一、选择题

1. Which of the following is not an example of a type of extracellular matrix?

A. basement membrane

B. the cornea of the eye

C. intermediate filaments

D. bone

2. Which of the following proteins of the ECM has a membrane bilayer-spanning domain?

A. fibrillar collagen

B. heparin sulfate proteoglycans

C. fibronectin

D. laminin

3. Embryos injected with antibodies to fibronectin show inhibited movement of neural crest cells during development of the nervous system. These experiments show that:

A. development of the neural crest involves the expression of antibody genes

B. developing neurons must synthesize fibronectin

C. fibronectin-antibody complexes from pathways for neural migration

D. neurons in embryos must transiently bind to fibronectin during migration

4. Although the protein families that comprise the ECM are very different, they have one of the following characteristics in common:

A. They all have two or more distinct domains with specific binding sites.

B. They are all derived from proteins of the immune system.

C. They all have membrane-spanning domains.