MTC week4

Question 1

Aquaporins are found in which 3 kinds of cells?

How many alpha-helices are arranged to make an aquaporin channel protein?

Answer 1

Aquaporins are found in:
plant, red blood cells, and kidney cells

6: alpha-helices are arranged to make an aquaporin channel protein.

Question 2

how many Glucose and Na+ are brought into the cell via the Na+/glucose symporter?

how many transmembrane helices form the symporter

Answer 2

how many Glucose and Na+ are brought into the cell via the Na+/glucose symporter: 1 glucose + 2 Na+ ions

how many transmembrane helices form the symporter: 14

Question 3

the Na+/Ca2+ antiporter is found where?

it pumps Na+ (in/out) and Ca2+ (in/out)?

Does this reduce or increase strength of muscle contraction?

Answer 3

The Na+/Ca2+ antiporter is found where: cardiac muscle cell

It pumps Na+ in and Ca2+ out

This reduces strength of muscle contraction.

Question 4

Integrin proteins maintain cell structure via its interaction with the__________.

Answer 4

Integrin proteins maintain cell structure via its interaction with the ___cytoskeleton___.

Question 5

4 main processes by which substances cross membranes?

Answer 5

4 main processes by which substances cross membranes?

Answer: 
1 Diffusion 
2 Facilitated diffusion 
3 Active transport 
4 Secondary active transport

Question 6

what does digoxin do?

Answer 6

what does digoxin do?

Answer:
- Digoxin stops the Na+/K+ ATPase from working in heart muscle.

• This causes the Na+/Ca2+ antiporter to stop functioning (because Na+ is not being taken out of the cell with the Na/K pump but is building up in the muscle each time Ca2+ is taken out),… hence the Ca2+ stops leaving the muscle (to reduce Na+ concentration in the cell) causing the heart muscle to contract more powerfully.

Question 7

what kind of mutation causes Cystic fibrosis transmembrane conductance regulator (CFTR)?

Answer 7

what kind of mutation causes Cystic fibrosis transmembrane conductance regulator (CFTR)?

Answer:
the deletion of the codon for phenylalanine

Question 8

in Cystic fibrosis transmembrane conductance regulator (CFTR) what happens?

Answer 8

in Cystic fibrosis transmembrane conductance regulator (CFTR) what happens?

Answer:
chloride ions do not move across the membrane because CTFR channel is absent or defective. This causes less water to travel in the lungs airway (and more to reside inside cells). This also causes more Na+ to be attracted into the cell (pulling more water out of the airways). As a result, mucus build up on the outside of the cell and bacteria in the mucus cause infections and death.

Question 9

what is the role of CFTR in Cholera?

Answer 9

what is the role of CFTR in Cholera?

Answer:
- Cholera bacteria produce toxins that activate CTFR and pump Cl- out of cell and into small intestines.

• Na+ and water to follow Cl- out of the cell.
• dehydration and death are the result
• treatment: oral and intravenous rehydration

Question 10

macromolecules enter cells through 3 types of Endocytosis

Answer 10

macromolecules enter cells through 3 types of Endocytosis

Answer:
- phagocytosis

• pinocytosis
• receptor-mediated endocytosis
  (These membrane regions are called coated pits and their cytoplasmic surfaces are coated by other proteins, such as clathrin.)

Question 11

Inherited disease familial hypercholesterolemia have a deficient ______ receptor in their livers

Answer 11

Inherited disease familial hypercholesterolemia have a deficient ___LDL___ receptor in their livers.

Prevents receptor-mediated endocytosis of LDLs, resulting in very high levels of serum cholesterol.