Chapter 3: Nonenzymatic Protein Function and Protein Analysis

Question 1

____________ has a characteristic trihelical fiber (three left-handed helices woven together to form a secondary right-handed helix) and makes up most of the extracellular matrix of connective tissue.

Answer 1

Collagen

Question 2

___________ is another important component of the extracellular matrix of connective tissue.

Answer 2

Elastin

Question 3

____________ are intermediate filament proteins found in epithelial cells.

Answer 3

Keratins

Question 4

__________ is a protein that makes up microfilaments and the thin filaments in myofibrils. It is the most abundant proteins in eukaryotic cells. It has a positive side and negative side.

Answer 4

Actin

Question 5

__________ is the protein that makes up microtubules. It has polarity.

Answer 5

Tubule

Question 6

_____________ motor proteins play key roles in aligning chromosomes during metaphase and depolymerizing microtubules during anaphase of mitosis.

Answer 6

Kinesins

Question 7

___________ motor proteins are involved in the sliding movement oof cilia and flagella.

Answer 7

Dyneins

Question 8

___________________ (_________) are proteins found on the surface of most cells and aid in binding the cell to the extracellular matrix or other cells.

Answer 8

Cell adhesion molecules (CAMs)

Question 9

______________ are a group of glycoproteins that meditate calcium-dependent cell adhesion.

Answer 9

Cadherins

Question 10

___________ are a group of proteins that all have two membrane-spanning chains called alpha and beta. They play a role in host immune defense.

Answer 10

Integrins

Question 11

___________ are unique because they bind to carbohydrate molecules that project from other cell surfaces. They are expressed on WBCs and the endothelial cells that line blood vessels.

Answer 11

Selectins

Question 12

_______________, a type of passive transport, is a diffusion of molecules down a concentration gradient through a pore in the membrane created by this transmembrane protein.

Answer 12

Facilitated diffusion

Question 13

______________ is used for molecules that are impermeable to the membrane (large, polar, or charged).

Answer 13

Facilitated diffusion

Question 14

______________ have no gates and are therefore unregulated.

Answer 14

Ungated channels

Question 15

In _________________, the gate is regulated by the membrane potential change near the channel.

Answer 15

Voltage-gated channels

Question 16

For __________________, the binding of a specific substance or ligand to the channel causes it to open or close.

Answer 16

Ligand-gated channels

Question 17

The ________________ have 3 primary protein domains: a membrane-spanning domain, a ligand binding domain, and a catalytic domain.

Answer 17

Enzyme-linked receptors

Question 18

Three main types of heterotrimeric G proteins:
____________
____________
____________

Answer 18

• Gs
• Gi
• Gq

Question 19

________ stimulates adenylate cyclase, which increases levels of cAMP in the cell.

Answer 19

Gs

Question 20

________ inhibits adenylate cyclase, which decreases levels of cAMP in the cell.

Answer 20

Gi

Question 21

_______ activates phospholipase C, which cleaves a phospholipid from the membrane to form PIP2.

Answer 21

Gq

Question 22

Proteins and other biomolecules are isolated from body tissues or cell cultures by cell lysis and ________________ - crushing, grinding, or blending the tissue of interest into an evenly mixed solution.

Answer 22

Homogenization

Question 23

________________ can isolate proteins from much smaller molecules before other isolation techniques must be employed.

Answer 23

Centrifugation

Question 24

________________ works by subjecting compounds to an electric field, which moves proteins according too their net charge and size.

Answer 24

Electrophoresis

Question 25

______________________ (_______) is a method for analyzing proteins in their native states. Unfortunately, it is limited by the varying mass-to-charge and mass-to-size ratios of cellular proteins because multiple different proteins may experience the same level of migration.

Answer 25

Polyacrylamide gel electrophoresis (PAGE)

Question 26

___________________ is most useful to compare the molecular size or the charge of proteins known to be similar in size.

Answer 26

Polyacrylamide gel electrophoresis (PAGE)

Question 27

___________________ (_______) - polyacrylamide gel electrophoresis is useful tool because it separates proteins on the basis of relative molecular mass alone.

Answer 27

Sodium dodecyl sulfate (SDS)

Question 28

______________ exploits the acidic and basic properties of amino acids by separating on the basis of isoelectric point (pI).

Answer 28

Isoelectric focusing

Question 29

Proteins that are positively charged will begin migrating toward the cathode and proteins that are negatively charged will begin migrating toward the anode. As the protein reaches the portion of gel where the pH is equal to the protein's pI, the protein takes on a neutral charge and will stop moving. This is the description of ________________.

Answer 29

Isoelectric focusing

Question 30

Anode in isoelectric focusing: A+ Anode has __________ (H+ rich) gel and a (_____) charge.

Answer 30

Anode has acidic (H+ rich) gel and a (+) charge

Question 31

________________ is another tool that uses physical and chemical properties to separate and identify compounds from a complex mixture.

Answer 31

Chromatography

Question 32

Before _____________________ analysis, the protein must be isolated and crystallized.

Answer 32

X-ray crystallography

Question 33

_________________ measures electron density on an extremely high-resolution scale and can also be used for nucleic acids.

Answer 33

Crystallography

Question 34

The small dots in the diffraction pattern from ____________________ can then be interpreted to determine the protein's structure.

Answer 34

X-ray crystallography

Question 35

Small proteins are best analyzed with the _________________, which uses cleavage to sequence proteins of up to 50 to 70 amino acids.

Answer 35

Edman degradation

Question 36

Protein concentration is determined almost exclusively through ________________.

Answer 36

Spectroscopy

Question 37

Because proteins contain aromatic side chains, they can be analyzed with ________________ without any treatment; however this type of analysis is particularly sensitive to sample contaminants.

Answer 37

UV spectroscopy

Question 38

Proteins cause colorimetric changes with specific reactions, particularly the _________________ (______) assay, _________________ assay, and __________________ assay.

Answer 38

- Bicinchoninic assay (BCA) assay - Lowry reagent assay - Bradford protein assay

Question 39

The _________________ mixes a protein in solution with Coomassie Brilliant Blue dye. The due is protonated and gives up protons upon binding to amino acid groups, turning blue in the process.

Answer 39

Bradford protein assay