Chapter 4

Question 1

structural proteins

Answer 1

provides cell with shape and structure

Question 2

enzymes

Answer 2

catalyze covalent bond breakage or formation

Question 3

transport protein

Answer 3

carries other molecules or ions

Question 4

motor protein

Answer 4

generates movement in cell and tissue

Question 5

storage protein

Answer 5

stores small molecules or ions

Question 6

signal protein

Answer 6

carries signal from cell to cell

Question 7

receptor protein

Answer 7

detects signals and transmits them to cells response machinery

Question 8

gene regulatory protein

Answer 8

binds to DNA to switch genes on or off

Question 9

what bonds link amino acids?

Answer 9

peptide bonds

Question 10

what is protein made of?

Answer 10

amino acids linked together into polypeptide chain

Question 11

what 3 noncovalent bonds help proteins fold?

Answer 11

hydrogen bonds, electrostatic attractions, van der waals attraction

Question 12

what interaction is most important for protein folding?

Answer 12

hydrophobic interaction

Question 13

what causes proteins to denature?

Answer 13

urea. denature proteins unfold to natural shape

Question 14

how are prion diseases caused?

Answer 14

by rare proteins whose misfolding is infectious.

Question 15

what is a common folding pattern?

Answer 15

alpha helix

Question 16

alpha helix

Answer 16

the amino group of every peptide bond is h-bonded to carboxyl group of neighboring peptide bond located 4 amino acids away.

Question 17

what is another common folding pattern of proteins?

Answer 17

beta sheets

Question 18

beta sheet

Answer 18

individual strands in sheet held together by h-bonding between peptide bonds in different strands.

Question 19

what are the two varieties of beta sheets?

Answer 19

parallel and Antiparallel

Question 20

what is comprised of a family of proteolytic enzymes?

Answer 20

serine proteases

Question 21

many protein molecules contain _____ of a single protein subunit.

Answer 21

multiple copies

Question 22

proteins can assemble into what?

Answer 22

complex structures. dimer, helix, and ring

Question 23

what is an actin filament composed of?

Answer 23

identical protein subunits

Question 24

single protein subunits can pack to form what?

Answer 24

a filament, tube, or a spherical shell

Question 25

what is a collagen?

Answer 25

a triple helix formed by 3 protein chains to wrap around one another

Question 26

what do disulfide bonds do?

Answer 26

help stabilize a favorable protein confomation

Question 27

folding of a polypeptide chain creates what on protein surface?

Answer 27

cavity

Question 28

binding sites allow proteins to do what?

Answer 28

interact with specific ligands.

Question 29

what is an antibody?

Answer 29

y-shaped and has two identical binding sites for its antigen.

Question 30

what is feedback inhibition?

Answer 30

regulates the flow through biosynthetic pathways

Question 31

what does feedback inhibition do?

Answer 31

triggers a conformational change

Question 32

what does an increase in ligand (ADP) concentration do?

Answer 32

activates the enzymatic reaction for oxidation of sugars

Question 33

what conformation can ADP bind to? why?

Answer 33

closed. lowers energy of closed conformation, locking enzymes in the active site

Question 34

What is a common mean of regulating protein activity?

Answer 34

protein phosphorylation

Question 35

what does GTP-binding proteins from?

Answer 35

molecular switches.

Question 36

an allosteric motor protein driven by ATP hydrolysis moves in what direction? why?

Answer 36

one direction. repeated cycles of conformation changes, the proteins moves continuously

Question 37

how is protein behavior controlled?

Answer 37

modification of a protein at multiple sites produce a regulatory code that controls the PB

Question 38

how can the structure of protein be determined?

Answer 38

x-ray crystallography

Question 39

cells in culture display properties that reflect what?

Answer 39

their origin

Question 40

what is affinity chromatography used for?

Answer 40

to isolate the binding partners of a protein of interest