1.11 Proteins are essential

Question 1

Main point

Answer 1

Proteins are essential to cell structure and function

Question 2

Proteins in the cell membrane:

Transmembrane proteins

Answer 2

These span the membrane
they are usually hydrophilic on either side with a hydrophobic section in the middle

Question 3

Proteins in the cell membrane:

Peripheral proteins

Answer 3

These are on the surface of the membrane
surface protein example: marker protein

Question 4

Marker proteins

Answer 4

are like nametags that identify the cell to other cells

each organism has its own unique marker proteins on its membrane

enables a persons immune system to distinguish its cells from those of invading cells

Question 5

Transport proteins

Answer 5

are responsible for shipping and receiving materials in and out of the cell.

Some of them function as pores that allow substances to diffuse through the membrane

others act as pumps that use energy to pull molecules across the membrane, a process called active transport

Question 6

Carrier protein

Answer 6

selectively interacts with a specific molecule or ion so that it can cross the plasma membrane

the inability of some persons to use energy for sodium potassium transport has been suggested as the cause of their obesity

Question 7

Channel protein

Answer 7

Allows a particular molecule or ion to cross the plasma membrane freely.

Cystic fibrosis, an inherited disorder is caused by a faulty chloride channel a thick mucus collects in airways and in pancreatic and liver ducts.