Chapter 7: Sickle Cell

Question 1

What is the observable effect of sickle cell anemia (in terms of the physical appearance of red blood cells)?

Answer 1

It changes the red blood cells’ shape

Question 2

where in the body are hemoglobin proteins found?

Answer 2

inside red blood cells

Question 3

in what way are sickle cell red blood cells misshapen?

Answer 3

they are elongated like a sickle

Question 4

what can ultimately happen to red blood cells that are stretched/misshapen because of sickle cell anemia?

Answer 4

they can eventually rupture and break open

Question 5

which mutation did Dr. Shimko discuss as a cause of sickle cell?

Answer 5

a glutamate get mutated to a valine on the surface of the hemoglobin’s beta subunit

Question 6

why is it bad when a valine is present where a glutamte should be (on a hemoglobin beta subunit)?

Answer 6

when you have a val instead of a glutamine, The valine creates a very hydrophobic patch on the hemoglobin surface and has a lock and key interaction with non-polar regions of other hemoglobins’ beta subunits

Short answer: the valine mutated hemoglobin gets stuck to things.

Question 7

In what state will the valine in a sickle cell hemoglobin beta subunit get stuck to the hydrophobic region of another hemoglobin’s hydrophobic beta subunit: R state or T state?

Answer 7

when both are in the T state

Question 8

what do you call the complex that occurs when a sickle cell hemoglobin valine gets lock and keyed to another hemoglobin?

Answer 8

an octomer

Question 9

can a sickle cell hemoglobin octomer complex be unbound?

Answer 9

No. Both hemoglobins are now trapped together and trapped in their T states

Question 10

Does a cooperative binding type of process occur in sickle cell hemoglobin?

Answer 10

Yes. Once a single octomer is created, it starts binding to other hemoglobins, trapping them in their T states as they become part of an ever growing polymer.

Question 11

are there other ways that mutations can cause the hydrophobic hemoglobin interactions seen in sickle cell?

Answer 11

Yes but they aren’t on the test

Question 12

What reason did Dr. Shimko gave for why we call it sickle cell ‘anemia’?

Answer 12

Because the blood cells get trapped in the T state and are thereby limited in their ability to carry and deliver molecular oxygen.

Question 13

what is the complex structure of a sickle cell hemoglobin aggregate called?

Answer 13

a fibril

Question 14

How do sickle cell red blood cells come to be misshapen?

Answer 14

The sickle cell hemoglobins blobs get so big that they stretch the red blood cells membrane

Question 15

what is erythrocyte another name for?

Answer 15

another word for red blood cell

a red blood cell that (in humans) is typically a biconcave disc without a nucleus.

Question 16

can sickle cell mutations be silent?

Answer 16

yes. People with silent sickle cell mutations are considered sickle cell trait

Question 17

do all sickle cells anemias require that both your parents have the trait?

Answer 17

yes????

Question 18

do different sickle cell mutations cause different degrees of disease?

Answer 18

yes.

Question 19

Under which conditions did Dr. Shimko say that sickle cell events could be triggered?

Answer 19

if the body is under stress that stabilizes the T state

such as the football player who had sickle cell and tried to play a game in Denver, CO

Question 20

what other people have sickle cell besides black people

Answer 20

people from Southern Asia

Question 21

in what 3 ways is sickle cell trait protective against malaria?

Answer 21

it’s less nutritious to parasite

it triggers a more pronounced inflammatory response to fight the parasite

it makes the blood a more oxidizing environment (which is harmful to the parasite)

Question 22

What will happen if the sickle cell hemoglobin blob gets too big?

Answer 22

This will eventually break the red blood cell open and cause an inflammatory response