Prions and Protein Structure Concepts

Dr. Mahmoud's lecture continues the discussion on protein classification, focusing on the structural and functional differences between fibrous and globular proteins. Fibrous proteins, like collagen and keratin, play structural roles, while globular proteins, such as hemoglobin, are functional. The lecture also covers the importance of amino acid sequences in protein function, highlighting sickle cell disease as an example. Additionally, prions and their association with brain disorders like kuru and mad cow disease are discussed. The lecture concludes with a preview of the next topic: nucleic acids.

What is the main structural difference between fibrous and globular proteins?

• Fibrous proteins are sensitive to temperature changes, while globular proteins are not.

• Fibrous proteins have a spherical shape, while globular proteins are elongated.

• Fibrous proteins are soluble in water, while globular proteins are not.

• Fibrous proteins have no specific arrangement of polar and nonpolar groups, while globular proteins do.

Which of the following is a characteristic of fibrous proteins?

• They are soluble in water.

• They play a structural role in the body.

• They are highly sensitive to pH changes.

• They have a spherical shape.

Which protein is an example of a fibrous protein?

• Myoglobin

• Collagen

• Hemoglobin

• Insulin

What role do globular proteins primarily play in the body?

• Structural

• Transport

• Insulation

• Energy storage

Which of the following is true about globular proteins?

• They are insoluble in water.

• They have a long, narrow shape.

• They are highly sensitive to temperature and pH changes.

• They are primarily involved in structural functions.

What determines the primary structure of a protein?

• The protein's solubility

• The sequence of amino acids

• The shape of the protein

• The protein's function

How can a single amino acid substitution affect a protein?

• It can increase the protein's stability.

• It can make the protein more soluble.

• It can cause the protein to fold differently, altering its function.

• It can enhance the protein's function.

What are prions?

• Normal proteins that help in digestion

• Misfolded proteins associated with brain disorders

• Proteins that transport oxygen in the blood

• Proteins that provide structural support

Which disease is associated with prions?

• Osteoporosis

• Sickle cell disease

• Diabetes

• Kuru

How are prions transmitted in the case of Kuru?

• Through insect bites

• Through water

• Through air

• Through cannibalistic ingestion of an infected brain