Unit #4: Proteins and Enzymes

Question 1

What are the monomers of proteins?

Answer 1

Amino acids

Question 2

Describe the structure of an amino acid.

Answer 2

An amino group, hydroxyl group, hydrogen and unique R group all bonded to central carbon.

Question 3

How many amino acids are there and what differentiates them?

Answer 3

There are 20 different amino acids which are differentiated by 20 different R groups.

Question 4

When identifying amino acid properties, do we look at both charge and polarity?

Answer 4

No. First determine if it is acidic or basic and then look at polarity.

Question 5

What charge will an acidic amino acid have?

Answer 5

Negative

Question 6

The presence of oxygen and sulphur at the end of the R group means that the amino acid is..

Answer 6

Polar

Question 7

What is the dehydration linkage that connects amino acids called?

Answer 7

Peptide bond

Question 8

How many levels of protein structure are there?

Answer 8

4

Question 9

Describe primary protein structure.

Answer 9

The simple amino acid chain linked by the peptide bonds.

Question 10

Describe secondary protein structure.

Answer 10

Alpha helix or beta pleated sheet caused by hydrogen bonds between the polypeptide backbones.

Question 11

Describe tertiary protein structure.

Answer 11

Determined by the R group, if polar it will be on the outside of the protein, non-polar it will be buried in middle of protein. The bonds included are hydrogen bonds between the R-groups, covalent bonds, Van der Waal forces, ionic bonds.

Question 12

Is a fully formed protein produced after it reaches tertiary structure?

Answer 12

Yes, but we can get it to quaternary structure.

Question 13

Describe quaternary protein structure.

Answer 13

Various bonds between separate polypeptide chains. ex. Hemoglobin, collagen.

Question 14

What does the ribbon protein model show and what is it used for?

Answer 14

Just the backbone, used for showing secondary structures.

Question 15

What does the space filling model show and what is it used for?

Answer 15

Shows the electron orbitals, tells us where an active site may be for substrate to bind.

Question 16

What does the wireframe model show and what is it used for?

Answer 16

Shows all of the covalent bonds on backbone and R-groups, good for drug production.

Question 17

What is metabolism?

Answer 17

The process of cells breaking down external energy into usable cellular energy (ATP).

Question 18

What is an anabolic reaction?

Answer 18

A reaction that builds from little pieces, requiring an input of energy.

Question 19

What is a catabolic reaction?

Answer 19

Reaction breaking down a large piece into little pieces, releasing energy.

Question 20

Why do metabolic pathways have so many intermediates?

Answer 20

To have multiple points of control and alternate end products.

Question 21

What is the first law of thermodynamics?

Answer 21

Energy cannot be created or destroyed, but it can be transformed.

Question 22

What is the second law of thermodynamics?

Answer 22

Entropy (disorder) increases in isolated symptoms.

Question 23

What is the free energy change formula?

Answer 23

G final - G initial

Question 24

What is an exergonic reaction?

Answer 24

A reaction in which the reactants have more energy than products, meaning that energy is released.

Question 25

What is an endergonic reaction?

Answer 25

A reaction in which products have more energy than reactants, meaning that an energy input is required.

Question 26

Which reaction is spontaneous and why?

Answer 26

Exergonic reactions are spontaneous because they were bound to happen, even if it takes forever, because the energy is bound to be released.

Question 27

What is activation energy?

Answer 27

The minimum energy required for a reaction to occur.

Question 28

What does an enzyme do to a reaction?

Answer 28

Catalyzes it by lowering the activation energy.

Question 29

Describe the lock and key model.

Answer 29

The concept that only certain enzymes can fit into a given active site.

Question 30

Describe the induced fit model.

Answer 30

The theory that an enzyme will change shape based on the given active site.

Question 31

How does an increase in temperature affect protein structure?

Answer 31

Breaks hydrogen and disulfide bonds, breaking apart the protein.

Question 32

How does a change in pH impact protein structure?

Answer 32

Breaks ionic bonds, breaking down the protein.

Question 33

What is a competitive inhibitor.

Answer 33

It is an inhibitor that resembles the substrate, binding to the active site of the enzyme so that the substrate cannot.

Question 34

What is a non-competitive inhibitor?

Answer 34

An inhibitor binding to somewhere other than the active site, changing the shape of the enzyme so that the substrate cannot bind.

Question 35

How do inhibitors impact the rate of reaction?

Answer 35

Slow it down.

Question 36

What is allosteric enzyme regulation?

Answer 36

Enzyme complex oscillating from active to inactive as activators and inhibitors respectively bind tot he active site.

Question 37

How does the allosteric enzyme regulation impact reaction rate?

Answer 37

Depending on the form of the enzyme complex, the rate of the reaction will increase (active form), or decrease (inactive form).

Question 38

What is the purpose of feedback inhibition?

Answer 38

To ensure that product is not being synthesized when there is enough, and to ensure that when that product is sued up,