Protein Structure and Function

Question 1

Protein function is affected by what

Answer 1

Conformations (shape of protein)

Question 2

Protein structure can be defined at what 4 levels?

Answer 2

-Primary: sequence of amino acids
-Secondary: formation of a coil or sheet
-Tertiary: all coils/sheets together
-Quaternary: interaction of one or more polypeptides to form a functional protein

Question 3

Amino acids in a polypeptide are connected by what

Answer 3

Peptide bonds

Question 4

How many amino acids are used to form polypeptides

Answer 4

20

Question 5

Amino acids within a polypeptide can form noncovalent interactions that cause the polypeptide to do what?

Answer 5

The polypeptide folds

Question 6

The interactions of amino acids with each other leads to a what level of protein structure

Answer 6

The 2 degree structure

Question 7

What is secondary structure determined by

Answer 7

Energetic considerations

Question 8

In a secondary structure free energy is minimized so it is ________

Answer 8

Energetically favorable

Question 9

Noncovalent interactions can be broken, causing the structure to unfold/ denature including what

Answer 9

-chemicals
-heat
-pH
-Others

Question 10

In the tertiary structure, an individual polypeptide chain can have multiple regions of what structure

Answer 10

Secondary structure

Question 11

tertiary structure is the full 3D conformation of the polypeptide including

Answer 11

-helices
-sheets
-loops
-and other folds

Question 12

All polypeptides will have

Answer 12

1 degree, 2 degree, and 3 degree structure

Question 13

Some 3 degree structures are functional ________

Answer 13

By themselves

Question 14

What can 3 degree polypeptide structures do before a functional unit (protein) occurs

Answer 14

interact with other 3 degree polypeptide structures

Question 15

The interaction of two or more 3 degree polypeptides structures is what

Answer 15

4 degree structure

Question 16

Quaternary structure is a complex of two or more __________

Answer 16

Polypeptide chains

Question 17

Does it matter if the polypeptides interacting with one another are the same or different?

Answer 17

No they can be either the same or different

Question 18

Is protein structure related to function

Answer 18

yes

Question 19

All proteins bind to what

Answer 19

other molecules

Question 20

What is a binding site?

Answer 20

where a ligand binds a protein

Question 21

Are the interactions at protein binding sites covalent or noncovalent

Answer 21

non covalent and specific

Question 22

binding the ligand changes what

Answer 22

The protein conformation

Question 23

One the ligand is binded and the protein conformation occurs, what happens

Answer 23

Activation or inactivation of a protein

Question 24

What are enzymes

Answer 24

Proteins that catalyze chemical reactions

Question 25

Do enzymes make reactions occur faster?

Answer 25

Yes, 1,000,000

Question 26

Enzymes hold substrates in ways that allows chemical reactions to occur more easily that does what

Answer 26

Reduces activation energy

Question 27

Different mechanisms for reducing activation energy depends on what

Answer 27

The enzyme

Question 28

What are 5 ways that protein activity is controlled

Answer 28

-feedback inhibition -multiple binding sites -phosphorylation -GTP-binding -ATP hydrolysis

Question 29

Anabolic pathways produce what for the cell

Answer 29

organic compounds

Question 30

What are protein kinases

Answer 30

enzymes that add phosphates to other proteins

Question 31

What are protein phosphatases

Answer 31

Removes phosphates from other proteins

Question 32

What kind of enzymes have more than one binding site and are active or inactive based on what is bound

Answer 32

allosteric enzymes

Question 33

ATP binding and ATP hydrolysis causes what type of change in a protein

Answer 33

Conformational change

Question 34

Motor proteins are involved in what

Answer 34

muscle contractions and transport of materials in cells

Question 35

GTP is what

Answer 35

Nucleotide triphosphate

Question 36

When the GTP is hydrolyzed what happens to the protein

Answer 36

the protein is inactivated

Question 37

Protein is reactivated when

Answer 37

GTP binds again

Question 38

Phosphorylation may do what to the protein

Answer 38

activate or inactivate