What role do proteins play in plasma?

What role do proteins play in plasma?

• A. Plasma proteins regulate transcription inside red blood cells.
• B. Proteins like albumin and lipoproteins are essential for maintaining osmotic pressure and transporting substances.
• C. Plasma proteins function solely as immune molecules with no other roles.
• D. Plasma proteins primarily serve as a source of energy for tissues.

Answer: (B)

Proteins in plasma mainly keep fluid balance and move substances around the body. Albumin, the major plasma protein, contributes to colloid (oncotic) pressure, pulling water back into blood vessels and helping maintain blood volume. This prevents excess fluid from leaking into tissues. Proteins also serve as transporters. Albumin binds and carries various substances such as fatty acids, bilirubin, hormones, and some drugs. Lipoproteins are specialized complexes that transport lipids—triglycerides, cholesterol, and fat-soluble vitamins—through the aqueous plasma, enabling lipid distribution and metabolism. There are additional roles as well—clotting factors help blood coagulate, and immunoglobulins provide immune defense—but the primary idea reflected here is that plasma proteins maintain osmotic balance and facilitate transport of vital substances. Transcription doesn’t occur in mature red blood cells, so that particular option isn’t relevant to plasma protein function.

Proteins in plasma mainly keep fluid balance and move substances around the body. Albumin, the major plasma protein, contributes to colloid (oncotic) pressure, pulling water back into blood vessels and helping maintain blood volume. This prevents excess fluid from leaking into tissues.

Proteins also serve as transporters. Albumin binds and carries various substances such as fatty acids, bilirubin, hormones, and some drugs. Lipoproteins are specialized complexes that transport lipids—triglycerides, cholesterol, and fat-soluble vitamins—through the aqueous plasma, enabling lipid distribution and metabolism.

There are additional roles as well—clotting factors help blood coagulate, and immunoglobulins provide immune defense—but the primary idea reflected here is that plasma proteins maintain osmotic balance and facilitate transport of vital substances. Transcription doesn’t occur in mature red blood cells, so that particular option isn’t relevant to plasma protein function.