Week 7

Question 1

_______________ is the covalent addition or removal of groups from proteins.

Answer 1

Covalent modification

Question 2

________________ are inactive enzyme precursors that require proteolytic activation.

Answer 2

Zymogens.

Question 3

_____________ cleavage is an example of enzyme activation.

Answer 3

Proteolytic

Question 4

_____________ is another example of protein activation and is facilitated by protein kinases.

Answer 4

Phosphorylation

Question 5

Protein ____________ add phosphate groups (from ATP donor).

Answer 5

Kinases

Question 6

_____________ remove phosphate groups.

Answer 6

Phosphatases.

Question 7

_______________ increases or decreases the enzymatic activity by binding at a site other than the active site. It is the most rapid and most direct form of regulation.

Answer 7

Allosteric regulation

Question 8

Allosteric regulation exhibits ______________ activity curves.

Answer 8

Sigmoidal

Question 9

______________ is used to describe the regulation of a molecule such as an enzyme, receptor, or transport protein through a conformational change induced by the binding of a regulator.

Answer 9

Allosterism.

Question 10

_____________ is the opposite of allosteric regulation. Competitive inhibition is an example of this.

Answer 10

Orthosteric regulation

Question 11

Orthosteric regulation requires sufficient ___________ between the product of the reaction and the binding site.

Answer 11

Homology.

Question 12

____________ model is when all of the subunits of the complex change states at once.

Answer 12

Concerted

Question 13

____________ model is when subunits of the complex change one at time as regulators are bound.

Answer 13

Sequential

Question 14

_____________ is a linear plot depicting the degree to which the sites in an allosteric protein or complex cooperate.

Answer 14

Hill Plot.

Question 15

The hill equation is:

Answer 15

Theta= Ln/ Kd+ [L]n

Question 16

In _________________ the protein is regulated by its own substrate.

Answer 16

Homotropic regulation

Question 17

In _________________ the protein is regulated by a molecule that’s not its substrate.

Answer 17

Heterotropic regulation.

Question 18

An example of homotropic regulation is ____________

Answer 18

O2 binding to hemoglobin

Question 19

_____________ is an example of a monomeric allosteric enzyme.

Answer 19

Glucokinase

Question 20

Hemoglobin is a ___________ protein with an ____________ topology.

Answer 20

Tetrameric, alpha2Beta2

Question 21

Fetal hemoglobin has an _______________ topology.

Answer 21

Alpha2Gamma2

Question 22

________________ has a greater affinity for oxygen than maternal hemoglobin, which creates an oxygen gradient so oxygen can flow from the mother to fetus.

Answer 22

Fetal hemoglobin

Question 23

The ____________ within the heme group is the active site of hemoglobin.

Answer 23

Iron.

Question 24

Myoglobin which shows a greater binding affinity to O2 shows a ______________ curve because it is not ______________.

Answer 24

Hyperbolic, allosterically regulated.

Question 25

As _____________ increases and _____________ decreases, oxygen's affinity for hemoglobin also ____________, shifting the oxygen curve to the right.

Answer 25

CO2, pH, decreases.

Question 26

The ___________ effect helps get rid of excess CO2.

Answer 26

Bohr

Question 27

When pH drops, His is _________ and a ___________forms between the His 146 and the carboxyl group of ___________.

Answer 27

Protonated, salt bridge, Asp.

Question 28

CO2 is transported by _____________

Answer 28

Hemoglobin

Question 29

CO2 reacts with the amino terminus of each of hemoglobin's alpha subunits to form a _____________.

Answer 29

Carbamate.

Question 30

Protons released by carbamate formation favor stabilization of the ______________ state.

Answer 30

Deoxygenated

Question 31

Binding of _____________ stabilizes the deoxygenated T state of hemoglobin, lowering the affinity of hemoglobin for oxygen.

Answer 31

2,3-bPG

Question 32

______________ binds with a 250- fold higher affinity for hemoglobin than O2 and it also binds to hemoglobin irreversibly.

Answer 32

Carbon monoxide

Question 33

Carbon dioxide is derived from ____________

Answer 33

Bicarbonate

Question 34

_________________ catalyzes the reversible formation of carbon dioxide from bicarbonate.

Answer 34

Carbonic anhydrase

Question 35

_____________ is a single shape mutation in the hemoglobin beta gene Glutamate to Valine.

Answer 35

Sickle cell anemia

Question 36

______________ are mutations in genes coding for alpha, beta, and gamma hemoglobin subunits.

Answer 36

Thalassemias

Question 37

____________ are molecules that bind to and activate a receptor. Can be competitive, noncompetitive, or inverse.

Answer 37

Agonists.

Question 38

______________ are molecules that bind to the receptor but activate it to a lesser extent than the native ligand.

Answer 38

Partial agonists.

Question 39

______________ are molecules that bind to a receptor and block its activation.

Answer 39

Antagonists