fibrin.

Forms a mesh that traps blood cells to create a clot.

Why do mature red blood cells rely on glycolysis?

They lack mitochondria and therefore cannot perform aerobic respiration.

Which blood component is not a complete cell?

Platelets

Which plasma protein maintains osmotic pressure?

Albumin

Which cells leave blood vessels to fight infection?

White blood cells